AXIAL SKELETON 1 



1. Examine the skull of a Dog or Cat. Note that it consists of the 

 brain case (cranium), and the facial portion which forms the frame- 

 work of the face and j aws. Locate the bony sense capsules which enclose 

 and protect the nose, eyes, and ears. Observe the articulation of the lower 

 jaw (mandibles) at the posterior end of the skull with the posterior por- 

 tion of the prominent zygomatic arch. Note the similarity and the 

 relation of the teeth of both jaws and their adaptation for different pur- 

 poses. Various openings (foramina) are present in the skull bones, which 

 serve as exits for the cranial nerves and blood vessels. The largest of 

 these is the foramen magnum at the posterior end of the skull, through 

 which the spinal cord passes into the cranium. On each side of the fora- 

 men magnum is a smooth, rounded prominence (occipital condyle). 

 The condyles fit into depressions on the first vertebra of the vertebral 

 column, and thus articulate the skull with it. 



2. Examine the surface of the skull and note that it is composed of a 

 considerable number of bones which are jointed together by irregular 

 sutures. Identify the following bones : (a) the occipitals, which form 

 the posterior part of the skull around the foramen magnum; (b) the 

 parietals, which form a considerable portion of the dorsal and lateral 

 walls of the cranium ; (c) the temporals, in which the ears are located, 

 consist chiefly of the dorsal squamosal portions and he ventral to the 

 parietals. From each of them there is (d) a curved projection (zygo- 

 matic process) which unites anteriorly with (e) the malar bone to form 

 the zygomatic arch ; (/) the frontals which he anterior] to parietals 

 and dorsal to the eye ; (g) the median nasals which form the dorsal wall 

 of the nasal cavity ; (h) the maxillae and (£) the small premaxillae, 

 which together form the upper jaw and a large portion of the roof of the 

 mouth ; (j) the palatines which he in the roof of the mouth posterior to 

 the maxillary bones ; (k) the median sphenoids, posterior to the palatines ; 

 and (0 the mandible, or lower jaw. 



3. Draw the skull from the left side, showing as many as possible of the 

 parts mentioned above. 



4. Examine a vertebra from either the thoracic or lumbar region of the 

 spinal column. Note : (a) the large, solid centrum, with (b) the neural 

 arch lying dorsal and surrounding (c) the neural canal ; (rf) the trans- 

 verse processes for the attachment of muscles, projecting laterally from 

 each side ; (e) the neural spine, which projects dorsally from the neural 

 arch, and (/) the anterior and posterior articular processes. Draw 

 the vertebra from either an end or a side view. 



» B. pp. 175-179. 

 321 



