# Musculotendinous Anatomy in Congenital Split Foot: Anatomical Description of a Rare Case and Literature Review

## TL;DR

This paper describes the detailed anatomy of a rare foot deformity called congenital split foot, revealing unique tendon structures that could inform surgical approaches.

## Contribution

The study provides the first detailed macroscopic anatomical description of soft tissue adaptations in congenital split foot.

## Key findings

- A unique tendon loop formed by the extensor digitorum longus tendon was found in the central cleft of the foot.
- The deformity involved significant musculotendinous adaptations beyond skeletal abnormalities.
- The tendon loop is a previously rarely reported feature, indicating asynchronous development of skeletal and soft tissues.

## Abstract

Background: Congenital split foot/hand is a rare limb anomaly. Although various surgical techniques have been described, detailed gross anatomical studies of soft tissue adaptation, particularly in the foot, are extremely rare. This study presents a detailed anatomical description of a case of severe bilateral split foot. Methods: A comprehensive dissection was performed on the lower limb of a 64-year-old male donor with bilateral split foot/hand. Results: Radiographic evaluation classified the deformity as Blauth type IV, characterized by the absence of the lateral cuneiform bone and severe hypoplasia/aplasia of the second and third metatarsals. Significant changes were revealed in the musculotendinous apparatus. The key finding was a unique tendon loop passing through the central cleft, formed by the tendon of the extensor digitorum longus and connecting with the tendons of the flexor digitorum longus and flexor hallucis longus. Conclusions: This study presents the first detailed macroscopic anatomical description of split foot, demonstrating that this congenital anomaly involves complex, structured tendon and muscle adaptations that extend beyond skeletal deficiencies alone. The discovery of a persistent tendon loop—previously reported only once in split hand—indicates asynchronous development of skeletal and soft tissue structures. These findings should be taken into account for surgical planning, emphasizing the need to identify and manage such abnormal soft tissue structures during reconstructive procedures.