A Case Report on Bilateral Absent Peroneus Tertius Muscle in a 70 Years Old Male Cadaver.

During routine dissection for the first MBBS students, we observed that the peroneus tertius was absent on the dorsum of both the feet of a 70 years old, donated embalmed male cadaver in the Department of Anatomy, K. J. Somaiya Medical college, Sion, Mumbai, India. The exposure of the dorsum of the foot was achieved following classical incisions and dissection procedures. All the extensor tendons on the dorsum of the foot were observed. There was no thickening seen on the tendon of extensor digitorum longus going to the little toe. There was no signs of any muscle fibres arising from the lower part of the medial surface of the shaft of the fibula. There was no evidence of presence of peroneus tertius on the dorsum of the left foot. The photographs of the dorsum of the feet were taken for proper documentation and for ready reference. There were no associated neurovascular variations found in the same specimen.
Conclusion
The bilateral absence of the peroneus tertius is very rare and not found in literature. Usually, the peroneus tertius is involved in dorsiflexion and eversion of the foot. The existence of peroneus tertius may help in the swing phase of bipedal walking. The peroneus tertius may be used for tendon graft surgeries. The pull of the peroneus tertius may be responsible for causing stress on the fifth metatarsal bone and account for all stress fractures in any individual. The absent peroneus tertius may misguide foot surgeons performing graft operations and transplant. The absent peroneus tertius is an interesting finding, which could be clinically important for Anatomists, Anthropologists, Surgeons, Plastic and Orthopedic Surgeons.