Absence of the fourth tendon of flexor digitorum brevis in the right foot of a male cadaver: A case report with clinical implications

• Author Details:   
• Sancy Charly
• Rajasekhar S.S.S.N ^*

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The Flexor digitorum brevis (FDB) muscle of the plantar aspect of the foot typically forms four tendons that insert into the lateral four toes. Although variations in tendon number and insertion patterns are common (13-83% worldwide), they are critically understudied with respect to biomechanical implications, especially in populations with high prevalence for variation (77.3% in South Asians). The present case report describes the unilateral absence of the fourth FDB tendon of a 60-year-old male cadaver of South Asian origin using comprehensive morphometric analysis using digital callipers: muscle belly length measured 82.20 mm and widths varied (proximal: 9.10 mm, midpoint: 11.4 mm, distal: 5.92 mm); the remaining three tendons measured 79.09 mm, 65.24 mm, and 56.77 mm. This quantitative documentation adds to limited morphometric data available for South Asian populations and provides population-specific reference values crucial to surgical planning as well as demonstrating a need for biomechanical analysis and standardized clinical assessment protocols in high-variation populations.