A Gibbus deformity is a form of structural kyphosis, where one or more adjacent vertebrae become wedged. Gibbus deformity can be a sequela of advanced skeletal tuberculosis and is the result of collapse of vertebral bodies. This can in turn lead to spinal cord compression causing paraplegia.
When viewed from behind, the deformity is sharply angled, with the resulting hunchback being more easily seen when bending forward.
A Gibbus deformity may result from the sail vertebrae associated with cretinism, the childhood form of hypothyroidism. It is also seen with tuberculosis and certain congenital syndromes, including achondroplasia.
References
Gibbus deformity Wikipedia(Text) CC BY-SA