Table XVI

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Organ of taste

This is a model of the head and the neck in which attention is drawn to nerves of the tongue for their full lenght. Among these three nerves that go to the tongue, each forming an arch, one can recognize: anteriorly the lingual nerve, originating just below the foramen ovale of the sphenoid bone (scalpelled and open) from the mandibular division of the trigeminal nerve, that goes to the margin of the tongue having below it the submandibular ganglion.

Behind, and medially to the lingual nerve, the glossopharyngeal nerve appears over the styloid process of the temporal bone, posteriorly, and then lateral, to the internal carotid artery on which it detaches some pharyngeal branches. It is then hidden by the styloglossus muscle (resected) but appears again on the lateral wall of the pharynx finally reaching the root of the tongue where, under the mucosa, here raised, it emits its terminal branches.

More posteriorly, the hypoglossal nerve appears behind the vagus nerve and crosses laterally the same nerve and both the internal and external carotid artery (the latter sectioned just after emitting the external maxillary and the lingual arteries). It then goes under the tongue ending in a number of muscular branches.

In this preparation the vagus nerve is clearly visible, first behind the internal carotid artery, and behind the common one. In this nerve we notice, along its lenght, the inferior ganglion and, of its branches, the superior pharyngeal nerve, the superior laryngeal nerve, the superior cardiac nerve and the inferior laryngeal nerve; furthermore, over the anterior vertebral muscles, there is the trunk of the cervical sympathetic with the superior cervical ganglion at whose lower end originates the superior cardiac nerve, and with the middle cervical ganglion from which the ansa subclavia (of Vieussens) is detached which encircles the subclavian artery and then joins the stellate ganglion (here the latter is hidden by the artery).

One can also observe two tongues, a human and a bovine one, with demonstrations of the mucosa. In the cow tongue (reproduced in a smaller size), in the right half of its dorsum, the mucosal epithelial layers are demonstrated as they can be obtained by means of the anatomical artifice described by Malpighi in the De lingua, consisting of boiling it and dividing it into laminae.

After removing the cornified layer, the pigmented black layer is exposed and is subsequently removed and pushed forward in order to highlight the reticular (white) layer; the latter is then taken away next at the tip of the tongue in order to show its corium. In the human tongue the epithelium has been raised disclosing the corium of the mucosa together with its papillae.

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