Lateral Perspective of the C5 Root of the Brachial Plexus

Description

Seen from a lateral neck perspective, the C5 spinal nerve root emerges from the intervertebral foramen and courses laterally between the anterior and middle scalene muscles before joining the adjacent C6 root to form the superior trunk of the brachial plexus. Superior and posterior to the root, cervical vertebrae and their transverse processes provide the bony corridor that frames the nerve’s exit point. Anteriorly, the carotid sheath region and nearby venous channels sit in close proximity, while inferior and medial soft tissues can include the thyroid gland and related fascia. Small lymph nodes may appear along the deep cervical chain. Tight anatomy. This side-on view matters because it clarifies the scalene triangle, the space where the proximal brachial plexus and subclavian artery run and where neurogenic thoracic outlet syndrome often declares itself. Needle placement for interscalene brachial plexus block targets roots and trunks at the level of C5 to C7, so understanding the C5 root’s relationship to the anterior scalene, prevertebral fascia, and adjacent vessels helps anticipate spread of local anesthetic and recognized complications such as phrenic nerve palsy. Traction injuries can also involve C5, classically contributing to an Erb-Duchenne pattern of weakness when the superior trunk is affected. Use this illustration for teaching the formation of trunks in gross anatomy, neuroanatomy, and regional anesthesia modules, where a clean lateral perspective makes proximal plexus relationships easier to explain than a crowded anterior view. It also fits operative and procedural content on scalenectomy, first rib resection, and ultrasound-guided interscalene approaches for orthopedic shoulder surgery publications. Anatomical accuracy verified by SciePro's Medical Advisory Board.