Nerve = musculocutaneous (C5,6) from lateral cord of BP.
Arises: apex of coracoid process (fused with short head of biceps)
Insertion: medial border of humerus (lower border of insertion = nutrient foramen).
Nerve supply: musculocutaneous nerve, which passes through the muscle.
Action: weak flexor & adductor. Functionally unimportant; = arm counterpart of thigh adductors
Arises: long head from supraglenoid tubercle & glenoid labrum
- runs through synovial sheath, emerges beneath transverse ligament then intertubercular groove.
Short head from apex of coracoid process
¨ two fleshy bellies lying side by side
¨ fuse at elbow joint to become flattened cord in cubital fossa
Inserts tendon rotates laterally to enter at the radial tuberosity (separated by a bursa beneath)
Bicipital aponeurosis extends from medial border of tendon via deep fascia of forearm to proximal ulna.
Nerve supply: musculocutaneous nerve.
Action: elbow flexion, forearm supination (puts in corkscrew & pulls out cork); weak shoulder flexor.
- during supination the distal ulnar is brought anteromedially by the bicipital aponeurosis.
- Also helps stabilise the shoulder jt.
Test: flex against resistance: palpate.
Arises: anterior lower 1/2 of humerus & medial intermuscular septum (origin clasps deltoid insertion)
- ¨ flattens out to cover anterior aspect of elbow joint
Inserts: coronoid process & tuberosity of ulna.
Nerve supply: musculocutaneous; lateral part has innervation from branch of radial nerve (C7).
Action: elbow flexion (picks up drink & puts down glass).
Extends along medial supracondylar line up to posterior of coracobrachialis insertion.
Fades out above between coracobrachialis and triceps long head.
Gives origin to medial head of triceps, medial brachialis;
- pierced by ulnar nerve (below insertion of coracobrachialis) and by superior ulnar collateral artery.
Along lateral supracondylar line, fades out behind deltoid insertion.
Gives origin to brachioradialis and extensor carpi radialis longus (ECRL)
- pierced by radial nerve & profunda brachii artery (radial collateral branch).
Neurovascular bundle passes from axilla into flexor compartment. Some branches run to extensor compartment via quadrilateral space (circumflex vessels & axillary nerve).
- in upper arm radial nerve & profunda brachii pass to extensor compartment through triangular space between humerus (note there are two triangular spaces, this is the main one), teres major & long head of triceps. (see 403).
Runs with venae comitantes (which become the axillary vein once reinforced with basilic)
- median nerve initially lateral to artery; crosses in front to lie medial below
- and ulnar nerve initially posterior to artery; slopes back in lower arm to pierce medial intermuscular septum.
ÒSuperficialÓ throughout course in arm; push lateral into humerus to palpate it.
- abducted straight from middle of clavicles to midpoint of humeral epicondyles
Surgical access: expose at medial border of biceps, between biceps & triceps.
(1) Profunda brachii: leaves through triangular space runs in spiral groove with radial nerve
- Supplies triceps and nutrient artery to humerus
- ends as middle collateral & radial collateral which join cubital anastomosis.
(2) Superior ulnar collateral runs with ulnar nerve.
(3) Inferior ulnar collateral ¨ anterior & posterior branches joining cubital anastomosis
(4) Radial & Ulnar: terminal branches.
(5) Muscular: to flexors
(6) Nutrient: (enters bone near coracobrachialis attachment)
Venae comitantes accompany brachial artery & all branches.
Basilic & cephalic veins run subcutaneously;
- basilic pierces deep fascia in middle of arm.
- cephalic lies in groove b/n deltoid and pectoralis major
Formed from branches of medial & lateral cords of BP, which clasp the axillary artery.
No muscular branches in arm; gives sympathetic fibres to artery and maybe to pronator teres at elbow.
Surface marking: in line from behind coracobrachialis to cubital fossa medial to brachial artery (starts lateral to it).
Passes between fused parts of coracobrachialis (supplies it) ¨ lies between biceps & brachialis (supplies both) ¨ persists at lateral margin of biceps as lateral cutaneous nerve of forearm.
- branch to brachialis supplies the elbow jt.
From medial cord of BP; runs posterior to vessels ¨ pierces medial intermuscular septum with superior ulnar collateral artery & branch of radial nerve to medial head of triceps.
- no branches in arm, branch to elbow comes off post to medial epicondyle (where palpable)
From medial cord of BP ¨ medial to vessels ¨ pierces deep fascia in upper arm.
- supplies skin on front and medial side of arm
From medial cord of BP ¨ passes anterior to vessels and pierces deep fascia with basilic vein.
- divides into anterior and posterior, anterior passes in front of medial cubital vein (¨ lower front of arm);
- in upper arm is useful as a graft, long length without branches.
Lateral cutaneous branch of 2nd intercostal nerve.
3rd intercostal may give a similar branch.
¨ extends variable distance into skin of medial upper arm.
Two groups of only 1-2 nodes each.
Infraclavicular group along cephalic vein in upper deltopectoral groove ¨ drain via clavipectoral fascia into apical nodes; receive supply from thumb, lateral forearm and arm
Supratrochlear groups (lie in subcutaneous fat) ¨ lateral group of axillary nodes.
- drain superficial tissues of medial hand and forearm.