OSTEOLOGY 27 



foramen magnum and articulates with the atlas. At the base of 

 the condyle a small subcondyloid fossa receives the body of the atlas 

 during extreme flexion of the head. In the center of the lateral 

 wing of the occipital bone there is a small foramen through which_ 

 passes the hypoglossal nerve. Somewhat laterally from this foramen 

 there is an opening through which the vagus, or pneumogastric 



PIG. 6. View of the frontal region of the skull of a hen. I, Parietal. 2 

 Frontal. 3, Nasal. 4, Premaxilla. 5, Temporal. 6, Inferior jaw. 7, Jugal 



bone. 



nerve passes. Laterally from these is the canalis caroticus et ju- 

 gularis. Between the os occipitale superius, or dorsal portion, 

 and the ossa parietalia is a space to which ligaments are attached, 

 called the fontanel. 



The Ethmoid. Location. The ethmoid, or os ethmoidale, 

 forms the anterior wall of the cranium, and the orbital septum. 

 It is related anteriorly with the vomeral, superiorly with the nasal 



