Phylogenetic Variation of Muscle Flexor Digitorum Brevis- Rare Variation on the Right Foot.

Background: Flexor digitorum breves is an intrinsic muscle of the sole of the foot that lies superior to the central part of planter apponurosis and inferior to the tendons of flexor digitorum longus. This flat spindle shaped muscle arise from the medial process of tuber calcanei, proximal part of planter apponurosis, inter muscular septa and adjacent fascial layers. The muscle fiber conver anteriorly forming four tendons one each for the four lateral toes at the bases of proximal phalenges each tendon splits into two slips around the tendon of flexor digitorum longus, reunites into a chiasma, devides again to insert into margins of intermediate phalenges of lateral four toes. Methods: This study was carried out by routine dissection classes for undergraduate medical students classes from July 2010 to January 2014 in the department of anatomy, Teerthanker Mahaveer medical college Moradabad; department of anatomy, Rama medical college Kanpur; Department of Anatomy, Hamdard Institute of Medical Science & Research, Jamia Hamdard New Delhi. Total no. of 80 cadavers (48 male and 32 female) all the cadavers were been preserved in 10% of formalin and age ranged between 45 to 67 years. Results: Summarising the result indicates out of 80 cadavers 25% were having none anatomical variation, 46% of cadavers had bilateral absence of tendon for fifth toe of flexor digitorum breves while 18% of cadavers having variation on the left foot and rare 9% of cadavers were represented having variation on the right foot while the left foot was anatomically normal. Conclusion: Variation of flexor digitorum breves may occur as phylogenetical changes due to minimal use of little toe in evolved bipedal posture.