Muscle Group

Muscle

The entire muscle that attaches to bones and produces movement.

Fascicle

Bundles of muscle fibers inside a muscle.

Muscle Fiber

One long muscle cell that contains nuclei, mitochondria, and myofibrils.

Myofibril

Structures inside each muscle fiber that contract.

Sarcomere

The smallest functional unit of muscle contraction.

Thick Filament (Myosin)

A protein that pulls on actin during muscle contraction.

Thin Filament (Actin)

A protein that slides toward the center of the sarcomere during contraction.

Epimysium

Protective covering around the entire muscle.

Perimysium

Protective covering around a bundle of fascicles.

Endomysium

Protective covering around each individual muscle fiber.

Quadriceps

Muscles on the front of the thigh that kick and straighten the knee.

Hamstrings

Muscles on the back of the thigh that bring the heel back.

Gastrocnemius

Calf muscle that allows you to stand on your tiptoes.

Erector Spinae

Muscles that keep you standing upright.

Biceps

Muscle responsible for bending the elbow.

Triceps

Muscle responsible for straightening the elbow.

Pectoralis Major

Chest muscle that is involved in pushing movements.

Deltoid

Shoulder muscle involved in lifting the arm.

Latissimus Dorsi

Back muscle associated with pulling movements.

Rectus Abdominis

Muscle associated with bending and stabilizing the trunk; known as the six-pack.

Gluteus Maximus

Largest muscle in the glutes, involved in hip movement.

Trapezius

Muscle located in the upper back that helps to move the shoulder blade.

Rhomboids

Muscles located between the shoulder blades that retract the scapula.

Serratus Anterior

Muscle that helps in protracting the shoulder blade and stabilizing it against the chest wall.

Quadratus Lumborum

Muscle located in the lower back that helps with lateral flexion and stabilization of the spine.

Tibialis Anterior

Muscle located in the front of the lower leg that helps lift the foot.

Adductors

Muscle group located in the inner thigh that helps to pull the legs together.

Rotator Cuff

A group of muscles and tendons that stabilize the shoulder joint and allow for arm rotation.

Obliques

Muscles located on the sides of the abdomen that aid in twisting and bending movements.

Calves (Soleus and Gastrocnemius)

Muscle group in the back of the lower leg that facilitates walking, running, and jumping.

Hip Flexors

Muscle group at the front of the hip that lifts the thigh towards the torso.