THE SKULL. 61 
pletely filled by the ethmoid and the conche nasales, superior 
and inferior. It is bounded caudally by the lamina cribrosa of 
the ethmoid (Fig. 42, 0). The nasal cavity communicates with 
the cranial cavity by the foramina for the olfactory fibres in the 
lamina cribrosa; with the nasopharynx by the choanz; with the 
exterior of the body by the nares; with the mouth-cavity by 
the foramina incisiva or anterior palatine foramina (Fig. 42, s); 
with the orbit by the sphenopalatine foramen and the naso- 
lachrymal canal. It communicates directly also with the 
frontal sinuses (Fig. 43, mz, mz’), the sphenoidal sinuses (Fig. 
43, 2), and with the cells of the labyrinths of the ethmoid. 
JOINTS AND LIGAMENTS OF THE SKULL. 
Sutures of the Skull.—The bones of the skull join each 
other by means of immovable articulations known as sutures. 
These sutures are designated by combining the names of the 
bones between which they are situated: as, sphenofrontal suture 
(sutura sphenofrontalis), between the sphenoid and frontal; 
nasomaxillary suture (sutura nasomaxillaris), between the 
nasal and maxillary bones. When a suture joins the two 
corresponding bones of opposite sides the prefix inter is used, 
as the intermaxillary suture (sutura intermaxillaris) between 
the maxillaries. The sutures bounding the parietals have, 
however, received special names not derived in this manner. 
The suture caudad of the parietals, separating them from the 
occipital and interparietal, is known as the lambdoidal suture; 
that between the two parietals is the sagittal suture; that 
separating the parietals and squamous portions of the temporals 
is the squamous suture; that between the parietals and frontals 
is the coronal suture. The suture separating the two frontals 
also is known as the frontal suture, in place of interfrontal. 
Articulations of the Mandible.—In man the two halves of 
the mandible are united craniad, so as to form a single bone. 
In the cat the two halves are separate, but articulate closely at 
the symphysis menti by a thin interarticular cartilage. 
The articulation of the mandible at the mandibular fossa of 
the temporal is covered with a close articular capsule. The 
