60 SPECIAL ANATOMY. 



Figure : a right angle, consisting of a horizontal palate por- 

 tion, and a narrow vertical plate. 



Conjunctions: with one another and with the upper jaws, the 

 sphenoid bone, the inf. Turbinate and the Vomer. 



1. Pars horizontalis ; a. Superior surface, which forms the floor of the nasal 

 cavity, with the Crista nasalis for the Vomer. 



b. Inferior surface, which forms the buccal cavity ; hard palate, with spina 

 nasalis posterior, for m. levatores uvula. The internal border forms the sutura 

 Palatina, the anterior, sut. cruciata. 



2. Pars ascendens, thin, quadrilateral, longer and broader than the plate 

 before described, from the external border of which it ascends on the nasal 

 wall of the upper jaw, even to the orbit. 



1. Internal surface presents, the linea transvers. s. crvsta turbinalis media and 

 inferior, for the inferior and middle turbinate bones. 



2. External surface lies anteriorly on the upper jaw, behind on the pterygoid 

 process ; presents Sulcus palatinus, a part of the Canal, pterygo-palatinus, for 

 art. and nerv. 



3. Processes : a. Proc. pyramidalis, triangular, external and posterior, lies in 

 the incisur a pterygoid. of the Sphenoid. On it two canals; Can. palatinus extern. 

 and intern, between fossa spheno-maxillar. and palate, for nerv. and art. palatin. 

 Above : 



b. Proc. orbitalis ; triangular, looks with its superior surface into the orbit, 

 lies with the external, behind on the upper jaw, with the internal on the pa- 

 pyraceous plate of the Ethmoid. Behind it, inclining backwards : 



c. Proc. sphenoidalis, to the Body and the cornua of the sphenoid. 

 Between the processes b and c, and the body of the sphenoid, the Foram. 



sphenopalatinum, for the nervi na&ales, art. et ven. spheno-palatina, leads from 

 the fussa spheno-maxillar into the nose. 



Development. The first osseous nucleus appears about the 

 40th to the 50th day at the point of junction of the processes. 

 The orbital process is yet wanting at birth. 



61. 3. Ossa Malaria s. jugatia, s. zygomatica, Malar, 

 Cheek bones, 2. 



Situation : at the superior lateral parts of the face, externally 

 upon the upper jaws. 



Shape : an irregular quadrangle, consisting of a body and three 

 processes. 



Conjunctions with: Frontal, sphenoid, sup. maxillary and tem- 

 poral bones. 



1. Body, with 3 surfaces and 3 borders ; contains sometimes a cavity, the 

 size of a bean, sinus jugalis (Mayer), especially in Mongolians and Malays, 

 which is connected with the Antrum of Hightnore. 



a. External, facial surface, convex, for muse, orblcularis palpebrarunt^zygo- 

 maticus major et minor / it presents foramen zygomatic. anterius, sometimes 

 several ; this is the commencement of the canal, zygomat. (inter. 



b. Internal, orbital surface 5 this is the anterior part of the orbit ; externally 



