Brachial Plexus Flashcards
Musculocutaneous nerve (C5 - C7)
Motor - elbow flexion (supplies biceps brachii) and supination
Sensory - lateral part of the forearm
Isolated injury rare - injured as part of brachial plexus injury
Axillary nerve (C5, C6)
Motor - shoulder abduction (deltoid muscle)
Sensory - inferior region of the deltoid muscle
Injured in humeral neck fracture/dislocation resulting in flattened deltoid
Radial nerve (C5 - C8)
Motor - extension (forearm, wrist, fingers, thumb)
Sensory - small area between the dorsal aspect of the 1st and 2nd metacarpals
Injured in humeral midshaft fracture resulting in a palsy presenting as a wrist drop
Median nerve (C6, C8, T1)
Motor - LOAF muscles
Sensory - palmar aspect of lateral 3½ fingers
Wrist lesion (carpal tunnel syndrome) - paralysis of thenar muscles, opponens pollicis
Elbow lesion - loss of pronation of forearm and weak wrist flexion
Ulnar nerve (C8, T1)
Motor - wrist flexion (intrinsic hand muscles except LOAF)
Sensory - medial 1½ fingers
Injury to medial epicondyle fracture presenting as a claw hand
Long thoracic nerve (C5 - C7)
Motor - serratus anterior
Often injured during sport (following a blow to the ribs)
Also possible complication of mastectomy
Damage results in a winged scapula
Erb-Duchenne palsy
Damage of the upper trunk of the brachial plexus (C5,C6)
Secondary to shoulder dystocia during birth
Arm hangs by the side and is internally rotated and the elbow is extended -> waiter’s tip
Klumpke injury
Damage of the lower trunk of the brachial plexus (C8, T1)
Secondary to shoulder dystocia during birth
Can be caused by a sudden upward jerk of the hand
Associated with Horner’s syndrome
LOAF muscles
Lateral two lumbricals
Opponens pollicis
Abductor pollicis brevis
Flexor pollicis brevis
Wrist drop
Damage to the radial nerve (C5 - C8)
Secondary to humeral midshaft fracture
Claw hand
Damage to ulnar nerve (C8, T1)
Secondary to medial epicondyle fracture
Winged scapula
Damage to the long thoracic nerve (C5 - C7)
Secondary to trauma or repetitive movements
Carpal tunnel syndrome
Damage to median nerve (C6, C8, T1) in the wrist
Causes paralysis of thenar muscles, opponens pollicis
Associated with hypothyroidism, diabetes, obesity and arthritis
Mx - corticosteroid injection, wrist splints at night, surgical decompression by dividing the flexor retinaculum
Brachial plexus
A – C5
B – C6
C – C7
D – C8
E – T1
F – Long thoracic nerve
G – Upper subscapular nerve
H – Medial pectoral nerve
I – Thoracodorsal nerve
J – Lower subscapular nerve
K – Radial nerve
L – Medial cutaneous nerve of the arm
M – Medial cutaneous nerve of the forearm
N – Ulnar nerve
O – Median nerve
P – Axillary nerve
Q – Musculocutaneous nerve
R – Lateral pectoral nerve
S – Nerve to subclavius
T – Suprascapular nerve
U – Dorsal scapular nerve
