Table XI

Inside the open pharynx cavity, we can see the pharyngeal isthmus with the tongue root and the palatine tonsils, the back of the larynx covered by its mucous membrane and, on the sides, the piriform recesses and, on the top, the pharynx outlets of the auditory tubes.

We can see the vagus nerve, descending the neck vertically behind the internal carotid and then the common carotid artery, with its branches directed to larynx and pharynx. We can notice: the superior laryngeal nerve which emerges in front of the external carotid and divides into its two branches: the internal, the bigger of the two descending under the thyrohyoid muscle, the outer, thinner, coursing behind the superior thyroid artery; the recurrent (or inferior) laryngeal nerve appears at the base of the neck in the angle of bifurcation of the brachiocephalic trunk, then is hidden behind the common carotid artery and appears again higher up over the inferior thyroid artery. The superior and inferior pharyngeal branches are connected to the side-wall of the pharynx; the bottom one derives from the recurrent laryngeal nerve. On the top part of the neck the hypoglossus nerve (here, to sustain it, the nerve has been placed over the medial side of the external carotid) emits, when it crosses the internal carotid, its descending branch which joins below a branch of the cervical plexus (applied to the scaleni muscles) forming the ansa cervical is; arising from the latter we can see the branches for the infrahyoid muscles excepting of the one for the thyrohyoid which is innervated directly from the hypoglossus nerve.

We can observe how the recurrent nerve, climbing upwards between the trachea and the oesophagus, gives small branches to these two organs and how, at the inferior margin of the cricoid cartilage, divides into an anterior branch for the lateral muscles of the larynx (to show this the right lamina of the thyroid cartilage has been cut and turned forwards) and a posterior one which innervates the posterior laryngeal muscles and then joins the inner branch of superior laryngeal nerve (clearly visible near the greater horn of the hyoid bone) forming the communicating branch (ansa Galeni).