Bones of the Skull. 



Ala mag-na 



Corpus 

 Ala parva Concha sphenoidalis Fissura orbitalis superior 



I Apertura sinus 

 ; sphenoidalis 

 Foramen 

 opticum 



Facies orbitalis 



Crist, sph. 

 Kostr. sph. 

 Can.basiphar. 

 Proc. vaginalis 



Can. pharyngeus 

 Can. pterygoideus,' 

 Sulcus pterygopalat. 



Facies 

 temporalis 



Margo 

 zygomaticus 



I'ro''ssns 

 pterygoidens 



Lamina medialis 

 Pulcns hamuli 



Crista infra- 

 temporalis 



Facies infra- 

 temporalis 

 Spina angularis 

 Foramen rotundum 

 Facies sphenomaxillaris 



- - Lamina lateralis 



Fissura pterygoidea 

 Hamulus pterygoideus 



5. Sphenoid bone, os sphenoidale, from in front. 



The alae magnae ossis sphenoidalis (large wings of the sphenoid bone) (see also 

 Figs. 4, 6, 55, 56, 59, 60 and 63 71) arise from the lateral surface of the body of the bone 

 and turn first lateralward, then upward and forward. Each possesses an upper, internal, 

 concave surface or fades cerebralis with jug a cerebralia and impressiones digitalae, and a 

 much divided external surface. Of the latter, the quadrangular part which, median ward, is 

 directed forward into the orbit, is called the orbital surface or fades orbitalis ; its posterior 

 border is smooth and together with the ala parva forms the fissura orbitalis superior (for the 

 vv. ophthalm. sup. et inf. ; nn. oculomot., trochlearis, ophthalm., abducens) ; the inferior border, 

 also smooth, forms, along with the posterior border of the orbital surface of the maxilla, the 

 fissura orbitalis inferior (for the a. infraorbital. ; v. ophthalm. inf. ; nn. zygomat., infraorbit.) ; 

 the lateral serrated border, margo zygomaticus, unites with the frontosphenoidal process of the 

 zygomatic bone to form the sutura sphenozygomalica ; the lateral superior angle, a part of the 

 margo frontalis, unites with the orbital portion of the frontal bone and thus helps to form the 

 sutura spheno frontalis. Below the orbital surface and encroaching upon the pterygoid process 

 lies the triangular fades sphenomaxillaris (sphenomaxillary surface) which helps to form the 

 fossa pterygopalatina. The rest of the external surface is divided by the crista infratemporalis 

 (0. T. pterygoid ridge), passing from before backward, into an inferior, horizontal field or fades 

 infratemporalis (for the m. pterygoid. ext.) which looks into the fossa infratemporalis, and a superior 

 vertical field or fades temporalis (for the m. temporalis). The posterior border of the latter, margo 

 squamosus, is serrated below, somewhat bevelled from without inward above, and serves for appo- 

 sition with the squama temporalis (sutura spkenosquamosa). The uppermost angle 1 (angulus 

 parietalis), is bevelled from within and lies upon the angulus sphenoidalis oss. parietalis (sutura 

 sphenoparietalis). Passing downward from the most posterior angle of the large wing is the spina 

 angularis (0. T. spinous process of the sphenoid) (for the lig. sphenomandibulare ; m. tensor 

 veli palatini). In addition, there extends from this point forward and medianward, a short, 

 serrated margin for apposition with the angulus anterior of the petrous portion of the temporal 

 bone (fissura and synchondrosis sphenopetrosa). Perforating the root of the large wing are 

 three foramina : passing forward from above and behind, to the sphenomaxillary surface is the 

 foramen rotundum (for the n. maxillaris) ; passing downward, from above, to the infratemporal 

 surface is the foramen ovale (for the rete fojaminis ovalis; n. mandibul.); and the foramen 

 spinosum (for the a. mening. med., vv. meningeae mediae ; n. spinosus, plexus inening.) ; the 

 latter foramen lies just in front of the most posterior angle and is sometimes incomplete. 



