MSK Anatomy💪🩻🦴 Flashcards

Question

How do wrist joints move?

Answer 1

Flexion and extension, abduction and adduction.

Answer 2

Flexion and extension, adduction and abduction

Answer 3

The clavicle is a slender, S-shaped bone, which is easily palpable in most individuals. It is the most commonly fractured bone

Answer 4

It articulates with the manubrium of the sternum at its proximal (medial) end (the sternoclavicular joint) and with the acromion of the scapula at its distal (lateral) end (the acromioclavicular joint) – both of these joints are synovial.

Answer 5

It is mostly flat but has some important bony projections and, whilst located on the posterior thorax, some parts of the scapula can easily be palpated through the skin. Movements of the scapula can also be seen on examination.

Answer 6

Ridge of bone on post. surface Easily palpable

Answer 7

Expansion of the lateral end of the spine of the scapula which articulates with the lateral end of the clavicle The acromion can also be palpated easily.

Answer 8

Projection of bone Just inferior to the acromion on the anterior surface of the scapula This is a site of attachment for several muscles

Answer 9

Combination of the clavicle, scapula and the attached muscles

Answer 10

Shallow fossa on the lateral aspect of the scapula Articulates with the proximal humerus to form the shoulder (glenohumeral) joint. The glenoid fossa is shallow, making it a poor fit for the humerus This increases the range of movement possible at the shoulder but compromises the stability of the joint

Answer 11

Two small projections of bone Just superior and inferior to the glenoid fossa Important sites for muscle attachments

Answer 12

The humerus is the long bone of the arm. It has a shaft and an expanded proximal and distal end.

Answer 13

The head of the humerus articulates with the glenoid fossa of the scapula

Answer 14

Immediately distal to the smooth head of the humerus is a groove which is the position of the anatomical neck of the humerus.

Answer 15

Laterally, the proximal humerus bears a projection of bone called the greater tubercle – an important site for muscle attachments

Answer 16

A smaller anterior projection – the lesser tubercle – is also a site for muscle attachment.

Answer 17

Just distal to the tubercles, the bone narrows and becomes continuous with the shaft. This region is called the surgical neck and is clinically important because it is commonly fractured, especially in the elderly as a result of a fall. The axillary nerve runs close to this region and can be injured by fractures of the surgical neck or dislocation of the humeral head.

Answer 18

The upper lateral aspect of the humeral shaft has a slight protuberance called the deltoid tuberosity which is the site of attachment for the deltoid muscle

Answer 19

Another key landmark is the radial (or spiral) groove – this marks the path of the radial nerve over the posterior aspect of the humeral shaft. The radial nerve runs along a spiral route very close to the humerus here and can be injured in mid-shaft humeral fractures.

Answer 20

Whilst the clavicle can also move, we will concentrate on the movements of the scapula – these are vital for normal movement of the shoulder joint. The scapula is surrounded by muscles and so there is no bony articulation between the scapula and the posterior thoracic wall.

Answer 21

Protraction Retraction Elevation Depression Rotation

Answer 22

This extends the upper limb, for example, when we stretch out the arm to push open a door.

Answer 23

'squaring’ the shoulders or pulling them backwards

Answer 24

shrugging the shoulders.

Answer 25

lowering the shoulders.

Answer 26

This tilts the glenoid fossa cranially to aid elevation of the upper limb. Rotation of the scapula is very important. When raising the arm above the head, for every 2˚ of abduction of the shoulder, the scapula rotates 1˚. If you observe someone from behind as they raise their arm, you will see the movement of the scapula.

Answer 27

Several muscles attach the scapula to the vertebral column. When these muscles contract, the scapula moves. The attachment points of the muscles and the orientation of the muscle fibres determine the direction in which the scapula moves when the muscles contract.

Answer 28

Serratus anterior

Answer 29

Trapezius and latissimus dorsi

Answer 30

These are large, flat muscles with extensive attachments to the vertebral column (and in the case of trapezius, to the skull). Latissimus dorsi attaches to the anterior aspect of the proximal humerus, not the scapula (so it moves the shoulder joint, rather than the scapula), but it is often considered with the posterior pectoral girdle muscles.

Answer 31

There are three smaller, deeper muscles: * Levator scapulae * Rhomboid major * Rhomboid minor. These muscles attach to the medial border of the scapula and to the vertebral column.

Answer 32

Rotation, and individually: the upper part elevates, middle part retracts, and the lower part depresses the scapula.

Answer 33

Extends, adducts, and medially rotates the humerus

Answer 34

The origin is the more ‘fixed’ or stable bone, and the insertion point is located on the bone that moves when the muscle contracts.

Answer 35

Origin: Skull, cervical and thoracic vertebrae Insertion: Clavicle and scapula (spine and acromion)

Answer 36

Origin: Lower thoracic vertebrae Insertion: Humerus – proximal and anterior

Answer 37

Origin: Upper cervical vertebrae Insertion: Scapula - medial border

Answer 38

Origin: C7 and T1 vertebrae Insertion: Scapula - medial border

Answer 39

Origin: Thoracic vertebrae Insertion: Scapula - medial border

Answer 40

Brachial plexus

Answer 41

Trapezius is not supplied by the brachial plexus but instead it is innervated by the 11th cranial nerve, the accessory nerve. Therefore, testing the function of trapezius is part of the cranial nerve examination.

Answer 42

A branch of the brachial plexus called the thoracodorsal nerve

Answer 43

The shoulder joint (glenohumeral joint) has an extensive range of movement. This allows us to position our hand where we want to. It is a synovial ball and socket joint formed by the articulation between the glenoid fossa of the scapula and the head of the humerus.

Answer 44

The movements possible at the shoulder joint are flexion, extension, abduction, adduction, internal (medial) and external (lateral) rotation and circumduction.

Answer 45

When we look at the scapula and humerus, we can see that the fit between the joint surfaces – the glenoid fossa of the scapula and the head of the humerus – is poor. This is key for extensive mobility at the joint. The downside of the shallow socket and poor fit is that the joint is less stable – the shoulder joint is the most commonly dislocated joint in the body.

Answer 46

Six muscles attach the scapula to the humerus. They move and stabilise the shoulder joint. Except for deltoid, all of these muscles lie deep to the posterior pectoral girdle muscles (discussed above). The six muscles are: * Deltoid * Supraspinatus* * Infraspinatus* * Subscapularis* * Teres minor* * Teres major *Alongside their individual actions moving the shoulder joint, these four muscles work together to provide vital stability to the shoulder joint – they are referred to as the ‘rotator cuff’.

Answer 47

Deltoid is the large muscle over the lateral aspect of the shoulder. It attaches the humerus to the lateral part of the clavicle and to the spine of the scapula. It gives the shoulder its rounded contour. It inserts onto the humerus at a landmark called the deltoid tuberosity.

Answer 48

It is a powerful abductor of the shoulder joint. However, deltoid cannot initiate abduction – another muscle initiates the first 15˚ of abduction before deltoid takes over. Additionally, the anterior and posterior fibres of deltoid contribute to flexion and extension of the shoulder, respectively.

Answer 49

It is innervated by a major branch of the brachial plexus called the axillary nerve.

Answer 50

Injury to the axillary nerve can lead to atrophy and weakness (or even paralysis) of deltoid, which greatly impacts a patient’s activities of daily living.

Answer 51

Teres major is an interesting muscle as although it arises from the posterior aspect of the scapula, its tendon slots underneath the humerus and inserts onto the anterior aspect of the humerus. This arrangement explains its action as an internal rotator and adductor of the shoulder joint.

Answer 52

Made up of Supraspinatus, infraspinatus, teres minor and subscapularis all move the shoulder joint. They are short muscles which attach the scapula to the tubercles of the humerus.

Answer 53

Supraspinatus, infraspinatus, and teres minor originate from the posterior surface of the scapula and insert onto the greater tubercle. Their tendons fuse with the fibrous capsule that surrounds the shoulder joint

Answer 54

Supraspinatus is particularly clinically important because as it travels from the supraspinous fossa to the greater tubercle it travels under the acromion. The tendon can become inflamed and pinched between the acromion and humerus during movements of the shoulder. This is called impingement and is a common cause of shoulder pain, particularly during large movements of the shoulder joint, such as serving in tennis.

Answer 55

The quadrilateral space is a square-shaped space bounded by: teres minor above, teres major below, the long head of triceps medially and the surgical neck of the humerus laterally. The axillary nerve travels through this space to enter the posterior scapula region and innervate deltoid and teres minor

Answer 56

originates from the anterior surface of the scapula and inserts onto the lesser tubercle of the humerus.

Answer 57

Action at shoulder joint: Abduction beyond 15 degrees Origin at scapula: Spine and acromion of the scapula and the clavicle Insertion on the humerus: Deltoid tuberosity

Answer 58

Action at shoulder joint: Internal rotation + adduction Origin at scapula: Post. surface, inf. part of lateral border Insertion on the humerus: Ant. humerus

Answer 59

Action at shoulder joint: First 15 degrees of abduction Origin at scapula: Supraspinous fossa Insertion on the humerus: Greater tubercle- sup. facet

Answer 60

Action at shoulder joint: Ext. rotation Origin at scapula: Infraspinous fossa Insertion on the humerus: Greater tubercle- middle facet

Answer 61

Action at shoulder joint: Ext. rotation Origin at scapula: Lateral border Insertion on the humerus: Greater tubercle- inf. facet

Answer 62

Action at shoulder joint: Int. rotation Origin at scapula: Subscapular fossa Insertion on the humerus: Lesser tubercle

Answer 63

The poor fit of the articular surfaces allows for the extensive range of movement at the shoulder joint (facilitated by a loose joint capsule), but this compromises stability. However, although shoulder dislocation is common, most of us haven’t dislocated a shoulder. This tells us that there are factors working to stabilise the joint and compensate for the poor fit of the articular surfaces.

Answer 64

As a group, the four rotator cuff muscles provide vital stability. Contraction of the rotator cuff muscles holds the head of the humerus in the glenoid fossa and the rotator cuff tendons fuse with the capsule of the shoulder joint. * A rim of fibrocartilage around the margin of the glenoid fossa – the glenoid labrum – which deepens the shallow fossa and aids stability. Labrum is derived from Latin meaning ‘lip’. * The capsule is reinforced by ligaments. * The tendon of biceps brachii, which lies in the anterior arm, also reinforces the joint.

Answer 65

The rotator cuff muscles and / or tendons can be injured, become inflamed or degenerate. When this happens, patients usually experience pain and impaired movement, and the stability of the joint is compromised.

Answer 66

The axilla is the anatomical term for the armpit – the space between the torso and the upper arm. It is pyramid-shaped and has 6 boundaries

Answer 67

* Anterior wall – pectoralis major and minor * Posterior wall – subscapularis, teres major and latissimus dorsi * Lateral wall – proximal humerus * Medial wall – serratus anterior and the thoracic wall * Apex – first rib, clavicle, and scapula. It is the passage between the neck and the axilla. * Base – skin and fascia between the thoracic wall and arm (the skin of armpit).

Answer 68

* Lymph nodes – which drain the upper limb, thorax, breast, and the abdominal wall as far as the umbilicus. * Axillary artery – the major artery of the upper limb. * Axillary vein – the major vein draining the upper limb. * Brachial plexus (specifically the cords and branches) – a plexus of nerves that innervate the upper limb. * Fat

Answer 69

There are five groups of lymph nodes in the axilla. They drain the upper limb, breast, chest wall, scapular region and the abdominal wall as far as the umbilicus. The lymph nodes located in the apex of the axilla – the apical nodes – receive lymph from all other lymph nodes in the axilla.

Answer 70

The axillary artery is the continuation of the subclavian artery as it progresses laterally. The subclavian artery travels over the first rib and under the clavicle and into the axilla. It becomes the axillary artery after it passes over the lateral border of the first rib. The axillary artery gives rise to several branches. It continues into the arm as the brachial artery (it becomes the brachial artery as it crosses the inferior border of teres major).

Answer 71

The axillary vein is a large vein which drains the upper limb and is continuous with the subclavian vein. The axillary vein travels alongside the axillary artery. The axillary vein is formed by the union of the brachial veins with the basilic vein. The cephalic vein also joins the axillary vein in the axilla. At the lateral border of the first rib, the axillary vein becomes the subclavian vein.

Answer 72

In a dislocation of the shoulder, the humeral head moves out of the glenoid fossa. Anterior dislocation, where the humeral head ends up resting anterior to the glenoid fossa, is much more common. It is often caused by blunt force trauma, such as a fall. X-ray imaging confirms the direction of displacement of the humeral head and whether there is an associated fracture. Dislocation can injure the axillary nerve.

Answer 73

The rotator cuff can be injured by acute trauma or by repetitive use. The tendons can also degenerate with age. Tears of the rotator cuff are usually painful at rest and on movement, and cause weakness. If the supraspinatus tendon becomes injured and inflamed it may become impinged between the acromion and the humeral head, as the space here is small. The first part of abduction is not painful, but between 60˚– 120˚ of abduction, the inflamed tendon is compressed against the acromion, and this is when patients experience pain. An inflamed tendon may ultimately rupture.

Answer 74

Because lymph from the breast drains to the axillary lymph nodes, breast malignancy typically metastasises first to these nodes. A malignant axillary node may be felt as a lump in the armpit and may be noticed before a mass in the breast itself. Axillary lymph nodes can be biopsied to assess whether or not breast malignancy has metastasised and can be removed as part of the patient’s treatment. Because they drain lymph from the upper limb, removal of the nodes can lead to fluid accumulation and swelling in the affected upper limb.

Answer 75

* The long thoracic nerve innervates serratus anterior and lies superficially on the surface of the muscles in the medial wall of the axilla. Injury to this nerve causes weakness or paralysis of serratus anterior. One of the functions of this muscle is to hold the anterior border of the scapula flat against the posterior thoracic wall. If the muscle is paralysed, the anterior border lifts off the thoracic wall and the scapula appears to ‘stick out’. This is called a ‘winged scapula’.

Answer 76

The thoracodorsal nerve to latissimus dorsi is also vulnerable to injury as it runs along the subscapularis muscle, which forms part of the posterior wall of the axilla.

Answer 77

The shaft of the humerus expands distally to form bony prominences called the medial and lateral epicondyles – these are palpable on examination

Answer 78

Prominences of the distal humerus which articulate with the trochlear notch of the ulna and the head of the radius, respectively, at the elbow joint.

Answer 79

The arm lies between the shoulder and elbow. Intermuscular septa, which extend from the deep brachial fascia which surrounds the arm, separate the arm into anterior and posterior compartments.

Answer 80

The anterior compartment of the arm contains three muscles: biceps brachii, brachialis and coracobrachialis. All three act as flexors and all three are innervated by the musculocutaneous nerve.

Answer 81

) lies most superficially in the anterior arm. It has two heads – the long head and the short head

Answer 82

Proximally, both heads are attached to the scapula; the long head to the supraglenoid tubercle and the short head to the coracoid process. The tendon of the long head of biceps pierces the capsule of the shoulder joint and helps to stabilise the joint. The two muscle bellies converge to their insertion via a common tendon onto the radial tuberosity of the radius.

Answer 83

Biceps is a flexor of the elbow joint – you can feel biceps contracting if you place a hand over it whilst flexing your elbow. However, because it crosses the shoulder joint, it is also capable of contributing to flexion of the shoulder joint.

Answer 84

Biceps is also a powerful supinator of the forearm when the elbow is flexed. Using a screwdriver helps understand this. When a right-handed person tightens a screw (turning to the right) they supinate the forearm – however, the power to turn the screw very tightly depends upon the elbow being flexed at the same time; supination is much weaker if the elbow is extended.

Answer 85

Brachialis lies deep to biceps. Proximally, it is attached to the anterior aspect of the distal half of the shaft of the humerus, and it crosses the elbow joint to insert distally upon the ulna tuberosity. It is a powerful flexor of the elbow joint, but it does not cross the shoulder joint, so cannot act upon it.

Answer 86

Coracobrachialis is a deep and much smaller muscle that attaches proximally to the coracoid process of the scapula and distally to the medial aspect of the middle part of the humerus. It crosses the shoulder joint and acts upon it as a weak flexor.

Answer 87

A single large muscle – triceps brachii – is located in the posterior compartment of the arm

Answer 88

It has three muscle bellies, or heads, which all converge via a common tendon onto a single insertion point – the olecranon of the ulna. The muscle crosses the posterior aspect of the elbow joint, therefore, when it contracts, it extends the elbow.

Answer 89

Infraglenoid tubercle of the scapula. It is the most medial part of triceps.

Answer 90

Posterior humerus, proximal to the radial groove.

Answer 91

Posterior humerus, distal to the radial groove.

Answer 92

Yes bc of its attachment to the scapula

Answer 93

All three parts of triceps are innervated by the radial nerve. The radial nerve is a major terminal branch of the brachial plexus. It winds around the posterior aspect of the humerus in the radial (spiral) groove between the medial and lateral heads of triceps. The nerve runs along the surface of the bone in this region, so a fracture of the shaft of the humerus may also cause injury to the radial nerve.

Answer 94

In anatomy, the term ‘plexus’ is used to describe complex networks of nerves or blood vessels.

Answer 95

The brachial plexus is the network of nerves that provides motor and sensory innervation to the upper limb. It is formed by the spinal nerves that leave the lower cervical spinal cord segments and the first thoracic spinal cord segment: these are spinal nerves C5, C6, C7, C8 and T1. The spinal nerves are mixed nerves, which carry motor and sensory fibres.

Answer 96

Roots, trunks, divisions, cords, and branches.

Answer 97

Also located in the neck, they are formed from the roots. * C5 and C6 combine to form the superior trunk. * C7 continues as the middle trunk. * C8 and T1 combine to form the inferior trunk.

Answer 98

Each trunk divides into an anterior and a posterior division under the clavicle.

Answer 99

Named relative to their position around the second part of the axillary artery, they are formed by various combinations of the anterior and posterior divisions. * Anterior divisions of the superior and middle trunks combine to become the lateral cord. * Posterior divisions of all the trunks combine to becomes the posterior cord. * Anterior division of the inferior trunk continues as the medial cord.

Answer 100

Located in the axilla, they are formed from the cords. They then travel distally to reach the structures that they innervate in the shoulder, arm, forearm or hand. * Axillary – a branch from the posterior cord. * Radial – the continuation of the posterior cord. * Musculocutaneous – a branch from the lateral cord. * Ulnar – a branch from the medial cord. * Median – formed by branches from the lateral and medial cords.

Answer 101

In addition to giving rise to the five large terminal branches in the axilla, the different segments of the brachial plexus give rise to other nerves that innervate the shoulder and pectoral muscles

Answer 102

Axillary nerve Radial nerve Musculocutaneous nerve Median and ulnar nerves

Answer 103

It innervates deltoid and teres minor and a small region of skin over the upper lateral arm. * It is a branch of the posterior cord and contains fibres from spinal nerves C5 and C6. * It runs close to the surgical neck of the humerus and is vulnerable to injury in fractures of the surgical neck of the humerus or dislocations of the humeral head.

Answer 104

The radial nerve innervates triceps in the posterior arm. The radial nerve also innervates all the muscles in the posterior compartment of the forearm which are extensors of the wrist and digits. The radial nerve also innervates regions of skin over the arm, forearm, and hand. * It is the continuation of the posterior cord and contains fibres from C5 - T1. * It runs along the radial (spiral) groove on the posterior surface of the humerus and is vulnerable in mid-shaft fractures of the humerus.

Answer 105

The musculocutaneous nerve innervates the three muscles in the anterior compartment of the arm: biceps brachii, brachialis and coracobrachialis. * It arises from the lateral cord and contains fibres from spinal nerves C5 - C7. * After supplying motor fibres to three muscles named above, it continues as a sensory nerve that innervates a region of skin over the lateral forearm. * Because of its location, the musculocutaneous nerve is rarely injured in isolation.

Answer 106

The median nerve is formed from contributions from both the lateral and medial cords. * Normally, it contains fibres from C6-T1, but in some individuals, it may contain fibres from C5-T1. * It innervates most of the muscles of the anterior forearm, which are flexors of the wrist and digits. * It also innervates the small muscles of the thumb. * It provides sensory innervation to skin over the lateral aspect of the palm of the hand and over the lateral digits*. * It is most vulnerable in the arm as it crosses the anterior aspect of the elbow, in a region called the cubital fossa.

Answer 107

The ulnar nerve is formed by the continuation of the medial cord, after it has given a contribution to the median nerve. * It contains fibres from spinal nerves C8 - T1. * It innervates most of the small muscles in the hand and therefore is vital for fine movements of the digits. * It also innervates skin over the medial aspect of the hand and medial digits*. * It is vulnerable to injury behind the medial epicondyle as it lies in a superficial position here (it is easily palpable in this location).

Answer 108

Injuries to different parts of the brachial plexus result in different clinical presentations. The most catastrophic type of brachial plexus injury occurs when all five roots of the brachial plexus are injured – this is uncommon but devastating, as it effectively denervates the whole of the upper limb.

Answer 109

Because of its close proximity to the surgical neck of the humerus, the axillary nerve can be injured by fractures in this region (which are common in the elderly) or dislocation of the shoulder joint. The motor fibres of the axillary nerve innervate deltoid and teres minor. Its sensory fibres innervate a patch of skin over the upper lateral arm. Injury to the axillary nerve can therefore result in weakness or paralysis of deltoid – this presents functionally as difficulty abducting the shoulder - and altered sensation or numbness over the upper lateral arm.

Answer 110

As it travels along the radial groove of the posterior humerus, the radial nerve lies very close to the bone, thus fractures of the humeral shaft can injure the nerve. This can lead to weakness or paralysis of the muscles that are innervated by the radial nerve ‘downstream’ of the point at which the nerve is injured. As most of the radial nerve fibres that supply the triceps have already branched and entered the triceps at the point of the mid-humerus, the triceps itself is not likely to be significantly affected by damage to the radial nerve at this level. However, it will likely affect movements at the wrist because the radial nerve innervates all the muscles of the posterior forearm, which extend the wrist and digits

Answer 111

The ulnar nerve is vulnerable in the lower arm as it travels behind the medial epicondyle – it is superficial here. Fractures of the medial epicondyle may injure the nerve. Injury to the nerve at this level leads to motor impairments of the hand (as it innervates most of the small muscles of the hand) and causes sensory impairment in the hand (the medial side and the medial 1½ fingers). It is extremely common to knock the elbow in this region - referred to as the ‘funny bone’. A blow to the nerve here causes pain and tingling in the same regions of the hand.

Answer 112

In this type of injury - which is uncommon - the upper parts of the brachial plexus are affected. It may involve C5 - C6, or C5 - 7. The typical picture is one of paralysis of the lateral rotators of the shoulder and the extensors of the wrist. The affected limb typically appears medially rotated with the wrist flexed.

Answer 113

It is typically caused by trauma – specifically mechanisms that stretch the head away from the shoulder. This may be seen when someone is thrown from a motorbike or a horse. It may also be seen in new-borns if the baby’s shoulder becomes stuck during delivery and its neck is excessively stretched to one side.

Answer 114

This type of injury is also uncommon. The lower parts of the brachial plexus are affected, classically C8 and T1. The typical picture is one of paralysis of the small muscles of the hand. Again, it is most often caused by trauma – specifically mechanisms that forcefully and suddenly pull the arm upwards – this stretches the lower nerves of plexus. It may be sustained in babies during delivery if their arm is forcefully pulled superiorly to aid delivery.

Answer 115

Horner’s syndrome is the triad of drooping of the eyelid (ptosis), a constricted pupil (miosis) and lack of sweating (anhidrosis) on one side of the face. It results when the sympathetic nerve supply to the face is interrupted. The T1 spinal nerve carries sympathetic fibres which are destined to supply the face. Therefore, a brachial plexus injury affecting the T1 nerve root may result in Horner’s syndrome as well.

Answer 116

They are connected by an interosseous membrane. The radius and ulna also articulate with each other at the proximal and distal radioulnar joints.

Answer 117

It articulates at its proximal end with the distal humerus to form the elbow joint: the trochlea notch of the ulna articulates with the trochlea of the humerus

Answer 118

the radial head articulates with the capitellum of the humerus

Answer 119

The radiocarpal joint is referred to as the wrist joint. Flexion, extension, abduction and adduction occur at the wrist joint. These movements are achieved by muscles in the anterior and posterior forearm.

Answer 120

Posteriorly, the proximal ulna forms a bulky process known as the olecranon. This can be easily palpated in all individuals. The olecranon fits into the olecranon fossa on the posterior distal humerus to allow full extension.

Answer 121

The ulna has a process that protrudes anteriorly near its proximal end called the coronoid process. The coronoid process fits into the coronoid fossa of the anterior distal humerus when we flex our elbow fully

Answer 122

The radius has a roughened lump near it proximal end, but distal to the head and neck, known as the radial tuberosity. This is where the biceps brachii tendon inserts onto the radius. Often implicated in fractures

Answer 123

Distally, both the radius and ulna have a styloid process. These are distal protrusions of the radius and ulna that are often implicated in fractures in this region.

Answer 124

This synovial hinge joint is formed by articulations between the trochlea of the humerus and the trochlear notch of the ulna, and the capitellum of the humerus and the radial head. The trochlear notch of the ulna forms a deep recess and the trochlear of the humerus fits into it very well, providing a very stable joint. The coronoid process (distally) and the olecranon (proximally) of the ulna ‘pinch’ the trochlea of the humerus to help maintain stability.

Answer 125

The joint capsule is reinforced by medial (ulnar) and lateral (radial) collateral ligaments

Answer 126

These joints are a pair of synovial, pivot-type joints between the radius and ulna. The radius rotates around the ulna when the forearm is pronated and supinated. The annular ligament of the radius, which wraps around the radial neck, is attached to the ulna and holds the radial head in place. The radial head rotates within it to produce pronation and supination

Answer 127

The carpus is comprised of eight small bones that articulate with each other at small joints. The bones are roughly arranged into two rows of four bones.

Answer 128

The proximal row of carpal bones comprises, from lateral to medial: the scaphoid, lunate, triquetrum and the pisiform. The pisiform is not a true carpal bone, but rather is a small bone that develops in the tendon of flexor carpi ulnaris.

Answer 129

The distal row of carpal bones comprises, form lateral to medial: the trapezium (base of the thumb), trapezoid, capitate (located centrally and is the largest carpal bone) and the hamate. The hamate bears a bony process anteriorly (the hook), which is obvious when you view the bone on a skeleton and is palpable on examination.

Answer 130

The radiocarpal joint (wrist joint) is a condyloid synovial joint formed by the articulation of the distal radius with the scaphoid and lunate. It is surrounded by a joint capsule which is reinforced by ligaments. It allows flexion, extension, ulnar deviation (adduction) and a small amount of radial deviation (abduction).

Answer 131

The intercarpal joints between the carpal bones are synovial joints, which are also reinforced by ligaments, but they do not allow much movement.

Answer 132

The hand is composed of many small bones and joints. * The metacarpals are located distal to the carpus. * The bones of the digits are phalanges; there are three phalanges in each finger and two phalanges in the thumb. Several muscles of the forearm travel into the hand and move the fingers and thumb.

Answer 133

The cubital fossa is the region anterior to the elbow joint. In clinical practice it is often referred to as the antecubital fossa and abbreviated in medical notes to ‘ACF’.

Answer 134

* the lateral border is formed by brachioradialis, a posterior forearm muscle. * the medial border is formed by pronator teres, an anterior forearm muscle. * the superior border (or base) is formed by an imaginary line drawn between the medial and lateral epicondyles of the humerus. * The apex is most distal, ‘pointing’ towards the forearm and hand.

Answer 135

Tendon of biceps brachii Bicipital aponeurosis Brachial artery Median nerve Radial nerve

Answer 136

The tendon of biceps brachii can be traced into the cubital fossa as it travels to its insertion point on the radial tuberosity. The tendon is easily palpated with the elbow flexed

Answer 137

The bicipital aponeurosis is a fascial extension of the biceps tendon. It is continuous with the fascia on the surface of the anterior forearm muscles, and it separates the superficial veins from deeper structures in the fossa: the brachial artery and the median nerve.

Answer 138

The brachial artery is medial to the biceps tendon, and it can be palpated here. The brachial artery bifurcates into its terminal branches – the radial and ulnar arteries – deep in the cubital fossa. Great care must be taken during venepuncture and cannulation to avoid puncturing the brachial artery. Deep veins accompany the arteries

Answer 139

The median nerve is medial to the brachial artery. The median nerve does not innervate any muscles in the arm, but travels through the anterior compartment of the arm and the cubital fossa on its journey to the anterior forearm and hand.

Answer 140

The radial nerve also passes through the lateral aspect of the cubital fossa. It is deep to brachioradialis here.

Answer 141

The superficial veins that are located in the subcutaneous tissue over the cubital fossa include the cephalic, basilic and median cubital veins. They are of clinical importance as they are commonly accessed for venepuncture and intravenous access. Highly variable

Answer 142

This is seen in young children and is often caused by the child being pulled upwards by their arm. The annular ligament is partially torn, and the radial head moves distally out of the ligament (subluxation). It is painful and when assessing children in whom you suspect this injury, you may only notice that are not using the affected limb. The subluxed head can be reduced with relative ease using a simple manoeuvre.

Answer 143

The scaphoid forms from two bones, each with its own blood supply, that fuse together. With fusion, the artery to the proximal end degenerates, and the bone is supplied from its distal end. For this reason, fractures must not be missed. However, scaphoid fractures are not always evident on X-rays taken soon after the fracture has occurred. If a fracture is suspected but not seen on X-ray, patients are still followed-up.

Answer 144

When the scaphoid fractures, the proximal part of the bone may be disconnected from the blood supply and death of the proximal segment results – this is called avascular necrosis. Avascular necrosis is a serious problem because the proximal scaphoid articulates with the distal radius at the wrist joint

Answer 145

A fracture of the distal radius is very common in older people, especially females (in whom osteoporosis is more common). It is usually caused by a Fall Onto an OutStretched Hand (FOOSH). Simple distal radius fractures can be manipulated into an acceptable position for healing in the emergency department, but more complex fractures may require surgery.

Answer 146

* They are arranged in three layers: superficial, middle, and deep. * Most of them act as flexors of the wrist, fingers, or thumb. * Most of them are innervated by the median nerve.

Answer 147

* Pronator teres * Flexor carpi radialis * Palmaris longus * Flexor carpi ulnaris

Answer 148

These superficial muscles are attached proximally to the medial epicondyle of the humerus. As most of these muscles are flexors, this region of the humerus is also commonly referred to as the ‘common flexor origin’.

Answer 149

As its name suggests – is a pronator (of the proximal radioulnar joint), rather than a flexor.

Answer 150

Flexes and abducts the wrist. It inserts onto the radial side of the carpus and hand, hence its name.

Answer 151

Has a small muscle belly but a long, thin, easily recognisable tendon when present (approximately 15% of us do not have one). Its tendon inserts into the fascia of the palm of the hand.

Answer 152

Flexes and adducts the wrist. It inserts onto the ulnar side of the carpus and hand. This muscle is another exception to the general rule, as it is innervated by the ulnar nerve, not the median.

Answer 153

There is one muscle in the middle layer: flexor digitorum superficialis (FDS). It gives rise to four tendons. Its name tells us that it is a flexor of the digits – so we can deduce that its tendons must travel beyond the wrist, into the hand and to the fingers (digits 2-5). It is innervated by the median nerve, which travels between flexor digitorum superficialis and one of the deep muscles, flexor digitorum profundus.

Answer 154

There are three muscles in the deep layer: * Flexor digitorum profundus * Flexor pollicis longus * Pronator quadratus

Answer 155

A flexor of the digits and is located deep to flexor digitorum superficialis. It too gives rise to four tendons, which travel into the hand and to the fingers (digits 2-5). The tendons of superficialis and profundus are closely related in the hand and digits.

Answer 156

The lateral half of the muscle, which gives rise to the tendons that travel to the index and middle fingers, is innervated by the median nerve.

Answer 157

The medial half of the muscle, which gives rise to the tendons that travel to the ring and little fingers, is innervated by the ulnar nerve.

Answer 158

Flexes the thumb (pollex is the Latin word for thumb). ‘Longus’ distinguishes it from another muscle, flexor pollicis brevis, which is much smaller and located within the hand.

Answer 159

Is the deepest forearm muscle (it is considered a fourth layer by some). It is square-shaped (‘quadratus’) and is located over the distal ends of the radius and ulnar. It pronates the distal radioulnar joint.

Answer 160

* they are arranged in two layers: superficial and deep. * most of them are extensors of the wrist, digits, or thumb. * they are all innervated by the radial nerve.

Answer 161

There are seven superficial muscles. They are: * Brachioradialis * Extensor carpi radialis longus * Extensor carpi radialis brevis * Extensor digitorum * Extensor digiti minimi * Extensor carpi ulnaris * Anconeus

Answer 162

These muscles are attached proximally to the lateral epicondyle of the humerus and, as most of them are extensors, their origin is known as the ‘common extensor origin’.

Answer 163

Is an exception to some of the rules of posterior compartment muscles. It is located on the boundary between the posterior and anterior compartments. It originates from the humerus, proximal to the lateral epicondyle, and inserts on the distal radius. It acts as a weak flexor of the elbow joint and hence functions as an anterior compartment muscle of the arm. However, it is innervated by the radial nerve

Answer 164

Are located on the radial side of the posterior compartment. ECRL inserts onto the 2nd metacarpal and ECRB inserts onto the 3rd metacarpal, hence they extend and abduct the wrist. Brevis is the Latin word for ‘short’.

Answer 165

Extends the digits via four long tendons that insert onto the dorsal aspects of the fingers (digits 2-5). The tendons of ED are connected by fibrous bands – this makes it difficult to fully extend the middle or ring fingers independently.

Answer 166

Extends the little finger via its insertion onto the dorsum of the little finger.

Answer 167

Is the most medial of the superficial muscles. It extends and adducts the wrist via its insertion onto the 5th metacarpal.

Answer 168

At the wrist, the tendons of these muscles travel under a band of tissue, the extensor retinaculum. It prevents the tendons from bowing when the wrist is extended.

Answer 169

Anconeus is another small muscle in the superficial posterior compartment of the forearm. It is found proximally, near the olecranon so it is sometimes considered to be part of the posterior compartment of the arm instead. Its small size and position spanning from the lateral epicondyle of the humerus to the olecranon means it acts as a very weak extensor of the elbow. It is also innervated by the radial nerve.

Answer 170

There are five deep muscles. From lateral to medial they are: * Supinator * Abductor pollicis longus * Extensor pollicis brevis * Extensor pollicis longus * Extensor indicis.

Answer 171

Except for supinator, they attach proximally to the forearm bones and the interosseous membrane. Two deep muscles are exceptions to the general rules as they are not extensors

Answer 172

supinates the forearm and is attached proximally to the humerus. It wraps around the proximal part of the radius.

Answer 173

Abducts the thumb. It inserts on the 1st metacarpal.

Answer 174

Extend the thumb EPB inserts on the proximal phalanx, so extends the metacarpophalangeal joint. Although their proximal muscle attachments are deep in the forearm, the tendons of EPB and APL lie superficially at the wrist as they wrap around the distal radius

Answer 175

Extends the thumb EPL inserts on the distal phalanx, so is the only muscle capable of extending the interphalangeal joint of the thumb. Although their proximal muscle attachments are deep in the forearm, the tendons of EPB and APL lie superficially at the wrist as they wrap around the distal radius.

Answer 176

Inserts on the dorsum of the index finger, allowing independent extension of this digit.

Answer 177

* extensors, except for brachioradialis, supinator and abductor pollicis longus. * innervated by the radial nerve. The muscles that cross the wrist also contribute to wrist extension

Answer 178

* flexors, except for pronator teres and pronator quadratus. * innervated by the median nerve, except FCU and the medial half of FDP.

Answer 179

The brachial artery bifurcates in the cubital fossa into two terminal branches – the radial artery and the ulnar artery.

Answer 180

The radial artery travels along the lateral aspect of the forearm and it can usually be easily palpated at the wrist by locating the tendon of flexor carpi radialis at the level of the distal radius and palpating just laterally to this.

Answer 181

The ulnar artery travels along the medial aspect of the forearm. It can also be palpated, but not easily as it is located deep to the flexor carpi ulnaris tendon.

Answer 182

The radial and ulnar arteries enter the hand. They anastomose in the palm of the hand to form palmar arches. These anastomoses ensure that the hand remains adequately perfused in the event that either artery becomes occluded or injured.

Answer 183

There are both superficial and deep veins in the upper limb, which communicate with each other. Ultimately, all venous blood drains to the axillary vein. Two important superficial veins of the upper limb are the cephalic vein and the basilic vein.

Answer 184

Superficial vein Courses laterally in the forearm Typically connected to the basilic vein in the region of the cubital fossa by the median cubital vein. The cephalic vein courses proximally in the lateral aspect of the arm and drains into the axillary vein after passing through the deltopectoral groove

Answer 185

Superficial Courses medially Typically connected to the cephalic vein in the region of the cubital fossa by the median cubital vein. * The basilic vein courses proximally into the arm. It receives the deep veins of the arm to form the axillary vein.

Answer 186

Deep veins accompany arteries, and they are often paired. For example, two brachial veins accompany the brachial artery. Deep veins of the upper limb ultimately drain to the axillary vein.

Answer 187

The carpal tunnel is a narrow passageway at the wrist. Its floor and sides are formed by the carpal bones. A fibrous band called the flexor retinaculum completes the tunnel, forming the roof, and is attached to the scaphoid and trapezium laterally and to the hook of the hamate and pisiform medially.

Answer 188

The tendons of the anterior forearm muscles that insert onto the digits travel through the carpal tunnel. These are the tendons of: * flexor digitorum superficialis (4 tendons, to digits 2-5). * flexor digitorum profundus (4 tendons, to digits 2-5). * flexor pollicis longus (1 tendon to the thumb – the 1st digit).

Answer 189

The median nerve also travels through the carpal tunnel. The carpal tunnel is very narrow, so the tendons and median nerve are tightly packed into it. Any condition that further reduces space in the carpal tunnel, such as swelling of the tendons or arthritis between the joints of the carpal bones, will decrease the space and increase the pressure in the carpal tunnel. This can compress the median nerve and cause carpal tunnel syndrome (CTS).

Answer 190

* impaired or altered sensation over the skin of the hand supplied by the median nerve. The patient may experience tingling, numbness, or pain in the hand. * weakness of the hand muscles supplied by the median nerve – particularly the small muscles of the thumb.

Answer 191

It is important to recognise and treat CTS. If left untreated, the small muscles of the thumb may atrophy and weakness may be permanent, which has serious consequences for a patient. The flexor retinaculum is divided to alleviate the compression. The radial artery, ulnar artery and ulnar nerve do not travel through the carpal tunnel.

Answer 192

The flexor tendons are at risk from lacerations over the anterior forearm and wrist. In patients with such injuries, it is important to test the movements of the wrist and fingers to ascertain whether any tendons have been injured. Patients with confirmed or suspected tendon injuries require a surgical assessment. Failure to recognise tendon injuries may leave patients with permanent impairment.

Answer 193

This describes an inability to extend the wrist (and fingers) due to weakness or paralysis of the posterior forearm muscles. It results from injury to the radial nerve proximal to the forearm. It is typically caused by a mid-shaft humeral fracture, as the radial nerve lies close to the bone here. Sensation is also impaired over the lateral aspect of the dorsum of the hand (i.e. in the regions of skin of the hand supplied by the radial nerve).

Answer 194

This is inflammation of the tendinous insertions of the superficial extensor muscles in the forearm at the lateral epicondyle, or the superficial flexor muscles in the forearm at the medial epicondyle. It tends to be caused by repetitive use and strain of the muscles, such as during a tennis serve for lateral epicondylitis (‘tennis elbow’), or a golf swing for medial epicondylitis (‘golfer’s elbow’). Pain is felt around the affected epicondyle and may radiate down the forearm.

Answer 195

The vast majority of blood tests require venous blood, which can be relatively easily taken from the superficial veins in the forearm and hand as discussed. However, to accurately assess a patient’s blood-oxygen and blood-carbon dioxide level, a sample of arterial blood is required. Most often, this is taken from the radial artery. As it a deep structure, clinicians must know the anatomy well to be able to use one hand to palpate the pulse and use the other to direct a needle into the radial artery to acquire the sample.

Answer 196

The carpus is comprised of eight small bones that articulate with each other at small joints. The bones are roughly arranged into two rows of four bones: one proximal, one distal. The distal radius articulates with the scaphoid and lunate to form the radiocarpal joint.

Answer 197

Metacarpals Phalanges

Answer 198

The metacarpals are located distal to the carpus. They are numbered 1 – 5 from the lateral (thumb) side to the medial (little finger) side.

Answer 199

The bones of the digits are phalanges (singular: phalanx). There are three phalanges in each finger (digits 2-5) and two phalanges in the thumb (digit 1). The three phalanges of the fingers are named proximal, middle, and distal phalanges. The two phalanges of the thumb are named proximal and distal phalanges.

Answer 200

The digits may be referred to by their number from lateral to medial (1-5) or by their names (thumb, index finger, middle finger, ring finger, little finger). In clinical practice it is preferred to identify them by their name, not their number, as it is less confusing.

Answer 201

Located between the distal row of carpal bones and the proximal parts (the bases) of the metacarpals. The first carpometacarpal (CMC) joint is between the trapezium and the 1st (thumb) metacarpal. It is a saddle joint and is key to the range of movement possible at the thumb.

Answer 202

Are often known as the ‘knuckles’, these joints are located between the distal parts (the heads) of the metacarpals and the proximal phalanges. The metacarpophalangeal joints are condyloid synovial joints

Answer 203

Interphalangeal joints (IPJs) are between the phalanges. They are hinge synovial joints. * The thumb contains two phalanges so there is only one interphalangeal joint (IPJ) in the thumb. * The fingers contain three phalanges so there are two interphalangeal joints: * the proximal interphalangeal (PIP) joints are located between the proximal and middle phalanges. * the distal interphalangeal (DIP) joints are between the middle and distal phalanges

Answer 204

The human hand is highly evolved and allows us to manipulate objects in a variety of ways. The hand and digits can perform a wide range of grips. E.g power grip, hook grip, precision grip

Answer 205

For example, we use a power grip to hold or squeeze objects tightly.

Answer 206

The hook grip is important for carrying objects with handles, such as bags.

Answer 207

The precision grip allows us to hold objects between the pads of our thumb and fingers, such as a pen or needle

Answer 208

The fingers (digits 2-5) are able to move in the following ways: * Flexion and extension * Abduction (moving the fingers apart) and adduction (bringing the fingers together).

Answer 209

The movements of the thumb are a little more complex. They are: * Flexion and extension ¬ * Abduction and adduction * Opposition ¬(a mixture of flexion, adduction, and internal rotation of the thumb metacarpal

Answer 210

The extrinsic muscles are located in the anterior and posterior forearm and their tendons travel into the hand.

Answer 211

* Flexor carpi radialis - inserts onto the 2nd (index) metacarpal. * Flexor carpi ulnaris - inserts onto the 5th (little finger) metacarpal. * Palmaris longus (if present) - inserts onto the palmar fascia.

Answer 212

* Flexor digitorum superficialis (FDS). * Flexor digitorum profundus (FDP). * Flexor pollicis longus (FPL). Because their tendons cross the wrist, these muscles also contribute to wrist flexion They travel through the carpal tunnel and into the hand

Answer 213

The tendon of flexor digitorum superficialis (FDS) splits into two ‘slips’ which insert on either side of the middle phalanx of digits 2-5. It flexes the MCP joints and PIP joints of digits 2-5.

Answer 214

The tendon of flexor digitorum profundus (FDP) passes through the gap in the FDS tendon to insert onto the palmar aspect of the distal phalanx of digits 2-5. It is the only muscle capable of flexing the DIP joint. It also flexes the PIP joint and the MCP joint of digits 2-5.

Answer 215

The tendon of flexor pollicis longus (FPL) inserts onto the distal phalanx of the thumb. It flexes the IP joint of the thumb and is the only muscle that can do so.

Answer 216

It is important for clinical practice to know these specific distal insertion points of the long flexor tendons. When patients present with injuries to the hand, such as lacerations, you must be able to test the movements of the digits to assess if the tendons have been injured – being able to do this competently relies on knowing where the tendons insert and what movements they control.

Answer 217

Fibrous sheaths enclose the long flexor tendons. They maintain the position of the flexor tendons in the midline of each finger. Within the fibrous sheaths, the tendons are enclosed within a synovial sheath, which reduces friction and allows the tendons to slide freely within their fibrous sheath during flexion and extension.

Answer 218

The thick palmar aponeurosis protects the long flexor tendons, tendon sheaths and vessels as they pass through the palm of the hand.

Answer 219

If penetrating injuries of the hand and fingers (e.g. lacerations, bites or thorns piercing the skin) pierce the tendon sheaths they may become infected. Inflammation of the tendon and synovial sheath is called tenosynovitis.

Answer 220

Aka small muscles of the hand, both the origins and insertions of the intrinsic muscles are within the hand itself. There are four groups of intrinsic muscles (thenar eminence, hypothenar eminence, lumbricals, interossei) and one single muscle that does not fit into any of the groups (adductor pollicis) Innervated by ulnar and median nerves

Answer 221

This is the fleshy mass on the palm of the hand at the base of the thumb. It contains: * Flexor pollicis brevis (FPB) - flexes the thumb. * Abductor pollicis brevis (APB) - abducts the thumb. * Opponens pollicis - (OP) - opposes the thumb (deep to flexor and abductor)

Answer 222

Both groups of muscles are attached to the carpal bones proximally

Answer 223

Movement- Flexion Insertion- Proximal phalanx Innervation- Recurrent branch of the median nerve

Answer 224

Movement- Abduction Insertion- Proximal phalanx, lateral aspect Innervation- Recurrent branch of the median nerve

Answer 225

Movement- Opposition Insertion- 1st metacarpal Innervation- Recurrent branch of the median nerve

Answer 226

The recurrent branch of the median nerve leaves the median nerve after it has passed through the carpal tunnel, therefore the thenar eminence muscles will be affected in carpal tunnel syndrome. If left untreated, they become weak and atrophy.

Answer 227

This muscle moves the thumb but differs from the thenar eminence muscles in two ways: it is located deep in the palm, not in the thenar eminence, and it is innervated by the ulnar nerve. Adductor pollicis is attached to the 3rd (middle) metacarpal and to the proximal phalanx of the thumb. Contraction of the muscle pulls the thumb towards the palm.

Answer 228

The thenar muscles are important for a precision grip. The thumb is abducted, flexed, and internally rotated at the CMC joint so it can oppose with the one of the fingers. This grip can be performed with or without power

Answer 229

This is the fleshy mass on the medial side of the palm of the hand, proximal to the little finger. It contains three small muscles that act upon the little finger. They mirror the thenar eminence muscles, in their names and locations. * Flexor digiti minimi (FDM) - flexes the little finger. * Abductor digiti minimi (ADM) - abducts the little finger. * Opponens digiti minimi (ODM) - opposes the little finger. The hypothenar muscles are attached to the carpal bones proximally. Their distal attachments, actions and innervation are summarised below

Answer 230

Movement- Flexion Insertion- Proximal phalanx Innervation- Deep branch of the ulnar nerve

Answer 231

Movement- Abduction Insertion- Proximal phalanx Innervation- Deep branch of the ulnar nerve

Answer 232

Movement- Opposition Insertion- 5th Metacarpal Innervation- Deep branch of the ulnar nerve

Answer 233

There are four lumbrical muscles, one for each finger (digits 2-5). Their origins are the tendons of flexor digitorum profundus. They then travel along the lateral aspects of digits 2-5 to insert onto the dorsal aspects of digits 2-5. The action of the lumbricals is to flex the MCP joints and simultaneously extend the IP joints. The innervation of the lumbricals follows that of the FDP tendons from which they arise: * the lateral two (digits 2 and 3) are innervated by the median nerve. * the medial two (digits 4 and 5) are innervated by the ulnar nerve.

Answer 234

These muscles are attached to, and located between, the metacarpals and insert onto the dorsal aspects of digits 2-5. There are two groups, a palmar group, and a dorsal group Their movements can be remembered by ‘PAD-DAB’ (Palmar ADduct, Dorsal ABduct).

Answer 235

There are three palmar interosseous muscles The arrangement of the palmar interossei and their insertion points allows them to adduct the fingers (i.e. draw them towards the middle finger) when they contract.

Answer 236

Four dorsal interosseous muscles The arrangement of the dorsal interossei and their insertion points allows them to abduct the fingers (i.e. move away from the middle finger) when they contract.

Answer 237

The dorsum of the hand is far less complex than the palm in terms of muscles – only the four dorsal interossei are seen on the dorsal aspect. The extensor tendons are often visible under the skin over the dorsum of the hand.

Answer 238

The superficial veins of the dorsum of the hand are often visible and palpable under the skin. They comprise the dorsal venous network, but the pattern is variable between individuals. Veins of the dorsal venous network can be cannulated. The dorsal venous network drains into the cephalic vein laterally and into the basilic vein medially.

Answer 239

Also called the extensor hood, this fibrous structure is located on the dorsal aspect of the digits. It is attached to the base of the proximal phalanx and gives rise to a central slip and two marginal slips. The central slip inserts on the middle phalanx and the marginal slips converge on the distal phalanx.

Answer 240

The tendons of ED, EI and EDM insert onto the dorsal aspect of the extensor expansion. This helps keep the tendons fixed in the midline of the digits. The lumbricals and interossei insert onto the sides of the proximal parts of the extensor expansion. Via this attachment, they contribute to extension of the interphalangeal joints of the fingers.

Answer 241

The anatomical snuffbox (ASB) is a triangular-shaped depression on the lateral aspect of the wrist, at the base of the thumb. It is best seen when the thumb is fully extended. The boundaries of the snuffbox are the tendon of EPL medially and the tendons of EPB and APL laterally

Answer 242

It is a clinically important region because: * The scaphoid bone is located in the floor of the ASB. ASB tenderness on palpation may indicate a scaphoid fracture. * The radial artery travels through it. * The cephalic vein travels across it. * The superficial branch of the radial nerve travels over the anatomical snuffbox to supply the skin over the lateral aspect of the dorsum of the hand.

Answer 243

The radial and ulnar arteries supply the hand. These are the terminal branches of the brachial artery.

Answer 244

The radial artery courses down the lateral aspect of the forearm. The radial pulse can be palpated over the lateral aspect of the wrist.

Answer 245

The ulnar artery courses down the medial aspect of the forearm. The ulnar nerve travels alongside the ulnar artery.

Answer 246

The radial and ulnar arteries anastomose deep in the palm to form two palmar arches The palmar arches give rise to metacarpal and digital arteries that supply the palm and digits. These are accompanied by digital nerves.

Answer 247

The superficial palmar arch is formed largely by the ulnar artery with a smaller contribution from the radial artery.

Answer 248

The deep palmar arch is formed largely by the radial artery with a smaller contribution from the ulnar artery

Answer 249

The palmar surface of the lateral side of the hand, the palmar surface of the lateral 3 ½ digits, the skin over the dorsum of the distal phalanges of the lateral 3 ½ digits.

Answer 250

The palmar and dorsal surfaces of the medial side of the hand and the medial 1 ½ digits.

Answer 251

The dorsal surface of the lateral side of the hand and the skin over the dorsum of the lateral 3 ½ digits as far as the DIP joint.

Answer 252

* Median: tested on the central palm, just proximal to the middle finger. * Ulnar: tested on the medial border of the hand * Radial: tested on dorsum of the hand in the thumb and index webspace.

Answer 253

The superior aspect of the shoulder.

Answer 254

The lateral shoulder over the deltoid, and anterior and posterior aspects of the arm.

Answer 255

The lateral side of the anterior and posterior surfaces of the forearm, the lateral sides of the anterior and posterior surfaces of the palm, and the anterior and posterior surfaces of the thumb and index finger.

Answer 256

The anterior and posterior surfaces of the middle finger and middle of the palm (over the 3rd metacarpal).

Answer 257

The medial side of the anterior and posterior surfaces of the forearm, the medial side of the anterior and posterior surfaces of the palm, and the anterior and posterior surfaces of the ring and little fingers.

Answer 258

The medial side of the anterior and posterior surfaces of the arm.

Answer 259

Testing sensation in dermatomes C5 – T1 gives us information about the spinal nerves and their corresponding spinal cord segments. The areas of skin innervated by the spinal nerves (dermatomes) are different to the areas supplied by peripheral nerves because of how the spinal nerve fibres are ‘shuffled’ in the brachial plexus and distributed within the peripheral nerves.

Answer 260

● C5: upper lateral arm, over the deltoid muscle. ● C6: thumb. ● C7: middle finger. ● C8: little finger. ● T1: medial border of the arm, just proximal to the elbow.

Answer 261

In the case of palmar injuries (e.g., a laceration over the palmar aspect of a finger), we need to assess if the long flexor tendons are intact. The tendons of FDS and FDP both cross, and hence can move, the PIP joint. However, only FDP can move the DIP joint. To test FDP, the PIP joint is held immobile by the examiner and the patient is asked to flex the finger. If the FDP tendon is intact, flexion is seen at the DIP joint. To test the tendon of FPL, movement at the IP joint of the thumb is assessed.

Answer 262

In this condition, the fingers (usually the little and ring fingers) are pulled into flexion by progressive fibrosis of the palmar fascia and palmar aponeurosis. The palmar fascia is attached to the flexor tendon sheaths of the fingers. The fascia shortens and pulls the fingers into flexion. The fascia can be released surgically.

Answer 263

Osteoarthritis is ‘wear and tear’ arthritis and is more common in older people. It primarily affects large, ‘load bearing’ joints like the hips and knees. However, rheumatoid arthritis is an autoimmune condition that affects various synovial joints, and the small joints of the hands are typically involved. The MCP and PIP joints are predominantly affected. Rheumatoid arthritis can damage these joints causing significant deformity such as ulnar deviation of the digits at the MCP joints, and fixed flexion and extension deformities of either of the interphalangeal joints. This can lead to significant functional impairment for these patients.

Answer 264

Otherwise known as a ‘boxer’s fracture’, as it is typically sustained by punching something hard, there is usually pain, swelling and tenderness over the 5th metacarpal.

Answer 265

The pelvis is a bony ring formed by the articulation of the left and right innominate (hip) bones and the sacrum. The pelvis takes the weight of the body and transmits it to the lower limbs.

Answer 266

Each hip bone is formed from three separate bones – the pubic bone, the ilium and ischium, which fuse at the acetabulum – the socket of the hip joint. The hip bones articulate anteriorly with each other at the pubic symphysis and posteriorly with the sacrum at the sacroiliac joints.

Answer 267

The superior and inferior pubic rami (singular: ramus) surround the obturator foramen. In life, the obturator foramen is almost completely closed over by the obturator membrane and muscles attached to it. A small gap in the membrane and the muscles – the obturator canal – allows vessels and nerves to pass between the pelvis and thigh.

Answer 268

The uppermost part of the ilium is the iliac crest. These are palpable through the skin. Anteriorly, the anterior superior iliac spine (ASIS) and anterior inferior iliac spine (AIIS) are prominent. Also the pubic symphysis

Answer 269

● The sharp ischial spine. The sacrospinous ligament attaches to it. ● The bulky ischial tuberosity. The sacrotuberous ligament attaches to it along with muscles of the posterior thigh. This part is often palpable through the skin, and we sit on this part of the pelvis.

Answer 270

Above and below the ischial spines, are two notches known as the greater and lesser sciatic notches. The sacrotuberous and sacrospinous ligaments close these notches to form the greater and lesser sciatic foramina. These ligaments connect the sacrum to their respective bony prominence, the ischial tuberosity or ischial spine. The foramina allow structures to pass between the pelvis and the gluteal region and perineum.

Answer 271

The femur is the long bone of the thigh. Like the humerus, it has a head, neck and shaft, and its distal end is expanded to from two condyles.

Answer 272

Articulates with the acetabulum of the pelvis to form the hip joint.

Answer 273

The neck of the femur extends laterally and distally from the head.

Answer 274

Located distal to the neck. They are sites of muscle attachment similar to the tubercles of the humerus

Answer 275

is located between the greater and lesser trochanters on the anterior surface of the femur.

Answer 276

The linea aspera is a bony vertical ridge on the posterior aspect of the shaft of the femur. It is a site of muscle attachment.

Answer 277

The gluteal tuberosity is located just inferior to the trochanters on the posterior aspect of the femur. It is a site of muscle attachment.

Answer 278

The distal end of the femur is expanded to form the medial and lateral femoral condyles. These articulate with the proximal tibia at the knee joint.

Answer 279

Just superior to the medial femoral condyle

Answer 280

Located anterior to the knee joint.

Answer 281

The hip is a synovial ball and socket joint formed by the articulation between the acetabulum of the hip (innominate) bone and the femoral head. The weight of the body is transmitted through the lumbar vertebrae and the sacroiliac joints to the hip joints

Answer 282

The hip is a stable joint as the acetabulum is deep and there is a good fit between it and the femoral head. A rim of fibrocartilage - the acetabular labrum – deepens the acetabulum for even more stability.

Answer 283

The ligament of the head of the femur is a weak ligament that attaches the femoral head to the centre of the acetabulum. The joint capsule is reinforced by other strong ligaments.

Answer 284

The arteries to the hip joint (medial and lateral circumflex femoral arteries) arise mainly from the profunda femoris. They give rise to retinacular arteries that run along the neck of the femur to supply the femoral head. They can be torn by fractures of the femoral neck.

Answer 285

Flexion, extension, abduction, adduction, internal (medial) and external (lateral) rotation and circumduction

Answer 286

Flex the thigh at the hip joint

Answer 287

Adduct the thigh at the hip joint

Answer 288

Extend the thigh at the hip joint.

Answer 289

region extend, abduct and rotate the thigh at the hip joint.

Answer 290

The hip joint is stabilised by three ligaments - the iliofemoral, pubofemoral and ischiofemoral ligaments. The iliofemoral and pubofemoral are anterior ligaments, whilst the ischiofemoral is posterior to the joint. As the hip is extended, these ligaments become taut and hold the femur more tightly.

Answer 291

The knee is a synovial hinge joint formed by the articulation between the femoral condyles and the tibial condyles. The most superior aspect of the tibial condyles forms a pair of flat surfaces known as the tibial plateaus. As the tibial plateaus are flat, they do not provide a good fit for the femoral condyles

Answer 292

The femur and tibia achieve their ‘best fit’ with each other when the knee is extended, hence the knee is most stable in extension. To help us to stand for long periods, the femur rotates a very small amount as the knee reaches full extension. The means the knee ‘locks’ in place and becomes very stable. A small muscle called popliteus is responsible for ‘unlocking’ the knee by rotating the femur back again to permit flexion.

Answer 293

The muscles, tendons, cartilage, and ligaments that surround the knee joint also contribute to its stability, as does the iliotibial tract which attaches to the lateral aspect of the tibia.

Answer 294

The movements possible at the knee joint are flexion and extension. Muscles in the anterior thigh extend the leg at the knee joint. Muscles in the posterior thigh flex the leg at the knee joint.

Answer 295

The menisci (singular = meniscus) are C-shaped cartilages that sit on the tibial plateaus. They are wedge-shaped, with the thickest part at the periphery and the thinnest part in the centre. They act to deepen the tibial condyles for articulation with the femoral condyles, thus improving the fit between them.

Answer 296

The medial meniscus is attached to the joint capsule along its peripheral margin and is attached to the medial (tibial) collateral ligament. These attachments make it prone to injury if the knee is twisted

Answer 297

Not attached to the lateral (fibular) collateral ligament; it can move more freely, so is less prone to injury.

Answer 298

Collateral and the cruciate ligaments

Answer 299

The medial (tibial) and lateral (fibular) collateral ligaments support the knee and resist sideways movement of the tibia on the femur.

Answer 300

The medial collateral ligament (MCL) connects the femur to the tibia, the medial collateral ligament is attached to the medial meniscus,

Answer 301

The lateral collateral ligaments (LCL) connects the femur to the fibula. The lateral collateral ligament is not attached to the lateral meniscus

Answer 302

The anterior and posterior cruciate ligaments connect the tibia to the femur and are named according to their attachments to the tibia. ‘Cruciate’ is derived from the Latin for ‘cross’.

Answer 303

The anterior cruciate ligament is attached to the anterior part of the intercondylar area of the tibia. It attaches to the medial aspect of the lateral condyle of the femur. It prevents the tibia moving anteriorly relative to the femur (or, to think of it another way, it prevents the femur moving posteriorly relative to the tibia). Being able to pull the tibia anteriorly indicates ACL injury. The ACL is taut in knee extension, and lax when the knee is flexed.

Answer 304

The posterior cruciate ligament is attached to the posterior part of the intercondylar area of the tibia. It attaches to the lateral aspect of the medial condyle of the femur. It prevents the tibia moving posteriorly relative to the femur (or, to think of it another way, it prevents the femur moving anteriorly relative to the tibia). This ligament is therefore crucial for stability of the knee when walking downhill or downstairs. Being able to push the tibia posteriorly indicates PCL injury. The PCL is most taut in knee flexion.

Answer 305

A ‘fractured hip’ refers to a fracture of the femoral neck. This is very common in the elderly population and can be caused even by a low energy fall. Osteoporosis is often a contributing factor. Patients typically have pain in the groin and are unable to bear any weight on the affected leg. The typical finding on examination is shortening and external rotation of the affected limb compared to the uninjured limb. The fracture may tear the vessels that supply the femoral head and neck, leading to avascular necrosis of the femoral head.

Answer 306

Dislocation of the patella is common. Dislocation is almost always lateral because the femur is angled obliquely relative to the tibia and so the angle of the pull of quadriceps is also oblique. The distal fibres of vastus medialis are arranged horizontally and these usually resist lateral movement of the patella. Additionally, the patellofemoral joint has a larger ridge laterally in an attempt to resist to lateral dislocation. Dislocated patellae are relatively easy to relocate and often simply require extension of the leg at the knee, and a small push on the patella.

Answer 307

Osteoarthritis of the hip joint and knee joint is very common. It causes progressive pain and limited mobility. Hip and knee replacements are two of the most common surgical procedures undertaken in the UK.

Answer 308

Dislocation of the hip requires significant force because the joint is very stable. Posterior dislocation of the femoral head tends to occur in car accidents when the knee forcibly impacts the dashboard. The force is transmitted along the femur and the head is forced posteriorly. The acetabulum may fracture. A posterior dislocation risks injury to the sciatic nerve, which is located just behind the hip joint.

Answer 309

The menisci can be torn by twisting injuries of the knee. Tears of the medial (tibial) collateral ligament result from a lateral blow to the knee or twisting injuries. Because it is attached to the medial meniscus, the meniscus may also tear. Anterior cruciate injury is typically also caused when there is a lateral blow to a partially flexed knee. In some cases, all three of these structures can be damaged in a single injury, and this is known as the ‘unhappy triad of the knee’. It is most often seen as a sporting injury, particularly amongst those who play football or rugby. Ligament injuries cause instability of the joint.

Answer 310

● Gluteus maximus ● Gluteus medius ● Gluteus minimus ● Tensor fascia latae (this muscle is displayed on the image of the anterior thigh later in this handbook due to its location in the thigh).

Answer 311

Most superficial muscle. It has several proximal attachments. It is attached to the most posterior parts of the posterior surface of the ilium, the sacrotuberous ligament and the sacrum. Distally, most fibres insert into the iliotibial band, with a smaller proportion attaching onto the gluteal tuberosity (note, this is not the same as the greater trochanter)

Answer 312

Extensor of the hip and is important for standing from a sitting position, and also acts as an external rotator of the hip. Because it inserts onto the iliotibial tract, it stabilises the knee joint too

Answer 313

Gluteus medius is deep to maximus. Gluteus minimus is deep to medius. These muscles have similar points of attachment to the posterior ilium and they both insert onto the greater trochanter. Because of their similar bony attachments, they move the hip in the same way – they abduct and internally rotate it.

Answer 314

Play an important role in normal gait. When we walk or run, for much of the time we have only one leg in contact with the ground and the other is off the ground. When we stand on one leg, gluteus medius and minimus in the limb that we are standing on contract and hold the pelvis ‘level’, so that it does not tilt to the side that is unsupported (i.e. the side with the leg off the ground). If gluteus medius and minimus are weak or paralysed in one limb, the pelvis tilts down on the contralateral side every time the contralateral leg is off the ground, resulting in a limp.

Answer 315

Attached to the ASIS and inserts into the iliotibial band, which itself inserts onto the lateral part of the proximal tibia. It acts as its name suggests – contraction of the muscle tenses the fascia lata and the iliotibial band. It stabilises the knee when it is extended and it also weakly flexes the hip joint

Answer 316

The fascia lata is a thick fascia that envelops the muscles of the thigh, from the iliac crest proximally, to the tibia distally. There is a thickening of the fascia lata laterally known as the iliotibial band.

Answer 317

The superficial gluteal muscles are innervated by the gluteal nerves which leave the sacral plexus in the pelvis via the greater sciatic foramen: ● Gluteus maximus is innervated by the inferior gluteal nerve. ● Gluteus medius and minimus, and TFL, are innervated by the superior gluteal nerve.

Answer 318

The deep gluteal muscles are small muscles that primarily stabilise and laterally rotate the hip joint. They are: ● Piriformis ● The superior and inferior gemelli ● Obturator internus ● Quadratus femoris They all insert onto, or close to, the greater trochanter.

Answer 319

Piriformis is a key landmark. It attaches to the anterior surface of the sacrum, passes through the greater sciatic foramen, and inserts on the greater trochanter. The nerves of the sacral plexus are located on its surface in the pelvis. The sciatic nerve emerges below its inferior border in the gluteal region.

Answer 320

The other deep gluteal muscles arise from the ischium, except for obturator internus, which arises from the obturator membrane. Its tendon passes through the lesser sciatic foramen.

Answer 321

The anterior compartment of the thigh contains seven muscles. As a group they primarily act as extensors of the knee and some of them act upon the hip joint. They are all innervated by the femoral nerve (derived from spinal nerves L2-L4).

Answer 322

The muscles are: ● Quadriceps femoris – a group of four large muscles. ● Sartorius ● Iliopsoas ● Pectineus.

Answer 323

This is the primary extensor of the knee, and this group forms the bulk of the anterior thigh: ● Rectus femoris ● Vastus lateralis ● Vastus medialis ● Vastus intermedius. These four muscles converge onto the quadriceps tendon which runs over the patella (kneecap) to insert onto the tibial tuberosity via the patellar ligament.

Answer 324

Rectus femoris lies in the midline of the anterior thigh. It is attached to the AIIS proximally. Because it crosses the hip, it can also contribute to flexion of the hip.

Answer 325

Vastus lateralis lies lateral to rectus femoris. It attaches to the linea aspera on the posterior aspect of the femoral shaft

Answer 326

Vastus medialis lies medial to rectus femoris. It also attaches to the linea aspera.

Answer 327

Vastus intermedius lies deep to rectus femoris. It attaches to the anterior aspect of the femoral shaft.

Answer 328

is located superficially in the anterior thigh. Its name is derived from the Latin word for ‘tailor’, as a reference to how tailors used to often sit in a cross-legged position, which is a demonstration of this muscle’s actions. It attaches proximally at the ASIS and twists across the thigh to insert on the medial aspect of the proximal tibia. It crosses both the hip and knee joints, so it is able to flex and externally rotate the hip joint and flex the knee joint. Sartorius is not the primary mover of these joints, but rather contributes to more delicate control.

Answer 329

Iliopsoas is located proximally in the anterior thigh. Psoas major and iliacus converge via a common tendon onto the lesser trochanter of the femur. Their names are merged into iliopsoas due to their shared attachment and function and it is the primary flexor of the hip joint. Psoas major is innervated directly by branches of the L1-L3 spinal nerves. Iliacus is innervated by the femoral nerve.

Answer 330

Pectineus is located in the proximal anterior thigh, medial to iliopsoas. Some consider it a muscle of the anterior thigh, whilst others consider it part of the medial thigh, because it has features of both. It attaches proximally at the superior pubic ramus and distally on the femur, just inferior to the lesser trochanter, and it flexes and adducts the hip joint.

Answer 331

The medial compartment of the thigh contains five muscles. As a group they primarily act as adductors of the hip and are innervated by the obturator nerve (spinal nerves L2-L4). The adductors play an important role in normal gait as they help to draw the leg towards the midline as we walk

Answer 332

. The muscles of the medial thigh are: ● Adductor brevis ● Adductor longus ● Adductor magnus ● Gracilis ● Obturator externus (As mentioned, some consider pectineus to be part of the medial compartment).

Answer 333

Adductor brevis and adductor longus have similar points of attachment to the pubic bone and the linea aspera. Adductor brevis is deep to longus. The obturator nerve is between them.

Answer 334

Adductor magnus is a large muscle that has an adductor part and a hamstring part. These two parts function differently and have different nerve supplies

Answer 335

The adductor part attaches to the inferior pubic ramus and the linea aspera. It acts as an adductor and is innervated by the obturator nerve.

Answer 336

The hamstring part attaches to the ischial tuberosity and the adductor tubercle. It acts as an extensor of the hip and is innervated by the tibial part of the sciatic nerve.

Answer 337

The adductor hiatus is a gap formed between the distal attachments of the two parts of adductor magnus. The femoral artery and vein travel through the adductor hiatus to enter the posterior thigh.

Answer 338

Gracilis is the most medial muscle. It attaches to the pubic bone and the medial aspect of the tibia. It is a weak adductor and flexor of the hip and a weak flexor of the knee.

Answer 339

Obturator externus is attached to the external surface of the obturator membrane and inserts on the femur near the greater trochanter. It stabilises and laterally rotates the hip joint.

Answer 340

The posterior compartment of the thigh contains four muscles. These are: ● Semimembranosus and semitendinosus ● Biceps femoris (a long and a short head) ● Hamstring part of adductor magnus.

Answer 341

Three of these muscles - semimembranosus, semitendinosus, and the long head of biceps femoris - span both the hip and knee joints and are referred to as the ‘hamstrings’. As a group, these muscles are attached proximally to the ischial tuberosity, they extend the hip and flex the knee and they are innervated by the tibial part of the sciatic nerve.

Answer 342

Semimembranosus and semitendinosus insert on the medial aspect of the proximal tibia, whereas the long head of biceps femoris forms a common tendon with the short head and inserts onto the head of the fibula.

Answer 343

The short head of biceps femoris arises from the linea aspera, therefore it flexes the knee, but does not move the hip joint. It is innervated by the common fibular part of the sciatic nerve.

Answer 344

The hamstring part of adductor magnus arises from the ischial tuberosity and inserts onto the adductor tubercle of the femur, therefore it extends the hip but does not move the knee joint. It is innervated by the tibial part of the sciatic nerve.

Answer 345

● lateral - formed by the medial border of sartorius. ● medial - formed by the lateral border of adductor longus. ● superior - formed by the inguinal ligament. ● The apex is distal, where sartorius and adductor longus meet. ● The floor of the triangle is formed by iliopsoas laterally and pectineus medially.

Answer 346

● The femoral artery can be palpated and accessed for clinical procedures in the femoral triangle. ● The femoral vein is located medial to the femoral artery. It receives an important tributary in the femoral triangle – a superficial vein called the great saphenous vein. ● The femoral nerve is located lateral to the femoral artery. It travels deep to the inguinal ligament to enter the anterior thigh.

Answer 347

The femoral artery and vein are located superficially in the femoral triangle. This means they may be vulnerable to penetrating injuries, but they are also quite easily accessible for clinical procedures.

Answer 348

From lateral to medial, they are Nerve, Artery, Vein. More medially, there are Lymphatics so the mnemonic NAVaL is used to remember the order from lateral to medial.

Answer 349

Posteriorly, the gluteal muscles are supplied by the superior and inferior gluteal arteries, which are branches of the internal iliac artery. They leave the pelvis via the greater sciatic foramen to enter the gluteal region.

Answer 350

Anteriorly, the femoral artery is the continuation of the external iliac artery. It travels deep to the inguinal ligament to enter the proximal anterior thigh. It is located relatively superficially here and can be palpated

Answer 351

Branch of the femoral artery which travels deep into the thigh and supplies it. The femoral artery continues distally, traverses the adductor hiatus, and enters the distal part of the posterior thigh where it becomes the popliteal artery.

Answer 352

Medially, the obturator artery is a branch of the internal iliac artery. It travels through the obturator canal into the medial compartment of the thigh. It anastomoses with branches from the femoral artery.

Answer 353

There is no large artery in the upper posterior thigh. The hamstring muscles are supplied by three or four perforating arteries that arise from the profunda femoris. These perforating arteries travel through small apertures in the adductor magnus to reach the posterior compartment.

Answer 354

Posteriorly, superior and inferior gluteal veins follow the corresponding arteries through the greater sciatic foramen into the pelvis. They drain into the internal iliac vein.

Answer 355

Anteriorly, the femoral vein follows the course of the femoral artery. It is located medial to the femoral artery in the proximal thigh. The femoral vein is a continuation of the popliteal vein after it leaves the popliteal fossa (behind the knee joint) and enters the anterior thigh via the adductor hiatus.

Answer 356

This vessel – now the femoral vein – ascends through the anterior thigh. It receives the great saphenous vein in the femoral triangle before travelling under the inguinal ligament to become the external iliac vein.

Answer 357

The obturator vein follows the course of the obturator artery. It travels through the obturator canal and joins the internal iliac vein in the pelvis.

Answer 358

The gluteal muscles are innervated by the superior and inferior gluteal nerves. These nerves leave the sacral plexus in the pelvis and travel through the greater sciatic foramen to enter the gluteal region.

Answer 359

The femoral nerve is formed from the L2 - L4 spinal nerves. It travels deep to the inguinal ligament to enter the proximal anterior thigh lateral to the femoral artery. Branches innervate the anterior thigh muscles. The saphenous nerve is a sensory branch of the femoral nerve that innervates skin over the leg.

Answer 360

The obturator nerve is also formed from the L2 – L4 spinal nerves. It travels along the lateral wall of the pelvis and exits through the obturator canal. It emerges onto the superficial surface of adductor brevis and gives rise to branches that innervate the medial compartment muscles and skin over the medial thigh.

Answer 361

The sciatic nerve is a large nerve composed of fibres from the L4 – S3 spinal nerves. It leaves the pelvis via the greater sciatic foramen and enters the gluteal region inferior to the lower border of piriformis. The nerve is really composed of two separate nerves bound together – the tibial nerve and the common fibular nerve.

Answer 362

The tibial nerve innervates the muscles of the posterior thigh and posterior leg. The common fibular nerve innervates the muscles of the anterior and lateral leg. Thus, a lesion of the sciatic nerve can result in severe functional deficits.

Answer 363

The femoral artery can be accessed in the femoral triangle. This is very commonly undertaken for angiography. The femoral vein is medial to the femoral artery. Using knowledge of anatomy and surface landmarks, in emergency situations, it can be easily accessed for blood samples if they cannot be obtained from peripheral veins.

Answer 364

This is a commonly performed procedure in the emergency department where a relatively large volume (around 30-40ml) of local anaesthetic is injected, usually under ultrasound guidance, just underneath the fascia of the iliacus muscle near the femoral triangle. In this ‘compartment’, there are several nerves that carry pain sensation from the around the neck of the femur, including the femoral and obturator nerves, so it is performed to provide analgesia (pain relief) to patients that have sustained a neck of femur fracture. Care must be taken not to accidentally inject the anaesthetic into an artery or vein.

Answer 365

Similar to an inguinal hernia, this is an abnormal protrusion of intestine into the upper anterior thigh. It is more common in females. The intestine passes deep to the inguinal ligament and causes a lump to appear just distal to the inguinal region. Strangulation of the herniated intestine leads to ischaemia and infarction of the tissue.

Answer 366

Along its course on the lateral wall of the pelvis, the obturator nerve runs close to the ovary. Ovarian pathology, such as a cyst, may irritate the nerve. This typically results in sensory abnormalities (tingling, itching or pain) in the medial thigh.

Answer 367

Gluteus maximus is a common site for intramuscular injection, but the sciatic nerve must be avoided. Given the position of the nerve deep to the gluteal muscles, the only safe place to give an injection is into the upper outer quadrant of the buttock to safely avoid the sciatic nerve.

Answer 368

This term is in common use and describes pain that is felt in the posterior thigh and leg due to compression of nerve roots that contribute to the sciatic nerve (L4 - S3). Most commonly it is the result of a prolapsed (‘slipped’) intervertebral disc between L5 and S1

Answer 369

The leg contains two bones, the tibia and fibula. They are connected via two joints and a strong interosseous membrane. The distal ends of both bones articulate with the talus at the ankle joint.

Answer 370

The tibia is a thick and strong bone. Its expanded proximal end articulates with the femur to form the knee joint. Its distal end is tapered and articulates with the talus and fibula.

Answer 371

The proximal part of the tibia forms medial and lateral tibial condyles. The superior surfaces of the condyles, the medial and lateral tibial plateaus, are flattened. They articulate with the femoral condyles to form the knee joint

Answer 372

The intercondylar tubercles are prominent ridges located between the tibial plateaus.

Answer 373

The tibial tuberosity projects from the upper anterior surface of the tibia and is easily palpable through the skin. The patellar ligament inserts here.

Answer 374

Distal to the tibial tuberosity, the sharp anterior border of the shaft of the tibia is easily palpable through the skin.

Answer 375

Posteriorly, the soleal line is an oblique ridge on the posterior surface of the tibia.

Answer 376

Distally, the medial malleolus projects medially from the distal end of the bone and forms part of the ‘socket’ for the talus

Answer 377

The fibula is a slender bone. Its proximal end does not contribute to the knee joint.

Answer 378

Its proximal end does not contribute to the knee joint. The proximal part of the fibula is expanded and forms the head, which is palpable through the skin and the neck is located just distal to the head. The common fibular nerve runs close to the bone here.

Answer 379

The shaft of the fibula is slender and is an attachment site for muscles. Distally, the lateral malleolus projects from the distal end of the bone and forms part of the ‘socket’ for the talus.

Answer 380

The human foot carries the weight of the body and is adapted for bipedal gait. The small joints of the foot allow it to deform and absorb shock when walking over uneven ground. Part of the sole of the foot does not make contact with the ground when we stand but is raised by the longitudinal and transverse arches of the foot. These are formed by the arrangement of the bones of the foot and allow shock absorption. The arches are supported by ligaments and tendons in the foot.

Answer 381

The tarsal bones comprise the following: the talus, calcaneus (heel bone), navicular, cuboid and three cuneiforms (medial, intermediate, and lateral).

Answer 382

The talus articulates with the tibia and fibula at the ankle joint.

Answer 383

Talus and calcaneus

Answer 384

Navicular, cuboid and cuneiforms

Answer 385

The metatarsals and phalanges comprise the forefoot. The metatarsals are numbered 1 – 5 from the medial (great toe) side to the lateral (little toe) side.

Answer 386

Just like in the hand, the bones of the digits (toes) are phalanges (singular = phalanx). There are three phalanges in toes 2-5 and two phalanges in the great toe (digit 1). The three phalanges of the toes are named proximal, middle, and distal. The two phalanges of the great toe are named proximal and distal.

Answer 387

Located between the metatarsals and the proximal phalanges

Answer 388

Are located between the phalanges of the toes

Answer 389

The great toe contains only two phalanges and so there is only one joint between them – this is the interphalangeal joint of the great toe (IPJ). Toes 2-5 contain three phalanges and so there are two joints between them: the proximal interphalangeal joint between the proximal and middle phalanx (PIPJ) and the distal interphalangeal joint between the middle and distal phalanx (DIPJ).

Answer 390

● Flexion and extension ● Abduction (moving the toes apart) and adduction (bringing the toes together).

Answer 391

Flexion at the MTP joints, especially the MTP joint of the great toe, is important for pushing the foot off the ground and forward propulsion during walking and running.

Answer 392

The ankle is a synovial hinge joint formed by the articulation between the distal tibia, distal fibula, and the talus.

Answer 393

The socket formed by the tibia and fibula for the talus is called the ankle mortise.

Answer 394

To ‘grip’ the talus.

Answer 395

There two movements that occur at the ankle joint are: ● Dorsiflexion (bringing the toes closer to the shin). ● Plantarflexion (pointing the toes). Note that there is no ‘extension’ of the ankle joint, only two different types of flexion. Both are vital for normal gait.

Answer 396

Three key ligaments support the lateral aspect of the ankle joint, and they all attach to the lateral malleolus. They are the anterior talofibular, posterior talofibular and the calcaneofibular. However, we will simply think of them as the lateral ligaments of the ankle.

Answer 397

Several ligaments support the medial aspect of the ankle joint. They all attach to the medial malleolus. We can think of them simply as the medial ligament of the ankle; this is often also referred to as the deltoid ligament, because of the overall shape of the ligaments as a group.

Answer 398

This joint is formed by the articulation of the talus with the calcaneum and navicular. It is at this joint that inversion and eversion of the foot takes place. Inversion and eversion are important in allowing us to walk on uneven ground. Forced inversion and eversion often sprain the ligaments of the ankle.

Answer 399

Brings the sole of the foot medially

Answer 400

Raises the lateral border of the foot and brings the sole of the foot laterally.

Answer 401

High energy forces are required to fracture a healthy tibia. When the tibia fractures, the broken ends of the bone may break through the skin because there is little subcutaneous tissue between the anterior surface of the tibia and skin. If a there is broken skin overlying a fracture, or the bone penetrates out through the skin, it is called an ‘open’ or ‘compound’ fracture. Open fractures must be managed carefully to prevent infection from entering the exposed bone and ensuring the skin heals over the surface.

Answer 402

In critical emergency situations, where vascular access is required immediately to provide life-saving treatment directly into the bloodstream, and there is difficulty or delay in accessing peripheral veins, vascular access can be gained through the bone. The flat antero-medial part of the proximal tibia is a common site for IO access. A small handheld drill is used to ‘drill’ a cannula into the bone, and into the medullary cavity, providing a route to give treatment.

Answer 403

Ankle sprains are very common and almost always result from a forced inversion of the foot. Forced inversion stretches and tears the lateral ligament of the ankle, resulting in pain and swelling over the lateral aspect of the ankle and foot.

Answer 404

An ankle fracture refers to a fracture of the lateral and/or medial malleolus. Small lateral malleolus fractures, depending on their exact location, may be treated conservatively (without surgery). However, medial malleolus fractures and more proximal lateral malleolus fractures, or fractures with a dislocation of the ankle joint will require surgical fixation.

Answer 405

This is a diamond-shaped depression behind the knee joint. The two superior borders are formed by semimembranosus and semitendinosus medially, and biceps femoris laterally. The inferomedial and inferolateral borders are formed by the two heads of gastrocnemius, a superficial muscle in the posterior leg.

Answer 406

Popliteal artery Popliteal vein Tibial nerve Common fibular (peroneal) nerve

Answer 407

The continuation of the femoral artery. It traverses the adductor hiatus to enter the popliteal fossa. It is possible to palpate the popliteal pulse in the fossa, but it can be difficult. It bifurcates into the anterior and posterior tibial arteries, which supply the leg.

Answer 408

Formed by the deep veins of the leg. It traverses the adductor hiatus and continues proximally as the femoral vein.

Answer 409

This nerve descends through the midline of the fossa and innervates the muscles of the posterior leg.

Answer 410

this nerve travels along the superolateral border of the popliteal fossa, alongside the tendon of biceps femoris. It wraps around the neck of the fibula and then splits into a superficial and a deep branch. The superficial fibular nerve innervates the muscles of the lateral leg, and the deep fibular nerve innervates the muscles of the anterior leg.

Answer 411

The leg is located between the knee and ankle joints. Deep fascia surrounds the leg like a sleeve. Intermuscular septa extend from the deep fascia and separate the leg into anterior, lateral, and posterior compartments.

Answer 412

The anterior compartment of the leg contains three muscles which arise from the tibia, fibula, and interosseous membrane. They primarily act as dorsiflexors of the foot at the ankle joint and extensors of the toes and they are innervated by the deep fibular nerve.

Answer 413

● Tibialis anterior ● Extensor hallucis longus (EHL) ● Extensor digitorum longus (EDL).

Answer 414

Crosses the anterior aspect of the ankle and inserts onto the medial cuneiform. It dorsiflexes and inverts the foot.

Answer 415

Extends the great toe. Its tendon crosses the anterior aspect of the ankle and inserts onto the distal phalanx of the great toe. It also dorsiflexes the foot.

Answer 416

Extensor digitorum longus gives rise to four tendons. They cross the anterior aspect of the ankle and insert onto the distal phalanges of toes 2-5, extending them. It also dorsiflexes the foot at the ankle joint. Extensor retinacula cover the extensor tendons at the ankle joint.

Answer 417

Extends from the fibula to the base of the 5th metatarsal. Due to its position, it is able to weakly dorsiflex and evert the foot. It is relatively small, weak and is not present in all patients. You may find it on some of the models in the MTU.

Answer 418

The lateral compartment of the leg contains two muscles that attach to the fibula. They evert the foot at the subtalar joint and are innervated by the superficial fibular nerve. The muscles of the lateral compartment are fibularis longus and fibularis brevis. (In some older textbooks these muscles are called peroneus longus and brevis).

Answer 419

Is the more superficial muscle. It inserts onto the plantar surface of the medial cuneiform bone.

Answer 420

Is the deeper muscle of the two. It inserts onto the base of the 5th metatarsal. The tendons of both muscles travel posterior to the lateral malleolus to their insertions in the foot.

Answer 421

The posterior compartment of the leg contains a superficial and a deep group of muscles. They primarily act as plantarflexors of the foot at the ankle joint and flexors of the toes. They are all innervated by the tibial nerve.

Answer 422

There are three superficial muscles: gastrocnemius, soleus and plantaris. The tendons of all three muscles insert onto the calcaneus via the calcaneal (Achilles) tendon. The ‘Achilles’ tendon is so called as a reference to the hero of popular Greek mythology whose heel was his only vulnerable part.

Answer 423

Is the most superficial muscle of the leg. It attaches via two heads to the distal femur. This means it can flex the knee in addition to plantarflexing the ankle.

Answer 424

Is a large, flat muscle that is deep to gastrocnemius. It is attached to the soleal line of the tibia. Contraction of soleus compresses the deep veins of the leg and is important for venous return. The name ‘soleus’ is derived from the Latin for ‘sandal’. When removed, soleus has a very flat, foot-shaped appearance similar to that of a sandal.

Answer 425

Is a very small muscle that is located close to the popliteal fossa. It gives rise to a very long, thin tendon which merges with the calcaneal tendon. Plantaris, like palmaris longus in the forearm, is a non-essential muscle as its primary function can be carried out by other, stronger muscles. For this reason, the tendon of plantaris can be harvested and used to repair or replace damaged ligaments or tendons as a graft.

Answer 426

There are four deep muscles: popliteus, tibialis posterior, flexor hallucis longus (FHL) and flexor digitorum longus (FDL). The tendons of the latter three muscles all travel posterior to the medial malleolus and insert into the plantar surface of the bones of the foot.

Answer 427

Is located deep in the popliteal fossa. It is attached to the tibia and the femur. It allows for a small degree of rotation of the knee. As discussed in the last session, to help us to stand for long periods, the femur rotates a very small amount as the knee reaches full extension. This means the knee ‘locks’ in place and becomes very stable. Popliteus is responsible for ‘unlocking’ the knee by rotating the femur back again to permit flexion.

Answer 428

Plantarflexes and inverts the foot. Its tendon attaches to multiple bones in the foot.

Answer 429

Flexes the great toe via its insertion onto the distal phalanx. It also plantarflexes the foot.

Answer 430

Gives rise to four tendons that insert onto the distal phalanges of toes 2-5. Its primary action is flexion of the toes, but it also plantarflexes the foot.

Answer 431

The dorsum of the foot is similar to the hand in that superficial veins and extensor tendons are usually visible under the skin. The dorsum of the foot also contains a small muscle called extensor digitorum brevis. It is located laterally and inserts onto the tendons of EDL that correspond to toes 2 – 4. It is innervated by the deep fibular nerve.

Answer 432

The plantar aspect of the foot contains numerous intrinsic muscles, much like the palm of the hand. They are arranged in four layers and mirror those of the palm. They include abductors of the great and smaller toes, flexors of the toes, an adductor of the great toe, lumbricals and interossei. They are innervated by the medial and lateral plantar nerves, which are the terminal branches of the tibial nerve.

Answer 433

The popliteal artery bifurcates in the popliteal fossa into anterior and posterior tibial arteries

Answer 434

The anterior tibial artery pierces the interosseous membrane to enter the anterior compartment of the leg, which it supplies. Distally, it crosses the anterior aspect of the ankle joint and enters the dorsum of the foot.

Answer 435

In the dorsum of the foot, the artery is called the dorsalis pedis artery, and is palpable in the foot lateral to the tendon of extensor hallucis longus. The dorsalis pedis artery gives rise to branches that travel between the metatarsals and anastomose with arteries in the plantar aspect of the foot.

Answer 436

The posterior tibial artery supplies the posterior compartment of the leg and sole of the foot. The posterior tibial artery travels posterior to the medial malleolus, along with the tendons of tibialis posterior, FHL and FDL to enter the plantar aspect of the foot. The artery is palpable here.

Answer 437

Comes from the posterior tibial artery and supplies the lateral compartment

Answer 438

Into medial and lateral plantar arteries, which supply the sole.

Answer 439

Branches of the dorsalis pedis artery, which enter the sole of the foot from the dorsum, anastomose with branches of the plantar arteries. The deep plantar arch is an important vessel formed by the lateral plantar artery and a branch of the dorsalis pedis. Metatarsal and digital arteries supply the forefoot and toes.

Answer 440

The posterior tibial, anterior tibial and fibular arteries are accompanied by deep veins. These veins unite to form the popliteal vein.

Answer 441

The dorsal venous network of the foot drains medially to the great saphenous vein. The great saphenous vein travels anterior to the medial malleolus and courses all the way up the medial aspect of the lower limb to its termination at the femoral vein in the femoral triangle.

Answer 442

The dorsal venous network of the foot also drains laterally to the small saphenous vein. The small saphenous vein travels posterior to the lateral malleolus and courses up the posterior aspect of the leg to its termination at the popliteal vein in the popliteal fossa.

Answer 443

After leaving the popliteal fossa, the common fibular nerve wraps around the neck of the fibula and divides into two branches – the superficial and deep fibular nerves. ● The superficial fibular nerve innervates the muscles of the lateral leg. ● The deep fibular nerve innervates the muscles of the anterior leg.

Answer 444

The common fibular nerve and its branches provide sensory innervation the skin over the anterolateral leg and dorsum of the foot.

Answer 445

After leaving the popliteal fossa, the tibial nerve travels vertically distal into the posterior compartment of the leg and it innervates all the muscles in the posterior compartment of the leg and plantar surface of the foot. At the ankle, it travels posterior to the medial malleolus along with the tendons of tibialis posterior, FHL and FDL.

Answer 446

It enters the sole of the foot and divides into two branches: the medial and lateral plantar nerves, which travel along the medial and lateral aspects of the sole of the foot, respectively, alongside the corresponding arteries of the same name. These nerves innervate all the intrinsic muscles in the plantar aspect of the foot. The digital nerves branch from the plantar nerves and supply the toes.

Answer 447

The tibial nerve innervates most of the skin on the plantar surface of the foot.

Answer 448

Like the carpal tunnel in the wrist, the tendons of the deep posterior compartment of the leg travel into the foot through a tunnel covered by a flexor retinaculum, which, in this case connects the medial malleolus to the calcaneus. The tunnel created is called the ‘tarsal tunnel’.

Answer 449

* Tibialis posterior tendon. * Flexor digitorum longus tendon. * Posterior tibial artery. * Posterior tibial vein. * Tibial nerve. * Flexor hallucis longus tendon. The contents of the tarsal tunnel in this order can be remembered using the mnemonic: ‘Tom, Dick And Very Nervous Harry’.

Answer 450

Just as in the upper limb, these are the approximate territories of each nerve and there is some variation between individuals. However, testing sensation over these areas of skin should allow us to assess the integrity of the corresponding nerves

Answer 451

● Femoral: anterior thigh and anteromedial leg (via the saphenous nerve). ● Obturator: medial thigh. ● Common fibular: anterolateral leg and dorsum of the foot. ● Superficial fibular: lower anterolateral leg, most of the dorsum of the foot. ● Deep fibular: 1st interdigital webspace. ● Tibial nerve: sole of the foot

Answer 452

Just as in the upper limb, the territories of skin supplied by the peripheral nerves are different to those innervated by spinal nerves due to the ‘shuffling’ of nerve fibres in the lumbar plexus. On the anterior surface of the lower limb the dermatomes are arranged in roughly oblique ‘strips’, running inferiorly from the lateral aspect of the lower limb to the medial aspect. On the posterior aspect of the lower limb, the dermatomes are arranged more vertically.

Answer 453

Over the inguinal ligament

Answer 454

Proximal half of the anterior thigh.

Answer 455

Distal anterior thigh and the medial aspect of the knee.

Answer 456

Lateral thigh, anterior knee, anteromedial leg, medial malleolus, medial foot, and great toe.

Answer 457

Lateral leg, distal anterior leg, dorsal and plantar strip down the middle of the foot, and the dorsal and plantar surfaces of toes 2-4

Answer 458

Vertical strip of skin in the middle of the posterior thigh and leg, distal lateral leg, lateral malleolus, and little toe.

Answer 459

Vertical strip of skin over the posterior aspect of the thigh and leg, plantar strip of skin on the foot and the heel

Answer 460

* L1: region over the inguinal ligament * L2: upper anterior thigh * L3: medial aspect of the knee * L4: anteromedial leg * L5: anterolateral leg * S1: little toe / lateral side of the foot.

Answer 461

The common fibular nerve is located relatively superficially as it wraps around the neck of the fibula. Fractures of the fibular neck, caused by a lateral blow to the leg, can injure the nerve. This leads to weakness of the anterior and lateral leg muscles. The foot cannot be dorsiflexed, and the toes will drag on the ground when walking. This condition is called foot drop. Patients may compensate either by lifting the leg higher when walking (by flexing the hip and knee to a greater degree) or by swinging the affected leg out laterally – both allow the toes to clear the ground without catching.

Answer 462

Thrombus, or clot, can develop in the deep veins of the leg. If this occurs, venous return from the leg is impaired, causing swelling, pain, redness, and warmth of the affected leg. It is important to recognise and treat DVT, as the clot may migrate proximally and enter the pulmonary circulation, causing pulmonary embolism – a potentially fatal condition.

Answer 463

The typical mechanism of this injury is a sudden, forceful plantarflexion of the ankle, such as pushing off from the ground to jump or run, or by sudden, forceful dorsiflexion of the ankle, stretching the calcaneal tendon. Patients present with pain and altered gait, as they cannot plantarflex the foot to push-off from the ground when walking.

Answer 464

Because the deep fascia and intermuscular septa of the leg do not stretch, swelling in one of the compartments of the leg (e.g. caused by oedema or bleeding) increases pressure in the compartment and compresses muscles, nerves, and blood vessels. Once the pressure exceeds capillary perfusion pressure, ischaemia and infarction of the tissues occurs if not treated promptly by releasing the fascia (fasciotomy).

Answer 465

The pulsation of the dorsalis pedis artery is usually palpable over the dorsum of the foot, just lateral to the tendon of extensor hallucis longus, between the first and second metatarsals. The pulse of the posterior tibial artery is palpable posterior to the medial malleolus. It is important to be able to palpate both pulses when examining a patient’s vascular system.

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