Table 1

Outline of focal neuropathies in the upper limb

Nerve	Site of lesion	Common causes	Motor deficit	Sensory deficit	Differential diagnosis
Common
Median	Carpal tunnel	Entrapment, diabetes, hypothyroidism, connective tissue disease	Abductor pollicis brevis, opponens pollicis	Thumb, index and middle finger	C6 or C7 radiculopathy; local pathologies
Ulnar	Elbow (cubital tunnel)	External compression, trauma (recent or distant)	Long flexors of little and ring fingers, finger abductors and adductors and lumbricals	Little and ring fingers	More distal or proximal ulnar lesion; motor neurone disease; T1 lesions
Uncommon
Radial	Upper arm	External compression, trauma	Finger and wrist extensors, some weakness of brachioradialis	Anatomical snuffbox	C7 radiculopathy
Axillary	Humeral head	Trauma, humeral head	Deltoid	Lateral shoulder
Ulnar	Wrist (Guyon’s canal) or hand	Compression (cycling), entrapment	Wrist: adductor pollicis, interosseous muscles and hypothenar muscles Hand: adductor pollicis, interosseous muscles	Wrist: little and half ring finger Lesions in the hand: none	Motor neurone disease, Syringomyelia, T1 radiculopathy
Long thoracic	Not clear	Usually unknown; trauma	Serratus anterior; winging of scapular	None	Neuralgic amyotrophy
Rare
Anterior interosseous branch of median nerve	Just below the elbow	Fibrous bands, trauma	Flexor pollicis longus, flexor digitorum profundus of index finger (loss of pinch sign), pronator quadratus
Posterior interosseous branch of radial nerve	As nerve enters supinator muscle	Entrapment, trauma	Finger extensors: finger drop without wrist drop	None	C7 radiculopathy, upper motor neurone lesions, neuralgic amyotrophy
Suprascapular	Suprascapular notch	Trauma, lifting (rucksack)	Supraspinatus and infraspinatus	None	Shoulder pathology, neuralgic amyotrophy
Musculocutaneous		Trauma, iatrogenic	Biceps	Lateral forearm	C6 radiculopathy