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Median sagittal section through the occipital bone and first three cervical vertebrae, showing ligamentous attachments The posterior arch forms about two-fifths of the circumference of the ring: it ends behind in the posterior tubercle, which is the rudiment of a spinous process and gives origin to the recti capitis posteriores minores and the ...
It is the space within the thecal sac which extends from below the end of the spinal cord (the conus medularis), typically at the level of the first to second lumbar vertebrae down to tapering of the dura at the level of the second sacral vertebra. The dura is pierced with a needle during a lumbar puncture (spinal tap).
However, the cervical spine is comparatively mobile, and some component of this movement is due to flexion and extension of the vertebral column itself. This movement between the atlas and occipital bone is often referred to as the "yes joint", owing to its nature of being able to move the head in an up-and-down fashion.
The spinal nerves arise from the spinal column. The top section of the spine is the cervical section, which contains nerves that innervate muscles of the head, neck and thoracic cavity, as well as transmit sensory information to the CNS. The cervical spine section contains seven vertebrae, C-1 through C-7, and eight nerve pairs, C-1 through C-8.
The number of vertebrae in a region can vary but overall the number remains the same. In a human spinal column, there are normally 33 vertebrae. [3] The upper 24 pre-sacral vertebrae are articulating and separated from each other by intervertebral discs, and the lower nine are fused in adults, five in the sacrum and four in the coccyx, or tailbone.
Within these compartments, the neck houses the cervical vertebrae, the cervical portion of the spinal cord, upper parts of the respiratory and digestive tracts, endocrine glands, nerves, arteries and veins. The muscles of the neck, which are separate from the compartments, form the boundaries of the neck triangles. [2]
At each cervical level, the vertebral artery sends branches to the surrounding musculature via the anterior spinal arteries. Segments of vertebral artery anterior projection. The vertebral artery may be divided into four parts: The first (preforaminal) part runs upward and backward between the anterior scalene and the longus colli muscles.
Cross section of central canal. The central canal below at the ventricular system of the brain, beginning at a region called the obex where the fourth ventricle, a cavity present in the brainstem, narrows. The central canal is located in the anterior third of the spinal cord in the cervical and thoracic regions.