Ganglion impar

NervousNervesPelvis

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What it is
The single, unpaired ganglion in front of the coccyx where the lower ends of the two sympathetic trunks fuse.
Function
Supplies sympathetic fibres to the perineum, distal rectum, anus and the end of the urethra and vagina.
Size
About 3-5 mm
Clinical note
Injecting local anaesthetic at the ganglion impar (through the sacrococcygeal joint) relieves otherwise intractable perineal and tailbone (coccydynia) pain.

Nearby nervous structures Co1 spinal nerve, Pudendal nerve, S1 spinal nerve, S2 spinal nerve, S3 spinal nerve, S4 spinal nerve, S5 spinal nerve, Superior and inferior hypogastric plexuses