This radiograph illustrates that although achondroplasia is primarily a rhizomelic dwarfism (proximal segment), the intermediate segments are also affected to a lesser degree. Notice the characteristic "ball-in-socket" deformity of the knee consisting of a broad indented metaphysis with a rounded femoral epiphysis. Also characteristic is the greater shortening of the tibia relative to the fibula.
The radiograph of the humerus shows the classic metaphyseal flaring of the distal humerus with bowing of the shaft. Notice that the shaft thickness is preserved, due to preserved periosteal intramembraneous bone formation.