Brachial plexus – Anatomy Atlas

Table of Contents

Overview

Brachial plexus The brachial plexus is formed by five anterior rami that originate from the spinal nerves C5-T1 (these are known as the roots of the brachial plexus). These roots merge to form three trunks, the superior (C5-6), middle (C7) and inferior (C8-T1). Each trunk then divides into an anterior and posterior division, therefore forming six divisions altogether. The six divisions then reform, resulting in three cords -posterior, lateral and medial cords. Finally, the brachial plexus gives off five terminal branches that are in charge of the motor and sensory supply to the upper limb. From lateral to medial, these are the musculocutaneous nerve, axillary nerve, median nerve, radial nerve and ulnar nerve. The brachial plexus also gives off a number of lateral branches along the way.

Keypoints

Key points about the brachial plexus
Roots	C5, C6, C7, C8, T1
Structural organization	Trunks: Superior, middle, inferior Divisions: Three anterior and three posterior Cords: Posterior, lateral and medial
Terminal branches	Musculocutaneous nerve, axillary nerve, median nerve, radial nerve, ulnar nerve
Lateral branches	Anterior: Medial and lateral pectoral nerves, subclavian nerve Posterior: Dorsal scapular nerve, suprascapular nerve, subscapular nerves, long thoracic nerve, thoracodorsal nerve
Function	Complete sensory and motor innervation of the arm