Session 3

Question 1

What are the functions of the skeleton?

Answer 1

Support, protection, movement, mineral & growth factor storage and heamatopoeisis.

Question 2

List the different classifications of bones by shape

Answer 2

Long - eg femur
Short - eg carpal
Sesamoid - embedded within a tendon or muscle, eg patella
Flat - eg frontal bone of cranium
Irregular - eg vertebra
Sutural bone - within a cranial suture

Question 3

Describe the blood supply to long bones

Answer 3

Metaphyseal arteries enter metaphysis at the site of attachment of the capsule. Periosteal arteries supply the periosteum and 1/3 of the cortex. The nutrient artery enters the diaphysis via the nutrient foramen.

Question 4

How many bones are in the vertebral column, upper limb and lower limb?

Answer 4

26 vertebral
64 upper limb
62 lower limb

Question 5

What are the different structural classifications of joints?

Answer 5

Fibrous
Cartilaginous
Synovial

Question 6

What are the different functional classifications of joints?

Answer 6

Synarthrosis - immovable
Amphiarthrosis - slightly moveable
Diarthrosis - freely moveable

Question 7

What are the 3 different types of fibrous joints?

Answer 7

Suture - restricted to cranium. Synostosis (fusion) on completion of growth.
Syndesmosis - amphiarthrosis, two bones held together by connective tissue. Examples include inferior tibiofibular joint and radioulnar interosseous membrane.
Gomphosis - immovable joint between teeth and maxilla/mandible

Question 8

What are the different types of cartilaginous joints?

Answer 8

Primary cartilaginous joint - hyaline cartilage, synarthrosis. Eg 1st sternocostal joint, ephyseal growth plates
Secondary cartilaginous joint - fibrocartilage, amphiarthrosis. Eg intervertebral disc, pubic symphysis

Question 9

What are the characteristics of a synovial joint?

Answer 9

Articular hyaline cartilage (sternoclavicular, acromioclavicular, temporomandibular joints are fibrocartilage).
Fibrous capsule completely enclosing joint with longitudinal and interlacing collagen bundles - stabilises joint.
Thin, highly vascularised synovial membrane that lines the capsule and covers exposed osseous surfaces, tendon sheaths and bursa. Does not cover articular cartilage. Produces synovial fluid.
Clear synovial fluid composed of hyaluronic acid, lubricin,proteinase and collagenase. It reduces friction, absorbs shock and transports nutrients and waste.

Question 10

What are bursae and tendon sheaths?

Answer 10

A bursa is a sac filled with synovial fluid. They can be communicating for non-communicating with the joint cavity.
A tendon sheath is an elongated bursa wrapped around a tendon.

Question 11

Describe the blood supply over synovial joints

Answer 11

Periarticular arterial plexus. Articular cartilage is avascular. Fibrous cartilage and ligaments have poor blood supply. Synovial membrane has rich blood supply.

Question 12

What is Hilton’s law?

Answer 12

The nerves supplying the joint capsule also supply the muscles moving the joint and the skin overlying the insertions of these muscles.

Question 13

What are the different types of synovial joint? & examples

Answer 13

Pivot - uniaxial, eg proximal radioulnar joint and atlantoaxial joint
Hinge - uniaxial
Saddle - biaxial joint, one bone is concavoconvex, eg 1st carpometacarpal joint
Planar - flat articulating surface, sliding movements, no axis of movement. Eg sternoclavicular, acromioclavicular, intercarpal and vertebral facet joints.
Condyloid - biaxial joint, oval shaped condyle of one bone rests on the elliptical cavity of another. Eg metacarpophalangeal, radiocarpal joints
Ball and socket

Question 14

What are the effects of ageing on joints?

Answer 14

Decreased production of synovial fluid. Thinning of articular cartilage. Shortening of ligaments and decreased flexibility.

Question 15

What are the signs and symptoms of arthritis?

Answer 15

Pain, swelling, stiffness, redness

Question 16

What is rheumatoid arthritis?

Answer 16

An auto immune disorder where antibodies attack the synovium. Women more commonly affected. Joint erosion and deformity - MCP and PIP joints of hands, cervical spine, feet, can involve large joints.

Question 17

Describe the articulation of the glenohumeral joint

Answer 17

The large round humeral head articulates with the shallow glenoid cavity of the scapula, which is deepened by the glenoid labrum.

Question 18

What factors contribute to the stability of the shoulder joint?

Answer 18

Rotator cuff muscles - their resting tone acts to pull the humeral head into the glenoid cavity.
Glenoid labrum - a fibrocartilaginous ridge surrounding and deepening the glenoid cavity.
Ligaments
Lesser extent - deltoid, long head of triceps and long head of biceps

Question 19

Where does the glenohumeral joint capsule attach?

Answer 19

Glenoid labrum to anatomical neck of humerus

Question 20

Why does the joint capsule of the shoulder joint have a small opening anteriorly?

Answer 20

Allows the synovial membrane to communicate with the subscapular bursa

Question 21

What are the ligaments involved in stabilising the shoulder joint?

Answer 21

Glenohumeral ligaments (superior, middle and inferior) - part of the fibrous capsule. Stabilise the anterior aspect of the joint.
Coracohumeral ligament - attaches the base of the Coracoid process to the greater tubercule of the humerus. Supports the superior part of the joint capsule.
Transverse humeral ligament - spans between the two tubercules, holds the tendon of the long head of the biceps in place.
Coracoacromial ligament - forms the coraco-acromial arch which overlies the shoulder joint to prevent superior displacement of humerus.

Question 22

What are the two clinically important bursa in the shoulder joint?

Answer 22

Subacromial - located inferiorly to the deltoid and acromion and superiority to the supraspinatus tendon. It facilitates movement of these muscles. Inflammation causes painful arch syndrome.
Subscapular - located between the subscapularis tendon and the scapula, reducing wear and tear

Question 23

Outline the movements at the shoulder joint and the muscles that produce them.

Answer 23

Flexion - clavicular head of pectoralis major, anterior deltoid, coracobrachialis and both heads of biceps brachii.
Extension - posterior deltoid, latissimus dorsi and teres major.
Abduction - first 15 degrees by supraspinatus. Middle deltoid up to 90 degrees. After this the trapezius and serratus anterior rotate the scapula.
Adduction - pectoralis major, latissimus dorsi and teres major
Medial rotation - subscapularis, teres major, pectoralis major and latissimus dorsi.
Lateral rotation - infraspinatus and teres minor.

Question 24

Outline the neurovascular supply to the shoulder joint

Answer 24

Arterial supply via the posterior humeral and Suprascapular arteries. They form an Anastamotic network around the joint.
Nervous supply via the Suprascapular, axillary and lateral pectoral nerves (C5&6)

Question 25

What direction is the shoulder most commonly dislocated? How is this caused?

Answer 25

Inferior - described as anterior dislocation because the humeral head locates anteriorly due to the pull of powerful adductors. Usually caused by excessive extension and lateral rotation of the humerus or by trauma on fully abducted arm.

Question 26

Why does one dislocation increase the risk of further shoulder dislocations?

Answer 26

Tearing of the joint capsule

Question 27

What nerve damage can result from a shoulder dislocation?

Answer 27

Axillary nerve.

Question 28

What is rotator cuff tendinitis and how is it detected?

Answer 28

Inflammation of the muscle tendons, usually die to overuse. Causes degenerative changes in the subacromial bursa and supraspinatus tendon, increasing friction between structures. Results in pain during 50-130 degrees of abduction, due to impingement between acromion and head of humerus.

Question 29

How is the accessory nerve damaged and assessed?

Answer 29

Iatrogenic. Ask patient to shrug shoulders against resistance (trapezius).

Question 30

What are the superficial and deep extrinsic muscles of the shoulder?

Answer 30

Superficial - trapezius and latissimus dorsi | Deep - levator scapulae, rhomboid minor and rhomboid major

Question 31

How many muscles are in each layer in the anterior forearm?

Answer 31

Superficial - 4. Intermediate - 1. Deep - 3. | 4-1=3

Question 32

Why is the flexor digitorum superficialis a useful anatomical landmark?

Answer 32

The median nerve and ulnar artery pass between its two heads

Question 33

What nerve innervates the deep muscles of the anterior forearm?

Answer 33

Anterior interosseous branch of the median nerve

Question 34

What structures form the border of the carpal tunnel?

Answer 34

Carpal arch - concave on the palmar side. Formed laterally by scaphoid and trapezium tubercules. Formed medially by the hook of hamate and the pisiform. Flexor retinaculum - thick connective tissue that bridges between the medial and lateral parts of the arch.

Question 35

What is the contents of the carpal tunnel?

Answer 35

The tendon of flexor pollicis longus, surrounded by its own synovial sheath. The 4 tendons of the flexor digitorum superficialis and the 4 tendons of the flexor digitorum profundus, surrounded by a single synovial sheath. Median nerve

Question 36

What tendon is commonly confused as being in the carpal tunnel?

Answer 36

Flexor carpi radialis - located within the flexor retinaculum .

Question 37

What causes carpel tunnel syndrome and how does it present?

Answer 37

Compression of the median nerve in the carpal tunnel due to thickened ligaments and tendon sheaths. Weakness and atrophy of the thenar muscles - progressive loss of strength and coordination of the thumb Paresthesia, hypoesthesia and anesthesia of the palmar surface and fingertips of the lateral 3.5 digits. The Palm is not affected because the palmar cutaneous branch of the median nerve does not pass through the carpal tunnel.

Question 38

How is carpal tunnel syndrome tested and treated?

Answer 38

Tinel's sign - tapping the nerve in the carpal tunnel to elicit pain in median nerve distribution Phalen's manoeuvre - hold the wrist in flexion for 60 seconds to elicit pain/numbness in median nerve distribution Treatment involves using s splint to hold the wrist in dorsiflexion overnight. Corticosteroid injections or even carpal tunnel release tunnel surgery in severe cases.

Question 39

What type of synovial joint is the sternoclavicular joint and what are its articulations?

Answer 39

Saddle. Sternal end of the Clavicle, manubrium and 1st costal cartilage.

Question 40

What ligaments are present in the sternoclavicular joint?

Answer 40

Anterior and posterior sternoclavicular ligaments - strengthen the joint capsule anteriorly and posteriorly Interclavicular ligament - spans the gap between the sternal ends of each clavicle and strengthens the joint capsule superiorly. Costoclavicular ligament - joins the 1st rib and cartilage to the anterior and posterior borders of the clavicle.

Question 41

Outline the neurovascular supply to the sternoclavicular joint.

Answer 41

Arterial - internal thoracic and Suprascapular arteries | Nervous - medial supraclavicular nerve and the nerve to subclavius

Question 42

Outline the movements at the sternoclavicular joint

Answer 42

``` Elevation of the shoulders - shrugging of abductiong the arm over 90 degrees Depression of the shoulders Protraction of the shoulders Retraction of the shoulders Rotation ```

Question 43

How can the sternoclavicular joint become dislocated and why are they rare?

Answer 43

By a blow to the anterior shoulder (anterior dislocation - more common) or posterior shoulder. Rare because the costoclavicular ligament and the articular disc is effective at absorbing and transmitting forces away from the joint.

Question 44

What type of synovial joint is the acromioclavicular joint and what are its articulations?

Answer 44

Plane. Lateral end of the clavicle and acromion of the scapula.

Question 45

What are the major ligaments of the acromioclavicular joint?

Answer 45

Acromioclavicular - reinforces the joint capsule superiorly Coracoclavicular - made up of the trapezoid and conoid ligaments, effectively suspends the weight of the upper limb from the clavicle

Question 46

Describe the movements of the acromioclavicular joint

Answer 46

A small amount of axial rotation and anteroposterior movement. Passive because no ,uncles act on the joint.

Question 47

Outline the neurovascular supply to the acromioclavicular ligament

Answer 47

Arterial - Suprascapular and thoraco-acromial arteries | Nervous - Suprascapular and lateral pectoral nerves

Question 48

How can a dislocation of the acromioclavicular joint become more serious?

Answer 48

If the coracoclavicular ligament is torn - the weight of the upper limb is not supported and the shoulder moves inferiorly.