DORSAL VERTEBRAE LUMBAR VERTEBRA. 



53 



each a small foramen for the transmission of the vertebral vein, and pre- 

 sent only a rudimentary bifurcation at their extremity. Sometimes the 

 anterior tubercle represents a small but distinct rib. 



Dorsal Vertebra. The body of a dorsal vertebra is as long from before 

 backwards as from side to side, particularly in the middle of the dorsai 

 region ; it is thicker behind than before, and marked on each side by two 

 half-articulating surfaces for the heads of two ribs. The pedicles are strorig > 

 and the lamina broad and thick ; the spinal foramen small and round, 

 and the inferior intervertebral notch of large 

 size, the superior can scarcely be said to exist. 

 The spinous process is long, prismoid, directed 

 very obliquely downwards, and terminated by 

 a tubercle. The transverse processes are large 

 and strong, and directed obliquely back- 

 wards. Upon the anterior and superior as- 

 pect of their summits is a small facet for the 

 articulation of the tubercle of a rib. The ar- 

 ticular processes are vertical, the superior facing 

 directly backwards, and the inferior directly 

 forwards. 



The peculiar vertebrae in the dorsal region are the first, ninth, tenth, 

 eleventh, and twelfth. The first dorsal vertebra approaches very closely 

 in character to the last cervical. The body is broad from side to side, 

 and concave above. The superior articular processes are oblique, and 

 the spinous process horizontal. It has an entire articular surface for the 

 first rib, and a half surface for the second. The ninth dorsal vertebra has 

 only one half articular surface at each side. The tenth has a single entire 

 articular surface at each side. The eleventh and twelfth have each a single 

 entire articular surface at each side ; they approach in character to the 

 lumbar vertebra? ; their transverse processes are very short, trifid at their 

 summits, and have no articulation with the corresponding ribs. The 

 transverse processes of the twelfth dorsal vertebra are quite rudimentary, 

 and its inferior articular processes look outwards. 



Lumbar Vertebra. These are the largest 

 pieces of the vertebral column. The body 

 is broad and large, and thicker before than 

 behind. The pedicles very strong ; the la- 

 mina short, thick, and broad ; the inferior 

 intervertebral notches very large, and the 

 spinal foramen large and oval. The spin- 

 ous process is thick and broad. The trans- 

 verse processes (costifonn processes) are 

 slender, pointed, and directed only slightly 



* A lateral view of a dorsal vertebra. 1. The body. 2, 2. Articular facets for tho 

 heads of ribs. 3. The pedicle. 4. The superior intervertebral notch. 5. The inferior 

 intervertebral notch. 6. The spinous process. 7. The extremity of the transverse pro- 

 cess, marked by an articular surface for the tubercle of a rib. 8. The two superior 

 articular processes looking backwards. 9. The two inferior articular processes looking 

 forwards. 



j- A lateral view of a lumbar vertebra. 1. The body. 2. The pedicle. 3. The su- 

 perior intervertebral notch. 4, The inferior intervertebra] notch. 5. The spinous pro- 

 cess. 6. The transverse process. 7. The superior articular processes. 8. The mferioi 

 articular processes. 9. Tiie posterior transverse process. 



Fig. 20.f 



