ANATOMY IN A NUTSHELL. 



267 



consist of two layers; the superficial extends from one vertebra to the third or 

 fourth, and the deeper connect adjacent vertebrae. 



The intervertebral substance or discs forms about one-fourth of the spinal 

 column. They conform to the shape of the bones adjacent. They are thicker 

 at the anterior than at the posterior border in the cervical and lumbar regions, 



PLATE CX. 



BASILAR PROCESS OF OCCIPITAL 



RECTUS CAPITIS _\ 

 ANTICUS MINOR 



RECTUS CAPITIS LATERALIS 



2ND RIB 



SCALENUS ANTICUS 



Muscles of Anterior Vertebral Region. 



thus helping to form the curve in these regions, while in the dorsal or thoracic 

 region they are of a uniform thickness, the difference in the thickness of the 

 bodies of the vertebra? making the curve in this region. They form the main 

 bond between the bodies of the vertebra?; they are compressible, elastic, and 

 tough. In number they are twenty-three, extending from the axis to the 

 sacrum. They consist of an outer ring and an inner substance, the ring is com- 

 posed of fibro-cartilagenous tissue of concentric layers. The fibers of the layers 

 are not parallel but pass into the layers above and below. The central sub- 

 stance has cartilage cells set in fine connective tissue matrix. 



The lateral or short vertebral Ligaments connect the adjacent margins of. 

 the bodies of the vertebra? between the anterior and posterior common liga- 

 ments with which they are continuous. In the dorsal region they overlie the 

 stellate ligaments and in the lumbar they radiate towards the transverse pro- 

 cesses. In the cervical region they are less well marked. 



The Ligamenta subflava conned the lamina between the axis and the sac- 



