A patient reports insidious plantar surface pain and forefoot burning with numbness between the 3rd and 4th metatarsal heads, reproduced when the metatarsal heads are squeezed. The MOST likely diagnosis is?

• A. Freiberg disease
• B. Morton neuroma
• C. Anterior tarsal syndrome
• D. Sesamoiditis

Answer: (B)

Morton neuroma is an interdigital neuropathy from entrapment of the common digital nerve between the metatarsal heads, most often between the third and fourth. This condition classically produces insidious burning pain on the plantar forefoot with numbness between those two toes, matching the symptoms described. The fact that squeezing the metatarsal heads reproduces the symptoms (a positive Mulder sign) supports nerve entrapment in the intermetatarsal space. Other disorders affect different areas or have different patterns: Freiberg disease involves avascular necrosis of a metatarsal head with focal joint pain, sesamoiditis affects the first MTP under the big toe, and anterior tarsal syndrome causes dorsum foot symptoms from nerve compression rather than plantar forefoot neuropathy between the third and fourth heads.