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Response Details:
The reflex arc for the PR comprises of the afferent and efferent fibres in the tibial nerve and the L4-5 to S1-2 cord segments. The reflexogenic area is the first sacral dermatome, with the receptor nerve endings being located in the skin on the sole of the foot. The afferent fibres travel in the tibial nerve which is a branch of the sciatic nerve, to relay in the L4-5 to S1-2 cord segments.The efferent fibres from the spinal cord travel back in the sciatic nerve which divides into two large branches just proximal to the knee.Fibres supplying the toe flexors travel in the tibial nerve while those supplying the toe extensors travel in the peroneal nerve to reach the foot
The Babinski’s sign isencountered in patients with pyramidal tract dysfunction and is characterised by a dorsiflexion or of the great toe with or without fanning or abduction of the other toes. The fully developed response is also accompanied by dorsiflexion of the ankle and flexion of the hip and knee joint and slight abduction of the thigh,leading to a withdrawal of the leg on plantar stimulation.The Babinski sign is always pathological. There is no such thing as a negative Babinski sign.The muscles taking part in a fully developed response include the extensor hallucis longus, tibialis anterior,extensor digitorum longus, hamstring group of muscles, and the tensor fasciae latae. The dorsiflexion of the toes may be the only visible effect, but the contraction of the thigh and leg muscles is always present and can be detected by palpation. Contraction of the tensor fasciae latae has been referred to as Brissaud’s reflex. . It involves flexion of the hip and knee, dorsiflexion of the ankle and of the great toe.
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