Median Nerve Anatomy and Function The Median nerve is the nerve of pre-axial hand function; pinch, delicate hand movement and sensation. The nerve brings function to the human opposable thumb in lateral/key/tripod pinch. It is formed by the C5 to T1 roots. The median nerve is formed by the Lateral Contribution to the Median Nerve (LCMN) (C5,6,7) which brings the sensory fibres to the hand and the proximal extrinsic muscles (PT PL). The Medial Contribution to Median Nerve (MCMN) (C8 & T1) brings the long flexor and intrinsic motor and no sensory fibres (C8 sensory fibres run to the ring and little finger through the Ulnar nerve, T1 sensory in the medial cutaneous nerves). When assessing the Median nerve: • Compression can occur at many points along the course of the neurones - it is not all carpal tunnel compression. • Carpal tunnel compression does not affect the palmar cutaneous branch. • Anterior interosseous nerve (AIN) palsy leaves a hand of ‘benediction’ where the index finger and thumb do not flex. There will be no cutaneous sensory change. • Compression of the lateral contribution to the median will provide a similar sensory exam to carpal tunnel compression but will also have involvement of pronator teres and FCR. • At the antecubital fossa remember the mnemonic TAN for (Biceps) Tendon, (Brachial) Artery and (Median) Nerve from lateral to medial. • LOAF mnemonic reminds us of the intrinsics of the median (medial 2 Lumbricals, Opponens, Abductor and Flexor Pollicis). by Dr. Tom Quick @TJQPNI via orthohub.xyz @OrthohubXYZ #Median #Nerve #Anatomy #diagnosis #neurology #orthopedics
