Muscular System Origin, Insertion, Action. Muscles of the Scalp Occipitofrontalis – Frontal Belly...

Muscular System

Origin, Insertion, Action

Muscles of the Scalp

• Occipitofrontalis– Frontal Belly– Occipital Belly

Frontalis

• O: Galea aponeurotica• I: Skin of eyebrows• A: Raises eyebrows,

wrinkles forehead skin

Occipitalis

• O: Occipital Bone• I: Galea aponeurotica• A: Pulls scalp posterior

Muscles of Facial Expression

Orbicularis Occuli

• O: Frontal and Maxillary bones

• I: Tissue of eyelid• A: Blinking, squinting

Orbicularis Oris

• O: Maxilla and Mandible

• I: Encircles mouth, angles of mouth

• A: Closes lips, purses and protrudes lips (kissing and whistling)

Muscles of Mastication

Masseter

• O: Zygomatic arch and maxilla

• I: Mandible• A: Closes jaw by

elevating mandible

Temporalis

• O: Temporal fossa• I: Coronoid process of

mandible• A: Closes jaw (elevates

and retracts mandible)

Buccinator

• O: Maxilla and mandible

• I: Orbicularis oris• A: Compresses cheek

(whistling and sucking), holds food between teeth (during chewing)

Muscles of the Anterior Neck and Throat (Swallowing)

• Digastric• All of the muscles that attach to the hyoid

Digastric

• O: Mandible and mastoid process

• I: Hyoid bone• A: Elevate hyoid during

speech and swallowing,• Open mouth and

depress mandible

Anterolateral Neck Muscles

Sternocleidomastoid

• O: Sternum and Clavicle

• I: Mastoid process of temporal bone

• A: B/l – head flexion; unilateral – laterally flex towards and rotates away from itself

Scalenes

• O: Transverse processes of cervical vertebrae

• I: 1st two ribs• A: elevate first two ribs

(inspiration), flex and rotate neck

Intrinsic Muscles of the Back

Splenius Capitus

• O: Ligamentum nuchae, spinous processes of C7 – T-6

• I: Occipital bone, mastoid process of temporal bone

• A: b/l – extend head; unilateral – lateral flex and rotate towards

Splenius Cervicis

• O: Ligamentum nuchae, spinous processes of C7 – T-6

• I: Transverse Processes of C2 – C4

• A: b/l – extend neck; unilateral – lateral flex and rotate towards

Erector Spinae (Sacrospinalis)

• Iliocostalis (Most lateral)• Longissimus (Intermediate)• Spinalis (Most medial)

Iliocostalis

• O: iliac crest (lumborum); inferior 6 ribs (thoracis); ribs 3 to 6 (cervicis)

• I: ribs (lumborum and thoracic); TPs of C6-C4 (cervicis)

• A: B/L - Extend spine, posture; unilateral – lateral flex towards

Longissimus

• O: TPs of vertebrae• I: Superior TPs and

superior ribs; capitis portion inserts on Mastoid process

• A: B/L – extend spine; unilateral – laterally flex; capitis portion extends head and rotates towards

Spinalis

• O: Spines of upper lumbar and lower thoracic vertebrae

• I: Spines of upper thoracic and cervical vertebrae

• A: Extends spine, maintains erect posture

Quadratus Lumborum

• O: Iliac crest• I: TPs of upper lumbar

vetebrae and 12th rib• A: Unilaterally –

laterally flexes spine; b/l – extends L-spine

Muscles of the Thorax (Breathing)

External Intercostals

• O: Inferior border of rib above

• I: Superior border of rib below

• A: Pull ribs toward one another, elevate rib cage; INSPIRATION

• Fibers run down and anterior

Internal Intercostals

• O: Superior border of rib below

• I: inferior border of rib above

• A: Draw ribs together and depress rib cage; EXPIRATION

• Fibers run down and posterior

Diaphragm

• O: Inferior surface of rib cage and sternum, costal cartilages, lumbar vertebrae

• I: Central tendon• A: Flattens on

contraction; Prime mover of Inspiration

Muscles of the Anterior and Lateral Abdominal Wall

Rectus Abdominus

• O: Pubic crest and symphysis

• I: Xiphoid process and costal cartilages ribs 5-7

• A: Flex and rotate lumbar region, stabilize pelvis during walking

External Oblique

• O: Outer surfaces of lower eight ribs

• I: Linea alba• A: B/L – aid in trunk

flexion; unilateral – trunk rotation and lateral flexion

Internal Oblique

• O: Lumbar fascia, iliac crest

• I: linea alba, pubic crest, costal margin last 3 – 4 ribs

• A: B/L – aid in trunk flexion; unilateral – trunk rotation and lateral flexion

Transverse Abdominus

• O: Inguinal ligament, lumbar fascia, cartilage of last 6 ribs, iliac crest

• I: Linea alba, pubic crest

• A: Compresses abdominal contents

Muscles of the Anterior Thorax

Pectoralis Minor

• O: Anterior surface of ribs 3-5

• I: Coracoid process of scapula

• A: Ribs fixed – draws scapula forward and down; scapula fixed – draws rib cage superior

Muscles of the Posterior Thorax

Trapezius

• O: Occipital bone, ligamentum nuchae, spines from C7 to T12

• I: Acromion and spine of scapula, lateral 1/3 of clavicle

• A: Superior – elevates scapula; middle – retract (adduct) scapula; inferior – depress scapula

Levator Scapulae

• O: Transverse processes of C1 – C4

• I: Medial border of scapula (superior to spine)

• A: Elevates / adducts scapula, flexes neck to same side

Rhomboids

• O: Spinous processes of C7 – T5

• I: Medial border of scapula

• A: Retract (adduct) scapula, stabilize scapula

Muscles Crossing the Shoulder Joint

Pectoralis Major

• O: Sternal end of clavicle, sternum, cartilage ribs 1-6

• I: Greater tubercle of humerus

• A: Flexes arm, medially rotates arm, adducts arm (climbing, throwing, pushing)

Latissimus Dorsi

• O: Fascial connection to spines of T7 – L5, lower 3-4 ribs, iliac crest

• I: Intertubercular sulcus of humerus

• A: Arm extension, arm adductor, medially rotates arm (hammering, swimming)

Deltoid

• O: Embraces insertion of trapezius; lateral third of clavicle, acromion, spine of scapula

• I: Deltoid tuberosity of humerus

• A: Abducts arm; anterior fibers – flexion, medial rot.; posterior fibers – extension, lateral rot.

Rotator Cuff Muscles

• SITS• Suprapinatus• Infraspinatus• Teres Minor• Subscapularis

Supraspinatus

• O: Supraspinous fossa of scapula

• I: Greater tubercle of humerus

• A: Stabilizes shoulder joint. Prevents downward dislocation. Initiates shoulder abduction.

Infraspinatus

• O: Infraspinous fossa of scapula

• I: Greater tubercle of humerus posterior to supraspinatus insertion

• A: Holds head of humerus in glenoid cavity, shoulder stabilization

Teres Minor

• O: Lateral border of scapula (dorsal surface)

• I: Greater tubercle of humerus inferior to infraspinatus insertion

• A: Stabilize shoulder, adducts arm

Subscapularis

• O: Subscapular fossa of scapula

• I: Lesser tubercle of humerus

• A: Medial rotation of humerus, stabilizes shoulder joint

Teres Major

• O: Inferior angle of scapula

• I: Intertubercular sulcus of humerus

• A: Extends, medially rotates, and adducts humerus

Coracobrachialis

• O: Coracoid process of scapula

• I: Medial humerus• A: Flexion and

adduction of humerus

Muscles Crossing the Elbow Joint

Posterior

Triceps Brachii

• O: Scapula and humerus

• I: Olecranon process of ulna

• A: Forearm extensor

Brachialis

• O: Front of distal humerus

• I: Coronoid process of ulna

• A: Forearm flexor

Brachioradialis

• O: Distal end of humerus

• I: Styloid process of radius

• A: Forearm flexion

Muscles of the Forearm

Anterior Superficial

Pronator Teres

• O: Medial epicondyle of humerus

• I: Lateral radius• A: Pronates forearm

Flexor Carpi Radialis


• I: 2nd and 3rd metacarpals

• A: Flexor of wrist, abducts hand

Palmaris Longus


• I: Skin and fascia of palm

• A: Wrist flexor

Flexor Carpi Ulnaris

• O: Medial epicondyle of humerus, olecranon process and posterior ulna

• I: Pisiform, hamate, and 5th metacarpal

• A: Wrist flexion, adducts hand

Flexor Digitorum Superficialis

• O: Medial epicondyle of humerus, coronoid process of ulna, shaft of radius

• I: Middle phalanges 2-5.

• A: Flexes wrist and middle phalanges

Anterior Deep

Flexor Pollicis Longus

• O: Anterior radius, interosseus membrane

• I: Distal phalanx of the thumb

• A: Flexes distal phalanx of the thumb

Flexor Digitorum Profundus

• O: Anteromedial surface of ulna and interosseus membrane

• I: Distal phalanges 2-5• A: Finger flexion

Posterior Superficial

Extensor Carpi Radialis

• O: Lateral epicondyle of humerus

• I: 3rd metacarpal• A: Extends wrist

Extensor Carpi Digitorum

• O: Lateral epicondyle of humerus

• I: Distal phalanges 2-5• A: Finger extension,

extends wrist

Extensor Carpi Ulnaris

• O: Lateral epicondyle of humerus, posterior ulna

• I: 5th metacarpal• A: Extends wrist,

adducts wrist

Posterior Deep

Supinator

• O: Lateral epicondyle of humerus, proximal ulna

• I: Proximal radius• A: Supinates forearm

Extensor Pollicis

• O: Dorsal radius and ulna, interosseus membrane

• I: Proximal and distal phalanx of thumb

• A: Extends thumb

Thenar Muscles

Abductor Pollicis

• O: Posterior radius and ulna, interosseus membrane

• I: 1st metacarpal and trapezium

• A: Abducts and extends thumb, abducts wrist

Opponens Pollicis

• O: Flexor retinaculum and trapezium

• I: Anterior 1st metacarpal

• A: Opposition: moves thumb to touch tip of middle finger

Adductor Pollicis

• O: Metacarpals 2-4• I: Medial side of

proximal phalanx of thumb

• A: Adducts thumb

Muscles Crossing the Hip and Knee Joints

Anterior and Medial Muscles

Iliopsoas

• O: Iliac crest, TPs, bodies, and discs of T12 – L5

• I: Lesser trochanter of femur

• A: Thigh flexor, trunk flexor, lateral flexion of trunk

Sartorius

• O: Anterior Superior Iliac Spine (ASIS)

• I: Medial aspect of proximal Tibia

• A: Flexes, abducts, and laterally rotates thigh; flexes knee

Medial Compartment of the Thigh

Gracilis

• O: Body of pubis• I: Medial surface of

Tibia• A: Adducts thigh; flexes

thigh; medially rotates thigh

Anterior Compartment of the Thigh

Quadriceps Femoris

• Four Heads– Rectus Femoris– Vastus Lateralis– Vastus Medialis– Vastus Intermedius

Rectus Femoris

• O: Anterior Inferior Iliac Spine (AIIS)

• I: Patella and tibial tuberosity

• A: Extends knee; flexes thigh at hip

Vastus Lateralis

• O: Greater trochanter• I: Patella and tibial

tuberosity• A: Extends and

stabilizes knee

Vastus Medialis

• O: Linea aspera, intertrochanteric line


• A:Extends knee; inferior fibers stabilize patella

Vastus Intermedius

• O: Anterior and lateral surface of proximal femur


• A: Extends knee

Tensor Fascia Latae

• O: Iliac crest, ASIS• I: Iliotibial tract• A: Flexes and abducts

thigh; pulls iliotibial tract taut

Posterior Muscles

Gluteus Maximus

• O: Dorsal ilium, sacrum, coccyx

• I: Gluteal tuberosity of femur, ITB

• A: Extends thigh

Gluteus Medius & Minimus

• O: Surface of ilium• I: Greater trochanter of

femur• A: Abducts and

medially rotates thigh

Lateral Rotators

Piriformis

• O: Anterolateral surface of sacrum

• I: Greater trochanter of femur (superior border)

• A: Laterally rotates thigh

Posterior Compartment of the Thigh

Hamstrings

• Biceps femoris (two heads)• Semitendinosus• Semimembranosus

Biceps Femoris

• O: Ischial tuberosity• I: Head of fibula and

lateral condyle of tibia• A: Extends thigh; flexes

knee; laterally rotates leg

Semitendinosus

• O: Ischial tuberosity• I: Medial aspect of

Tibia• A: Extends thigh; flexes

knee; medially rotates leg

Semimembranosus

• O: Ischial tuberosity• I: Medial condyle of

tibia; lateral condyle of femur

• A: Extends thigh; flexes knee; medially rotates leg

Muscles of the Leg

Anterior Compartment

Tibialis Anterior

• O: Upper 2/3 of tibia, interosseus membrane

• I: Medial cuneiform and 1st metatarsal bone

• A: Dorsiflexion of foot

Extensor Digitorum

• O: Proximal ¾ of fibula; interosseous membrane

• I: Middle and distal phalanges of toes 2-5

• A: Toe extension; dorsiflexes foot

Extensor Hallucis

• O: Fibula; interosseous membrane

• I: Distal phalanx of great toe

• A: Extends great toe; dorsiflexes foot

Lateral Compartment

Peroneus

• O: Lateral fibula• I: Long tendon curves

under foot to the 1st metatarsal and medial cuneiform (longus); fifth metatarsal (brevis)

• A: Plantar flexes foot; everts foot.

Posterior Compartment

Triceps Surae

• Gastrocnemius (Two heads)• Soleus

Gastrocnemius

• O: Two heads from medial and lateral condyles of the femur

• I: Calcaneus• A: Plantar flexes foot;

can flex knee when the foot is dorsiflexed

Soleus

• O: Superior tibia and fibula; interoesseous membrane

• I: Calcaneus• A: Plantar flexes foot

Flexor Digitorum Longus

• O: Posterior femur• I: Calcaneus• A: Plantar flexion of

foot and flex leg at the knee

Muscular System Origin, Insertion, Action. Muscles of the Scalp Occipitofrontalis – Frontal Belly...

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Transcript of Muscular System Origin, Insertion, Action. Muscles of the Scalp Occipitofrontalis – Frontal Belly...