The pathological anatomy of convex pes valgus.

Convex pes valgus (vertical talus) is a rare form of congenital foot deformity, the etiology of which remains unexplained. The 10 per cent incidence in a large series of patients with foot deformities in myelomeningocele (Sharrard and Grosfield 1968) suggests that a specific neuromuscular imbalance may be responsible, at least in myelodysplastic patients, for the development of the “Persian slipper foot”. The single report in the literature discussing the anatomy of this deformity (Patterson, Fitz and Smith 1968) does not describe the significant changes in the course of major tendons and their consequent altered function, nor does it discuss the intrinsic foot musculature. This paper presents a detailed description ofthe pathological anatomy in a case of myelomeningocele with congenital pes valgus. The concept that a neuromuscular imbalance between the invertors and evertors of the foot causes this deformity will be discussed.