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Pathophysiology


- Discussion:
   - medial capsule:
         - related to repetitive loading of the hallux that leads to attenuation of the medial capsular structures;
   - medial migration of first metatarsal:
         - first metatarsal head has no musculotendinous attachments;
         - head of 1st metatarsal, w/ increased valgus, progressively moves medially off
sesamoids,  which remain w/ attached to & move w/ proximal phalanx;

   - sesamoids:
            - because the transverse metatarsal ligament anchors the sesamoids to neck of the 2nd metatarsal, the sesamoids  remain in constant position, and the first MT head moves off of them;
            - w/ continued hallux valgus progression, sesamoids become displaced laterally until fibular sesamoid becomes located in metatarsal interspace;
    - pronation of the hallux:
            - during this process there is pronation of the hallux;
            - hallux rotates, & callous forms at plantar aspect of its IP joint;
            - when hallux assumes a valgus position, the action of the abductor hallucis becomes one of flexion and pronation of the first metatarsal;
    - wt bearing under 1st MT head is ineffectual because Windlass Mech is dependent on adequate dorsiflexion of the hallux