Human Bio 11 The Muscular System: Skeletal Muscles

Neck Muscles Sternocleidomastoid Flexes and rotates the head.

Back Muscles Trapezius Moves the scapula and supports the arm.

Back Muscles Latissimus Dorsi Adducts the arm. Laterally flexes the spine.

Anterior Trunk Muscles Pectoralis Major Flexes and adducts the humerus. Medially rotates the humerus.

Anterior Trunk Muscles Rectus Abdominis Important postural muscle. It flexes the lumbar spine.

Arm Muscles Deltoid Allows arm abduction. Helps with shoulder flexion and extension.

Arm Muscles Biceps Brachii Supinates the forearm. Flexes the elbow.

Arm Muscles Triceps Brachii Extends the elbow.

Arm Muscles Brachioradialis Flexes the forearm at the elbow. Pronates and supinates the forearm depending on its position.

Leg Muscles Gluteus Maximus Maintains the trunk in an upright posture. Extends the femur.

Leg Muscles Gluteus Medius and Gluteus Minimus

Leg Muscles Quadriceps (4 muscles) Extend the knee. Flex the hip.

Leg Muscles Hamstrings (3 muscles) Extend the hip when the trunk is fixed or when walking. Flex the knee and rotates the lower leg.

Leg Muscles Tibialis Anterior Dorsi flexes and inverts the foot.

Leg Muscles Gastrocnemius Plantar flexes the foot. Flexes the leg at the knee joint.