PREVERTEBRAL REGION 263 



The next step in the dissection consists in making two saw- 

 cuts through the cranial wall. The head having been placed 

 upon its side, the saw must be applied to the lateral aspect of 

 the skull, half an inch posterior to the mastoid process, and be 

 carried obliquely forwards and medially to reach a point immedi- 

 ately posterior to the jugular foramen. A similar saw-cut must 

 be made upon the opposite side of the head. 



To complete the dissection the dissector must again use 

 the chisel. Placing the preparation so that the floor of 

 the cranial cavity looks upwards, divide the base of the skull, 

 on each side, in the interval between the petrous portion of the 

 temporal bone and the basilar portion of the occipital bone. 

 Anteriorly, this cut should reach the lateral extremity of the 

 incision already made through the basilar portion ; whilst 

 posteriorly, it should be carried to the medial side of the jugular 

 foramen to reach the medial end of the corresponding saw-cut. 

 When that has been done upon both sides of the basilar portion, 

 the anterior part of the skull, carrying the pharynx and the great 

 blood-vessels and nerves, can be separated from the posterior 

 part of the skull and cervical portion of the vertebral column. 

 The only large nerve which will be divided is the hypoglossal, 

 but, as it is cut close to the basis cranii, and above its connection 

 with the ganglion nodosum of the vagus, it retains its position. 



The pharynx and anterior portion of the skull should now 

 be covered with a piece of cloth soaked in preservative solution, 

 and the whole enveloped in an oil-cloth wrapper. It can then 

 be laid aside until the dissection of the prevertebral region and 

 the ligaments of the cervical vertebrae and the occiput has been 

 completed. 



Returning to the posterior part of the skull and the cervical 

 portion of the vertebral column, the dissector should proceed 

 to define the attachments of the muscles which lie anterior 

 to the transverse processes and the bodies of the vertebrae. 

 They are three in number on each side, viz. : 



1. The longus colli. 



2. The longus capitis (O.T. rectus capitis anticus major). 



3. The rectus capitis anterior (O.T. anticus minor). 



Musculus Longus Colli. The longus colli is the most 

 powerful of the prevertebral muscles of the neck, and it lies 

 nearest to the median plane. Its connections are somewhat 

 intricate, but when it has been thoroughly cleaned it will be 

 seen to consist of three portions viz., upper and lower 

 oblique parts, and a middle vertical part. 



The lower oblique division arises from the lateral aspect of 

 the bodies of the upper two or three thoracic vertebrae. It 

 extends upwards, and slightly laterally, and ends in two 

 tendinous slips which are inserted into the anterior tubercles 

 of the transverse processes of the fifth and sixth cervical 

 vertebrae. In the interval between that portion of the longus 

 colli and the scalenus anterior, the vertebral artery will be 

 in 17 c 



