46 OSTEOLOGY. 



complexus major muscle, and below it at the back is the occipital 

 tuberosity, on each side of which there is a roughened depression 

 for the attachment of the cordiform part of the ligamentum nuchse. 

 The occipital or mastoid ridge, continuous with the squamosal 

 bone, descends from the crest on each side, and gives attachment 

 to various muscles. The inferior or suboccipital portion presents 

 a little below the tuberosity, a large, oval hole, the foramen 

 magnum, through which pass the spinal cord, the spinal acces- 

 sory nerves, and the basilar artery ; the sides of this fora- 

 men, the transverse diameter of which is the larger, are slightly 

 roughened for the attachment of the long odontoid ligaments, 

 and on each side is a large rounded prominence, the condyle, 

 which articulates with the atlas. A large process, the 

 basilar process (basi-occipital bone), passes forwards from the 

 lower part of the condyles, and forms the floor of the foramen, 

 magnum, being flattened and slightly hollowed above, but rounded 

 below, where it gives attachment to the rectus capitis anticus 

 major and minor muscles; it articulates with the sphenoid bone in 

 front, and has a fissure, the basilar fissure, running along its under 

 surface, terminating posteriorly in the foramen magnum. Two 

 flattened styloid processes extend downwards from the sides, of 

 the bone, and give attachment to the obliquus capitis anticus, 

 stylo-maxillaris, and stylo-hyoideus muscles ; and between each 

 of these processes and the condyle is a deep notch, the condyloid 

 or stylo-condyloid notch, at the bottom of which and just in 

 front of the condyle, is the condyloid foramen which givea 

 passage to the twelth nerve. 



The internal or cerebral surface has, in the supraoccipital 

 portion, a vaulted concavity termed the occipital cupola, which 

 covers the cerebellum ; while the superior surface of the basilar 

 process presents a pit, the basilar fossa, in the anterior part of 

 which the pons varolii lies, and in the posterior part the medulla 

 oblongata. The small foramina which enter the basilar process 

 from within the foramen magnum are for the passage of nutrient 

 blood-vessels. The superior border is serrated, and articulates 

 with the parietal and the lateral borders with the petrosal bones. 

 The occipital bone resembles a vertebra more than any other 

 of the so-called cranial vertebrae ; in the young state it separates 

 into an inferior or basi-occipital part, representing the centrum ; 

 two lateral exoccipitals, representing the pedicles, laminae, &c. ; 

 and above, the supraoccipital portion, corresponding to the. 



