Air in the cervical annulus--the lucent cleft sign.

The lucent cleft sign is a sign of soft tissue injury. It was first described as a sign of acute cervical injury but it is neither confined to cases of trauma nor the cervical region. The sign is also seen in degenerative disease and in the lumbar spine. The lucent cleft sign is seen anteriorly, as an area of hyperlucency above the superior end plate of the vertebra. It is the result of a partial tear of the annulus. In complete avulsion, the sign may be absent and the radiograph, completely normal. We report our experience of 15 patients with the lucent cleft sign. Our patients are relatively young (commonest age group 30-35 years) and the majority (10 patients) had a history of acute trauma. Four patients had non-specific (3 cervical and one lumbar) aches while in the last patient, the lucent cleft was an incidental finding. Although we only documented the disappearance of the sign in 4 patients, we believe that with healing, the sign will eventually disappear. Although the sign is transient, it is useful as it may be the only sign present in cases of trauma.