Clinical Anatomy of the Upper Limb Flashcards
What makes up the shoulder girdle?
Clavicle/scapula, sternoclavicular joint, acromioclavicular joint, glenohumeral joint
What are the bones of the upper limb?
Shoulder girdle, humerus, elbow joint, radius/ulna, wrist (radio-carpal joint), carpus, MCPs, MCs, IPs
What muscle group move the shoulder girdle?
Superficial muscles of the back (e.g trapezius)
What is the origin and insertion of trapezius?
Origin = T12 spinous process Insertion = occiput and scapular spine
What innervates trapezius?
Accessory nerve (CN XI)
What are the functions of trapezius?
Elevates and depresses scapula
Retracts scapula
What are some pathologies that can affects the glenohumeral joint?
OA/RA, dislocation, adhesive capsulitis
What is the function of the labrum of the shoulder?
Increases capture of humeral head - increases stability
What do the rotator cuff muscles do as a whole?
Stabilise the shoulder girdle and move the arm
What are the four rotator cuff muscles?
Supraspinatus, infraspinatus, teres minor, subscapularis
What are some features of supraspinatus?
Originates from supraspinous fossa
Innervated by suprascapular nerve (C5/6)
Abducts arm
What are some features of infraspinatus?
Originates from infraspinous fossa
Innervated by suprascapular nerve (C5/6)
Externally rotates arm
What are some features of teres minor?
Originates from dorsal surface of lateral scapular border
Innervated by axillary nerve
Externally rotates the arm
What are some features of subscapularis?
Originates at anterior surface of scapula (scapular fossa)
Innervated by upper and lower subscapular nerves (C5/6)
Internally rotates the arm
Where are the insertions of the rotator cuff muscles?
Greater tuberosity of humerus = supraspinatus, infraspinatus and teres minor
Lesser tuberosity of humerus /shoulder capsule = subscapularis
What pathology may affects the rotator cuff muscles?
Susceptible to tears and impingement
What are the origins of the deltoid muscle?
Clavicle, acromion and scapular spine
Where does the deltoid insert, and what action does it perform?
Inserts at deltoid tuberosity on lateral aspect of humerus
Abducts the arm
What innervates the deltoid muscle?
Axillary nerve (C5/6)
What are the origins and insertion of the biceps brachii?
Origins = coracoid process (short head) and labrum/glenoid (long head) Insertion = tuberosity of radius
What innervates the biceps brachii, and what action does the muscle perform?
Innervated by musculocutaneous nerve (C5/6)
Flexes elbow and supinates forearm
What is the biceps brachii susceptible to?
Tendonitis
What are some pathologies that affect the elbow joint?
Fracture = radial neck/shaft, supracondylar process (especially children), olecranon
Bursitis = olecranon bursa
OA/RA and dislocation
Ligament tears or strains
What ligaments are present at the elbow joint?
Medial collateral, lateral collateral, annular
Where is the site of insertion for all the extensor muscles of the forearm?
Lateral epicondyle of humerus
What compartment of the forearm is the extensor compartment?
Dorsal compartment
Where is the site of insertion for all the flexor muscles of the forearm?
Medial epicondyle of the humerus
What compartment of the forearm is the flexor compartment?
Volar compartment
What bony features of the forearm are visible in supination?
Radial head, radial shaft, radial tuberosity, interosseous membrane, radial styloid, ulna styloid
What bony features of the forearm are visible in pronation?
Olecranon fossa, coranoid process, ulna shaft
What pathologies may affect the wrist?
OA/RA, dislocation, fractures (distal radius, scaphoid)
What are the to groups of muscles that act on the hand?
Intrinsic = located in hand, responsible for fine motor functions of hand Extrinsic = located in anterior and posterior forearm, control finger flexion/extension and wrist movement
What are the intrinsic muscles of the hand?
Thenar muscles, hypothenar muscles, interossei muscles, lumbrical muscles
What muscles make up the thenar muscles?
Opponens pollicis, flexor pollicis brevis, abductor pollicis brevis
What function do the thenar muscles have, and what innervates them?
Move the thumb
Innervated by median nerve
What muscles make up the hypothenar muscles?
Abductor digiti minimi (main one) and flexor digiti minimi brevis
What movements do the interossei muscles carry out?
All flex at MCP joints and extend at IP joints Dorsal interossei (x4) = abduct fingers at MCP joints Palmar interossei (x4) = adduct fingers at MCP joints
What nerve innervates the interossei muscles?
The ulnar nerve
How many lumbricals are there?
Four = one for each finger
Where do the lumbricals allow movement of?
Crucial for finger movement = link flexor and extensor tendons
What is the innervation of the lumbricals?
Median nerve = lateral two
Ulnar nerve = median two
What are the extrinsic muscles of the hand?
Flexor tendons (flexor digitorum profundus) Flexor pulleys = annular ligaments, cruciate pulleys
What action does the flexor digitorum profundus perform?
Extensor flexor muscle of the fingers = flexes fingers at DIPs
What nerves innervate the flexor digitorum profundus?
Anterior interosseous nerve (branch of median nerve - C8,T1) = second and third digits Ulnar nerve (C8,T1) = fourth and fifth digits
Where does the flexor digitorum profundus pass?
Through carpal tunnel, trained to metacarpals/phalanges by a pulley system
What are the two most biochemically important annular ligaments?
A2 and A4 = critical to preventing bowstringing
What structures do some of the annular ligaments overlie?
A1 = MP joint A3 = PIP joint A5 = DIP joint
What annular ligament is most commonly involved in trigger finger?
A1
What is the function of the cruciate pulleys?
Function to prevent sheath collapse and expansion during digital motion
How many cruciate pulleys are there at the level of the joints?
3
What is the function of the palmar fascia?
Separates the palmar muscle bellies and flexor tendons from the skin
What is the palmar fascia susceptible to?
Hypertrophy and fibrosis (Dupuytren’s contracture)
What forms the deep and superficial palmar arches in the hand?
The radial and ulnar arteries
What does the superficial palmar arch give rise to?
The common digital arteries
How are the radial and ulnar digital arteries named?
Named after the side of the digit they are on (not the artery they originate from)
What are the three peripheral nerves that supply the hand?
Median, ulnar and radial nerves
Where does the muscular aspect of the median nerve supply?
Flexors of forearm and LOAF muscles
Tested at abductor pollicis brevis
Where does the median nerve supply cutaneous sensation to?
Radial 3 and a half digits
Tested at tip of index finger and base of thenar muscles
Where does the muscular aspect of the ulnar nerve supply?
Small intrinsic muscles of the hand
Tested at abductor digiti minimi
Where does the ulnar nerve provide cutaneous sensation to?
Ulnar 1 and a half digits
Tested at dorsum and volar aspects of little finger
Where does the muscular part of the radial nerve supply?
Extensors of forearm
Tested at extensor digitorum communis (extensor indicis)
Where does the radial nerve supply cutaneous sensation to?
Variable portion dorsum of hand
Tested at dorsum of first webspace
What forms the cubital tunnel?
Formed by two heads of flexor carpi ulnaris muscle
Where does the ulnar nerve pass?
Posterior to medial epicondyle, then enters cubital tunnel and goes underneath arcuate ligament
What causes cubital tunnel syndrome?
Compression of the ulnar nerve
Where does the median nerve pass through the carpal tunnel?
At the level of the wrist
What are the boundaries of the carpal tunnel?
Carpal bones = dorsal, medial and lateral constraints
Flexor retinaculum/transverse carpal ligament
What causes carpal tunnel syndrome?
Compression of the median nerve
What forms the brachial plexus?
Ventral rami of C5-8 and T1 nerve roots
Where does the brachial plexus pass?
Proceeds through neck, then the axilla and into the arm
What does the brachial plexus give rise to?
Peripheral nerves of the entire upper limb
What is the order of structures in the brachial plexus?
Roots, trunks, divisions, cords, branches
