Learn all about muscles of the human body and how they work. The muscles theory section deals with the more scientific aspects of human muscles. We have grouped the major muscles of the body by the joint they are mainly associated with, although some muscles are relevant to more than one joint. Each muscle page has information on ther origin, insertion, joint actions, exercises and stretching.
The shoulder girdle consists of the scapula (shoulder blade) and the clavicle (collar bone). The muscles which produce movement of the shoulder girdle are the trapezius muscle, levator scapulae, rhomboids, serratus anterior, pectoralis minor, sternocleidomastoid and the subclavius muscle.
The shoulder joint, also known as the glenohumeral joint is a ball and socket joint and consists of the humerus (upper arm bone), clavicle (collar bone) and scapula (shoulder blade). The muscles which stabilize and enable movement of the joint are the pectoralis major, teres major, supraspinatus, deltoid and latissimus dorsi.
The elbow joint consists of the humers (upper arm bone), radius and ulna in the forearm. The ulna is the bone on the little finger side of the forearm (remember l in ulna for little finger) and the radius radiates around it. The muscles at the elbow joint are the biceps brachii, brachialis, brachioradialis, triceps brachii (triceps muscle), anconeus, pronator teres, pronator quadratus and supinator.
The main muscles which move the wrist and hand consist of the flexor carpi radialis, palmaris longus, flexor carpi ulnaris, extensor carpi ulnaris, extensor carpi radialis brevis, extensor carpi radialis longus, flexor digitorum superficiialis, flexor digitorum profundus, flexor pollicis longus, extensor digitorum, extensor indicis, extensor digiti minimi, extensor pollicis longus, extensor pollicis brevis and adductor pollicis muscle.
The knee joint consists of the femur (thigh bone), tibia and fiblua bones of the lower leg and the patella or kneecap. The muscles which flex and extend (bend and straighten) the joint are the quadriceps muscles (rectus femoris, vastus lateralis, vastus medialis) and the hamstring muscles at the back of the thigh (semitendinosis, semimembranosus and semitendinosis).
The main muscles of the hip and pelvis consis of the iliopsoas, pectinues, rectus femoris* and sartorius at the front. The gluteus medius, gluteus minimus, piriformis, tensor fasciae latae on the outside. Gluteus maximus, biceps femoris*, semitendinosus*, semimembranosus* at the back and the adductor or groin muscles (adductor brevis, adductor longus, adductor magnus and gracilis*). * means these muscle cross the knee joint as well.
The muscles of the lower leg consist of the gastrocnemius and soleus muscles which together are known as the calf muscles, the peroneus longus, peroneus brevis, extensor digitorum longus, extensor hallucis longus, tibialis anterior, tibialis posterior, flexor digitorum longus and flexor hallucis longus.
Major muscles of the neck and back include the erector spinae, multifidus, rectus abdominus, transversus abdominus, internal obliques, external obliques, splenius and quadratus lumborum.