Triangles of the neck - neurovasculature (English)

The anatomical relationships between several neurovascular structures of the neck can be appreciated from this lateral perspective. The carotid arteries ascend through the neck, just deep to the internal jugular vein. Travelling medial to the internal jugular vein is the vagus nerve (CN X). The accessory nerve (CN XI) descends posterolaterally, emerging from behind the posterior border of the sternocleidomastoid muscle, where it receives sensory contributions from spinal nerves C3/4. Branches of the cervical plexus, ansa cervicalis and phrenic nerve are also located deep to the sternocleidomastoid muscle. Passing beneath the intermediate tendon of the omohyoid muscle is the transverse cervical artery which branches from the thyrocervical trunk to supply muscles of the neck and back. The suprascapular artery also branches from the thyrocervical trunk within the supraclavicular fossa and extends laterally to supply structures of the pectoral girdle. Also located within this region is the supraclavicular part of the brachial plexus which passes between the anterior and middle scalene muscles (interscalenic space).