FACE. 



217 



and process ; the condyles and angles of the 

 jaw, its alveolar border and its base, which 

 terminates it below, and near which, at the 

 chin, are seen the depressions for the .digastric 

 muscles. 



The lateral or zygomatic surfaces on each 

 side are bounded above by the temporal border 

 of the malar bone and by the zygomatic arch ; 

 in front by a line extended vertically from the 

 external angular process of the frontal bone to 

 the base of the lower jaw, and behind and 

 below by the free border of the body and ramus 

 of the inferior maxilla. 



This region presents a superficial and a deep 

 portion : the former comprises the lateral aspect 

 of the malar bone, the zygomatic arch, and 

 the external surface of the ramus of the jaw. 

 On it we may remark, proceeding from above 

 downwards, the temporal border of the malar 

 bone and zygoma, forming the outer boundary 

 of the temporal fossa; the external malar holes, 

 the zygoma and its suture, which unites the 

 malar and temporal bones ; the inferior or 

 masseteric border of the zygoma, the sigmoid 

 notch of the lower jaw and the outer surface of 

 its ramus, coronoid and condyloid processes 

 and angle. The deeper division of this region 

 presents the large zygomatic fossa, and is 

 situated internal to the ramus of the jaw, which 

 forms its outer boundary, and which must be 

 removed to expose it completely : this done, 

 the fossa is brought into view, bounded in 

 front by the posterior surface of the upper jaw 

 and part of the malar bone ; superiorly by the 

 inferior surface of the great wing of the sphe- 

 noid below its temporal ridge; at this part of 

 the fossa are seen the spheno-temporal suture, 

 the spinous process, and the spinous and oval 

 foramina of the sphenoid bone. The narrow 

 inner boundary is formed by the external ptery- 

 goid plate of the sphenoid; behind and below 

 the fossa is open. At the bottom of the zygo- 

 matic fossa is situated the pterygo-maxillary 

 fissure, forming the external orifice of the 

 spheno-maxillary fossa, which is a cavity 

 situated between the tuberosity of the upper 

 jaw in front, and the pterygoid process and 

 palate bone behind : in this fossa are five holes, 

 viz. three which open into it from behind, the 

 foramen rotundum, the vidian or pterygoid, 

 and the pterygo-palatine ; one opening inter- 

 nally at the upper part; the spheno-palatine ; 

 one below, the upper orifice of the posterior 

 palatine canal. The zygomatic fossa presents 

 also at its upper and anterior part, the spheno- 

 maxillary fissure, which is directed from within 

 outw^ards and forwards, and is formed inter- 

 nally by the orbitar processes of the palate and 

 upper maxillary bones, externally by the orbitar 

 plate of the sphenoid, and at its outer extremity, 

 which is large, by the malar bone ; it forms a 

 communication between the orbit and the zygo- 

 matic fossa. Its inner end joins the spheuoidal 

 and the pterygo-maxillary fissures, with the 

 former of which it forms an acute, and with 

 the latter, a right angle: thus these three 

 fissures may be considered as branching from 

 a common centre at the back of the orbit; they 

 give passage to a number of vessels and nerves, 



and establish communications between the cavL 

 ties of the face and cranium. 



The superior or cranial region is very irregu- 

 lar, and is immoveably united to the cranium. 

 It presents along the median line, from before 

 backwards, the articulation of the nasal bone, 

 with the nasal spine of the frontal, the union 

 of this spine with the perpendicular plate of 

 the ethmoid, the articulation of this plate with 

 the vomer, the articulation of the vomer with 

 the sphenoid. 



Along the sides, from within outwards, are 

 seen the arched roof of the nasal fossae formed 

 in front of the nasal bones, in the middle by 

 the cribriform plate of the ethmoid, and behind 

 by the body of the sphenoid. External to these 

 parts are found the base of the pterygoid process, 

 the articulation of the palate with the body of 

 the sphenoid bone, the pterygo-palatine canal, 

 the spheno-palatine foramen ; next the spongy 

 masses of the ethmoid united behind with the 

 sphenoid, and anteriorly with the os frontis; 

 and still more forwards are seen the articula- 

 tions of this bone with the lachrymal, upper 

 maxillary, and nasal. To the outer side of 

 these articulations is the triangular roof of the 

 orbit, limited externally by the sphenoid and 

 malar bones and by the sphenoidal fissure. 

 Next may be observed the orbitar plates of the 

 sphenoid, forming the greater part of the outer 

 wall of the orbit, and lastly the zygoma. The 

 inner border of the orbitar plate of the frontal 

 bone presents the fronto-lachrymal and the 

 frontal-ethmoidal sutures ; the outer border the 

 spheno-frontal and fronto-jugal sutures. 



The internal structure of the face appears 

 to be very complex, presenting several cavities 

 and divisions which give it at the same time 

 strength and lightness. The arrangement of 

 these parts may be understood by observing, 

 1. the perpendicular septum formed by the 

 ethmoid and vomer, which divides the upper 

 part of the face into two equal halves ; 2. in 

 each half three horizontal divisions, viz. an 

 upper or frontal, which separates the cranium 

 from the orbit ; a middle or maxillary, placed 

 between the orbit and the cavity of the nose, 

 and an inferior or palatine situated between the 

 nose and mouth; 3. three outer divisions, viz. 

 an upper or spheno-jugal, forming the outer 

 wall of the orbit, and separating that cavity 

 from the temporal fossa; a middle, formed by 

 the maxillary tuberosity which separates the 

 cavity of the nose from the spheno-maxillary 

 and zygomatic fossae ; an inferior, formed by 

 the raraus of the jaw; 4. above and at the 

 centre the ethmoid and lachrymal bones sepa- 

 rate the orbits from each other and from the 

 cavities of the nose. 



The principal cavities of the face are the 

 orbits, the nasal fossae, and the mouth ; and 

 with these all the rest are more or less con- 

 nected. These cavities will be described under 

 the several articles, ORBIT, NOSE, MOUTH. 



Mechanism of the face. The face forms a 

 structure which combines both strength and 

 lightness ; the former quality is owing to the 

 arched form of its exterior and to the strong 

 pillars of supports (to be presently described; 



