Volume 1

Quain's Elements of anatomy.

  • Quain, Jones, 1796-1865.
Date:
1876
Catalogue details

Licence: Public Domain Mark

Credit: Quain's Elements of anatomy. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

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    are pierced by numerous small foramina for the passage of blood-ves- sels, one or two of which foramina situated near the middle of the pos- terior surface are much larger than the others. The arch consists of two symmetrical portions which spring, one on each side, from the posterior surface of the body, and meet in the middle line behind. The anterior part of each half, rounded and nar- row, is called the pedicle; the posterior partis broad and flat, and is called the lamina (neurapophysis, Owen). The concavities on the upper and lower borders of the pedicles are named notches, and consti- tute by the apposition of those of contiguous vertebra?, the intervertebral foramina, a series of rounded apertures, which communicate with the vertebral canal, and transmit the spinal nerves and blood vessels. The spinous process (neural spine, Ow.) projects backwards from the arch in the middle line. The transverse processes (diapophyses, Ow.), placed one on each side, project outwards from the anterior part of the arch. The articular processes (zygapophyses, Ow.), two superior and two inferior, project upwards and downwards from a point near the junction of pedicle and lamina. Their articular surfaces, coated with cartilage, in the superior pair look backwards, and in the inferior for- wards, so that the former face the latter in adjoining vertebrae. The foramen is bounded anteriorly by the body, posteriorly and later- ally by the arch. The series of rings thus formed, united by ligaments, constitutes the neural canal, in which the spinal cord is contained. Texture.—The bodies of the vertebras are almost entirely composed of spongy substance, the surface being covered with only a thin layer of compact tissue. Venous canals, commencing at the larger foramina behind, traverse the cancellated structure. The arch and processes contain a much smaller proportion of spongy substance, being covered with compact tissue of considerable density in some places. GROUPS OF VERTEBRiE. The vertebra are divided into five groups, named from the regions which they occupy, cervical, dorsal, lumbar, sacral, and coccygeal. Cervical Vertebrae.—These are seven in number. The first and second are so peculiar in form, as to require a separate description. The following characters belong to the five lower vertebras. Fig. 5. Fig. 5.—Third Cervical Vertebra. (A. T.) £ A, from above and slightly from behind ; B, from .the side. 1, the body?; behind a, the pedicle and inter-vertebral notch ; 3, lamina ; 4, vertebral ring,^ of a triangular form; 5, bifid spinous process ; 6, b , transverse process—6, posterior, 6 *, anterior tubercle ; a, foramen in the transverse process transmitting the vertebral artery; 7, 7', articular processes—/, the superior, 7', the inferior. B The body is small and broader from side to side than from before backwards. Its superior surface is transversely concave from the upward projection of its lateral margins, and is sloped down anteriorly. The under surface on the contrary is rounded off at the sides, while its anterior margin forms a marked projection downwards.