Radiology Cases Achondroplasia

Description: Achondroplasia is the commonest disproportionate dwarfism. It is inherited as an autosomal dominent. 85% of case incidence is from a spontaneous mutation. The main feature is a symmetrical proximal limb shortening, rhizomelia, the humeri and femora are particularly affected. Metaphyseal irregularity takes the form of cupping or a 'V' shaped metaphyseal notch.
The other features are: Smaller square iliac bones, horizontal acetabular roofs, delayed appearance of ossification, pelvic tilt with lumbar lordosis, narrow sacro-iliac notch, flattened verebral bodies, occasional short a-p diameter of vertebrae or occasionial bullet shape to anterior vertebral border, spinal stenosis, posterior scalloping of vertebrae, small skull base, compensating large vault with appearance of frontal bossing, small foramen magnum, short ribs with widened anterior ends, Trident hand, similar lengths of generally shorter fingers.