Backache among adolescents and young women is an unusual presenting feature to the Accident and Emergency Department as well as orthopaedic clinics. Here, we present a challenging case of a mullerian duct abnormality, which collectively has an incidence of 0.0001% of the population, and how its consideration and investigation will ensure optimum management in both acute and long term.A 14-year-old, healthy, post-menarchal, nulliparous woman presented to the Accident and Emergency (A&E) Department complaining of persistent backache of 3 months duration which radiated down her right buttock and was not relieved by simple analgesia. On her first presentation to the A&E Department, she was noted to have no bruising or swelling in the area, but her S4 region was tender. No other investigations were performed. She was reviewed by another consultant who prescribed analgesia and physiotherapy.One month later, after having been referred to an orthopaedic consultant by her general practitioner, she again presented to the A&E Department with worsening symptoms, keeping her awake at night and forcing her to stay away from school. There was no history of injury or new source of stress to the spine. On orthopaedic examination, she was noted to have no scoliosis, lordosis or kyphosis of the spine. There were no congenital abnormalities or muscle wasting noted, although there seemed to be a questionable 1.5 cm real leg length discrepancy as was borne out by the uneven wear of her shoes. She was noted to have a normal range of movement in her spine and at flexion was able to touch the floor flathanded. Straight leg when raised to 30˚was painful, especially on the right, but there were no neurological or vascular abnormalities. Radiographs of the spine were normal.In the orthopaedic Outpatient Department, she was found to demonstrate the same features as before although the pain had improved significantly. A full blood count (FBC), erythrocyte sedimentation rate (ESR), C-reactive protein test (CRP) were performed. All were normal. A magnetic resonance imaging (MRI) scan was arranged. The patient began to seek chiropractic treatment by this time.Three months after her first A&E presentation, she again presented to the department with the same pain but the severity was increasing. A thorough re-evaluation of the history revealed that the pain was related exactly to the onset of her periods. The pain would last for 3 weeks, subside for 1 week and then recur exactly on the first day of menstruation. She did not complain of any menstrual anomalies such as menorrhagia or metorrhagia. She was not sexually active, had no vaginal discharge, the urine was free of any pathology and the pregnancy test was negative. Her abdomen was noted to be soft and non-tender, and no masses or anomalies were identified. The Laseque test was positive and radiated around her buttock, but no neuropathology was noted.The gynaecological registrar was consulted due to the ensuing history, and it was decided to try her on oral contraceptive medication to exclude ...