orthopaedics/brachial plexus

1. Dr. Patrick Reynolds
F2 Trauma & Orthopaedics
Brachial plexus
Nerve supply of upper limb
Common clinical syndromes and presentation

9. Musculocutaneous nerve
•Supplied by C5, C6 and C7
•Formed by a branch of the lateral cord (superior
and medial trunks)
•Supplies “BBC” muscles - Biceps Brachii,
Brachialis and Coracobrachialis
•Gives off lateral cutaneous nerve of the forearm
– important structure to identify in surgery
around the ACF

11. Radial nerve
•Supplied by C5-8, T1 (inconsistent)
•Formed by a continuation of the posterior cord)
•Supplies Extensor muscles and brachioradialis
(extensor paradox) and abductor pollicis longus
•Proximally runs around the spiral groove, dives
deep through lateral intermuscular septum, runs
anterolaterally around the radial head and
reappears through the extensor compartment in
the forearm

13. Median nerve
•Supplied by C5-8, T1 (inconsistent)
•Formed by a confluence of the medial and lateral
cords
•Supplies flexor compartment of forearm, three
thenar muscles and two lumbricals of hand
•Supplies deep compartment as the anterior
interosseuous nerve
•Anterior interosseous nerve supplies radial half
of FDP, FPL and pronator quadratus, sensory to
wrist and carpal tunnel

15. Ulnar nerve
•Supplied by C7, C8 T1
•Direct continuation of medial cord (C8, T1) with
contribution of (C7) fibres from axilla
•Supplies some flexors on ulnar side, ulnar side of
FDP, all intrinsic muscles, lumbricals & interossei
of hand excluding LOAF
•Runs posteriorly on humerus, pass through
cubital tunnel

17. Ulnar claw hand
Ulnar nerve lesion at wrist or just below elbow gives
previous “claw” appearance
Position caused by loss of lumbrical function (flex MCPJ,
extend PIPJ) with unopposed effect of finger extensors
Paradoxically a higher lesion of the ulnar nerves leads to
less severe “clawing”, why?
FDP on ulnar side receives ulnar nerve supply. Paralysis of
ulnar FDP occurs in high lesions giving fingers a less
flexed appearance
Injury is more severe but appearance is better, hence
“Paradox”

18. Radial wrist drop

19. Erb’s Palsy

20. Erb’s Palsy
Traction injury to C5, C6 often birth injury during
difficult delivery
Abductors and lateral rotators of shoulder and
the supinators are paralysed
Arm hangs by side, medially rotated, pronated
with loss of sensation on the lateral side of arm
and forearm

21. Klumpke’s paralysis
Damage to the lowest roots (C8, T1)
Can also be a birth injury during breech delivery
where arms remain above head
Small muscles of hand are most affected. Often
get clawing
Ulnar sensory loss
Appearance as per claw hand

22. Useful mnemonics for hands
LOAF – Intrinsic muscles supplied by median nerve
lateral two lumbricals, opponens pollicis, abductor pollicis
brevis, flexor pollicis brevis
A OF A OF A –
Thenar (lateral to medial-palmar surface):
Abductor pollicis brevis Opponens pollicis Flexor pollicis
brevis Adductor pollicis
Hypothenar (lateral to medial-palmar surface):
Opponens digiti minimi Flexor digiti minimi Abductor
digiti minimi