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Anal reflex -Clinical significance

Anal reflex is an example of superficial reflex
Method of elicitation of Anal reflex
It is elicited by stroking or pricking the skin and mucous membrane in the perianal region (which is  a noxious or tactile stimulus) and feel the contraction of external anal sphincter  with the finger inserted into the anal canal
Response: Contraction of the external anal sphincter.
The stimulus is detected by the nociceptors in the perineal skin to the pudendal nerve, The response is integrated by the spinal cord sacral segments S2-S4.
Other names of anal reflex
Anal wink, Anocutaneous reflex, Perineal reflex 
Root value  of anal reflex -S3,S4,S5
Clinical significance of anal reflex
Absent reflex :
The absence of anal reflex occur due to  an interruption of the reflex arc, or damage to the spinal cord
1. Lesion of the local reflex arch of S4-S5.
2. Pyramidal lesions.