554 ANATOMY IN A NUTSHELL. 



petrosal sinus, through the middle one passes the glosso-pharyngeal, pneumo- 

 gastric, and spinal accessory nerves, through the posterior one the lateral 

 sinus, and meningeal branches of the occipital, and ascending pharyngeal 

 arteries. 



4. Mastoid foramen (often absent) is for a small vein and sometimes the 

 mastoid artery. 



.">. The anterior condyloid foramen which is for the hypoglossal nerve, and 

 meningeal branches of the ascending pharyngeal artery. 



(i. The posterior condyloid foramen (often absent) for posterior condyloid 

 vein. 



7. Foramen magnum which transmits the medulla oblongata and its 

 membranes, spinal accessory nerves, vertebral arteries, anterior and posterior 

 spinal arteries, and the occipito-axial ligaments. This foramen is a single one 



PLATE CCLXXXII. 



HELIX 

 ANTI- HELIX 



A\ \\\ | u 



ATTOLLENS AURICULAI 



ma fa 



ml ';'// f& 



fk \\ | ' / ///' / ATTRAHENS AURICULAM 



OBLIOUUS AURICULAM 



EXTERNAL AUDITORY MEATUS - ^ARTIUGINEUS 



Posterior View of the Ear With Auricular Muscles. 



and the others are in pairs. Thus we see there are thirteen foramina in the 

 posterior fossa. The eleven in the anterior fossa, and sixteen in the middle 

 fossa, and the thirteen in the posterior fossa make the forty foramina at the 

 base of the -hull. 



lesson cxc. 



The temporal fossa (Plate CCXXXIV) is hounded anteriorly by the ex- 

 ternal angular process of the frontal bone, superiorly by the temporal ridges, 

 posteriorly by the temporal ridges, inferiorly by the zygomatic arch. This 

 fossa is separated from the zygomatic fossa by tin 1 pterygoid ridge which is 

 on the outer surface of the greater wing of the sphenoid hone. The temporal 

 fossa is formed by five hone-, ill pari of the frontal hone, (2) greater wing of 

 the sphenoid hone. (3) pari of the parietal hone. (4) squamous portion of the 

 temporal, (5) malar bone. It has the following sutures: (1) a part of the trans- 

 verse facial -uture. ("_M spheno-malar suture, (3) coronal suture, (4) spheno-pari- 



