Sesamoid Fracture-Plain Film

An adult with history of  injury with pain and swelling near the great  toe. X rays AP/oblique  show three sesamoids instead of usual two, with jarred, and sharp margins of horizontally cleavaged medial sesamoid with soft tissue shadow in the vicinity . In view of local tenderness possibly represents fracture.

Teaching points by Dr MGK Murthy & Dr Sumer Sethi

·         Sesamoid bones occur in the tendon of flexor hallucis brevis(FHB)  in the plantar surface of great toe and are 2 in numbers called tibial and fibular sesamoids

·         Play an important role in giving mechanical advantage to FHB in assisting weight bearing  behind  great toe , in addition to keeping the  head of MT off the ground , with medial sesamoid playing more role  in this

·         Can  be bipartite in about 10% of people (amongst them 25% are bilateral), in which case it  looks 3 in numbers(medial is more bipartite than lateral), with occasional  one multipartite

·         Fracture shows  sharp edges, corners/jarred margins/invariably transverse or horizontal/more involving medial/Soft tissue swelling/pain/local tenderness /other side absent (bipartite is well defined and medial more along with corticated margins)

·         Bone scintigraphy positive only in fractures or MR shows marrow edema

·         Other diseases include sesamoiditis/avascular necrosis/displacement/stress fracture