Approximate area of “saddle anesthesia” seen from behind
Severe back pain
Saddle anesthesia, i.e. anesthesia or paraesthesia involving S3 to S5 dermatomes, including the perineum, external genitalia and anus; or more descriptively, numbness or “pins-and-needles” sensations of the groin and inner thighs which would contact a saddle when riding a horse.
Bladder and bowel dysfunction, caused by decreased tone of the urinary and anal sphincters. detrusor weaknesses causing urinary retention and post-void residual incontinence as assessed by bladder scanning the patient after the patient has urinated.
Sciatica-type pain on one side or both sides, although pain may be wholly absent
Weakness of the muscles of the lower legs (often paraplegia)
Achilles (ankle) reflex absent on both sides.
Severe back pain, saddle anesthesia, incontinence and sexual dysfunction are considered “red flags”, i.e. features which require urgent treatment.