The carotid triangle is formed from the sternocleidomastoid forming a base for 2 muscles attaching to the hyoid - posterior belly of digastric and omohyoid.
It gets its name because carotid vessels pass through it, and the common carotid bifurcates in it.
Lateral boundary: Sternocleidomastoid
Superior Medial: posterior belly of digastric
Inferior Medial: omohyoid.
Roof: skin/superficial fascia/platysma then the investing layer of deep fascia (the most superficial layer of deep fascia).
Floor: Pretracheal Fascia covering the muscles (inferior constrictor/middle constrictor) surrounding the midline viscera.
Vessels related to the Carotid Sheath
ECA + 5 branches
IJV + tributaries
**Nerve to carotid bulb (branch of glossopharyngeal)
Last 3 cranial Nerves
Superior Laryngeal and Branches coursing medially
Hypoglossal looping around occipital artery anteriorly/superficially.
Spinal Accessory Laterally.
Cervical" Nerves - Ansa Cervicalis and Cervical Sympathetic Trunk.
Ansa Cervicalis, superficial loop of nerves from the superior and inferior roots of the cervical plexus (c1 + c2,3) that supply infra-hyoid muscles.
Cervical Symphathetic Chain running posteriorly along the prevertebral fascia.