172 



ANATOMICAL 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 occipito-atlantal arthron. It 

 transmits the first or suboccipital nerve and the 

 vertebral artery ; Straus-Durckheim, A, I, 470. It 

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

 1,12. 



§ 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 vertebrae. It is most marked in the 6th. 

 Flower, A, 22, 23. 



§ 476. Pre. (Processus) odontoideus, az. — 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 vertebras, 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 

 contains 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-cartilage. For exceptions, see 

 § 458. 



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

 of the vertebra. Its base, in the cervical vertebrse (Fig. 52\ except the 7th, contains the 

 vertebrarterial foramen, (§ 473). 



§ 4S2. Fm. (Foramen) neurale, az.— Vertebral ring or foramen. — This is the space 



Fie. 52. — Ventral Aspect op 

 THE Cervical and op two 

 Thoracic Vertebra. (From 

 Straus-Durckheim.) x 1. 



