1052 DISSECTION OF THE HEAD AND NECK. 



lateral sinuses from that point to the jugular foramina. The cavernous 

 sinuses, joined together by means of the circular sinus, are then to be 

 opened ; and the superior and inferior petrosal sinuses, and the trans- 

 verse sinus (p. 461). In the vicinity of the cavernous sinus the relations of 

 the 3rd, 4th, 5th, and 6th nerves are to be exhibited, and also the internal 

 carotid artery and the Gasserian ganglion (pp. 594 and 359) ; after which 

 the nerves are to be replaced in situ and protected with cotton dipped in 

 spirits, that they may be ultimately traced forward in the dissection of the 

 orbit. The pituitary body is to be removed from its position in the sella 

 turcica, and its form and structure examined (p. 539). 



If the above examination of the sinuses cannot be accomplished, at this 

 stage of dissection, the interior of the skull must be carefully cleaned, and 

 protected from the air by replacing the skull-cap or otherwise. The dissectors 

 must also attend to the preservation of the parts at the back of the neck 

 before the subject is turned. 



3. Cervical Region superficially, and Posterior Cervical Triangle. It is 

 essential that within four days after the subject has been laid upon its back, 

 the dissection of the posterior and inferior triangle of the neck be completed, 

 so that the third part of the subclavian artery may be seen to advantage 

 before the clavicle and the vessels and nerves of the superior extremity are 

 divider] . 



With this view, a superficial dissection is advised of the whole cervical 

 region. Make an incision in the middle line from the sternum to the 

 chin ; another from the acromion, along the clavicle, to the sternum ; and 

 a third from the chin to the back of the ear ; and let the flaps so obtained 

 be reflected backwards ; care being taken not to injure the fibres of the 

 platysma myoides, nor the nerves which lie in the superficial fascia. The 

 platysma is to be examined and reflected upwards (p. 178) ; after which, 

 let the external and anterior jugular veins be laid bare, and also the cuta- 

 neous branches of the cervical plexus of nerves, viz. : superiorly, the super- 

 ficial cervical, great auricular, and small occipital nerves ; and, iuferiorly, the 

 suprasternal, supraclavicular, and supra-aero inial nerves : these will be 

 traced most easily from their line of emergenae at the posterior border of the 

 stern o-mastoid muscle (pp. 459 and 638). Let the disposition of the deep 

 cervical fascia also be noted (p. 197). 



The dissector will then cut down through the fat at the lower part of the 

 posterior border of the sterno-mastoid muscle, and uncover the omo-hyoid 

 muscle, whose posterior belly emerges from behind the sterno-mastoid, and 

 forms the superior boundary of the inferior division of the posterior triangle. 

 He will remove the fat and lymphatic glands from the inferior triangle, 

 until the scalenus anticus muscle is reached, which will serve as a guide to 

 the t*hird part of the subclavian artery and vein, and the superior trunks of 

 the brachial plexus of nerves (pp. 366 and 643). Besides these structures, 

 the dissector will observe, while engaged with this space, if the sterno- 

 mastoid muscle be narrow, the phrenic nerve upon the surface of the 

 scalenus anticus muscle ; he will find the suprascapular nerve and the 

 small branch to the subclavius muscle both coming from the trunk formed 

 by the fifth and sixth nerves, the transverse cervical and suprascapular 

 arteries, and part of the scalenus medius and posticus muscles, as well as the 

 lower set of the chain of lymphatic glands which lie along' the line of the 

 sterno-mastoid muscle (pp. 644 and 499), The superior part of the posterior 

 triangle is next to be dissected by clearing the upper attachments of the 

 scaleni muscles, with the splenius colli and levator scapulae (p. 177), when 



