Patients with neck pain can present with pain in the arm also. Many patients may also present with arm pain without complaints of neck pain.
In such a situation, a careful history will reveal past history of neck pain and almost always a past history of trauma.
Also, patients may not volunteer a history of neck stiffness since they may have gotten used to living with neck stiffness assuming it is a sign of aging.
Arm pain is often due to irritation of the cervical nerve roots that enter to form the brachial plexus.
Today’s topic will be on the nerves of the posterior cord.

Peripheral Nerves from the posterior cord (5 in number):
Upper and Lower subscapular nerves supply the subscapularis muscle. Lower subscapular nerve supplies the teres major muscle.
Nerve to the Latissimus dorsi
Circumflex nerve (supplies the deltoid and teres minor muscles).
Radial nerve (supplies the triceps, anconeus, brachioradialis, extensor carpi radialis longus muscles.
The sensory branches include lower lateral cutaneous nerve of arm (supplies the outer aspect of the lower arm) and posterior cutaneous nerve of forearm which supplies the back of the forearm.
The superficial branch of the radial nerve supplies sensation to the dorsal aspect of the thumb and index fingers excluding the tips of the fingers.

Posterior interosseous nerve supplies the extensor carpi radialis brevis, supinator, extensor digitorum, extensor digit minimi, extensor carpi ulnaris, abductor pollicis longus, extensor pollicis longus and brevis, and extensor indices. There are no sensory branches from the posterior interosseous nerve.