Bones of the Skull. 



59 



Sinus frontalis - ' 



Pars orbitalis 

 ossis frontalis 



Lamina cribrosa . 

 ossis ethmoidalis 



Corpus ossis _ 

 sphenoidalis 



Os lacrimale 



Lamina papyracea ossis ethmoidalis 



Corpus maxillae 

 / Sulcus infraorbitalis 



Os zygomaticum 



Processus orbitalis 

 ossis palatini 



Corpus ossis 

 spbenoidalis 



Fissura orbitalis superior [Foramen ovale 

 Foramen rotundum 



72. Right Orbital Cavity, orbita, inferior wall, from above. 



The inferior wall of the orbit, paries inferior, (see also Figs. 69 and 70) is inclined 

 somewhat obliquely downward, forward and lateralward. It is formed chiefly by the facies 

 orbitalis corporis maxillae, besides, lateralward, by a part of the facies orbitalis oss. zygomatici, 

 and behind by the processus orbitalis oss. palatini. At the boundary between the inferior and 

 the medial wall one sees the sutura lacrimomaxiltaris (between os lacrimale and corpus 

 maxillae), the sutura ethmoideomaxillaris (between os ethmoidale and corpus maxillae), the 

 sutura palatoethmoidalis (between os ethmoidale and proc. orbitalis oss. palatini), the sutura 

 sphenoorbitalis (between corpus oss. sphenoidalis and processus orbitalis oss. palatiui), besides, 

 near the posterior angle, the sutura palatomaxillaris (between corpus maxillae and processus 

 orbitalis oss. palatini) and near the lateral margin the sutura zyrjomaticomaxillaris (between 

 processus zygomaticus maxillae and os zygomaticum). It is united by bone with the lateral 

 wall only in the anterior half, but is separated from it in the posterior half by the fissura 

 orbitalis inferior (0. T. sphenomaxillary fissure). This slit, running between the posterior 

 margin of the facies orbitalis corporis maxillae and the inferior margin of the facies orbitalis 

 alae magnae oss. sphenoidalis, is, lateralward, closed either by a small process of one of these 

 two bones (see Figs. 69 and 70) or by the os zygomaticum (see Fig. 71). The slit is often 

 broader lateralward than medianward, leads externally into the fossa infratemporalis, internally 

 into the fossa pterygopalatina and is for the most part closed by tough connective tissue and 

 periosteum. From its medial extremity a groove passes to the fissura orbitalis superior. At 

 about its middle begins the sulcus infraorbitalis ; it is shut off from the orbit by the periorbita 

 and after a course of variable length is covered with bony substance thus becoming the canalis 

 infraorbitalis which opens on the facial surface at the foramen infraorbitale. 



