CERVICAL VERTEBRA. 51 



narrow and long, and the included spinal fo- -p. 16 



ramen large and triangular. The superior in~ 

 tervertebral notches are slightly deeper than the 

 inferior ; the inferior being the broadest. The 

 spinous process is short and bifid at the extre- 

 mity, increasing in length from the fourth to the 

 seventh. The transverse processes are also short 

 and bifid, and deeply grooved along the upper 

 surface for the cervical nerves. Piercing the 

 base of the transverse process is the vertebral 

 foramen f, which gives passage to the vertebral 

 artery and vein, and vertebral plexus of nerves. The transverse processes 

 in this region are formed by two small developments which proceed, the one 

 from the side of the body, the other from the pedicle of the vertebra, and 

 unite near their extremities to enclose the circular area of the vertebral 

 foramen. The anterior of these developments is the rudiment of a cervi- 

 cal rib ; and the posterior, the analogue of the transverse processes in the 

 dorsal region. The extremities of these developments are the anterior 

 and posterior tubercles of the transverse process. The articular processes 

 are oblique ; the superior looking upwards and backwards ; and the infe- 

 rior, downwards and forwards. 



There are three peculiar vertebra in the cervical region : The first, or 

 atlas ; the second, or axis ; and the seventh, or vertebra prominens. 



The Jltlas (named from supporting the head) is a simple ring of bone, 

 without body, and composed of arches and processes. The anterior arch 

 has a tubercle on its anterior surface, for the attachment of the longus colli 

 muscle : and on its posterior aspect is a smooth surface, for the articulation 

 of the odontoid process of the axis. 



The posterior arch is longer and more F . CT 17 



slender than the anterior, and flattened 

 from above downwards ; at its middle is 

 a rudimentary spinous process ; and upon 

 its upper surface, near the articular pro- 

 cesses, a shallow groove at each side, 

 which represents a superior intervertebral 

 notch, and supports the vertebral artery 

 previously to its passage through the 

 dura mater, and the first cervical nerve. 



* A central cervical vertebra, seen upon its upper surface. 1. The body, concave in 

 the middle, and rising on each side into a sharp ridge. 2. The lamina. 3. The pedi- 

 cle, rendered concave by the superior intervertebral notch. 4. The bifid spinous process. 

 5. The bifid transverse process. The figure is placed in the concavity between the an- 

 terior and posterior tubercles, between the two processes which correspond with the 

 rudimentary rib and the true transverse process. 6. The vertebral foramen. 7. The 

 superior articular process, looking backwards and upwards. 8. The inferior articular 

 process. 



j- Sometimes, as in a vertebra now before me, a small additional opening exists by 

 the side of the vertebral foramen, in which case it is traversed by a second vein. 



t The upper surface of the atlas. 1. The anterior tubercle projecting from the ante- 

 rior arch. 2. The articular surface for the odontoid process upon the posterior surface 

 of the anterior arch. 3. The posterior arch, with its rudimentary spinous process. 4. 

 The intervertebral notch. 5. The transverse process. 6. The vertebral foramen. 7. 

 Superior articular surface. 8. The tubercle for the attachment of the transverse liga- 

 ment. The tubercle referred to is just above the head of the figure; the convexity b*- 

 low it is the margin of the inferior articulating process. 



This groove is sometimes converted into a foramen. 



