Ligament · Foot

Lateral metatarsosesamoid ligament

Anchors the outer (fibular) sesamoid to the outer side of the head of the first metatarsal, holding it in its shallow groove on the underside of the bone. It is one arm of a four-cornered frame: each sesamoid is tied backwards to the metatarsal head and forwards to the base of the big toe, so the pair travel with the toe rather than staying put. Together with its medial twin it stops the sesamoids drifting sideways as the toe bends under load. What it protects is alignment — the outer sesamoid tracking under the metatarsal head rather than sliding off its edge.