8, Body of mandible; 28′, horizontal (molar) part of ramus; 30, vertical part of ramus; 9, zygomatic process of squamous temporal; 11, coronoid process of mandible; 12, supraorbital process; 13″, paramastoid (styloid) process of occipital; 19, orbit; 20, malar bone; 21, lacrimal bone; 22, nasal bone; 23, premaxilla; 23′, nasal process of premaxilla; 25, 29, canine teeth; 26, maxilla; 27, facial crest; 31, condyle of mandible; 32, atlas; 33, axis; x, wing of atlas; e, naso-maxillary notch. (After Ellenberger-Baum, Anat. für Künstler.) ] THE OCCIPITAL BONE The =occipital bone= (Os occipitale) is situated at the posterior part of the cranium, of which it forms the posterior wall and part of the ventral wall or base.[6] Its lower part is perforated centrally by a large, almost circular opening, the =foramen magnum= (Foramen occipitale magnum), at which the brain and spinal cord join. The foramen is bounded laterally and dorsally by the =lateral parts= of the bone, and ventrally by the =basilar part= or =process=. Above the lateral parts—but not entering into the formation of the foramen magnum—is the =squamous part=. [Illustration: FIG. 27.—LINE DRAWING OF POSTERIOR HALF OF BASE OF SKULL OF HORSE, WITHOUT MANDIBLE. (Key to Fig. 28.) 1, Incisura carotica; 2, incisura ovalis; 3, incisura spinosa; 4, external orifice of parieto-temporal canal; 5, Eustachian canal; 6, petro-tympanic fissure; 7, external auditory canal; 8, hyoid process; 9, Vidian groove; 10, supraorbital process; _A_, basilar part of occipital; _B_, body of sphenoid; _C_, temporal wing of sphenoid; _D_, squamous temporal bone; _E_, petrous temporal bone; _F_, orbital part of frontal bone. ] The =lateral parts= (Partes laterales) bear the =occipital condyles= (Condyli occipitales), which articulate with the atlas. The condyles are obliquely placed, wide apart dorsally, and separated by a small interval ventrally. The articular surface is curved so sharply in the dorso-ventral direction as to form a blunt ridge externally. The cranial surface is concave and smooth. External to the condyle is the =paramastoid= or =styloid process= (Processus jugularis), a strong flattened bar of bone which projects downward and backward; its external surface is convex and roughened for muscular attachment. Between the root of this process and the condyle is a smooth depression, the =condyloid fossa= (Fossa condyloidea inferior); in this is the =hypoglossal foramen= (Foramen hypoglossi), which transmits the nerve of like name.