The Muscular System

Biceps Femoris

Flexes Knee; Extension & Lateral rotation at hip

Semitendinosus

Flexes knee; Extension & medial rotation at hip

Semimembranosus

Flexes knee; Extension & medial rotation at hip

Tibialis Anterior

Prime mover for Dorsiflexion; foot inversion

Extensor digitorum Longus

Prime mover for toe extension; Dorsiflexion of foot

Gastrocnemius

Extension (Plantar flexion) at ankle; foot inversion; flex knee (superficial muscle)

Soleus

Plantar Flex foot (Extension at ankle) = Locomotor/postural help for walk, run, dance (Deep muscle)

Popliteus

Flexion at knee; medial rotation of tibia; Lateral rotation of femur (unlocks knee)

Flexor digitorium longus

Plantar flex; inversion; flexion at toe joints; allows toes to grip

Tibialis posterior

Prime mover for inversion; Adduction foot; extension at ankle/ plantar flex foot

Iliacus

Prime Mover for hip flexion; flexes trunk on thigh (a bow)

Psoas major

Prime mover for thigh flexion; flexes trunk on thing (a bow); flexes vert column laterally

Sartorius

Flexes, abducts, laterally rotates thigh; Helps create cross-legged position

Adductor Magnus

Adducts, medially rotates & flexes thigh; posterior part = lateral rotation & extends thigh with hamstring

Adductor Longus

Adducts, medially rotates & flexes thigh

Gracilis

Adducts thigh; flexes & medially rotates thigh

Rectus Femoris (Quadriceps Femoris)

Extends Knee & flexes thigh at hip

Vastus Lateralis (Quadriceps Femoris)

Extends Knee

Vastus Medialis (Quadriceps Femoris)

Extends Knee

Vastus Intermedius (Quadriceps Femoris)

Extends Knee

Tensor fasciae latae (Know iliotibial tract)

Steadies knee & trunk on thigh by making iliotibial tract taut; flexes & abducts thigh; rotates thigh medially

Gluteus Maximus

Major thigh extensor; laterally rotates & abducts thigh; climbing stairs/running

Gluteus Medius

Abduction & medial rotation of thigh; steadies pelvis; walking!!!

Gluteus Minimus

Abduction & medial rotation of thigh; steadies pelvis; walking!!! (Smaller)

Biceps brachii

Flexes elbow; forearm; weak shoulder flexion

Brachialis

Major elbow & forearm flexor

Brachioradialis

Flexes elbow; stabilizes elbow

Triceps brachii

Prime mover for elbow extension; extension and Adduction at shoulder

Pronator teres

Pronation

Flexor Carpi radialis

Powerful wrist flexion; abducts hand

Palmaris Longus

Tenses skin/fascia of palm; wrist flexion

Flexor Carpi ulnaris

Powerful wrist flexor; adducts hand

Flexor digitorum superficialis

Flexes wrist and middle phalanges of digits 2-5 (speedy flexion & flexion against resistance)

Flexor digitorum profundus

Flexes distal interphalangeal joints (slow acting flexor of fingers); helps wrist flexion

Extensor Carpi Radialis Longus

Extends & abducts wrist

Extensor Carpi Radialis brevis

Extends & abducts wrist

Extensor digitorum (Extensor digitiminimi = pinkie)

Primer Mover for finger extension; wrist extension; abducts (flares fingers)

Extensor Carpi ulnaris

Extends & adducts wrist

Supinator

Supination

Extensor indicis

Extends & adducts index finger

Pectoralis minor

Depresses & protracts shoulder; rotates scapula so glenoid cavity moves inferiorly

Serratus anterior

Prime Mover for protracting shoulder; rotates scapula so glenoid cavity moves superiorly; abducts & raises arm horizontally (pushing/punching = Boxer’s muscle)

Trapezius

Stabilizes, raises/elevates (shrugging), retracts (adducts) & rotates scapula

Levator Scapulae

Elevates Scapula

Romboids - Major & Minor

Adducts scapula; downward rotation

Pectoralis Major

Prime Mover for arm flexion; Adduction & medial rotation at shoulder (helps with climbing, throwing pushing)

Deltoid

Prime Mover for arm abduction; arm flexion & medial rotation (anterior part); arm extension & lateral rotation (posterior part)

Latissimus dorsi

Prime Mover for arm extension; Adduction; medial rotation at shoulder; brings arm down in power stroke (hammering, swimming, rowing)

Subscapularis (Rotator cuff muscle)

Chief medial Rotator of Humerus (holds head of humerus in glenoid cavity)

Supraspinatus (Rotator cuff muscle)

Initiates abduction; helps prevent downward dislocation of humerus

Infraspinatus (Rotator cuff muscle)

Rotates humerus laterally (holds head of humerus in glenoid cavity)

Teres Minor (Rotater cuff muscle)

Rotates humerus laterally (holds head of humerus laterally (Holds head of humerus in glenoid cavity)

Teres Major

Extends, medially rotates & adducts humerus (synergist with lat dorsi)

External Intercostals

Elevate ribs (aid inspiration)

Internal Intercostals

Depress ribs (aid in forced expiration)

Diaphragm

Prime Mover of inspiration; Contraction expands thoracic cavity (muscle flattens) & compresses abdominopelvic cavity

Rectus Abdominis

Depresses ribs; flex vert column; compresses abdomen (superficial) = sit-ups/six-pack

External Obliques

Compresses abdomen; depresses ribs; flexes/bends spine

Internal Obliques

Compresses abdomen; depresses ribs; flexes/bends spine

Transverse Abdominis

Compresses abdomen

Iliocostalis (Erector Spinae)

Extends & Laterally flex vertebral column; maintains posture

Longissimus (Erector Spinae)

Extends & laterally flex vertebral column; Maintains posture; Capitis portion = extends head; turns head to side

Spinalis (Erector Spinae)

Extends vertebral column

Frontalis

Raises eyebrows & wrinkles forehead

Occipitalis

Tenses & retracts scalp

Corrugator supercilii

Wrinkles brow (pulls skin inferiorly & anteriorly)

Orbicularis Oculi

Closes eye (squint/blink)

Zygomaticus

Retracts & elevates corner of mouth/upper lip (smile)

Risorius

Draws corner of mouth to the side (closed mouth smile)

Levator Labii superioris

Elevates upper lip (Elvis)

Depressor Labii inferioris

Depresses lower lip (pout)

Depressor anguli Oris

Depresses corner of mouth (tragedy grimace)

Orbicularis Oris

Compresses, purses lips (kissing)

Mentalis

Elevates & protrudes lower lip; wrinkles chin (ugly cry)

Buccinator

Compresses checks (whistling/sucking)

Masseter

Prime mover for jaw closure; Elevates mandible

Temporalis

Elevates mandible, closes jaw; maintains jaw position at rest

Sternocleidomastoid

Together = flex neck; Indy = flex head to shoulder & rotates face to opposite side