What is the primary action of the adductor brevis?

The primary action of the adductor brevis is to adduct the thigh, which means bringing the thigh closer to the midline of the body. Additionally, it also plays a role in flexing the thigh and may assist with lateral rotation, especially when the thigh is flexed. This muscle is located deep to the pectineus and adductor longus, forming part of the group of muscles that collectively act to bring the limbs toward the body’s center.

The other options describe actions that do not pertain to the adductor brevis. Extending the thigh is more associated with muscles located in the posterior compartment of the thigh, such as the hamstrings. Flexing and medially rotating the leg pertains to the actions of muscles in the lower leg, particularly around the knee joint, while plantar flexing the foot is primarily the function of the calf muscles, such as the gastrocnemius and soleus. Hence, they do not represent the correct actions of the adductor brevis.