1. A review' of the literature on the so-called "spastic flat-foot" simows variable, often contradictory, theories concerning its etiology and treatimment.
2. The prevailing conception is that it is a reflectony spasticity of the pronators, which develops in a flaccid flat foot as a result of irritation of the tarsal joints, attributed to faulty statics and mecimanics.
3. No satisfactory explanation for the fact that the spasticity is always limited exclusively to the pronators can be found in the literature, although various theonies have been advanced.
4. The accepted standard treatment of the so-called spastic flat-foot has been rest, immobilization, pimysiotherapy, manipulations, resection of peroneal tendons, or even induction of palsy of the pronators by interruption of conductivity of the peroneal nerve by means of injections or crusiming of the nerve.
5. A review of the anatomy and mecimanics of the subtalar joint shows that the interosseous talocalcaneal ligament is relaxed in pronation, and becomes tense in supination of the foot.
6. The author's theory of the cause of so-called spastic flat-foot as a lesion of the interosseous talocalcaneal ligament or of the subtalar joint with reflex spasm of the pronators to produce relaxation of the above ligament is given.
7. The syndrome of spasticity of the pronators is not peculiar to flat-foot, but is often observed in normal feet or even in cases of cavus. Therefore, the terms, "spastic subtalar lesion" or "subtalar arthritis witim spasm of the pronators" are offered as more appropriate designations than "spastic flat-foot".
8. A classification of cases with the method of treatment employed by the author is described.
9. The lesion of interosseous talocalcaneal ligament is the primary cause, and spasm of the pronators is the consequence. Therefore, any operations designed to eliminate the action of the pronator muscles (tenotomy or interruption of peroneal nerve) are strongly condenmned as being unsound, futile, and often harmful.