MAJOR MUSCLES

Major Muscles

Trapezius Deltoids Latissimus Dorsi Pectoralis Major Biceps Brachii Triceps Brachii Abdominals Gluteals Quadriceps Hamstrings Gastrocnemius

Lower Extremity

Upper Extremity

Superficial Muscles: Anterior

Superficial Muscles: Posterior

Muscles are attached to at least two points.

ORIGIN (Proximal attachment) – generally considered the least movable part or the part that attaches closest to the midline or center of the body.

INSERTION (Distal attachment) – generally considered the most movable part or the part that attaches farthest from the midline or center of the body.

Trapezius

Trapezius = large superficial muscle of upper back Origin

Occipital bone All cervical vertebrae All thoracic vertebrae

Insertion Clavicle Scapula

Action Adducts and elevates

scapula

Latissimus dorsi

“Lats” = Triangular shaped muscle Origin

Lower thoracic vertebrae

ilium Insertion

Intertubercular groove of humerus

Action Extends, adducts, &

rotates arm

Deltoid

Deltoid = forms the rounded contour of the shoulder Origin

Clavicle Scapular spine Acromion process

Insertion Humerus

Action Abducts arm Flexion Extension

Pectoralis Major

Pectoralis major Origin

Manubrium Ribs 1-6 Clavicle

Insertion Intertubercular groove

of humerus Action

Primary flexor and adductor

Medial rotation

Biceps Brachii

Biceps brachii Origin

Long head: supraglenoid tubercle on scapula just above glenoid fossa

Short head: coracoid process

Insertion Radial tuberosity

Action Weak flexor of shoulder Powerful supinator of forearm Flexor of elbow joint

Biceps Brachii

Triceps Brachii

Triceps brachii Origin

Long head: scapula Lateral heads: humerus Medial head: posterior

humerus

Insertion ulna

Action Extension of elbow joint

Abdominals & Gluteals

Rectus abdominusExternal and internal

abdominal obliquesTransversus abdominisGluteus maximusGluteus mediusGluteus minimus

Abdominals

Gluteals

Abdominals (anterior)

Rectus abdominis Origin

pubis Insertion

Lower ribs Xiphoid process

Action Flex vertebral column

Transversus abdominis Origin

Ilium Lower ribs

Insertion Xiphoid process Linea alba

Action Compresses abdomen

Abdominals (anterior)

External abdominal obliques Origin

ribs Insertion

Ilium Linea alba

Action Compresses abdomen

Internal abdominal obliques Origin

Ilium Insertion

Lower ribs Action

Compresses abdomen

External oblique

Internal oblique

Gluteals

Gluteus maximus Origin

Ilium Dorsal surface of sacrum

& coccyx Insertion

Iliotibial tract to lateral condyle of tibia

Gluteal tuberosity of femur Action

Extend thigh at hip Assist in lateral rotation

Gluteals

Gluteus medius Origin

Ilium Insertion

Lateral surface of greater trochanter of femur

Action Abducts & medially

rotates thigh at hip

Gluteals

Gluteus minimus Origin

Ilium Insertion

Anterior surface of greater trochanter of femur

Action Abduct & medially

rotate thigh at hip

Quadriceps & Hamstrings

Rectus femorisVastus medialisVastus lateralisVastus intermediusBiceps femorisSemimembranosusSemitendinosus

Quadriceps femoris

Hamstrings

Quadriceps

Rectus femoris Origin

Anterior inferior iliac spine

Ilium superior to acetabulum

Insertion Patella and patellar

ligament to tibial tuberosity

Action Extends leg at knee Stabilizes hip

Quadriceps

Vastus medialis Origin

Intertrochanteric line Linea aspera of femur

Insertion Base of patella Tibial tuberosity via

patellar ligament Action

Extends leg at knee joint

v. med

= Vastus medialis v. int

= Vastus intermedius v. lat

= Vastus laterals

Quadriceps

Vastus lateralis Origin

Greater trochanter Linea aspera of femur

Insertion Base of patella Tibial tuberosity via

patellar ligament Action

Extends leg at knee joint

v. med

= Vastus medialis v. int

= Vastus intermedius v. lat

= Vastus laterals

Quadriceps

Vastus intermedius Origin

Femur Insertion

Base of patella Tibial tuberosity via

patellar ligament Action

Extends leg at knee joint

v. med

= Vastus medialis v. int

= Vastus intermedius v. lat

= Vastus laterals

Hamstring

Biceps femoris Origin

Long head: ischial tuberosity

Short head: linea aspera & lateral supracondylar line of femur

Insertion Head of fibula

Action Flexes leg at knee Rotates leg laterally Extends thigh at hip

Hamstring

Semimembranosus Origin

Ischial tuberosity Insertion

Medial condyle of tibia

Action Extends thigh at hip Flexes leg at knee Rotates leg medially

Hamstring

Semitendinosus Origin

Ischial tuberosity Insertion

tibia Action

Extends thigh at hip Flexes leg at knee Rotates leg medially

Gastrocnemius

Gastrocnemius Origin

Lateral head: lateral condyle of femur

Medial head: popliteal surface of femur

Insertion Calcaneus via calcaneal

tendon Action

Plantar flexes foot at ankle

Raises heel during walking

Flexes leg at knee joint