Radial nerve

Radial nerve is the largest branch of the posterior cord of the brachial plexus with a root value of C5 – C8 and T1. The radial nerve is commonly injured in the region of the spiral groove. this result in the wrist drop and sensory loss over a narrow strip on the back of forearm, and on the lateral side of the dorsum of the hand.

Posterior interosseous nerve is the branch of radial nerve given off in the cubital fossa while anterior interosseous nerve is a branch of the median nerve given off in the upper part of the forearm.

Skin of the back of the forearm (i.e. extensor compartment) is supplied by the posterior cutaneous nerve of the forearm which is a branch of radial nerve.

A i.e. Branch of posterior cord; B i.e. Nerve of extensor compartment of forearm; C i.e. Arise from C5-T1

BRANCHES OF THE BRACHIAL PLEXUS

There are a total of 17 branches arising from the brachial plexus that are destined to supply the upper limb of the seventeen branches of the brachial plexus; three of the branches arise from the root, one from the trunk, three from the lateral cord, five from the medial cord and five from the posterior cord.

Branches from the roots

• Long thoracic nerve of bell (C5, C6, C7).
• Dorsal scapular nerve (C5).

Branches from the trunk

• Suprascapular Nerve (C5, C6)
• Nerve to subclavius (C5, C6)

Branches from the lateral cord

• Lateral pectoral nerve. (C5, C6).
• Musculocutaneous – (C5, C6, C7)
• Lateral root of median nerve (C5, C6, C7).

Branches from the medial cord

• Medial pectoral nerve (C8, T1)
• Medial cutaneous nerve of arm (C8,T1)
• Medial cutaneous nerve of forearm (C8,T1)
• Ulnar nerve(C7, C8, T1)
• Medial root of median nerve (C8,T1)

Branches from the posterior cord

• Axillary nerve (C5, C6)
• Upper subscapular nerve (C5,C6)
• Thoracodorsal nerve (C6, C7, C8).

Lower subscapular nerve (C5, C6)

Radial nerve (C5-T1).

Anatomy of radial nerve

Formed by: Axons from Roots: C5 to T1 Brachial plexus

Trunks: Superior, Medial and Inferior

Cord: Posterior

Axons pass through Spiral groove of humerus

Fibrous arch attachment of triceps to humerus

Lateral intermuscular septum below deltoid insertion

Arcade of Frohse: Above supinator and below elbow

• Branches
• Above elbow

– Above spiral groove (humerus)