THE SKULL AS A WHOLE. - SL29 
major and minor, and the digastricus, the suspensory ligament of the 
lesser cornu of the hyoid also being included in the ligament of the 
stylohyoideus minor. The nuchal surface is separated from the 
dorsal surface of the skull by a shield-shaped promontory and 
crest (crista nuchae). The lateral continuation of this crest is the 
superior nuchal line (linea nuchae superior). It forms a curved 
ridge, the position of which indicates the dorsal limit of the occipital 
musculature. The posterior, somewhat tri-radiate tip of the 

P. j. 
Fic. 59. Lateral surface of the skull: AS, alisphenoid (ala magna); BO, basioccipital 
(basilar portion of occipital); BS, basisphenoid (body of posterior sphenoid); F, frontal; 
I, interparietal; L, lacrimal; M, maxilla; MS, masteid portion of petrosal (petromastoid) ; 
N, nasal; OS, orbitosphenoid (ala parva); P, parietal; PL, palatine; PM, premaxilla; 
SO, supraoccipital (squamous portion of occipital); SQ, squamosal; T, tympanic; ZY, 
zygomatic. 
a.p., piriform aperture of nose; d.i., incisor teeth; d.m., molars; d.pm., premolars; 
f.i., infraorbital foramen; f.mx., maxillary fossa; f.o., optic foramen; f.s., stylomastoid 
foramen; f.t., temporal fossa; 1.f., lateral lamina of pterygoid process; 1.m., medial lamina; 
m.a.e., OSseous portion of external acoustic meatus; p.a., alveolar process. of maxilla; 
p.e., ethmoidal portion of orbitosphenoid; p.f., frontal process of premaxilla; p.j., jugular 
process of occipital; p.m., mastoid process of mastoid; p.mx., maxillary process of frontal; 
p.o., orbital process of maxilla; ‘p.o.e., external occipital protuberance; p.s., squamosal 
process of parietal; p.s.a., and p.s.p., anterior and posterior supraorbital processes of 
frontal; p.z., zygomatic process of squamosal; p.z.m., zygomatic process of maxilla; 
s, sphenoorbital process of maxilla; s.m., spina masseterica; sq., squamosal process of 
squamosal. 
projection, together with a thin ridge extending ventrad from it, is 
the external occipital protuberance (protuberantia occipitalis 
externa), an important median point of attachment for the occi- 
pital muscles and the ligamentum nuchae. 
The ventral wall of the cranial portion is the basal portion 
(basicranium) of the entire skull. Its axial line, the basicranial 
axis, continues, in general, that of the bodies of the vertebrae, 
and its posterior portion is equivalent, morphologically, to vertebral 
