THE ANTERIOR REGION OF THE SKULL. 217 



three on the posterior wall: the foramen rotund urn above: below and internal to 

 this, the 1'idian : and still more inferiorly and internally, \hepterygo-palatine. On 

 the inner wall is the spheno-palatine foramen, by which the spheno-maxillary 

 couiniunicates with the nasal fossa : and below is the superior orifice of the 

 posterior palatine canal, besides occasionally the orifices of the accessory posterior 

 palatine canals. The fossa contains the superior maxillary nerve and Meckel's 

 ganglion, and the termination of the internal maxillary artery. 



The Anterior Region of the Skull. 



The Anterior Region of the Skull, which forms the face, is of an oval form, 

 presents an irregular surface, and is excavated for the reception of two of the 

 organs of sense, the eye and the nose. It is bounded above by the glabella and 

 margins of the orbit ; below, by the prominence of the chin ; on each side by the 

 malar bone and anrerior margin of the ramus of the jaw. In the median line are 

 seen from above downward the glabella. and diverging from it are the superciliary 

 ridges, which indicate the situation of the frontal sinuses and support the eyebrows. 

 Beneath the glabella is the fronto-nasal suture, the mid-point of which is termed 

 the nasion. and below this is the arch of the nose, formed by the nasal bones, and 

 the nasal processes of the superior maxillary. The nasal arch is convex from side 

 to side, concave from above downward, presenting in the median line the inter- 

 nasal suture formed between the nasal bones, laterally the naso-maxillary suture 

 formed between the nasal bone and the nasal process of the superior maxillary 

 bone. Below the nose is seen the opening of the anterior nares, which is heart- 

 shaped, with the narrow end upward, and presents laterally the thin, sharp 

 margins serving for the attachment of the lateral cartilages of the nose, and in the 

 middle line below a prominent process, the anterior nasal spine, bounded by two 

 deep notches. Below this is the intermaxillaru suture, and on each side of it the 

 incisive fossa. Beneath this fossa are the alveolar processes of the upper and 

 lower jaws, containing the incisor teeth, and at the lower part of the median line 

 the symphysu of the chin, the mental process, with its two mental tubercles, 

 separated by a median groove, and the incisive fossa of the lower jaw. 



On each side, proceeding from above downward, is the supraorbital ridge, 

 terminating externally in the external angular process at its junction with the 

 malar, and internally in the internal angular process: toward the inner third of 

 this ridge is the supraorbital notch or foramen, for the passage of the supraorbital 

 Is and nerve, and at its inner side a slight depression, for the attachment of 

 the pulley of the Superior oblique muscle. Beneath the supraorbital ridge is the 

 opening of the orbit, bounded externally by the orbital ridge of the malar bone ; 

 below, by the orbital ridge formed by the malar and nasal process of superior max- 

 illary : internally, by the nasal process of the superior maxillary and the internal 

 angular process of the frontal bone. On the outer side of the orbit is the quadri- 

 lareval anterior surface of the malar bone, perforated by one or two small malar 

 foramina. Below the inferior margin of the orbit is the infraorbital foramen, the 

 termination of the infraorbital canal, and beneath this the canine fossa, which gives 

 attachment to the Levator anguli oris ; bounded below by the alveolar processes, 

 containing the teeth of the upper and lower jaws. Beneath the alveolar arch of 

 the lower jaw is the mental foramen, for the passage of the mental vessels and 

 nerve, the external oblique line, and at the lower border of the bone, at the point 

 of junction of the body with the ramus, a shallow groove for the passage of the 

 facial artery. 



The Orbits. 



The Orbits (Fig. 175) are two quadrilateral pyramidal cavities, situated at the 

 upper and anterior part of the face, their bases being directed forward and 

 outward, and their apices backward and inward, so that the axes of the two. if 

 continued backward, would meet over the body of the sphenoid bone. Each orbit 

 is formed of seven bones, the frontal, sphenoid, ethmoid, superior maxillary, malar. 



