Teaching Case

A 31 year old man complained of a painful neck after a hyperflexion injury to the neck. X rays revealed a possibility of a fracture (Fig 1 and 2). ACT scan was done to confirm the diagnosis.

A thirty-one year old man had a hyperflexion injury to his neck while snowboarding. He had immediate neck pain and stiffness with transient tingling of his finger tips. He was taken to the local hospital where he was treated in accordance with ATLS principles by triple immobilisation. Examination revealed tenderness over the C1 spinous process. There was no neurological deficit. There were no other injuries. Cervical spine X rays done raised the possibility of a fracture of the C1 vertebra (fig 1 and 2). He was airlifted to the regional spinal unit for further management where he underwent a CT scan. The scan revealed non-fusion of the anterior arch of C1 and mal-fusion of the spinous processes of C1 and C2 (Fig 3). There was no evidence of fracture or subluxation. X-rays were then obtained in flexion and extension of the cervical spine and showed no evidence of abnormal movement. The patient was treated symptomatically by immobilisation in a Philadelphia collar for 4 weeks followed by physiotherapy. He went on to make a good recovery.

Acute injuries of the cervical spine commonly present to the Accident and Emergency department. The difficulty in interpretation of cervical spine X rays after head and neck trauma can be compounded by the presence of a congenital anomaly. The recognition of a congenital abnormality in this situation is important for further management. The atlas ossifies from three centres: one each for the lateral masses and one for the anterior arch (2). The anterior arch is fibrocartilaginous at birth, a centre appears at the end of first year which unites with the lateral masses between the sixth and eighth year. Occasionally the anterior arch is formed by extension and ultimate union of centres in the lateral masses, sometimes from two lateral centres in the arch itself. " Split atlas" i.e., posterior arch rachischisis associated with anterior arch rachischisis is a rare congenital abnormality(3,4,5). The terms of bipartate atlas and clefts( anterior and posterior) of the atlas are synonyms and mean the the same as congenital split atas. Most atlas abnormalities produce no abnormal cranio-vertebral relationships. These congenital abnormalities include aplasias, hypoplasias, and clefts of the arches. This case highlights the importance of computerised tomography in the diagnosis of cervical spine conditions as it helps to distinguish between traumatic pathology (especially the jefferson's fracture) and congenital abnormality.Intact cortical margins and lack of adjacent soft tissue swelling are CT indices distinguishing congenital clefts from fracture. Any patient with a suspected cervical spine injury should remain immobilised in a hard collar until traumatic pathology has been positively excluded(1).