Flexores

Flexores, or flexor muscles, are a group of muscles that produce flexion at joints. The term is used in many languages, including Portuguese and Spanish, to describe muscles responsible for bending a limb or part of the body. Flexion is the movement that decreases the angle between two body parts, and flexores typically act as antagonists to extensor muscles, which straighten joints.

In the upper limb, flexor muscles are mainly located in the anterior compartments. Elbow flexors include the biceps brachii, brachialis, and brachioradialis. Wrist and finger flexors comprise the flexor carpi radialis, flexor carpi ulnaris, palmaris longus, flexor digitorum superficialis, and flexor digitorum profundus, with the flexor pollicis longus acting on the thumb. Innervation varies by muscle, with many forearm flexors supplied by the median nerve, the flexor carpi ulnaris and the medial half of the flexor digitorum profundus by the ulnar nerve, and the brachioradialis by the radial nerve.

In the lower limb, flexores include hip flexors such as the iliopsoas, rectus femoris, sartorius, and tensor fasciae latae, which bend the hip, and knee flexors—the hamstring group: biceps femoris, semitendinosus, and semimembranosus. The hamstrings are primarily innervated by the tibial portion of the sciatic nerve, with the short head of the biceps femoris supplied by the common fibular (peroneal) portion.

Clinically, tight or injured flexores can impair movement and posture. In the hand, flexor tendon dysfunction can affect grip and finger flexion, while nerve injuries can alter the strength and control of flexion movements.