Line 5: Line 5:     
==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==
1,351

edits