Background: Functional facial reanimation remains challenging and the quest for optimization continues. Objective: To characterize the anatomical conditions of the plantaris muscle for facial reanimation. Study Design and Methods: Forty-two plantaris muscle specimens were obtained from 23 post-mortem chemically fixed cadavers. The muscles were dissected, evaluated, and measured. Mock facial reanimation was performed on three cadaver heads. Results: The plantaris muscle was a consistently available muscle. Mean muscle belly length was 10.1 cm (standard deviation [SD] 1.4), and mean width was 1.7 cm (SD 0.4). The mean tendon length of 30.1 cm (SD 2.8) is unique in the human body. The main artery supplying the muscle had a mean length of 1.4 cm (SD 0.4). The mean nerve length was 2.2 cm (SD 0.7). Sixteen variations of vascular supply were identified. Mock facial reanimations demonstrated a good size match, and great versatility of the long tendon for oral fixation. Conclusions: The plantaris muscle as a free flap for facial reanimation could offer new possibilities in terms of oral fixation and volumetric aesthetic conditions.