Muscles of the upper and lower limbs Appendicular Muscles Upper limb muscles have 3 major groups Lower limb muscles are the largest

Upper limb Muscles 3 groups The first group arises from the shoulder girdle and insert into the humerus The second group encloses the humerus and insert into the forearm bones causing movement at the elbow joint The third group is the muscles of the forearm which insert into the hand and wrist

Upper limb Muscles Group 1 Group 2 Already discussed Biceps brachii Pectoralis major Latissimus dorsi Dletoid Group 2 Biceps brachii Most familiar muscle Two origin in the shoulder girdle Inserts into the radial tuberosity Prime mover of the forearm flexion and supinates the forearm

Upper limb Muscles Group 2 Brachialis Brachioradialis Deep to the biceps muscle and is a synergist to the biceps muscle in forearm movement Brachioradialis Weak muscle Arises on the humerus Inserts into the distal forearm

Upper limb muscles Group 2 Triceps brachii Only posterior muscle on the humerus Has 3 heads Origin in the shoulder girdle and proximal humerus Inserts into the olecranon process of the ulna Extends the forearm at the elbow

Upper limb muscles Group 3 Supinator muscle Pronator teres Under the upper posterior portion of the radius Works synergistically with the biceps brachii to supinate the hand Pronator teres Located on the upper medial side of the forearm Origin is in the medial epicondyle of the humerus Inserts on the upper lateral shaft of the radius Pronates the hand

Upper limb muscles Group 3 Pronator quadratus Extends between the ulna and the radius Origin is on the ulna, inserts on the radius Works synergistic with the pronator teres and rotates the palm

Lower limb muscles Divided into 3 groups Movement of the hip Movement of the knee Movement of the foot

Lower limb muscles Group 1 Gluteus maximus Superficial muscle of the hip Forms the buttock Hip extensor Not important in walking, but is important when power is needed for climbing Origin is in the sacrum and iliac Inserts into the gluteal tuberosity of the femur

Lower limb muscles Group 1 Gluteus medius Runs from the ilium to the femur Beneath the gluteus maximus Hip abductor Steadies the plevis during walking Used for injections

Lower limb muscles Group 1 iliopsoas Fused muscle Iliacus Psoas major Prime mover of the hip flexion Keeps the upper body from falling backwards

Lower limb muscles Group 1 Adductor muscles Group of muscles Medial side of each thigh Press the thighs together

Lower limb muscles Group 2 Muscles causing movement at the knee joint Quadriceps group Sartorius – obliquely crosses the anterior aspect of the thigh. It arises from the anterior superior spine of the ilium and extends medially to insert into the proximal medial surface of the tibia Acts on the hip and knee joints

Lower limb muscles Group 2 Quadriceps femoris – composite of 4 distinct muscles Have separate origins, but a common insertion via the patella tendon Function synergistically to extend the leg Rectus femoris – occupies a superficial position, functions with both the hip and the knee

Lower limb muscles Group 2 Muscles of the hamstring group Vastus lateralis – the largest muscle of the quadriceps femoris, extends the knee Vastus medialis – occupies the medial position along the thigh, extends the knee Vastus intermedius – lies deep to the previous 2 muscles, extends the knee Muscles of the hamstring group Biceps femoris – occupies the posterior lateral aspect of the thigh, flexes the knee and moves the hip joint. It has a superficial long head and a deep short head

Lower limb muscles Group 2 Muscles of the hamstring group Semitendinosus – is a fusiform muscle and is located on the posterior medial aspect of the thigh Works over 2 joints, the medial rotation of the leg (hip) and flexion of the lower leg Semimembranous – is deep to the semitendinosus, synergistic to the semitendinosus

Lower limb muscles Group 3 Muscles that move the foot (crural muscles) 3 groups of crural muscles Anterior crural muscles – tibialis anterior, extensor digitorum longus, extensor hallucis longus, and peroneus tertius Lateral crural muscles – peroneus longus, peroneus brevis Posterior crural muscles – gastrocnemius, soleus [triceps surae], plantaris, popliteus, flexor hallucis longus, flexor digitorum longus, and tibialis posterior