See axilla notes; supplemented here:
Muscular to arm flexors, cutaneous in forearm. From lateral cord (terminal division).
Enters coracobrachialis, pierces it, runs between biceps and brachialis (supplies all these)
Emerges at lateral biceps tendon, pierces deep fascia at elbow flexure crease ¨ lat cut n of forearm supplies skin to wrist with ant and post branches.
¨ most forearm flexors; 3 thenar muscles & 2 lumbricals.
¨ cutaneous to 3 1/2 radial digits + corresponding area of palm.
Passes obliquely across front of brachial artery lateral ¨ medial.
Descends between heads of pronator teres & beneath fibrous arch of FDS.
Emerges on radial side of FDS, lies between FCR and palmaris longus where it enters the carpal tunnel.
Arm: Nil muscular. Sympathetic twig to brachial artery, twig to elbow jt.
In cubital fossa: muscular branches to pronator teres, palmaris longus, FCR, FDS
- and gives off ant interosseous nerve (which descends over interosseous membrane to wrist).
- ¨ supplies FDP, FPL, PQ, and is sensory to wrist and carpal bones.
Wrist: Palmar cutaneous branch pierces deep fascia above flexor retinaculum ¨ radial palm.
Divides in carpal tunnel to enter hand as medial & lateral branches.
- Lateral branch gives off ÒrecurrentÓ motor branch to 3 thenar eminence muscles (¨ abductor & flexor pollicis brevis, opponens pollicis). LOAF.
- both medial & lateral branches continue as digital branches; lateral supplies 1st lumbrical, medial supplies 2nd.
Direct continuation of medial cord C8,T1, picking up C7 fibres in axilla from lateral cord for FCU.
¨ ulnar forearm flexors
¨ intrinsic hand muscles (except 3 of the thenar muscles and 2 lumbricals above)
¨ skin of ulnar 1 1/2 digits
Runs between brachial a & v (behind medial cut n of forearm) ¨ pierces medial intermuscular septum.
Lies on shaft of humerus between medial epicondyle and
olecranon
¨ passes between heads of FCU to enter flexor compartment of forearm.
Descends on FDP under cover of FCU and is joined by ulnar artery on lateral side (inside it).
Crosses flexor retinaculum above pisiform where it divides into terminal branches: superficial & deep.
1) Twigs to elbow jt
2) In forearm: FCU (C7), ulnar 1/2 of FDP (C8, T1).
3) Palmar cutaneous branch ¨ pierces fascia above f. retinac to skin over hypothenar muscles.
4) Dorsal cutaneous branch ¨ runs around lower ulnar to cross triquetral & supply dorsal skin of ulnar 1 1/2 fingers + corresponding skin of hand. (not uncommonly 2 1/2 fingers)
5) Superficial branch: runs beneath (supplies) palmaris, gives dig. branches to ulnar 1 1/2 fingers.
- digital supply includes nail beds of dorsal fingers
6) Deep branch: ¨ deep b/n abductor and flexor dig minimi and through opponens ¨ concavity of deep palmar arch ¨ 3 hypothenar muscles, 2 ulnar lumbricals, all interossei; ends by supplying adductor pollicis.
Direct continuation of posterior cord of BP.
¨ extensor compartments of arm & forearm, dorsal arm, forearm & hand skin.
Enters space between teres major + long head of triceps + humerus (397)
¨ crosses medial head of triceps to run in spiral groove of humerus.
¨ Pierces lateral intermuscular septum, descends between brachialis & brachioradialis.
¨ Gives off large posterior interosseous nerve and continues as smaller radial nerve which runs down on forearm flexors under cover of brachioradialis , spirals around radius deep to brachioradialis tendon (emerging over APL, EPB, EPL) to reach back of hand (content of snuff box)
Posterior cutaneous nerve of arm: pierces deep fascia ¨ strip of skin down to elbow.
Two muscular branches to triceps (¨ long & medial heads).
2 muscular & 2 cutaneous branches:
Two branches to triceps (lateral & medial heads)
Lower lateral cutaneous nerve of arm: pierces lat triceps head, suppling lateral surface arm ¨ elbow. Posterior cutaneous nerve of forearm: strip behind elbow to extensor surface of forearm to wrist.
Small branch to brachialis; main supply to brachioradialis and ECRL.
¨ ECRB & supinator in cubital fossa.
Enters extensor compartment of forearm between heads of supinator, crosses abductor pollicis longus & runs down on interosseous membrane to back of wrist.
Supplies 7 more muscles in forearm: 3 extensors from common extensor origin (ED, Extensor digiti minimi, ECU), 3 thumb muscles (AbPL, EPB and EPL) and extensor indicis.
Sensory to interosseous membrane and wrist joint.
Cross roof of snuffbox and reach radial 2- 3 1/2 digits + corresponding dorsum of hand (falls short of nail beds)