[Variations of the constrictor pharyngeal muscles in humans].

Fifteen halves of ten nonrandomized human cadavers were dissected under a stereoscopic microscope in order to examine the existence of variations in the constrictor pharyngeal muscles. Obvious variations of the constrictor muscles were found in three cases. The results are summarized as follows: 1. In the first case of variations, the superior constrictors arose from the pterygomandibular raphe and merged into the outer surfaces of the middle and inferior constrictors. This muscle was supplied by the upper part of the pharyngeal branches of the vagus. 2. In the second case, the muscle bundle of inferior constrictors originated from the thyroid cartilage and passed upward, joining the muscular fibers of the outer surface of the superior constrictors arising from the pterygomandibular raphe. Some of these muscular fibers extended to the surface of the posterior part of the pharyngobasilar fascia. This muscle was innervated by the lower part of the pharyngeal branches of the vagus. 3. In the third case, the lower part of the superior constrictors passed laterally between the stylopharyngeus and the glossopharyngeal nerve, running between the external and internal carotids in the retrostyloid space and reaching the cervical fascia around the submandibular triangle. This anomalous muscular bundle of superior constrictors was innervated by the carotid branch of the glossopharyngeal nerve and the middle part of the pharyngeal branches of the vagus.