Achondroplasia is a form of short stature associated with a genetic defect in the fibroblastic growth factor receptor 3 (FGFR3). The syndrome can often be identified based on the phenotypic findings, although it may be difficult to identify in the newborn.


Head and neck:

(1) large head with frontal bossing

(2) midface hypoplasia (including depression of the nasal bridge)


Chest and abdomen:

(1) thoracolumbar gibbus in infancy (thoracolumbar kyphosis)

(2) exaggerated lumbar lordosis (hyperlordosis), observed when walking begins



(1) short stature

(2) proximal shortening (rhizomelic) of the arms and legs (humerus and femur)

(3) redundant skin folds

(4) limitations of elbow extension

(5) genu varum (bow legs)

(6) short fingers with trident configuration (V-shaped separation of the 3rd and 4th fingers)


Radiographic findings:

(1) small skull base and foramen magnum

(2) narrowing of the interpediculate distance of the lumbar spine

(3) square iliac wings

(4) notch-like sacroiliac groove

(5) radiolucency of the proximal femur

(6) flared metaphyses

(7) short proximal and middle phalanges


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