LACHRYMAL AND MALAR BONES. 77 



poition lying externally to the infra-orbital groove and canal ; and one 

 for the palate process. The superior maxillary bone is one of the earliest 

 to show signs of ossification, this process beginning in the alveolar pro- 

 cess, and being associated with the early development of teeth. The 

 early development of the alveolar process, and the consequent fusion at 

 this point of the original pieces, explains the difficulties which have been 

 felt by anatomists in determining the precise number of the ossifying cen- 

 tres of this bone. 



Articulations. With nine bones; viz. with two of the cranium, and 

 with all the bones of the face, excepting the inferior maxillary. These 

 are, the frontal and ethmoid; nasal, lachrymal, malar, inferior turbinated, 

 palate, vomer, and its fellow of the opposite side. 



Attachment of Muscles. To nine; orbicularis palpebrarum, obliquus 

 inferior oculi, levator labii superioris alseque nasi, levator labii superioris 

 proprius, levator anguli oris, compressor nasi, depressor labii superioris 

 alseque nasi, buccinator, masseter. 



LACHRYMAL BONES (os unguis, from an imagined resemblance to a 

 finger-nail). The lachrymal is a thin oval-shaped plate of bone, situated 

 at the anterior and inner angle of the orbit. It may be 

 divided into an external and internal surface and four bor- 

 ders. The external surface is smooth and marked by a ver- 

 tical ridge, the lachrymal crest, into two portions, one of 

 which is flat and enters into the formation of the orbit, hence 

 may be called the orbital portion ; the other is concave, and 

 lodges the lachrymal sac, hence, the lachrymal portion. 

 The crest is expanded inferiorly into a hook-shaped process 

 (hamulus lachrymalis), which forms part of the outer boundary 

 of the fossa lachrymalis. The internal surface is uneven, and completes 

 the anterior ethmoid cells ; it assists also in forming the wall of the nasal 

 fossae and nasal duct. The four borders articulate with adjoining bones. 



Development. By a single centre, appearing in the early part of the 

 third month. 



Articulations. With four bones : two of the cranium, frontal and 

 ethmoid ; and two of the face, superior maxillary and inferior turbinated 

 bone. 



Attachment of Muscles. To one muscle, the tensor tarsi, and to an 

 expansion of the tendo oculi, the former arising from the orbital surface, 

 the other being attached to the lachrymal crest. 



MALAR BONES (mala, the cheek). The malar (fig. 39) is the strong quad- 

 rangular bone which forms the prominence of the cheek. It is divisible 

 into an external and internal surface and four processes, the frontal, orbital, 

 maxillary, and zygomatic. The external surface is smooth and convex, 

 and pierced by several small openings which give passage to filaments of 

 the temporo-malar nerve and minute arteries. The internal surface is 



* The lachrymal bone of the right side, viewed upon its external or orbital surface. 

 1. The orbital portion of the bone. 2. The lachrymal portion ; the prominent ridge 

 between these two portions is the crest. 3. The lower termination of the crest, the 

 hamulus lachrymalis. 4. The superior border which articulates with the frontal Done. 

 5. The posterior border, which articulates with the ethmoid bone. 6. The anteiior 

 border, which articulates with the superior maxillary bone. 7. The border which arn 

 culates with the inferioi turbinated bone. 

 7* 



