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




Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Tuesday, September 4, 2012 1:48 pm