Muscles

Frontalis

Raises eyebrows; useful when observing facial symmetry

Occiptalis

Moves the scalp

Orbicularis Oculi

Closes the eyelids; relevant to facial-nerve function

Orbicularis Oris

Closes and protrudes the lips; relevant to facial-nerve function

Buccinator

Compresses the check; helps keep food between the teeth during chewing

Zygomaticus major

Raises the corner of the mouth

Zygomaticus minor

Elevates the upper lip

Risorius

Retracts the corner of the mouth

Mentalis

Protrudes the lower lip

Platysma

Tenses skin of the neck and assists movement of the lower lip

Masseter

Elevates the mandible; major chewing muscle

Temporalis

Elevates and retracts the mandible

Medial pterygoid

Elevates and protracts the mandible; assists chewing

Lateral pterygoid

Protracts and helps depress the mandible

Superior rectus

Moves the eye upward

Inferior rectus

Moves the eye downward

Medial rectus

adducts the eye

Lateral rectus

abducts the eye

Superior oblique

Assists downward and inward rotation of the eye

Inferior oblique

Assists upward and outward rotation of the eye

Genioglossus

Protrudes the tongue; clinically important for tongue movement and airway patency

Hyoglossus

Depresses the tongue

Styloglossus

Retracts the tongue

Diagastric

Depresses the mandible and elevates the hyoid during swallowing

Mylohyoid

Elevates the floor of the mouth and hyoid during swallowing

Sternocleidomastoid

Flexes the neck and rotates the head; useful in neurological strength assessment

Scalenes

Flex the neck and can assist inspiration by elevating upper ribs

Trapezius

Elevates, retracts, and rotates the scapula; shoulder shrug is clinically useful

Deltoid

Abducts the arm; common landmark for intramuscular injection

Pectoralis major

Flexes, adducts, and medially rotates the arm

Pectoralis minor

Stabilizes and protracts the scapula

Latissimus dorsi

Extends, adducts, and medially rotates the arm

Serratus anterior

Protracts and stabilizes the scapula; weakness may produce scapular winging

Rhomboid major

Retracts and stabilizes the scapula - Larger, broader

Rhomboid minor

Retracts and stabilizes the scapula - Smaller, narrower

Levator scapulae

Elevates the scapula

Supraspinatus

Initiates arm abduction; rotator-cuff muscle

Infraspinatus

Laterally rotates the arm; rotator-cuff muscle - large, triangular muscle covering the back of the shoulder blade

Teres minor

Laterally rotates the arm; rotator-cuff muscle - small, narrow muscle

Subscapularis

Medially rotates the arm; rotator-cuff muscle

Teres major

Adducts and medially rotates the arm

Erector spinae group

Extends and stabilizes the vertebral column; important for posture

External intercostals

Elevate the ribs and assist inspiration

Internal intercostals

Assist forced expiration

Diaphragm

Primary muscle of inspiration; one of the highest-priority muscles for nursing students

Biceps brachii

Flexes the elbow and supinates the forearm

Brachialis

Primary elbow flexor

Brachiordialis

Flexes the elbow, especially with the forearm in neutral position

Triceps brachii

Extends the elbow

Coracobrachialis

Flexes and adducts the arm

Pronator teres

Pronates the forearm - Large muscle

Pronator quadratus

Pronates the forearm - small, deep, square shaped muscle at the wrist

Supinator

Supinates the forearm

Flexor carpi radialis

Flexes and abducts the wrist

Flexor carpi ulnaris

Flexes and adducts the wrist

Palmaris longus

Weak wrist flexor; variable and absent in some people

Flexor digitorum superficialis

Flexes the fingers, especially at the proximal interphalangeal joints

Flexor digitorum profundus

Flexes the distal finger joints

Flexor pollicis longus

Flexes the thumb

Extensor carpi radialis longus

Extends and abducts the wrist - starts higher up and can assist in bending the elbow

Extensor carpi radialis brevis

Extends and abducts the wrist - Starts lower down

Extensor carpi ulnaris

Extends and adducts the wrist

Extensor digitorum

Extends the fingers

Extensor pollicis longus

Extends the thumb - starts on ulna

Extensor pollicis brevis

Extends the thumb - starts on radius

Abductor pollicis longus

Abducts the thumb - Originates in forearm, sends tendon down to the wrist and thumb

Abductor pollicis brevis

Abducts the thumb - Sits entirely inside the hand

Flexor pollicis brevis

Flexes the thumb

Opponens pollicis

Produces thumb opposition; important for grasp

Adductor pollicis

Adducts the thumb

Lumbricals

Assists finger flexion and extension for fine hand movement

Dorsal interossei

Abduct the fingers

Palmar interossei

Adduct the fingers

Rectus abdominis

Flexes the trunk and compresses abdominal contents

External oblique

Rotates and flexes the trunk; compresses abdominal contents - Outside layer (Hands in front pockets)

Internal oblique

Rotates and flexes the trunk; compresses abdominal contents - (Hands in back pockets)

Transversus abdominis

Compresses abdominal contents and supports the core

Quadratus lumborum

Laterally flexes and stabilizes the trunk

Multifidus

Stabilizes and extends the vertebral column

Levator ani

Major pelvic-floor muscle group supporting pelvic organs

Pubococcygeus

Part of levator ani; supports the pelvic floor and contributes to continence

Pubortectalis

Part of levator ani; helps maintain fecal continence

Iliococcygeus

Part of levator ani; supports pelvic organs

Coccygeus

Supports the pelvic floor

External anal sphincter

Voluntary control of defecation

External Urethral sphincter

Voluntary control of urination

Gluteus maximus

Extends and laterally rotates the hip; important for rising and climbing

Gluteus medius

Abducts the hip and stabilizes the pelvis during gait; key ventrogluteal injection landmark region

Gluteus minimus

Abducts and medially rotates the hip; assists pelvic stability

Tensor fasciae latae

Abducts and stabilizes the hip and knee through the iliotibial tract

Iliacus

Flexes the hip

Psoas major

Flexes the hip and can flex the trunk

Iliopsoas

Powerful hip flexor formed primarily by iliacus and psoas major

Piriformis

Laterally rotates the hip; important deep gluteal landmark

Sartorius

Flexes, abducts, and laterally rotates the hip; also flexes the knee

Rectus femoris

Extends the knee and flexes the hip; part of the quadriceps

Vastus lateralis

Extends the knee; common intramuscular injection site, especially in infants

Vastus medialis

Extends the knee and helps stabilize the patella

Vastus intermedius

Extends the knee

Biceps femoris

Flexes the knee and extends the hip; part of the hamstring