Nutrition to the lumbar intervertebral disc is from the
(A) posterior spinal artery
(B) internal iliac artery
(D) anterior spinal artery
(C) The lumbar arteries supply the vertebrae at various levels. Each lumbar artery passes posteriorly around the related vertebra and supplies branches into the vertebral body. The terminal branches form a plexus of capillaries below each endplate. The disc is a relatively avascular structure. Nutrition to the disc is by diffusion from the endplate capillaries and blood vessels in the outer annulus fibrosus. Passive diffusion of fluids into the proteoglycan matrix is further enhanced by repeated compression of the disc by repeated flexion-extension of the spine associated with activities of daily living which pumps fluid in and out of the disc. The abdominal aorta does not provide any direct blood supply to the intervertebral disc.
A 65-year-old man presents with symptoms of pain in the cervical region. He also complains of radiation of his pain along the lateral part of his right forearm. He has a magnetic resonance imaging (MRI) of the cervical region with evidence of a herniated disc between the fifth and the sixth cervical vertebra. The nerve root that is most likely compressed is
(A) fourth cervical nerve root
(B) fifth cervical nerve root
(C) sixth cervical nerve root
(D) seventh cervical nerve root
(E) first thoracic nerve root
(C) Disc herniations in the cervical region are relatively less common than the lumbar region. In the cervical region the C5, C6, and C7 intervertebral disc are most susceptible to herniation. The C6 and C7 intervertebral disc herniation is the most common cervical disc herniations. In the cervical region each spinal nerve emerges above the corresponding vertebra. An intervertebral disc protrusion between C5 and C6 will compress the sixth cervical spinal nerve. There are seven cervical vertebra and eight cervical spinal nerves. These patients characteristically present with pain in the lower part of the posterior cervical region, shoulder, and in the dermatomal distribution of the affected nerve root.
The most common presenting symptom of rheumatoid arthritis is
(A) pain in the small joints of the hand