Clavipectoral fascia
The clavipectoral fascia (costocoracoid membrane; coracoclavicular fascia) is a strong fascia situated under cover of the clavicular portion of the pectoralis major. Clavipectoral fascia pierced by Cephalic vein, thoracoacromial artery and vein, lymphatics and lateral pectoral nerve.
Distubution of Cutaneous Nerves Upper Limb
Dermatomes/myotomes/reflexes
Sensory and motor innervation of the medial / ulnar / radial / musculocutaneous / axillary nerves.
See prior for median, ulna and radial
Musculocutaneous C5-C6
Motor (BBC) – brachialis, Biceps Brachii, Coracobrachialis
Sensory: lateral cutaneous nerve of forearm
Course: pierces the coracobrachialis muscle, near its point of insertion on the humerus. It then passes down the arm, anterior to the brachialis muscle but deep to the biceps brachii, innervating them both. The musculocutaneous nerve emerges laterally to the biceps tendon, and continues into the forearm as the lateral cutaneous nerve. It provides sensory innervation to the lateral aspect of the forearm .
Axillary C5, C6
Motor – Deltoid, teres minor
Sensory – superior lateral cutaneous nerve of arm –> lateral shoulder over regimental badge area
Course – Exit via quadrangular space.
Upper Limb Nerve injury patterns:
Brachial plexus
Upper brachial plexus – Erb’s palsy (C5 C6)
From difficult birth or blow to shoulder
Suprascapular, axillary, musculocutaneous, nerve to subclavius
Loss of sensation on lateral arm, arm hangs limp, medially rotated, extended at elbow, pronated
Lower brachial plexus – Klumpke palsy (T1)
From excess abduction – eg grabbing a branch when falling from tree
Motor loss in hand–> MCP extension and IP flexion
Sensory – medial side of arm
Axillary nerve
Anterior dislocation of glenohumoral joint
Fracture of humerus at surgical neck
Acutely pt cant abduct arm. In long standing case the deltoid wastes and the greater tubercle can be palpated.
Radial nerve
At axilla
From humerus dislocation, fracture of proximal humerus, excess pressure in axilla
Unable to extend at elbow, wrist or fingers. Hand is able to be supinated but has wrist drop.
Sensory loss over posterior arm, forearm, hand
At radial groove
From midshaft fracture of humerus
Unable to extend at wrist or fingers. Hand is able to be supinated but has wrist drop.
Sensory loss over posterior hand
At deep branch of radial nerve
From fracture of radial head or posterior dislocation of radial head
No sensory effect
Loss of everything in forearm except supinator and FCRL so no wrist drop.
At superficial radial nerve
From stabbing or laceration in forearm
No motor
Sensory loss in dorsum of hand
Musculocutaneous
In axilla – rare
From stabbing
Loss of sensation over lateral forearm
Weakened but present shoulder flexion, elbow flexion and supination
Ulnar nerve
At elbow
Fracture of medial epicondyle
Motor – little and ring finger flexion/extension very reduced, no finger abduction/adduction, wrist flexion occurs with abduction of wrist. Fromons positive
Ulna sensory loss
At wrist
From laceration
Motor – little and ring finger extension very reduced, no finger abduction/adduction, wrist flexion normal. Fromons positive.
Ulna sensory loss – more likely palmar
Ulna claw – MCP hyperextension, IP flexion
Median nerve
At elbow
From supracondylar fracture
Loss of median nerve sensation, loss of most flexors and all pronators so hand constantly supinated
Hand of Benediction when pt tries to make fist – only ulna side work
At wrist
Carpal Tunnel syndrome/lacerations