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==Cervical Region==

==Cervical Region==

[[Image:Cervical Vertebra.png|thumb|right|250px|Cervical Vertebra - Wikimedia Commons 2008]]

[[Image:Cervical Vertebra.png|thumb|right|250px|Cervical Vertebra - Wikimedia Commons 2008]]

Canines have seven cervical vertebrae, as do almost all other mammals. The first two cervical vertebrae are known as the '''atlas''' and the '''axis''' respectively, and have altered conformations to the other five vertebrae to allow movement of the head. The atlas has no conventional body, instead it is composed 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 Atlanto-occipital joint is between the condyles of the skull and corresponding cavities of the atlas. It functions as a ginglymus where movement is restricted to flexion/extension in the sagittal plane (eg nodding). The Atlantoaxial joint is where the ventral arch of atlas and the body of the axis face into a single synovial cavity with limited areas of contact. Movement is rotational about a longitudinal axis (eg. head shaking). 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 preceding it, and articulates with the first pair of ribs.

Canines have seven cervical vertebrae, as do almost all other mammals. The first two cervical vertebrae are known as the '''atlas''' and the '''axis''' respectively, and have altered conformations to the other five vertebrae to allow movement of the head. The atlas has no conventional body, instead it is composed 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 Atlanto-occipital joint is between the condyles of the skull and corresponding cavities of the atlas. It functions as a ginglymus where movement is restricted to flexion/extension in the sagittal plane (eg nodding). The Atlantoaxial joint is where the ventral arch of atlas and the body of the axis face into a single synovial cavity with limited areas of contact. Movement is rotational about a longitudinal axis (eg. head shaking). 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 preceding it, and articulates with the first pair of ribs. The remaining cervical vertebrae become progressively shorter caudally and the spinous process is initially small and is only more developed in C7. Each vertebrae has a transverse foramen which facilitates the passage of vertebral vessels and nerves.  

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[[File:Cambridge Natural History Mammalia Fig 191.png|thumb|left|250px|'''Cambridge Natural History Mammalia, Frank E. Beddard, 1902'''. A, Atlas of Dog in ventral view. B, Axis of Dog in lateral view. o, Odontoid process; pz, posterior zygapophysis; s, spinous process; sn, foramen for first spinal nerve; t, transverse process; v, vertebrarterial canal.]]

[[File:Cambridge Natural History Mammalia Fig 191.png|thumb|left|250px|'''Cambridge Natural History Mammalia, Frank E. Beddard, 1902'''. A, Atlas of Dog in ventral view. B, Axis of Dog in lateral view. o, Odontoid process; pz, posterior zygapophysis; s, spinous process; sn, foramen for first spinal nerve; t, transverse process; v, vertebrarterial canal.]]