Muscles: location and functions

Pectoralis major

location: mostly under the breast area; spans from sternum to humerus

function: pulls the arm forward and down

Serratus anterior

location: on the side of the body under the armpit (axillary) area

function: stabilizes the shoulder and contributes to arm movements such as pushing

Biceps brachii

location: on the anterior side of the arm (humerus)

function: bends (flexes) the arm at the elbow joint

Rectus abdominis

location: runs from the ribs to the pelvis on the anterior side of the body

function: bends (flexes) the backbone; compresses the abdomen

External oblique

location: lateral sides of the abdomen; angles down toward the center of the abdomen

function: acts the same as the rectus abdominis when both are contracted together; rotates trunk laterally

Sartorius

location: long, belt-shaped muscle that runs diagonally across the thigh from hip to inside of the knee area

function: bends the thigh at the hip; bends the lower leg at the knee; rotates the thigh outward

Deltoid

location: covers most of the shoulder

function: raises (abducts) the arm

Trapezius

location: large, diamond-shaped muscle of the upper back

function: pulls the head back (extension); moves and braces the shoulder

Triceps brachii

location: on the posterior side of the upper arm (humerus)

function: extends the arm at the elbow joint

Latissimus dorsi

location: large muscle of the middle back

function: pulls the arm back and down (adducts the arm)

Gluteus maximus

location: covers most of the buttocks area

function: kicks and rotates the leg backward (extends the leg)

Gastrocnemius

location: posterior calf muscle

function: bends the foot downward (extension)

Semimembranosus

location: posterior, most medial side of thigh

function: bends knee, extending hip joint, tibial and thigh rotation

Semitendinosus

location: posterior side, middle of 3 thigh muscles

function: bends knee, extending hip joint, tibial and thigh rotation

biceps femoris

location: posterior thigh that is most lateral of the 3 muscles

function: flexes knee, straightens thigh, lateral rotation of hip and kne

rectus femoris

location: anterior middle of thigh

function: knee extension, bends hip joint forward, stability

vastus medialis

location: middle side of anterior thigh, end is closer to medial plane

function: extending knee, stabilizing patella, hip abduction

vastus lateralis

location: anterior, lateral side of thigh (compared to vastus medialis)

function: extend knee, stabilize patella, hip flexion