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spinal reflex[′spīn·əl ′rē‚fleks]
a reflex whose center is located in the spinal cord. There are four types of spinal reflexes: somatic (motor), autonomic, segmental, and intersegmental. Somatic spinal reflexes are involved in the activity of the skeletal musculature of the trunk and extremities, and autonomic spinal reflexes in the activity of the musculature of the blood vessels and internal organs. Segmental spinal reflexes occur within a single segment of the spinal cord, and intersegmental spinal reflexes enter and emerge from different spinal segments.
Depending on the structure of the reflex arcs, spinal reflexes may be monosynaptic or polysynaptic. The former include tendon and muscular reflexes, including the quadriceps and triceps reflexes (extension of the extremities upon tapping a tendon). The latter include skin reflexes, for example, the flexion reflex (the jerking of an extremity in response to stimulation of the skin), reflex stepping (the extension of the leg upon touching the plantar surface), crossed reflexes of corresponding extremities, and interextremital reflexes, which are elements of locomotion, a complex motor activity. Vascular, bladder, and rectal reflexes are spinal reflexes of the internal organs.
The study of spinal reflexes is an important method used in examining individuals suffering various pathological conditions.
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P. A. KISELEV