THE TEMPORAL BONES. 17 



Inferior surface, presents from within outwards 



Rough Quadrilateral Surface,** for the origin of the tensor tympani and 



levator palati muscles. 

 Opening of the Carotid Canal, transmitting the internal carotid artery, and 



the carotid plexus of the sympathetic nerve. 

 Aqueductus Cochlea, transmitting a vein from the cochlea. 

 Jugular Fossa, a depression for the sinus of the internal jugular vein, form- 

 ing with the occipital bone the foramen lacerum posterius, which trans- 

 mits that vein and the 8th pair of cranial nerves, etc. (See page 35.) 

 Foramen for Jacobsoris Nerve (tympanic branch of the glosso-pharyngeal), 



in the ridge between the jugular fossa and the carotid canal. 

 Foramen for Arnold's Nerve (auricular branch of the pneumogastric), in 



the outer wall of the jugular fossa. 



Jugular Surface, for articulation with the jugular process of the occipital bone. 

 Vaginal Process,* ensheathing the root of the styloid process. 

 Styloid Process^ a long projection for the stylo-pharyngeus, stylo-hyoid, 

 and stylo-glossus muscles (3); and the stylo-hyoid and stylo-maxillary 

 ligaments (2), which are attached thereto. 

 Stylo-mastoid Foramen?* between the styloid and mastoid processes, for the 



exit of the facial nerve, and the entrance of the stylo-mastoid artery. 

 Auricular Fissure, for the exit of Arnold's nerve. 

 In the angle between the petrous and squamous portions, are seen the 



Septum Tubes, a lamina separating the following canals. Its inner end pro- 

 jects into the tympanum, and is called the Processus cochleanformis. 

 Opening of the canal for the tensor tympani muscle. 

 Osseous Opening of the Eustachian tube inferiorly. 



The Anterior Border articulates partly with the spinous process of the sphe- 

 noid bone. 

 The Posterior Border assists in forming the jugular foramen, and is grooved 



for the inferior petrosal sinus. 



The Superior Border separates the anterior fossa of the skull from the middle 

 fossa ; to it is attached the tentorium cerebelli, and it is grooved for the su- 

 perior petrosal sinus. 10 



Describe its articulations and development. The temporal articulates 

 with 5 bones, the occipital, parietal, sphenoid, malar, and inferior maxillary. 

 It is developed by 4 centres, one each for the squamous portion, styioid pro- 

 cess, and auditory process, and one for the petrous and mastoid portions. Its 

 ossification is completed about the 2d or 3d year. 



What muscles are attached to it ? There are 14 muscles attached to the 

 following-named portions. To the 



Squamous Portion 2, the temporal and masseter. 

 2* B 



