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PinkMonkey Online Study Guide-Biology

d) Vertebra Prominens or Seventh cervical vertabra (Fig. 20.8). (1) It is called the vertebra prominens because of its long and thick prominent spinous process. (2) The spine is long, thick and horizontal. (3) Spine is not bifurcated; ends behind in a tubercle to which neck muscles are attached. (4) Big transverse processes with big, prominent posterior root and long, slender anterior root. (5) Foramen transversarium is small; may be double or absent.

 


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Figure 20.8



ii) Thoracic Vertebrae. Of the twelve thoracic vertebrae (thoracic region) the second to the eighth thoracic are called typical thoracic, while the first, and ninth, through the twelfth thoracic vertebrae present special features, hence called atypical thoracic vertebrae.

a) Typical thoracic vertebra (Fig. 20.9). (1) It is identified by the presence of long spine which passes backwards and caudaully and ends in tubercle for articulation with ribs (except last two or three vertebrate). (2) Body bears two costal facets on each side which articulate with heads of ribs. (3) Transverse processes are large and, club-shaped, face laterally and backwards and bear a facet on anterior side for articulation with the tubercles of a ribs.

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Table of Contents

20.0 - Introduction
20.1 - Axial Skeleton
20.2 - Appendicular Skeleton

 

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