520 ANATOMY IN A NUTSHELL 



shortest and has an inner portion which articulates with the sphenoid hone, and 

 an outer portion which joins with the squamous portion. 



The processus cochleariformis is a thin plate of hone which separates two 

 canals at the petro-squamous angle. The upper of these canals is for the 

 Tensor tynipani muscle, and the lower one for the Eustachian tube. They 

 lead into the middle ear. 



Ossification. — This hone ossifies from ten centers. 



ARTICULATION. It articulates with five hones; (1) the occipital. (2) parie- 

 tal. (3) sphenoid. (4) inferior maxillary. (5) malar. 



Attachment <>k Muscles.— It has fifteen muscles attached to it: 



1. T<> the SQI VMOUS PORTION of the temporal hone, the Temporal muscle 

 of the tempero-maxillary region. 



2. To the zygoma, the Masseter muscle of the temporo-maxillary region. 



3. To Tin-: mastoid portion, (a) the Occipito-frontalis of the cranial region, 

 (b) Sterno-cleido-mastoid of the superficial cervical region, (c) Splenius capitis 

 of the third layer of the hack, (d) Traehelo-mastoid of the fourth layer of the 

 hack. ie) Digastric of the supra-hyoid region, (f) Retrahens aurem of the auricu- 

 lar region. 



4. Tothe styloid process, (a) Stylo-pharyngeus of the pharyngeal region. 

 (b) Stylo-hyoid of the supra-hyoid region, (c) Stylo-glosstts of the lingual region. 



.">. To the petrous portion, (a) Levator palati of the soft palate, (b) Tensor 

 tynipani of the tympanic region, (c) Stapedius of the tympanic region. 



I'.i. > Supply. — The stylo-mastoid artery from the posterior auricular. 



It enters the stylo-mastoid foramen. The tympanic artery from the internal 

 maxillary . It passes through the Glaserian fissure. Petrosal artery from 

 the middle meningeal. It passes by the hiatus Fallopii. Tympanic from the 

 interna] carotid artery, while in the carotid canal. Auditory from the basilar, 

 which enter- the internal auditory meatus and is distributed to the cochlea and 

 vestibule. 



LESSON CLXXV. 

 Origin and Insertion <»f the Muscles Attached to Temporal Boxe. 



1. Temporal muscle which has been described on page 508. 



2. Masseter muscle. -Description. — There is a strong layer of fascia 

 which is derived from the deep cervical fascia which covers this muscle and is 

 connected with it. This fascia i- attached to the lower border of the zygoma, 

 and posteriorly it covers the parotid gland, making the parotid fascia. The 

 Masseter muscle consists of two portions, a superficial and a deep portion. The 

 deep portion is smaller and more muscular than the superficial portion. These 

 two portions are united ;it their insertion. The parotid gland overlaps 

 it- posterior margin, while it- anterior margin overlaps the Buccinator muscle. 

 The facial vein crosses it- lower anterior angle. 



Origin. The origin of the superficial portion is from the malar process 

 of the superior maxillary hone, and the anterior two-thirds of the lower border 

 of the zygomatic arch. The origin of the deep portion is from the posterior 



