Freiberg's disease. X-ray of the toes of a 50- year-old woman showing damage to the 2nd toe due to Freiberg's disease. Freiberg's disease is a type of avascular necrosis that affects the heads of the metatarsal bones of the feet. At right is the big toe which is unaffected. To the left of the big toe, the affected 2nd toe shows signs of flattening and hardening (sclerosis) around the head of the metatarsal (the lower bone) and the surface of the phalanx bone above. The space between these bones has become narrower compared to that seen in the 3rd and 4th toes at left. This bone flattening may be permanent and lead to osteoarthritis in later life.