 It forms the posterior limit of a fibrous compartment, which contains the larynx and trachea, the thyroid gland, and the pharynx and esophagus.Parallel to the carotid sheath and along its medial aspect the prevertebral fascia gives off a thin lamina, the buccopharyngeal fascia, which closely invests the constrictor muscles of the pharynx, and is continued forward from the constrictor pharyngis superior on to the buccinator.Anterior to it, the alar (retrovisceral) fascia is attached to it by loose connective tissue only, and thus an easily distended space, the retropharyngeal space, is found between them.