Morphology and Anomalies of the Palmaris Longus Muscle: A Cadaveric Study

Kassa, Joe, Kevin Kalnasy, Lisa Gates, and Mary Tracy-Bee

Historically, studies of the palmaris longus muscle have identified an absence in 10% of the population. More recent studies have observed a higher incidence of absence, especially in regards to different ethnic groups. We have expanded beyond typical studies by further investigating morphological features and variations of this muscle. In this study we observed 74 cadavers, 38 males and 36 females. We measured the length and width of the muscle belly and tendon. Actual presence of the muscle on the left side of the body was not significant (p=0.358); however, muscles on the right side of the body showed a significant difference (p<0.001) between males and females. A few anomalies were observed during this study including reversal of the muscle belly and tendon as well as differences in the insertion. These results illustrate that the many variations of the palmaris longus muscle should be considered before performing surgery.