The transversus abdominis (L. transversus, crosswise [trans, across ; vertere, to turn] ; abdo, to hide.) is a flat layer of muscle in the abdomen, whose fibers run transverse relative to the midline of the body. It is responsible for compressing the abdominal wall, helping to support and protect the internal organs, and assist in … Read more

The external oblique (L. externus, external ; obliquus, oblique.) is a broad, flat sheet of muscle on either side of the abs. It is named after its location (external to the internal oblique) and its fiber direction (oblique relative to the midline of the body). It is the prime mover in spinal rotation, and it … Read more

The serratus anterior (L. serratus, saw ; anterior, front.), named for its saw-like appearance, is located on the side of the ribcage. It acts on the scapula and is the prime mover in both scapular protraction and scapular upward rotation. It’s also a key scapular stabilizer, keeping the shoulder blades against the ribcage when at … Read more

The pronator quadratus is (L. pronus, lying face down ; quadrus, square.) is a rectangular muscle on the front of the forearm that connects between the radius and the ulna. It is the prime mover in forearm pronation, receiving help from the pronator teres during rapid pronation. It is also noted for its role in preventing … Read more

The supinator (L. supinare, to lay on back or turn up) is a relatively wide muscle on the upper forearm. It spirals from the back and outside of the forearm to the front, crossing over the space between the radius and ulna… …This unique location allows it to carry out its primary function of forearm supination. Note: It … Read more

The gluteus maximus (G. gloutos, buttock. L. maximus, largest.) is not only the largest buttock muscle, but the largest muscle in the human body, period. Its main responsibility is hip extension, and it’s classified as part of the superficial gluteal region. The gluteus maximus is the outermost buttock muscle. It lies superficial to the gluteus minimus and the … Read more

The gluteus medius (G. gloutos, buttock. L. medius, middle) is the second largest of the three gluteal, or butt, muscles. It is a fan-shaped muscle, whose main action is hip abduction. It is also noted for its essential role as a hip stabilizer in the gait cycle. The gluteus medius is classified as part of the superficial gluteal … Read more

The gluteus minimus (G. gloutos, buttock. L. minimus, smallest) is the smallest and deepest of the three buttock muscles. Its primary responsibility is hip abduction. It is like a mini version of the gluteus medius, sharing a similar shape, location and function. The gluteus minimus constitutes part of the superficial gluteal region. It is in the deepest … Read more

The average gym rat uses the term “hamstrings” to refer to the muscles on the back of thigh, whose primary function is knee flexion. If you want to get really technical, “hamstrings” technically refer to the tendons on either end of the posterior thigh muscles, namely the semitendinosus, semimembranosus and biceps femoris (which includes both … Read more

The brachioradialis (G. brachion, arm. L. radius, stake or rod [shape of radius bone]) is a large forearm muscle, whose name refers to its connection between the upper arm and radius. It is located in the superficial posterior compartment of the forearm, which includes many of the wrist extensor muscles… …But unlike the wrist extensors, the brachioradialis is mostly … Read more