Lab 1 Module 3: Posterior Triangle of the Neck - Page 3 of 5

Nerves of the Posterior Triangle

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Remember that the roots of the Brachial Plexus (ventral rami of C5-T1) rest in the posterior triangle just posterior to the anterior scalene muscle and anterior to the middle scalene muscle.

Add the Spinal Accessory Nerve (CN XI), which divides the posterior triangle into nearly equal superior and inferior parts. The superior part contains only the lesser occipital nerve while the inferior part contains many important nerves. The (Spinal) Accessory nerve is a motor nerve composed of both spinal (C1-C6) and cranial (CN XI) roots.