Flashcards in Upper Limb Session 1 and 2 Deck (115)
What are the functions of the axilla?
The pyramidal space below the shoulder joint. It provides passageway for vessels and nerves going to and from the upper limb
Outline the anterior wall of the axilla
Formed by Pec. Major and Minor
Outline the posterior wall of the axilla
Scapularis, teres minor and lat. dorsi
Outline the medial wall of the axilla
Thoracic wall and serrates anterior muscles
Outline the lateral wall of the axilla
Intertubercular sulcus of the humerus
Where does the axillary artery originate?
Subclavian artery at the upper margin of the first rib
What does the axillary artery continue as and where does it end?
Continues as the brachial artery beyond the lower border of the teres major muscle
What is the brachial plexus?
A major network of nerves innervating the upper limb
Where does the brachial plexus begin?
Cervical region and extends into the axilla
What forms the brachial plexus?
Ventral rami of C5, C6, C7, C8, T1
Outline the division of the brachial plexus
Roots, trunks, divisions, cords and branches
Read That Damn Cadaver Book
Roots, trunks, divisions, cords and branches
Describe Erb's Point
Site of the superior trunk
Located about 2-3cm above the clavicle
Describe what happens when Erb's point is injured?
Erb's Palsy - characteristic waiters tip where shoulder is internally rotated and wrist is flexed
What is the common aetiology of Erb's Palsy?
Undue separation (hyperextension) of the head from the shoulder - often from birth, falling on shoulder or anaesthesia
What nerve roots form the lower trunk?
C8 and T1
What does injury to the lower trunk cause?
Describe Klumpke's palsy
Intrinsic muscle of the hand are affected and ulnar flexors of the wrist and fingers
What is the common aetiology go Klumpke's palsy?
Undue abdurction of the arm
How are the three cords of the brachial plexus named?
According to their relation to the axillary artery
What are the main branches of the lateral cord?
Lateral pectoral nerve
Lateral root of median nerve
What are the main branches of the medial cord?
Medial pectoral nerve
Medial cut. nerve of the arm
Medial cut. nerve of the forearm
What are the main branches of the posterior cord?
In the upper arm the brachial artery immediately gives rise to what other artery?
Where does the profound brachii arise?
Just distal to the margin of the teres major
Where does the profound brachii travel?
Within the radial groove of the humerus
What other structures accompany the profound brachii in the radial groove?
What does the profound brachii supply?
Structures on the posterior aspect of the arm (principally the triceps muscle)
How does the profounda brachii terminate?
In an anastomosing network of vessels at the elbow joint
The brachial artery descends down the arm immediately posterior to what?
the median nerve
As the brachial a. crosses the cubital fossa it passes under what muscle?
How does the brachial artery terminate?
Bifurcatin into the radial and ulnar arteries
What vein arises from the dorsal venous plexus of the hand on the medial side?
The basilic vein
What happens to the basilic vein at the border of the teres major?
The vein moves deep and coalesces with cephalic vein to form the axillary vein
What vein arises from the dorsal venous plexus of the hand on the anterolateral side?
Outline the course of the cephalic vein
Moves through the deltoid groove between the deltoid and pec. major muscles to join the axillary vein
What is the large communicating vein that shunts blood from the basilic to the cephalic?
Median cubital vein
Axillary lymph nodes are divided into 5-6 distinct groups; name them.
Anterior mammary nodes
What is the pectoral girdle?
A set of bones which connect the upper limb to the axial skeleton on each side
What joint does the upper limb and the shoulder articulate at?
How do you determine the sternal end of the clavicle?
Oval shaped impression on inferior surface (attachement for the costoclavicular ligament)
How do you determine the acromial end of the clavicle?
Small facet for articulation with the acromial processs of the scapula
Coronoid tubercle - insertion for the coronoid ligament (medial part of the CC ligament)
How is the clavicle divided up?
Thirds (middle third being most susceptible to fracture)
What type of joint is the AC and SC joints?
AC - planar synovial
SC - synovial saddle
What is the function of the subscapular fossa?
Attachment for the subscapularis (rotator cuff)
What is the function of the coracoid process?
Attchement for the short head of the biceps brachii, coracobrachialis and pec. minor
What is the function of the glenoid fossa?
Shallow cavity that articulates with the head of the humerus
What is the function of the supraglenoid tubercle?
A roughening immediately superior to the glenoid fossa which serves the origin for the long head of the biceps brachii
What is the function of the infraglenoid tubercle?
A roughening immediately inferior to the glenoid fossa which serves as the origin to the long head of the triceps brachii
What is the function of the acromion?
Projection of the spine that arcehs of the GH joint and articulates with the clavicle
What is the function of the infraspinous fossa?
Slightly convex shape and serves as insertion for the infraspinatous
What is the function of the supraspinous fossa?
More convex shape and serves as the insertion for the supraspinous muscle
What muscles cause elevation of the scapula?
Levator scapulae , upper fibres of the trapezius
What muscles cause depression of the scapula?
Pec. minor, lower fibres of the traps, subscapularis, lat. dorsi
What muscles cause protraction of the scapula?
What muscles cause retraction of the scapula?
Trapezius (middle fibres)
What muscles cause lateral rotation of the scapula?
Upper and middle traps
What muscles cause medial rotation of the scapula?
Gravity, rhomboids, pec. minor
What is the rim of cartilarge around the GH joint called?
What is the function of the Glenoid labrum?
Deepens the joint adn provides more stability
Describe the joint capsule of the GH joint
Thickened to form definable ligaments (superior, middle and inferior)
What true ligaments of the shoulder are there?
Coracoacromial ligament - forms arch from acrominon to the coracoid process and protects the shoulder from superior dislocation
Corcaohumeral ligament - supports superior joint capsule
Describe the bursae of the shoulder
1. Subacrominal - superficial to the supraspinatous tendon and joint capsule and promotes free movement
2. Subscapular - located deep to supscapularis tendon, this bursa freely communicates with the joint capsule
What muscles form the rotator cuff?
Superspinatous, infraspinatous, supscauplaris, teres minor
What is the insertion of the supraspinatous?
Greater tubercle of the humerus
What is the innervation of the supra-infraspinatousa?
What is the only rotator cuff muscle to not insert on the greater tubercle?
Subscapularis (attaches to the lesser tubercle)
What nerve supplies the deltoid muscle?
What is the triangular space between the deltoid and pec. major called? What is its significance?
Deltoid triangle - for placement of central lines into subclavian vein
What nerve supplies the serrates anterior?
Long thoracic nerve
Injury of the long thoracic nerve causes what? What can cause injury of the LT nerve?
Winging of the scapula; breast surgery
What are the function fo the trapezius
Superior fibres -- elevate and rotate the scapula
Middle fibres - retract scapula
Infeior fibres - depress scapula
What is the action of the teres major muscle?
Medially rotate and adduct the arm (as does the lat. dorsi which also extends the arm)
Where does the intertubercular groove run?
Between the greater and lesser tubercles
What is the relevance of the surgical neck of the humerus?
It is a common site of fracture and can lead to injury of the axillary nerve and posterior circumflex artery
What is the insertion fo the deltoid muscle
The deltoid tuberosity
Describe the trochlear of the distal humerus
More medial the the capitulum
Serves as attachment for the ulnar bone
What are the three fossae at the distal part of the humerus?
Olecranon, coronoid and radial fossae
What are the two compartments of the arm?
Flexors (anterior) and extensors (posterior)
Describe the anterior compartment of the arm and it innervation
Three muscles (BBC)
All supplied by the musclulocutaneous nerve
Outline the functions of the biceps brachii
Attaches form the supraglenoid tubercle (long head) and the coracoid process (short head) and both insert into the radial tuberosity
Functions to supinate the forearm and flex at the elbow and shoulder
Outline the functions of the coracobrachialis
Originates from the coracoid process and inserts on the medial aspect of the shaft at the level of the deltoid tuberosity
Acts to flex the arm at the shoulder and its a weak adductor
Outline the functions of the brachialis
Originates on the medial/lateral surfaces of the humeral shaft and attaches to the ulnar tuberosity distal to the elbow
Flexes the elbow
Describe the posterior compartment of the arm
COntains the triceps brachii and the radial nerve
Ling head - originates from the infraglenoid tubercle
Medial head - originates from the humerus, inferior to the radial groove
Lateral head - originates from superior to the radial groove (covers the medial head)
Where does the MC nerve arise from?
Lateral cord of the brachial plexus
How does the MC nerve enter the arm?
Pierces the coracobrachialis and descends between the biceps and the brachilalis
After supplying the muscles of the arm what is the fate of the MC nerve?
Contrinues as the lateral cutaneous nerve of the forearm
What are the segmental roots of the MC nerve?
Where does the median nerve arise from?
Two roots - one from the medial cord and one from the lateral cord
What is the course of the median nerve?
Descends along the lateral side of the axillary nerve and upper brachial artery, crossing over the arm to the medial side of the brachial artery in the mid-arm and enters the cubital fossa giving no branches in the axilla or upper arm
What does the median nerve innervate?
All flexors and pronators of the forearm (except FCU and FDP) and also innervates thenar muscles and the lateral two lumbricals
Where does the ulnar nerve arise?
From the medial cord
What is the course of the ulnar nerve?
Descends along the medial side of the brachial artery and enters the posterior compartment throught the inter-muscular septum; then running along the medial head of the triceps and behind the medial epicondyle
What does the ulnar nerve innervate ?
Nothing in the arm
FCU and medial half go FDP and intrinsic muscles of the hand (bar those innervated by the median nerve)
There are three common sites for nerve injury in the arm: what are they?
Radial nerve - radial groove
Ulnar nerve - medial epicondyle
Axillary nerve - surgical neck
What are the borders of the cubital fossa?
Medial - lateral borders of the pronator teres
Lateral - medial border of the brachioradialis
Superior - imaginary line between the epicondyles
What are the contents of the cubital fossa?
(Aid: Really Need Beer To Be At My Nicest)
Radial Nerve, Biceps Tendon, Brachial Artery, Median Nerve
The common tendon of the triceps inserts where?
The olecranon process
The olecranon process and the coronoid process are both features of what bone?
How does the radial nerve are arise?
It is the terminal branch of the posterior cord of the brachial plexus
What does the radial nerve innervate?
The extensor compartment of the upper arm and forearm
Describe the course of the radial nerve
Enters the arm to the long head of the triceps and runs with the profound brachii, it then curves around the mid-shaft in the radial groove
What are the segmental roots of the radial nerve?
What is the characteristic feature of radial nerve injury
Describe the ligaments of the elbow
Fibrous capsule is thickened on the lateral and medial sides forming the medial (ulnar) collateral ligament and the lateral collateral (radial) ligament
There is also the annular ligament
What ligament hold the head of the radius in place?
Outline the flexors of the elbow joint
Outline the extensors of the elbow joint
Triceps brachii (+ anconeus)
What type of joint are the radio-ulnar joints?
How is pronation/supination allowed?
The head o the radius rotates within the annular ligament
Oultine pronator muscles
Pronator teres and pronator quadratus
Outline supinator muscles
Supinator and biceps brachii
What other muscles assist with pronation?
FCR, PL and brachioradialis
What other muscles assist with supination?