88 OSSA MAXILLARIA SUPERIORA. 



bones securely, and it forms a small ridge upon which the edge 

 of the vomer, or partition of the nose, is planted. Thus we 

 find the palate plates of the maxillary bones conjoined, forming 

 almost the whole of the palate ; while what properly belongs to 

 the palate bones forms a very small share of the back part only, 



As these thinner bones of the face have no medulla, they are 

 nourished by their periosteum only, and are of course perforated 

 with many small holes. 



The anterior, external or facial surface of the upper maxil- 

 lary bone is concave ; the margin formed by the lower edge of 

 the orbit, by the malar process, and by the alveolar processes, 

 being more elevated than the central part, which consists of a 

 depression called \\\Q fossa canina, which gives attachment to 

 two muscles, the compressor nasi, and levator anguli oris. At 

 a small distance below the orbit is the infra-orbitary foramen 

 for transmitting a branch of the superior maxillary nerve. 

 When these two bones are applied to each other, and the ossa 

 nasi are in their places, they form the anterior orifice of the 

 nasal cavity, which has a small resemblance to the inverted 

 figure of the heart on cards. The concave border of the open- 

 ing of the nostrils, is projected forwards at its lower surface 

 into a sharp process, forming with a similar process at the oppo- 

 site side the nasal spine. Beneath the nasal spine, and above 

 the two superior incisor teeth, is a slight depression called the 

 incisive or myrtiform fossa, which gives origin to the depressor 

 labii superioris alaeque nasi muscle . 



The posterior zygomatic surface has been called a process 

 or tuber. The tuberosity is pierced by a number of small 

 foramina, giving passage to the posterior dental nerves, and 

 branches of the superior dental artery. It expands to a con- 

 siderable size, and is united internally and posteriorly to the ossa 

 palati. The great cavity extends from the bottom of the orbit 

 of the eye to the roof of the mouth, and from the anterior to 

 the posterior surface of the bone ; it opens in the cavity of 

 the nose, and is called antrum maxillare, or Highmorianum.* 

 There is but a small portion of bone between this cavity 



* After an anatomist who described it. 



