It is known that the palmaris longus muscle is one of the most variable muscles in the human body. The
palmaris longus muscle has a high morphological diversity and variations are frequently reported in the literature.
Recognizing anatomical variation in the palmaris longus muscle and tendon is important for clinical associations
such as neurovascular entrapment and compression, as well as tendon graft and transfer for reconstruction. While
neglecting to identify palmaris longus variations rarely leads to an increase in mortality, it is essential to identify
for clinical relevance. During anatomical dissection of fifty cadavers in the 2020 undergraduate first-year anatomy
course at the Uniformed Services University of Health Sciences (USUHS), we found two separate cases of
accessory heads of the palmaris longus muscle. The first case involved a preserved 86-year-old White Female who
had one unilateral accessory head of the left palmaris longus muscle. The second case involved a preserved 81-
year-old White Male who had a unilateral pair of accessory heads of the right palmaris longus muscle.