THE TEMPORAL BONES. 111 
hollow, the glenoid fossa (fossa mandibularis), limited posteriorly by the tympanic 
plate, and crossed at its deepest part by an oblique fissure, the Glaserian fissure 
(fissura petro-tympanica). This cleft, which is closed externally, transmits about 
its middle the tympanic branches of the internal maxillary artery, and lodges the 
slender process of the malleus. At its inner end the lips of this fissure are 
frequently separated by a thin scale of bone, a downgrowth from the teemen 
tympani of the petrous part, which here separates the tympanic from the squamous 
elements, forming in its descent the major part of the outer wall of the osseous 
Eustachian canal, which lies immediately internal to it. Between this scale of bone 
and the posterior edge of the fissure there is a small canal (canal of Huguier), which 
transmits the chorda tympani nerve. The part of the glenoid fossa in front of the 
fissure articulates with the condyle of the inferior maxilla, through the medium 
of the interarticular cartilage, which is here interposed and rests as well on the 
tuberculum articulare. Anteriorly the part of the fossa behind the fissure is non- 
_ Temporal surface 
Groove for middle / i poral surface 
~ 
temporal artery —~____ / 
Supramastoid_ — 
crest 
Parietal notch— 
Mastoid Af : 
foramen &g ih 
Tubercle 
— 
; 2 Enminentia articularis 
Remains of Gl id fosse 
masto-squamosal RELNOMOT ROISISES 
suture S 
\ ‘\ 
) « Glaserian fissure 
\Post-glenoid process 
NY 
N Aaa Ae plate 
\ 
, Mastoid process 
| | 
| Vaginal 
Auricular External PFOCess 
fissure auditory 
process. 
‘i 
External auditory meatus 
Styloid process 
Fic. 85.—Ricut TEMPORAL BONE AS SEEN FROM THE OUTER SIDE. 
articular and lodges a portion of the parotid gland. At the angle formed by the 
divergence of the two roots of the zygoma, in correspondence with the outer part 
of the articular eminence, there is a rounded tubercle; to this are attached the 
fibres of the external lateral ligament of the temporo-mandibular joint. In front 
of the inner end of the articular eminence there is a small triangular surface, 
limited in front by the edge of the anterior root, and internally by a thick serrated 
margin which articulates with the outer side of the great wing of the sphenoid; 
this area forms part of the roof of the zygomatic fossa. Just anterior to the 
external auditory meatus and projecting downwards from the under surface of the 
posterior root there is a conical process, called the post-glenoid tubercle, which forms 
a prominent anterior lip to the external extremity of the Glaserian fissure ; it is the 
representative in man of a process which occurs in some mammals and prevents the 
backward displacement of the lower jaw. By some anatomists it is referred to as 
the middle root of the zygoma. 
The zygomatic process by its lower margin and inner surface gives origin to the 
masseter muscle, whilst attached to its upper edge are the layers of the temporal 
fascia. Behind the external auditory meatus, and below the supramastoid crest, the 
squamous element extends downwards as a pointed process, which assists in forming 
q bi a 
