Anatomy and Physiology- Muscles

Obicularis oculi

Closes eyelid

Zygomaticus major

Draws angles of the mouth upward and outward; major muscle used in smiling and laughing

Obicularis oris

Which muscle encircles the mouth, closes lips, protrudes lips as in kissing, and is uniquely developed in humans for speech

Buccinator

Muscles that compresses cheeks inward; whistling or kissing.

Mentalis

Protrudes lower lip

Masseter

Elevates mandible

Temporalis

Elevates and retracts mandible; assists in side to side movement of mandible

Genioglossus

Protracts and depresses tongue

Styloglossus

Retracts and elevates tongue

Stylohyoid

Elevates and retracts hyoid bone

Sternocleidomastoid

Contraction of one side: laterally flexes neck, rotates head to opposite side; Contraction of both sides together: flexes neck

Trapezius

Elevates, depresses, retracts, and rotates the scapula; rotates the arm

Latissimus dorsi

Extends, adducts, and medially rotates the arm; draws the shoulder downward and backward

Pectoralis major

Adducts and medially rotates the arm; flexes and extends humerus

Pectoralis minor

Deltoid

A large triangular muscle covering the shoulder joint and serving to abduct and flex and extend and rotate the arm.

Biceps brachii

Flexes and supinates forearm

Brachialis

flexes forearm

Triceps brachii

Extends the arm at the elbow

Anconeus

Extends forearm and stabilizes elbow joint

Brachioradialis

Flexes the arm at the elbow

Flexor carpi radialis

Flexes and abducts the wrist

Palmaris longus

Flexes the wrist

Flexor carpi ulnaris

Flexes and adducts wrist

Extensor carpi radialis longus

Extends the wrist and abducts the hand

Extensor digitorium

Extend medial four digits at MCP joint, extend hand

Exterior intercostals

Elevates ribs and enlarges thoracic cavity during inhalation. During exhalation, depresses ribs and decreases thoracic cavity

Interior intercostals

reduces thoracic cavity (forced exhalation)

Diaphragm

Large, flat muscle at the bottom of the chest cavity that helps with breathing

External oblique

Compresses abdomen; laterally flexes and rotates vertebral column

Internal oblique

Compresses abdomen

Transversus abdominus

Compresses abdomen

Rectus abdominus

Flex and rotate lumbar region of vertebral column. Aid in defecation, urination, childbirth

Gluteus maximus

extends and laterally rotates thigh

Gluteus medius

Abducts and rotates the thigh medially

Gluteus minimus

Medially rotates thigh; abducts the hip

Psoas major

Flexes thigh at the hip; flexes vertebral column

Pectineus

Adducts and flexes thigh at the hip

Adductor longus

Adducts, flexes, and rotates the thigh laterally

Adductor magnus

Adducts and extends thigh at the hip; assists in medial rotation

Gracilis

Adducts thigh at the hip and flexes leg at the knee; assists in medial rotation

Sartorius

Flexes, abducts, and laterally rotates thigh at the hip; flexes knee

Rectus femoris

extends knee, flexes thigh at hip

Vastus medialis

Extends leg at the knee; part of the quadriceps group

Vastus lateralis

Extends leg at the knee; part of the quadriceps group

Biceps femoris

extends thigh; flexes leg (Hamstrings)

Semitendinosis

Flex knee; extends thigh; medially rotates thigh at hip and knee (Hamstrings)

Semimembranosis

Flex knee, extend hip (Hamstrings)

Gastrocnemius

Plantar flexes foot

Soleus

plantar flexes foot

Flexor digitorum longus

Flexes lateral four toes; plantar flexion and inversion of foot

Flexor halluces longus

Flexes big toe

Tibialis anterior

Dorsiflexes and inverts foot

Extensor digitorium longus

Extend toes and dorsiflex foot

Fibularis longus

plantar flexes and everts foot

Fibularis brevis

plantar flexes and everts foot