.510 ANATOMY IN A NUTSHELL. 



Insertion. — Into the median raphe of the pharynx and to the pharyngeal 

 spine of the basilar process of the occipital bone by fibrous aponeurosis. 



Action. — To constrict the pharynx. 



Nerve Supply. — Branches from the pharyngeal plexus. 



Blood Supply. — It receives its blood supply from the blood supply to 

 the pharynx which is (1) superior thyroid, (2) ascending pharyngeal from the 

 external carotid, and (3) the pterygo-palatine and (4) descending palatine from 

 the internal maxillary. 



LESSON CLXXIII. 

 Temporal Bone. (Plates CCLXVI-CCLXVII-CCLXVIII-CCLXIX.) 



The temporal bone lies at the inferior lateral portion of the skull and con- 

 sists of a squamous, mastoid, and petrous portion. It contains the organs of 

 hearing. 



The squamous portion (scale-like) forms the anterior superior part of the 

 hone. 



The external surface of the squamous portion is convex and has grooves 

 on its posterior part for the deep temporal arteries. It has attached to it the 

 Temporal muscle, and forms part of the temporal fossa. A part of the tem- 

 poral ridge is situated between this portion of the bone and the mastoid portion. 



The zygomatic process arises by three roots and extends forward to artic- 

 ulate with the malar bone. Its anterior root, which runs inward and ends in 

 the eminentia articularis, is short and broad. Its middle root, also called post* 

 glenoid process, passes between the auditory process and the mandibular por- 

 tion of the glenoid fossa. The posterior root passes upward and backward 

 from the upper border of the zygoma and forms part of the temporal ridge (here 

 called supramastoid crest.) 



To THE (JPPEB BORDER of the ZYGOMA is attached the temporal fascia. 

 and to the lower border and concave inner surface is attached the Masseter 

 muscle. The external lateral ligamenl of the lower jaw is attached to a tubercle 

 at the anterior root of the zygoma. Between the anterior and middle roots of 

 the zygoma is the glenoid fossa, the anterior or mandibular portion of which 

 is for the articulation of the condyle of the lower jaw and is covered with car- 

 tilage, while its posterior part lodges the parotid "land. This posterior portion 

 i- formed chiefly by the tympanic plate which forms the antero-inferior wall of 

 the externa] auditory meatus and ends externally in the auditory process. Tin-: 

 Glaserian fissure divides the glenoid fossa and transmits the tympanic 

 branch of the internal maxillary artery and lodges the processus gracilis malleus. 

 The opening of the canal of Eugieb is situated in the angle between the 

 squamous portion and petrous portion of the temporal bone. It transmits 

 the chorda tympana nerve. 



The internal surface of the squamous portion is concave and has eminences 

 and depressions for the cerebral convolutions, also grooves for the middle 

 meningeal artery. 



