The Dissection of Vertebrates by Gerardo De Iuliis & Dino Pulerà

Author:Gerardo De Iuliis & Dino Pulerà [Iuliis, Gerardo De]
Language: eng
Format: epub
ISBN: 9780124105003
Publisher: Elsevier Science
Published: 2019-07-24T05:00:00+00:00

Postcranial Skeleton

Vertebral Column

The vertebral column is composed of a series of movable bones, or vertebrae. The column is an important structure in support and locomotion and has evolved in mammals into five distinct regions. Examine a mounted skeleton to identify these regions (Figure 7.1). Most anteriorly, in the neck, are the cervical vertebrae, which are followed by the rib-bearing thoracic vertebrae in the trunk. Next are the lumbar vertebrae, lying dorsal to the abdomen and between the thoracic vertebrae and sacral vertebrae. The latter are fused into a solid unit and articulate with the pelvis. Lastly, the caudal vertebrae support the tail. An opening, the intervertebral foramen, is present on each side between adjacent vertebrae for the passage of a spinal nerve.

Each vertebra generally possesses several parts. For the following, examine a typical cervical vertebra (Figure 7.8). The centra (sing., centrum) or vertebral bodies, oval or kidney-shaped in section, form the main support of the vertebral column. The neural canal, through which the spinal cord passes, lies dorsal to the centrum. The neural canal is enclosed laterally and dorsally by the neural arch. The arch is composed on each side by a pedicle, an oblique plate forming the side of the arch, and a lamina, a horizontal plate forming the top of the arch. A neural process projects dorsally from the neural arch. A transverse process projects laterally on either side from near the junction of the centrum with a pedicle. Near the junction between the pedicle and lamina, each vertebra has anterior and posterior projections for articulation with other vertebrae. The anterior projection, the prezygapophysis, bears a facet that faces dorsally or dorsomedially. The facet of the posterior process or the postzygapophysis faces ventrally or ventromedially. Thus, a prezygapophysis slips under the postzygapophysis of the preceding vertebrae.

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