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Publication Title

Discover Medicine


Purpose This study reports the findings of bilateral tensor fascia suralis muscles (TFS) and a unilateral accessory muscle belly of the biceps femoris (AMBF) in a 72-year-old female.

Case report The findings were initially identified during educational dissection of the lower extremities by medical students. The AMBF and bilateral TFS were further dissected to identify their origins and insertions. The left TFS (length, 22.83±0.05 cm; width, 6.24±0.14 mm) originated from the biceps femoris long head muscle (BFLH) and inserted onto the crural fascia overlying the lateral head of gastrocnemius muscle. The right TFS (length, 114.89 ±0.62 mm; width, 9.82±0.11 mm) originated from the BFLH and inserted onto the crural fascia overlying the medial head of gastrocnemius muscle. The length of the crural fascia insertion was 76.26±3.00 mm (left) and 127.69±1.41 mm (right). An AMBF was present in the left lower limb, originating from the greater trochanter and inserting on the distal end of the BFLH. The common peroneal nerve passed deep to the AMBF, 20.3 cm inferior to the inferior border of the piriformis.

Conclusion This data characterizes a novel finding of bilateral TFS muscles with a unilateral AMBF.



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Tensor fascia suralis muscle, Anatomical variation, Common peroneal nerve, Accessory muscle belly of biceps femoris