Week 7 - Upper limb Anatomy

What ligaments are involved in a acromioclavicular dislocation

Acromioclavicular and coracoclavicular

Shoulders girdle muscles (5)

Pectoralis major, pectoralis minor, subclavius, SCM and deltoid

Muscles inserting around the intertubercular groove

Teres major (Medial lip)
Latissimus dorsi (Intertubercular groove)
Pectoralis major (Lateral lip)

Insertion of serratus anterior

inserts along medial scapula border

Function of serratus anterior

Pulls scapula towards the trunk and rotates the angle laterally

Nerve supply for the serratus anterior

Long thoracic nerve

What happens if the long thoracic nerve is damaged?

Scapula will protrude from the trunk (winged scapula)

Adhesive capsulitis

Restricted, painful movement due to inflammation and adhesions of joint capsule

How does the humerus commonly dislocate? and why?

Anteroinferiorly because that’s where the shoulder joint is least strengthened

What happens when the surgical neck of the humerus is fractured?

Damage to the posterior cord of the brachial plexus to supply deltoid muscle and skin

Names of the rotator cuff muscles

Supraspinatus, infraspinatus, teres minor and subscapularis

Function of supraspinatus

Abduction of humerus

Function of infraspinatus

External rotation of the humerus

Function of the teres minor and subscapularis

Internal rotation of humerus

Insertion points of the rotator cuff muscles

All muscles into the greater tubercle except the subscapularis, which is in the lesser tubrecle

Contents of the axilla

Axillary vessels, lymphatics and brachial plexus

Klumpke’s palsy

C8/T1 roots damaged, leading to paralysis of intrinsic hand muscles

Appearance of Klumpke’s palsy

Claw hand

Erb-Duchenne palsy

C5/6 roots damaged, paralysis of deltoid, biceps and brachialis

Anterior muscles of the arm

Biceps, brachialis and coracobrachialis

Nerve and blood supply to the anterior muscles of the arm

Musculocutaneous nerve and brachial artery

Action of biceps muscle

Elbow and shoulder flexion, forearm supination

Origin of biceps

Long head = Supraglenoid tubercle
Short head = Coracoid process

Insertion of biceps

Radial tuberosity

Action of brachialis

Elbow flexion

Origin of brachialis

Humerus

Insertion of brachialis

Coronoid process of the ulna

Origin of coracobrachialis

Coracoid process

Insertion of coracobrachialis

Humerus

Posterior muscle of the arm

Triceps

Origin of triceps muscle

Long head - Infraglenoid tubercle
Medial head - Medial to radial groove
Lateral head - Lateral to radial groove

Insertion of triceps

Olecranon process of the ulna

Why does a mid-shaft humus fracture leave triceps innervation intact?

Radial nerve branches to triceps are given off early

What provides sensory innervation to the upper arm

Upper lateral cutaneous nerve

What provides sensory innervation to the lower arm?

Anterior: Medial cutaneous nerves
Posterior: Radial

Blood supply to the posterior compartment

Profunda brachial artery

What does the cephalic vein drain into?

Subclavian vein

What does the basilic vein drain into?

Axillary vein

Joints that make the elbow joint

Humeroulnear, humeroradial and radioulnar

Movements of the elbow joint

Flexion, extension, pronation and supination

Ligaments of the elbow joint

Medial & lateral collateral ligament and annular ligament

Muscles for supination

Biceps and supinator

Muscles for pronation

Pronator teres and pronator quadratus

Nerve supply to supinator

Radial nerve

Nerve supply to pronator muscles

Median nerve

Borders of the cubital fossa

Lateral border: Brachioradialis
Medial border: Pronator teres
Superior border: Medial epicondyle

Superficial veins

Cephalic, basilic and median cubital veins

Significance of the cubital fossa

Locate the median cubital vein to sample venous blood

Contents of the cubital fossa

Tendon of biceps, brachial artery and median nerve (TAN)

What is injured in a supracondylar fracture?

3 nerves: Radial, median and ulna

What does the brachial artery divide into?

Radial and ulna artery

What does the ulnar artery give rise to

Anterior and posterior interosseous arteries

Muscles in the anterior compartment of the forearm

Pronator teres, flexor carpi radialis, palmaris longus and flexor carpi ulnaris

Nerve supply of anterior compartment of the forearm

Median nerve

Origin for anterior muscles of the forearm

Medial epicondyle

Insertion of anterior muscles of the forearm

Wrist or palmar aponeurosis

Nerve supply to brachioradialis

Radial nerve

Intermediate muscles in anterior compartment of the forearm

Flexor digitorum superficialis

Deep muscles in the anterior compartment of the forearm

Flexos digitorum profundus and flexor pollicis longus

Pathway of flexor digitorum superficialis

Tendon splits and inserts on either side by the base of the middle phalanx

Action of the flexor digitorum superficialis

Flex the proximal interphalangeal joint

Pathway of the flexor digitorum profundus

Travels through a split in flexor digitorum superficialis tendon and down to the base of the distal phalanx

Action of the flexor digitorum profundus

Flexes distal interphalangeeal digit

What does the ulnar nerve supply in the anterior muscles of the forearm

Flexor carpi ulnaris and median ½ of flexor digitorum profundus

Muscles in the posterior compartment of the forearm

Brachioradialis
Extensor carpi radialis longus
Extensor carpi radialis brevis
Extensor digitorum
Extensor digiti minimi
Extensor carpi ulnaris
Anconeus

Origin of extensor carpi radialis longus and brevis

Lateral supracondylar ridge

Insertion of extensor carpi radialis longus

2nd metacarpal

Insertion of extensor carpi radialis brevis

3rd metacarpal

What condition happens when the radial nerve is damaged?

Wrist drop

Muscles in the deep posterior compartment

Supinator
Extensor pollicis longus
Abductor pollicis longus
Extensor pollicis brevis
Extensor indices

What is radial tunnel syndrome

Posterior interosseous nerve can be compressed by the tendinous arch of supinator

Proximal row of carpal joints (Lateral to medial)

Scaphoid, lunate, triquetrium

Distal row of carpal joints (Lateral to medial)

Trapezium, trapezoid, capitate, hanmate

Contents in the carpal tunnel

Median nerve
8 flexor tendons (4 from flexor digitorum profundus and 4 from flexor digitorum superficialis)
Flexor pollicis longus tendon

What can happen to the nerve in Guyon’s canal

Compressed as it passes deep to a thickened part of the flexor retinaculum at the wrist.

Superficial flexor tendons at the wrist

Flexor carpi radialis, palmaris longus and flexor carpi ulnaris

Intermediate flexor tendons at the wrist

Flexor digitorum superficialis

Deep flexor tendons at the wrist

Flexor digitorum profundus and flexor pollicis longus

Superficial extensor tendons at the wrist

Extensor carpi radialis longus and brevis
Extensor carpi ulnaris
Extensor digitorum
Extensor digiti minimi

Deep extensor tendons at the wrist

Extensor pollicis longus
Extensor pollicis brevis
Abductor pollicis longus
Extensor indicis

Muscles responsible for wrist abduction

Flexor and extensor carpi radialis

Muscles responsible for wrist adduction

Flexor and extensor carpi ulnaris

What tendons bound the anatomical snuff box?

Extensor pollicis longus and brevis
Abductor pollicis longus

Function of the anatomical snuff box

Feel the pulsations of the radial artery

What muscles insert into the palmar aponeurosis

Palmaris longus and brevis

Thenar muscles

Abductor pollicis brevis, flexor pollicis brevis and opponens pollicis

Hypothenar muscles

Abductor digiti minimi, flexor digiti minimi brevis and opponens digiti minimi

Function of dorsal interosseous muscles

Abduct digits

Function of palmar interosseous muscles

Adduct digits

Innervation of dorsal and palmar interreous muscles

Ulnar

Function of the lumbricals

Flexes metacarpal joint and extends proximal and distal interphalangeal joints

Function of the flexor digitorum superficialis

Flexes proximal interphalangeal joint

Function of flexor digitorum profundus

Flexes distal interphalangeal joint