PELVIC PAIN WITH SITTING: DIAGNOSTIC ALGORITHM A. Lee Dellon, MD, PhD, Johns Hopkins University Department of Plastic Surgery OBJECTIVE: RESULTS: PFCN through its inferior cluneal (IC) Painful sitting is a common nerve and distal branches innervates the complaint of both male and lower buttocks and posterior thigh skin, female patients with pelvic pain. the regions in which the pain of sitting is The most common peripheral perceived. PN, sciatic nerve (SN), nerve implicated in this problem is obturator nerve (ON), ilioinguinal (II), the pudendal nerve (PN).The iliohypogastric (IH) and genitofemoral “classic history”: pain is not (GF) nerves cannot transmit information present when sitting on a toilet about sitting that is interpreted as pain. seat. The posterior femoral (A) PFCN nerve innervates the region cutaneous nerve (PFCN) that about the ischial tuberosity.(B ) Injury to innervates the ischial tuberosity the anterior pelvic region can injure the II, and lower buttock (inferior cluneal IH, GF, and ON, and cause the patient to nerve), and, with its perineal sit leaning backwards, causing secondary branch, overlaps the pudendal pain with sitting (C), interpreted as nerve, giving rise to the “sciatica”, and can also cause compression probability of diagnostic confusion of the PCFN, which, through its perineal (A). B branch, can result then in secondary pain Ischial in the perineum and labia/vestibule, METHODS: Tuber. simulating PN compression symptoms. Treatment must be directed primarily to Anatomic pathways related to resection/decompression of the anterior the nerves surrounding the pelvis A nerves. were reviewed. Clinical experience (D )PN compression causes symptoms in with more than 50 pelvic pain distribution of its branches; anus, SITTING POSITION perineum, labia/scrotum, vestibule, patients who complain of painful E WITH GROIN PAIN sitting are reviewed. A model of vagina, clitoris/penis, but not true pain in chronic nerve compression for the D C the ischial tuberosity region, because the pelvis, based upon carpal tunnel PN does not innervate this region. syndrome, is constructed, in which CONCLUSION it is realized that the median nerve : crosses the wrist, but yet PFC nerve is the most common compression of median nerve cause of pain with sitting. PFC is usually injured in sports (hamstring tear) or as a results in numbness in fingers, but CAUSES 2ND does not result in wrist joint (bone) SITTING LOW complication of previous PN or SN surgery. WITH PRESSURE BACK PAIN pain because the median nerve Nerve blocks are best way to distinguish ON PUDENDAL etiology of pain with sitting. does not innervate the wrist joint. NERVE Dellon, AL, Pain with sitting related to injury of the posterior femoral cutaneous nerve, Microsurgery, 35:463‐468, 2015..