i6 



Anatomy of Skeleton 



Cervical Characters (third to sixth). The characters of a typical cervical vertebra 

 are : Body small, shallow from above downwards, concave transversely above and 

 sagittally below, so that it overlaps the next body in front, broader transversely than 

 antero-posteriorly in proportion 3 : 2. Pedicles rounded and near mid-level of the 

 body, so that upper and lower intervertebral notches are nearly equally deep. Lamina 

 flat, long, meeting nearly at a right angle, and overlapping those below. Transverse 

 process contains (vertebrarterial) foramen for the vertebral vessels, separating true 

 transverse and costal elements, these being joined by a costo-transverse bar, and 

 beyond this projecting as posterior and anterior tubercles respectively : the tubercles 

 separated by a neural groove for issuing spinal nerve lying on the " transverse process." 

 Articular processes on strong columns of bone : upper looks backwards and rather 

 upwards, lower looks forwards and rather downwards. Spinous process bifid, ending in 

 two angled projections. Spinal foramen large and more or less triangular in shape. 



SEVENTH CERVICAL VERTEBRA. 



This differs from those just described mainly in its long, strong, and non-bifid 

 spine, and in the smallness of its arterial foramen. The condition of the spine is. 

 associated with the attachment of the ligamentum nuchae and certain strong 

 muscles, and it can be felt in the living neck, whence this segment is sometimes termed 

 " vertebra prominens." The costo-transverse foramen is small because it does not 

 transmit the vertebral artery. 



Other modifications are seen in the smallness of the anterior and marked size of 

 the posterior tubercles on the " transverse process/' with corresponding differences in 

 the constituent elements : occasionally, however, the costal element may be enlarged 

 and become free, forming a cervical rib. Occasionally, on the othei hand, it may be 

 absent. The body may sometimes present a mark, though hardly a facet, showing 

 the situation of the head of the first rib, or the attachment of its ligaments on the 

 lower and lateral margin. 



ATLAS (Fig. ii). 



Easily recognised : it has no body attached to it, this part having joined the Axis. 

 It presents an anterior arch, and a posterior arch, with a thick lateral mass on each side 



j oining these arches : lateral 

 mass carries the upper and 

 lower articular processes, 

 of which the former is 

 markedly concave for recep- 

 tion of occipital condyle and 

 shows a tendency to be sub- 

 divided at junction of the 

 two arches. 



A prominent median an- 

 terior tubercle is on the front 

 of the anterior arch, and on 

 its back aspect a smooth ar- 

 ticular facet for the odontoid 

 process of the axis. A small 

 rough posterior tubercle re- 

 presents the spinous process 

 on the posterior arch. 



I.C.V 



tig. 



FIG. ii. First cervical vertebra, from above: art. groove and 

 foramen for vertebral artery ; 'a.l. anterior tubercle ; p.t. pos- 

 terior tubercle ; tig. ridge for posterior occipito-atloid ligaments ; 

 V. notch for small vein. 



