1574 A MANUAL OF ANATOMY 



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of all. Between the lingual nerve and the deep part of the submaxillary 

 gland he will, without much difficulty, be able to display the submaxillary 

 ganglion, and show its connections and the branches proceeding from it. 



In front of the hyo-glossus muscle the genio-hyo-glossus will be seen, and 

 resting upon it the dissector will find the sublingual gland, to which he should 

 give his attention. The genio-hyo-glossus cannot be dissected in full until 

 the mandible has been divided, and the tongue put upon the stretch by tying 

 its tip to the point of the nose. The following structures passing beneath 

 the posterior border of the hyo-glossus muscle are to be shown, in the following 

 order from above downwards: (i) the glosso-pharyngeal nerve; (2) the stylo- 

 hyoid ligament ; and (3) the lingual artery. 



The Face. — In the dissection of the face the dissectors of the head should, 

 if possible, dissect in concert. The muscles of expression should be shown 

 upon one side, together with the chief nerves and vessels. On the other side 

 a detailed dissection of all the nerves and vessels is to be made, which will 

 involve the division of certain of the muscles. The frontal and temporal 

 regions having been previously dissected, the skin is to be removed from 

 the face in an outward direction, for which purpose a median incision is to 

 be made frorn the root of the nose downwards to the symphysis of the inferior 

 maxilla. This incision is to embrace the nostril and one half of the oral 

 aperture. The reflection of the skin will be facilitated by making one or 

 more transverse incisions at the option of the dissector. An incision should 

 also be made around the orbit. The structures already dissected in the 

 frontal and temporal regions are to be revised. The orbicularis palpebrarum 

 is to be dissected by removing the skin very carefully from it in a direction 

 from the circumference to the ciliary margin of each eyelid, along which the 

 skin is to be cut. At the inner canthus the tendo palpebrarum or internal 

 tarsal ligament is to be displayed, and its relation to the lachrymal sac noted. 

 The corrugator supercilii is to be looked for arising from the inner end of the 

 superciliary ridge, and passing outwards and upwards under cover of the 

 frontalis. 



The pyramidalis nasi admits of easy dissection as it ascends from the 

 aponeurosis of the compressor naris over the nasal bone to the skin over the 

 glabella. The muscles between the eye, side of the nose, and upper lip are 

 next to be dissected, such as the compressor naris, levator labii superioris 

 alaeque nasi, levator labii superioris, depressor alae nasi, dilator naris anterior, 

 dilator naris posterior, levator anguli oris, and the two zygomatic muscles, 

 major and minor. The risorius of Santorini and the buccinator next fall to 

 be dissected, and in connection with the latter muscle the buccal pad of fat 

 is to receive attention, as well as the buccal lymphatic glands. The muscles 

 between the lower lip and the inferior maxilla come next in order, these being 

 the depressor anguli oris, depressor labii inferioris, and levator menti. The 

 last muscle is most easily shown by (i) everting the lower lip and dividing 

 the mucous membrane in the region of the incisor fossa of the inferior maxilla ; 

 and (2) dividing the skin at the median line close down to the bone, but 

 leaving the lower lip uncut. The dissection of the orbicularis oris requires 

 great care. The lips should be well everted, and maintained in this position. 

 The dissector is then to remove the mucous membrane, when the labial 

 mucous glands will be exposed. The deepest stratum of the orbicularis oris 

 is then to be dissected, and an effort made to expose the special muscles 

 which compose it, namely, (i) the musculus incisivus superior, coming from 

 the incisor fossa of the superior maxilla ; (2) the musculus naso-labialis, 

 coming from the back part of the nasal septum ; and (3) the musculus incisivus 

 inferior, coming from the incisor fossa of the inferior maxilla. The lips being 

 replaced in position, the superficial stratum of the orbicularis oris is to be 

 examined. It will be found to be composed of fibres derived from the elevators 

 and depressors of the angles of the mouth and lips, these fibres stopping at 

 the median line of each lip. The intermediate stratum of the muscle will 

 be seen to consist of buccinator fibres, those of opposite sides being directly 

 continuous at the median line. 



The nerves of the face are now to be fully dissected. The supra-orbital. 



