The carotid sheath is a condensation of the deep cervical fascia enveloping multiple vital neurovascular structures of the neck, including the common and internal carotid arteries, the internal jugular vein, the vagus nerve (CN X), and ansa cervicalis. The carotid sheath helps protects the structures contained therein.

One carotid sheath is situated on each side of the neck, extending between the base of the skull superiorly and the thorax inferiorly.

Superiorly, the carotid sheath encircles the margins of the carotid canal and jugular foramen.

Inferiorly, it terminates at the arch of the aorta; it is continuous inferiorly with the axillary sheath at the venous angle. Its inferior end occurs at the level of the first rib and sternum inferiorly (varying between the levels of C7 and T4).^{[citation needed]}

The carotid sheath is a fibrous connective tissue formation surrounding several important structures of the neck. It is thicker around the arteries than around the vein, allowing the vein to expand.

The three major fascial layers in the neck contribute to the carotid sheath: the investing fascia, the pretracheal fascia, and the prevertebral fascia. The carotid sheath has limited loose connective tissue.

Structures contained within the carotid sheath include the:

The carotid sheath occurs at the level of the oropharynx.