The cauda equina, literally meaning ‘horses tail’, refers to the nerve bundle that controls the pelvic organs and lower limbs. When these nerves are compressed or damaged it may give rise to cauda equina syndrome which includes symptoms of leg pain, altered sensation in the pelvic region (e.g. numbness), incontinence, and weakness of paralysis of muscles in the leg or foot. Sudden onset cauda equina syndrome is considered an emergency.