The Owl Winks

Adorable isnt he?
The winking owl.

Not so adorable if you spot one on the AP X ray.

Spinal metastases.

The owl's eye is the pedicle of the spinal vertebrae.

With spinal metastasis, the pedical is obliterated by the invasive growth, resulting in its 'disappearance' and the winking owl sign. The intervertebral disc, however, is usually spared.

With further progression, the vertebral body may collapse and become wedge-shaped or flattened (Vertebra plana).

A radioisotope scan will be helpful.

Most malignant growths will show up as warm lesions on the scan, whereas myeloma will charactertistically be cold.

Description of the X ray above:

- osteosclerotic spinal metastasis 2* prostatic Ca

Common osteolytic bone mets:

- Lung

- Breast

- Thyroid

- Large bowel (Colorectal)

Common Osteosclerotic bone mets:

- lung

- breasts

- prostate

Side note:

In Paget's disease (TB bone): usually affects 2 adjacent vertebrae with narrowing of joint space.