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

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 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

Longer and more uniform in shape than thoracic vertebrae
Shorter in height, with long, flattened transverse processes that project laterally

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