The Incidence of Palmaris Longus Muscle and Its Association with the Biodemographic Data of Medical and Allied Health Science Students

Background: The Palmaris longus (PL) muscle is one of the most anatomically variable muscles in the human body. The presence or absence of the muscle tendon is relevant information to hand and plastic surgeons. The muscle tendon can be harvested for reconstructive surgeries, tendon transfer and tendon surgeries, facial paralysis, repair ptosis, arthritis of the thumb and to repair oncologic defects of the head and neck. Therefore, this study aimed at identifying the incidence of PL and its association with the study participant’s age, gender and geo-political region of origin. Methods: This cross-sectional study was performed on students that were taught ‘muscles of the forearm’ during the 2021/2022 academic session of the Edo state university, Uzairue, Nigeria. Bio-demographic data was retrieved using a self-structured hard-copy questionnaire. Schaeffer’s, Thompson’s and Pushpakumar’s testing methods were used to assess the absence/presence of PL. Data was entered into Microsoft Office Excel 2019 and exported to IBM SPSS version 23 for analysis. Fisher’s and Pearson chi-square tests were used to determine association. Probability values < 0.05 were accepted as significant. Results: Of the 294 enrolled students taught the topic “muscle of the forearm” during the 2021/2022 academic session, 269 (91%) students willingly participated in this study. 155 were females (57.6%), and 114 were males (42.4%). Out of the 269 students assessed, 253 (94.1%) students had the PL tendon in both hands, nine (3.3%) students didn’t have the tendon in both hands, seven (2.6%) students didn’t have the tendon in either the left hand (2.2%) or the right hand (0.4%). While, gender was a significant predictor for left- and right-hand values of the absence or presence of PL muscle tendon (p < 0.05), age and geo-political zone of origin was not (p > 0.05). Conclusion: The Palmaris muscle varied in only 5.9% of our study population. It was found that the occurrence of PL is gender dependent but not dependent on age or the individual’s region of origin. The absence of the muscle was common in females and on the left hand.