Muscles Lab Parts To Know

Masseter Head Muscles

Main chewing muscle; elevates the mandible; located on the jaw.

Digastric Head Muscles

Opens the mouth; located under the jaw.

Orbicularis oculi Head Muscles

Closes the eyelids; muscle around the eye.

Orbicularis oris Head Muscles

Closes and puckers the lips; muscle around the mouth.

Zygomaticus major Head Muscles

Elevates corners of the mouth; smiling muscle.

Platysma Neck Muscles

Superficial neck muscle that tenses the neck and depresses the mandible.

Sternocleidomastoid Neck Muscles

Flexes the neck and rotates the head.

Pectoralis major Chest Muscles

Large chest muscle; flexes, adducts, and medially rotates the arm.

Serratus anterior Chest Muscles

Saw-toothed muscle on ribs; protracts and stabilizes the scapula.

External oblique Abdominal Muscles

Lateral abdominal muscle; rotates and flexes the trunk.

Rectus abdominis Abdominal Muscles

"Six-pack" muscle; flexes the vertebral column.

Trapezius Back Muscles

Large upper back muscle; elevates, retracts, and rotates the scapula.

Latissimus dorsi Back Muscles

Large back muscle; extends, adducts, and medially rotates the arm.

Erector spinae Back Muscles

Group of back muscles that extend the vertebral column and maintain posture.

Deltoid Shoulder and Arm Muscles

Shoulder muscle; abducts the arm.

Biceps brachii Shoulder and Arm Muscles

Anterior upper arm muscle; flexes the elbow and supinates the forearm.

Triceps brachii Shoulder and Arm Muscles

Posterior upper arm muscle; extends the elbow.

Gluteus maximus Buttocks Muscles

Largest buttock muscle; extends the thigh.

Gluteus medius Buttocks Muscles

Deep to gluteus maximus; abducts and medially rotates the thigh.

Quadriceps femoris (anterior) Upper Leg (thigh) Muscles

Group of four anterior thigh muscles; extends the knee.

Rectus femoris

Quadriceps femoris (anterior) Upper Leg (thigh) Muscles

Quadriceps muscle that extends the knee and flexes the hip.

Vastus lateralis

Quadriceps femoris (anterior) Upper Leg (thigh) Muscles

Lateral quadriceps muscle; extends the knee.

Vastus medialis

Quadriceps femoris (anterior) Upper Leg (thigh) Muscles

Medial quadriceps muscle; extends the knee.

Vastus intermedius (under rectus femoris)

Quadriceps femoris (anterior) Upper Leg (thigh) Muscles

Deep quadriceps muscle beneath rectus femoris; extends the knee.

Sartorius (hip to medial knee) Upper Leg (thigh) Muscles

Longest muscle in the body; flexes the hip and knee; runs from hip to medial knee.

Gracilis (groin) Upper Leg (thigh) Muscles

Medial thigh muscle; adducts the thigh.

Tensor fasciae latae (lateral) Upper Leg (thigh) Muscles

Lateral thigh muscle; abducts and medially rotates the thigh.

Hamstrings (posterior) Upper Leg (thigh) Muscles

Group of posterior thigh muscles; flex the knee and extend the hip.

Biceps femoris Hamstrings (posterior)Upper Leg(thigh) Muscles

Lateral hamstring muscle; flexes the knee and extends the hip.

Semitendinosus (medial) Hamstrings (posterior)Upper Leg(thigh) Muscles

Medial hamstring muscle; flexes the knee and extends the hip.

Tibialis anterior Lower Leg Muscles

Anterior lower leg muscle; dorsiflexes the foot.

Gastrocnemius (calf) Lower Leg Muscles

Superficial calf muscle; plantar flexes the foot and flexes the knee.

Soleus (deep to gastrocnemius, around Achilles tendon) Lower Leg Muscles

Deep calf muscle; plantar flexes the foot.

Achilles tendon (calf to calcaneus bone) Lower Leg Muscles

Tendon connecting gastrocnemius and soleus to the calcaneus.

Diaphragm Breathing Muscles

Primary muscle of breathing; contracts to inhale.

External intercostals Breathing Muscles

Elevate the ribs during inhalation.

Internal intercostals Breathing Muscles

Depress the ribs during forced exhalation.

Origin

Muscle Origins & Insertions, Actions, and Antagonist/Synergist

Attachment of a muscle to the less movable (anchoring) bone.

Insertion

Muscle Origins & Insertions, Actions, and Antagonist/Synergist

Attachment of a muscle to the more movable bone.

Action

Muscle Origins & Insertions, Actions, and Antagonist/Synergist

Movement produced when a muscle contracts.

Antagonist

Muscle Origins & Insertions, Actions, and Antagonist/Synergist

Muscle that performs the opposite action of another muscle.

Synergist

Muscle Origins & Insertions, Actions, and Antagonist/Synergist

Muscle that assists another muscle in performing the same movement.