Radiography of Congenital Skeletal Disorders in Cats and Dogs

The most important thing is to obtain two plain orthogonal radio- graphs of the region of main inter- est. This means medio-lateral and cranio-caudal views for the extremities or latero-lateral and dorso- ventral / ventro-dorsal views the head and spinal cord, respectively. Sometimes stressed or oblique views may be used in complex joints. Computed Tomography is valuable for further evaluation of ques- tionable or suspicious radiographic findings. Three- dimensional reconstructions may give additional infor- mation.
In the following skeletal congenital malformations and diseases that may be diagnosed on radiographs and computed tomography will be explained, although this list is not exhaustive.

Congenital disorders of the head:

• brachycephalic breeds are often presented with a domed calvarium

• congenital hydrocephalus: domed shape of the calvarium, thinning of the bones, uniform groundglass opacification, prominent or open fontanelles and suture lines; mostly miniature and small breeds

• occipital dysplasia: dorsal extension of the foramen magnum, seen on rostrocaudal view; may be accompanied by hydrocephalus

• increased thickness of the calvarian bones may be present in e.g. Pit Bull terriers

• CMO (craniomandibular osteopathy): West Highland White Terriers, Cairn Terriers, Scottish Terriers; sometimes large breeds: (para)periosteal new bone on skull, mostly on mandibules and tympanic bullae; sometimes distal ulnar and radial metaphyses

• Kartagener’s syndrome or immotile cilia syndrome: causes increased opacity of the nasal cavity, situs inversus and bronchitis or bronchiectasie; sinusitis may cause increased opacity of the frontal sinuses

• congenital anodontia (absence of teeth) or oligodontia (reduction in number of teeth); the latter is common in brachycephalic breeds; sometimes polyodontia; oblique intraoral views may demonstrate the teeth better than lateral and dorso-ventral views.

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