172 



AifATOMTCAL TECHNOLOGY. 



of the diapophyses of all but the last (rarely of the 

 last) cervical vertebrae. Through it pass the verte- 

 bral artery and vein. 



§ 474. Foramen atlantale — Atlantal foramen. — 

 This is a passage through the cephalic edge of the 

 atlas just dorsad of the ocoipito-atlantal arthron. It 

 transmits the first or suboccipital nerve and the 

 vertebra] artery ; Straus-Durckheim, A, I, 470. It 

 is present in man only as an exception ; Quain, A, 

 1,13. 



§ 475. Lamella ventralis — Ventral or inferior 

 lamella. — This is the thin plate-like projection ex- 

 tending ventrad from the diapophyses of some of the 

 cervical vertebrse. It is most marked in the 6th. 

 Flower, A, 32, 23. 



§ 476. Pre. (Processus) odontoideus, as.— Odon- 

 toid process. — This is a tooth-like projection from the 

 cephalic part of the centrum of the axis. It articu- 

 lates diarthrodially with the atlas, and serves as a 

 pivot on which the atlas and head rotate. It is kept 

 from encroaching upon the neural canal by a strong 

 ligament. 



§ 477. Explanation of Fig. 53-55. — Anapophy- 

 sis — Accessory tubercle. — This is a slender process 

 extending laterad from the caudal part of the neural 

 arch. It is ventrad of the postzygapophysis, and with 

 it clasps the prsezygapophysis of the following verte- 

 bra. It is present in the first six lumbar vertebrae, and 

 markedly in the 9th to the 13th thoracics, where, in 

 man, it is called the inferior tubercle ; Quain, A, 1, 14. 



§ 478. Arcus neuralis, az. — Neural arch. — This 

 is a bony arch projecting from the dorsal aspect of 

 the centrum. It is called neural arch because it over- 

 arches and encloses the myelon or neural axis. 



§ 479. Canalis neuralis, az. — Neural canal. — The 

 neural canal is formed by the neural foramina, each 

 foramen being a, short segment of the canal. It is 

 enclosed by the neural arches and by ligaments, and 

 contaius the myelon . 



§ 480. Centrum, az. — Body. — The vertebral cen- 

 trum is the solid subcylindrical ventral portion of the 

 vertebra. Contiguous vertebral centra articulate 

 amphiarthrodially by means of an interposed disk of fibro-cartUage. For exceptions, see 

 § 458. 



§ 481. Diapophysis — Transverse process. — The diapophysis is the lateral projection 

 of the vertebra. Its base, in the cervical vertebrse (Fig. 53), except the 7th, contains the 

 vertebrarterial foramen (g 473). 



g 483. Fm. (Foramen) neurale, az.— Vertebral ring or foramen. — This is the space 



Fig. 53. — Ventral Aspect op 



THE CBKVIOAL and OF TWO 



Thoracic Vertebra. (From 

 Straus-Durckheim.) x 1. 



