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Spinal Column - Anatomy & Physiology (view source)
Revision as of 14:19, 24 July 2008
, 14:19, 24 July 2008→Vertebrae and Joints
==Vertebrae and Joints==
==Vertebrae and Joints==
*Vertebrae consist of a body which encloses the vertebral foramen (through which the spinal cord runs), a spinous process, and a transverse process, as well as articular processes by which they join together
*The form of the spinous process varies with respect to species and region
=Cervical Vertebrae=
*The first two cervical vertebrae are known as the '''atlas''' and the '''axis''' respectively, and are modified to allow movement of the head
**The atlas has no conventional body: instead it is complsed of two lateral masses joined by dorsal and ventral arches
**The atlas and axis are fused in embryonic life
**The '''wing of the atlas''' is the transverse process of this vertebra and allows the spinal column to articulate with the skull by providing a resting place for the occipital condyles
**The axis is the longest vertebra
**The '''nuchal ligament''' connects the spinous process of the axis to the spinous process of the first thoracic vertebra (T1)
*The last (C7) cervical vertebra has a taller spinous process than those proceeding it, and articulates with the first pair of ribs
=Thoracic Vertebrae=
*Thoracic vertebrae articulate with the ribs
*They are distingushed by short bodies with flattened extremities, costal facets, short transverse processes, and prominent spinous processes
*They reach a maximum height a few vertebrae behind the cervicothoracic junction (constituting the '''withers''' of the horse) and then decline
*The orientation of spinous processes shifts from caudo- to craniodorsal
=Lumbar Vertebrae=
*Longer and more uniform in shape than thoracic vertebrae
*Shorter in height, with long, flattened transverse processes that project laterally
=Sacral Vertebrae=
*'''Sacrum''': a single bone formed by the fusion of several vertebrae that articulates with the pelvic girdle
*Allows the thrust of the hindlimbs to be transmitted to the trunk
*Narrows caudally and is curved to present a concave surface to the pelvic cavity
=Caudal Vertebrae=
*Number varies greatly even within species
*Progressive simplification of form
==Spinal Cord==
==Spinal Cord==
==Hypaxial and Epaxial Muscles==
==Hypaxial and Epaxial Muscles==