Eight-year-old Alex is in constant motion. The difference in the length of his legs and wearing a built-up sneaker doesn’t slow him down one bit. His ...
Due to its mild nature, it is often times difficult to differentiate between “familial” shortness of stature and hypochondroplasia. Hypochondroplasia seems to be the grey area between achondroplasia and being constitutionally shorter than average. The average adult height of hypochondroplastic patient varies between 52 and 58 inches.
The major radiographic features of hypochondroplasia include narrowing of interpediculate distances with anterioposterior shortening of pedicles. Vertebral bodies in lumbar region of spine have increased dorsal concavity. The height of the vertebral bodies is normal. The deformities of the spine, however, are not as pronounced as in the case of achondroplasia.
The pelvis is square with short ilia, although the flare of the iliac crests is normal. The sacrum is hypoplastic and low set on the iliac bones, effectively narrowing the transverse diameter of the pelvis. The tubular bones are short and with mild metaphyseal flare (most evident at the knees). The styloid processes of the ulnae are frequently long. Femoral necks are short and broad. Distal fibulae are long in comparison to tibia. In children, growth plates of distal femurs exhibit a shallow, V-shaped indentation. This is due to slower enchondral bone growth at the center of the growth plate as compared to growth at the periphery. Again, this change is more mild in hypochondroplasia than in achondroplasia. Generalized brachydactyly is mild to moderate. Occasionally, the neurocranium is slightly larger.
| For Patient Families & Health Professionals |
For Nemours Associates |