Occipital dysplasia in dogs – literature review

The foramen magnum is normally rounded or oval in shape and has a similar diameter to the vertebral foramen of the atlas. Occipital dysplasia is observed is small breed and brachycephalic dogs, and is characterized by a dorsal widening of the foramen magnum caused by an incomplete ossification of the supraoccipital bone. There are divergent opinions in the literature regarding the clinical relevance of occipital dysplasia in dogs, and doubts remain as to whether this presentation is only an anatomical variation or an actual disease. The objective of this paper is to clarify aspects related to occipital dysplasia by means of a literature review on this subject, focusing on the anatomy of the atlanto-occipital junction, as well as the clinical and diagnostic aspects of occipital dysplasia in dogs.