THE SPHENOID 



31 



wall of the or])it; it forms the inniT l)oundary of the sphenoidal fissure, and more 

 posteriorly is grooved for the internal earotid artery and eavernous sinus. 



Tlie process of hone over wliieh this artery turns is the lingula ; it constitutes a 

 flying Inittress for the su)»p()rt of the greater wings. 



The lesser or orbital wings (()rl)ito-sphenoids) are thin, triangular, horizontal 

 plates of ])on(? resting U})on that portion of the sphenoid anterior to the olivary 

 ridge (pre-sphenoid). The superior surface of each wing is smooth and slightly 



Fig. 37. — The Llit II.\lk of thk Sphenoid. 



ANTERIOR CLINOID PROCESS 



MIDDLE CLINOID PROCESS 



POSTERIOR CLINOID PROCESS 



ETHMOIDAL SPINE 



THE LIMBUS 

 OPTIC GROOVE 

 OLIVARY EMINENCE 



DORSUM EPHIPPII 



FOR OCCIPIfAU 



concave, and forms the posterior part of the anterior fossa of the skull; the under 

 surfaces constitute a portion of the roof of each orbit, and l)0und superiorly the 

 sphenoidal fissures. The anterior })order is serrated for articulation with the 

 horizontal plate of the frontal bone. The posterior border, smooth and rounded, 

 is received into the Sylvian fissure of the cerebrum. The inner extremity is i)ro- 

 longcd to form the anterior clinoid process to which the tentorium cerebelh is 

 attached. Each lesser wing is connected to the body of the bone by two processes 



Fig. 38. — The Sphenoid. (Anterior view 



OPTIC FORAMEN 



SPHENOIDAL FISSURE 



ORBITAL SURFACE (THE 

 POINTER CROSSES THE "C 

 MALAR CREST) 



cXT. PTERYGOID PUTE 



FORAMEN ROTUNOUM 



PTERYGOID NOTCH 

 HAMUUR PROCESS 



PTERYGO-PALATINE CANAL 



or roots; of these, the upper is thin and fiat, the lower one is thicki^r, and ])resents 

 near its junction with the body a small tubercle for the attachment of the common 

 tendon of three ocular muscles. The opening between the roots is tlie optic 

 foramen, and transmits the optic nerve and o})hthalmic artery. 



The greater wings ( ;ili-si)henoids) are two large plat(\s of l)one ankylosed to the 

 l^'xly by means of the lingulae. Each wing has three surfaces. The superior or 

 cerebral surface is concave and smooth; it supports tlie teinporo-spheiioidal lobe 

 of the ceriliium, and presents several foramina. At the anterior and internal part is 



