Prevalence of the absence of Palmaris longus muscle in the students of Kathmandu University

Background: Palmaris longus muscle is one of the superficial muscles of flexor compartment of forearm. Its main function is to anchor the skin and fascia of the hand. It is a weak flexor of the hand at wrist and tenses the palmar aponeurosis. It is one of the most variable muscles and is phylogenetically classified as a retrogressive muscle. The agenesis of Palmaris longus ranges from 0% to 63% with an overall 16% unilateral and 9% bilateral. It is very useful in orthopedics, cosmetic, plastic and reconstructive surgery. Objective: To determine the occurrence of unilateral and bilateral agenesis of Palmaris longus muscle in right and left forearms in the students of Kathmandu University. Materials and methods: The study was carried out on 1020 randomly selected normal students (570 male and 450 female) with an age ranging from 18 to 25 years. The volar aspect of the wrist was inspected to find out the presence or absence of Palmaris longus tendon in its usual anatomical position by performing different tests. Result: The present study showed overall agenesis of Palmaris longus in 27.65% cases. Overall agenesis in male and female was 28.42% and 26.67% respectively. Unilateral and bilateral agenesis were 77.16% and 22.84% respectively in male whereas 67.50% and 32.50% respectively in female. Left sided and right sided agenesis were 55.20% and 44.80% respectively in male whereas 53.09% and 46.91% respectively in female. Conclusion: Palmaris longus is absent unilaterally in 20.20% and bilaterally in 7.45% of its population with an overall absence of 27.65%.