372 



ANATOMY IN A NUTSHELL. 



The superior internal angle has (1) the lachrymo-ethmo-frontal suture, 

 anterior ethmoidal foramen which transmits the anterior ethmoidal vessels, and 

 nasal nerve, (2) the posterior ethmoidal foramen which transmits the posterior 

 ethmoidal vessels and sometimes a branch of the nasal nerve. The inferior ex- 

 ternal angle has the spheno-maxillary fissure which is formed by the greater 

 wing of thf sphenoid bone externally and the superior maxillary bone and palate 

 bone internally. This fissure connects the orbit with (1) the temporal fossa, 

 (2) zygomatic fossa, (3) spheno-maxillary fossa and transmits the infraorbital 

 artery, superior maxillary nerve and its orbital branches and the ascending 



PLATE CXCII. 



LIGAMENTUM DENTICULATUM 



POSTERIOR ROOT 



LINEA 

 SPLENDNS 



ANTERIOR ROOT 



Showing the Dura Mater, Arachnoid, and Piamater. 



branches of Meckel's ganglion. The inferior internal angle has the ethmo-max- 

 illo-palato-lachryma] suture. At the apex of the orbit is the optic foramen 

 which is between the two roots of tin h sser wing of the sphenoid. It transmits 

 the optic nerve and opthalmic artery, the nerve lying above and inner to the 

 arten-. The ligament of Zinn is attached to the circumference of the optic 

 foramen, deficient at the upper and outer part, and gives a common origin to the 

 four Recti OlUSCleS. The supraorbital notch or foramen is situated at the 

 junction of the inner and middle third of the upper circumference of the orbit. 

 It transmits the supraorbital vessels and nerve. A line drawn from this notch 

 or foramen In the mental foramen passes through the infraorbital foramen. 

 There are EIGHT MUSCLES in the orbit, viz.. the four Recti, the two Oblique, 





