Difference between revisions of "Spinal Column - Anatomy & Physiology"
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==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== | ||
Revision as of 14:19, 24 July 2008
Divisions and Landmarks
The common pattern of canine landmarks, according to Dyce, Sack, et al, can be quantified as such:
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