1058 DISSECTION OF THE HEAD AND NECK. 



anterior belly of the digastric muscle is to be divided at the chin and 

 turned down. The mylo-hyoid muscle is to be separated from its fellow 

 in the middle line and from the hyoid bone, and reflected toward the jaw, 

 in order to expose the deeper parts. The tongue is to be put on the 

 stretch by fastening it forward ; the lower jaw is to be divided by a 

 vertical saw-cut between the first and second incisor teeth, leaving intact 

 the attachment of the genio-hyoid muscle ; the fragment of loose bone is 

 to be raised, and the mucous membrane of the mouth slit up to the tip of 

 the tongue. The dissector will first trace carefully out the gustatory 

 nerve, where it is in contact with the submaxillary gland, and will exhibit 

 the submaxillary ganglion connected with it (p. 609). He will then isolate 

 the submaxillary and sublingual glands, and will observe the relations of 

 Wharton's duct, the sublingual ducts, and the gustatory and hypoglossal 

 nerves (p. 816). He will examine the hyoglossus muscle, the genio-hyoid, the 

 genio-hyoglossus, stylo-glossus, and stylo-pharyngeus muscles (p. 185) ; also 

 the glosso-pharyngeal nerve (p. 615), and the stylo-hyoid ligament (p. 52). 

 On dividing the hyo-glossus muscle, the subjacent part of the lingual artery 

 may be followed into its sublingual and raiiiue branches ; its small hyoid 

 branch and its branch to the dorsum of the tongue may also be seen ; as well 

 as those deep branches of the facial artery which have not yet been ex- 

 amined, viz., the ascending palatine and the tonsillar branches (p. 348). 



10. Parts close to the external basis of the Cranium. If the styloid pro- 

 cess be nipped through at its base and thrown down with the three styloid 

 muscles attached, the dissector will be enabled to examine more particularly 

 the pharyngeal plexus of nerves (p. 690). He may then also examine the 

 relations of the internal carotid artery and internal jugular vein (p. 359) : 

 and he will follow up the hypoglossal, spinal accessory, pneumo-gastric, 

 glosso- pharyngeal, and sympathetic nerves to the basis of the skull ; 

 examining the connexions of the superior ganglion of the latter with the 

 other nerves mentioned, and with the anterior divisions of the upper cer- 

 vical nerves (p. 620). The jugular foramen and the carotid canal are to be 

 opened into ; and the eighth nerve, and the internal carotid artery with the 

 carotid plexus accompanying it, are to be followed into the interior of the 

 cranium (pp. 619 and 688). Before leaving this part of the dissection, the 

 students dissecting the head ought to make together a complete revision of 

 all the parts in connexion with the basis of the cranium. 



11. Pharynx, Larynx, Palate, Tongue, Nares, <&c. Let the remains of 

 the carotid arteries be removed, and the pharynx drawn away from its 

 loose connection with the upper cervical vertebrae ; and let the base of the 

 skull be divided between the pharynx and the recti capitis antici muscles ; 

 then, leaving the neck and back part of the skull for a later examination, 

 let the pharynx, with the parts in its vicinity, be prepared for dissection by 

 distending its walls with hair or tow. The constrictor muscles of the 

 pharynx are to be cleaned and examined, as also the origins of the levator 

 and circumflexus palati muscles (p. 187). The next step is to open the 

 pharynx from behind, by an incision in the middle line, and a transverse 

 one close to the base of the skull ; and to examine the apertures of the 

 nares, fauces, glottis, oesophagus, and Eustachian tubes (p. 819). The 

 muscles of the soft palate are then to be dissected ; more particularly the 

 insertions of the levator and circumflexus palati ; the palato-pharyngeus 

 and palato-glossus corresponding in position to the posterior and anterior 

 pillars of the fauces, and in the middle line the azygos uvulae (p. 189). The 

 Eustachian tube should also be dissected out. 



