The carotid sheath is a condensation of the deep cervical fascia[1]: 578  enveloping multiple vital neurovascular structures of the neck,[2] including the common and internal carotid arteries, the internal jugular vein, the vagus nerve (CN X), and ansa cervicalis.

[2] One carotid sheath is situated on each side of the neck,[3][4]: 266  extending between the base of the skull superiorly[2][4]: 266  and the thorax inferiorly.

[citation needed] The carotid sheath is a fibrous connective tissue formation surrounding several important structures of the neck.

[2]: 551 The carotid sheath is situated at each lateral boundary of the retropharyngeal space,[3] deep to the sternocleidomastoid muscle.

[2] The carotid sheath may act as a conduit for infections, although this is rare due to the limited connective tissue.