OSTEOLOGY. 



one in front of an oval form, for articulation with the atlas ; another behind, for 

 the transverse ligament; the latter frequently encroaches on the sides of the 

 process ; the apex is pointed. Below the apex this process is somewhat enlarged, 

 and presents on either side a rough impression for the attachment of the odontoid 

 or check ligaments, which connect it to the occipital bone ; the base of the process, 

 where attached to the body, is constricted, so as to prevent displacement from the 

 transverse ligament, which binds it in this situation to the anterior arch of the 

 atlas. Sometimes, however, this process does become displaced, especially in 

 children, where the ligaments are more relaxed ; instant death is the result. The 

 pedicles are broad and strong, especially their anterior extremities which coalesce 

 with the sides of the body and the root of the odontoid process. The laminae are 

 thick and strong, and the spinal foramen very large. The superior articular 

 surfaces are round, slightly convex, directed upwards and outwards, and are 

 peculiar in being supported on the body, pedicles, and transverse processes. The 

 inferior articular surfaces, have the same direction as those of the other cervical 

 vertebras. The superior intervertebral notches are very shallow, and lie behind 

 the articular processes ; the inferior in front of them, as in the other cervical 

 vertebras. The transverse processes are very small, not bifid, and perforated by 

 the vertebral foramen, which is directed obliquely upwards and outwards. The 

 spinous process is of large size, very strong, deeply channelled on its under 

 surface, and presents a bifid tubercular extremity for the attachment of muscles, 

 which serve to rotate the head upon the spine. 



Seventh Cervical (fig. 4). The 



Fig. 4. 7th Cervical Vertebra or Vertebra most distinctive character of this 



Prominens. vertebra is the existence of a very 



long, and prominent spinous pro- 

 cess; hence the name Vertebra 

 prominens. This process is thick, 

 nearly horizontal in direction, not 

 bifurcated, and has attached to it 

 the ligamentum nuchas. The 

 transverse process is usually of 

 large size, especially its posterior 

 root, its upper surface has usually 

 a shallow groove, and seldom pre- 

 sents more than a trace of bifur- 

 cation at its extremity. The ver- 

 tebral foramen is sometimes as 

 large as in the other cervical ver- 

 tebras, usually smaller, on one or 

 both sides, and sometimes want- 

 ing. On the left side, it occasion- 

 ally gives passage to the vertebral 

 artery; more frequently the ver- 

 tebral vein traverses it on both 

 sides ; but the usual arrangement is for both artery and vein to pass through the 

 foramen in the transverse process of the sixth cervical. 



CHAEACTEES OF THE DOESAL VEETEBR^E. 



The bodies of the dorsal vertebras (fig. 5) resemble those in the cervical and 

 lumbar regions at the respective ends of this portion of the spine ; but in the 

 middle of the dorsal region their form is very characteristic, being heart-shaped, 

 and broader in the antero-posterior than in the lateral direction. They are 

 thicker behind than in front, fiat above and below, convex and prominent in 

 front, deeply concave behind, slightly constricted in front and at the sides, and 

 marked on' each side, near the root of the pedicle, by two demi-facets, one 



it-Root. 



