Pudendal nerve supplying motor pa to external sphincter is derived from?
S2-S3 roots. There are two sphincters of the urethra a. Internal urethral sphincter (also k/a sphincter vesicae) - it is involuntary in nature - made up of smooth muscle - supplied by sympathetic nerves, from lower thoracic & upper lumbar segments of spinal cord b. External urethral sphincter (also k/a sphincter vesicae) - it is voluntary in nature - made up of striated muscle fibres - supplied by the perineal branch of the pudendal nerve (derived from spinal nerves S2,S3 & S4) - it controls the membranous urethra and is responsible for the voluntary holding of urine.
L5-S1 roots
51-S2 roots
L2-L3 roots
S2-S3 roots