muscular system
DESCRIPTION
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 - PowerPoint PPT PresentationTRANSCRIPT
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Muscular System
Origin, Insertion, Action
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Muscles of the Scalp
• Occipitofrontalis– Frontal Belly– Occipital Belly
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Frontalis
• O: Galea aponeurotica• I: Skin of eyebrows• A: Raises eyebrows,
wrinkles forehead skin
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Occipitalis
• O: Occipital Bone• I: Galea aponeurotica• A: Pulls scalp posterior
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Muscles of Facial Expression
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Orbicularis Occuli
• O: Frontal and Maxillary bones
• I: Tissue of eyelid• A: Blinking, squinting
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Orbicularis Oris
• O: Maxilla and Mandible
• I: Encircles mouth, angles of mouth
• A: Closes lips, purses and protrudes lips (kissing and whistling)
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Muscles of Mastication
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Masseter
• O: Zygomatic arch and maxilla
• I: Mandible• A: Closes jaw by
elevating mandible
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Temporalis
• O: Temporal fossa• I: Coronoid process of
mandible• A: Closes jaw (elevates
and retracts mandible)
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Buccinator
• O: Maxilla and mandible
• I: Orbicularis oris• A: Compresses cheek
(whistling and sucking), holds food between teeth (during chewing)
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Muscles of the Anterior Neck and Throat (Swallowing)
• Digastric• All of the muscles that attach to the hyoid
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Digastric
• O: Mandible and mastoid process
• I: Hyoid bone• A: Elevate hyoid during
speech and swallowing,• Open mouth and
depress mandible
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Anterolateral Neck Muscles
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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
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Scalenes
• O: Transverse processes (anterior) of cervical vertebrae
• I: 1st two ribs• A: elevate first two ribs
(inspiration), flex and rotate neck
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Intrinsic Muscles of the Back
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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
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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
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Erector Spinae (Sacrospinalis)
• Iliocostalis (Most lateral)• Longissimus (Intermediate)• Spinalis (Most medial)
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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
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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
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Spinalis
• O: Spines of upper lumbar and lower thoracic vertebrae
• I: Spines of upper thoracic and cervical vertebrae
• A: Extends spine, maintains erect posture
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Quadratus Lumborum
• O: Iliac crest• I: TPs of upper lumbar
vetebrae and 12th rib• A: Unilaterally –
laterally flexes spine; b/l – extends L-spine
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Muscles of the Thorax (Breathing)
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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
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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
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Diaphragm
• O: Inferior surface of rib cage and sternum, costal cartilages, lumbar vertebrae
• I: Central tendon• A: Flattens on
contraction; Prime mover of Inspiration
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Muscles of the Anterior and Lateral Abdominal Wall
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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
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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
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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
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Transverse Abdominus
• O: Inguinal ligament, lumbar fascia, cartilage of last 6 ribs, iliac crest
• I: Linea alba, pubic crest
• A: Compresses abdominal contents
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Muscles of the Anterior Thorax
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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
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Muscles of the Posterior Thorax
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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
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Levator Scapulae
• O: Transverse processes of C1 – C4
• I: Medial border of scapula (superior to spine)
• A: Elevates / adducts scapula, laterally flexes neck to same side
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Rhomboids
• O: Spinous processes of C7 – T5
• I: Medial border of scapula
• A: Retract (adduct) scapula, stabilize scapula
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Muscles Crossing the Shoulder Joint
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Pectoralis Major
• O: Sternal end of clavicle, sternum, cartilage ribs 1-6
• I: Intertubercular sulcus of humerus
• A: Flexes arm, medially rotates arm, adducts arm (climbing, throwing, pushing)
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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)
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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.
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Rotator Cuff Muscles
• SITS• Supraspinatus• Infraspinatus• Teres Minor• Subscapularis
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Supraspinatus
• O: Supraspinous fossa of scapula
• I: Greater tubercle of humerus
• A: Stabilizes shoulder joint. Prevents downward dislocation. Initiates shoulder abduction.
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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
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Teres Minor
• O: Lateral border of scapula (dorsal surface)
• I: Greater tubercle of humerus inferior to infraspinatus insertion
• A: Stabilize shoulder, adducts arm
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Subscapularis
• O: Subscapular fossa of scapula
• I: Lesser tubercle of humerus
• A: Medial rotation of humerus, stabilizes shoulder joint
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Teres Major
• O: Inferior angle of scapula
• I: Intertubercular sulcus of humerus
• A: Extends, medially rotates, and adducts humerus
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Coracobrachialis
• O: Coracoid process of scapula
• I: Medial humerus• A: Flexion and
adduction of humerus
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Muscles Crossing the Elbow Joint
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Posterior
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Triceps Brachii
• O: Scapula and humerus
• I: Olecranon process of ulna
• A: Forearm extensor
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Anterior
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Biceps Brachii
• O: Short head – coracoid process; long head – lip of glenoid cavity
• I: Radial tuberosity• A: Flexes elbow joint,
supinates forearm
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Brachialis
• O: Front of distal humerus
• I: Styloid process of ulna
• A: Forearm flexor
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Brachioradialis
• O: Distal end of humerus
• I: Styloid process of radius
• A: Forearm flexion
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Muscles of the Forearm
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Anterior Superficial
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Pronator Teres
• O: Medial epicondyle of humerus
• I: Lateral radius• A: Pronates forearm
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Flexor Carpi Radialis
• O: Medial epicondyle of humerus
• I: 2nd and 3rd metacarpals
• A: Flexor of wrist, abducts hand
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Palmaris Longus
• O: Medial epicondyle of humerus
• I: Skin and fascia of palm
• A: Wrist flexor
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Flexor Carpi Ulnaris
• O: Medial epicondyle of humerus, olecranon process and posterior ulna
• I: Pisiform, hamate, and 5th metacarpal
• A: Wrist flexion, adducts hand
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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
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Anterior Deep
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Flexor Pollicis Longus
• O: Anterior radius, interosseus membrane
• I: Distal phalanx of the thumb
• A: Flexes distal phalanx of the thumb
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Flexor Digitorum Profundus
• O: Anteromedial surface of ulna and interosseus membrane
• I: Distal phalanges 2-5• A: Finger flexion
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Posterior Superficial
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Extensor Carpi Radialis
• O: Lateral epicondyle of humerus
• I: 3rd metacarpal• A: Extends wrist
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Extensor Carpi Digitorum
• O: Lateral epicondyle of humerus
• I: Distal phalanges 2-5• A: Finger extension,
extends wrist
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Extensor Carpi Ulnaris
• O: Lateral epicondyle of humerus, posterior ulna
• I: 5th metacarpal• A: Extends wrist,
adducts wrist
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Posterior Deep
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Supinator
• O: Lateral epicondyle of humerus, proximal ulna
• I: Proximal radius• A: Supinates forearm
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Extensor Pollicis
• O: Dorsal radius and ulna, interosseus membrane
• I: Proximal and distal phalanx of thumb
• A: Extends thumb
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Thenar Muscles
![Page 76: Muscular System](https://reader035.vdocuments.us/reader035/viewer/2022070402/568138ff550346895da0b6d2/html5/thumbnails/76.jpg)
Abductor Pollicis
• O: Posterior radius and ulna, interosseus membrane
• I: 1st metacarpal and trapezium
• A: Abducts and extends thumb, abducts wrist
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Opponens Pollicis
• O: Flexor retinaculum and trapezium
• I: Anterior 1st metacarpal
• A: Opposition: moves thumb to touch tip of middle finger
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Adductor Pollicis
• O: Metacarpals 2-4• I: Medial side of
proximal phalanx of thumb
• A: Adducts thumb
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Muscles Crossing the Hip and Knee Joints
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Anterior and Medial Muscles
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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
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Sartorius
• O: Anterior Superior Iliac Spine (ASIS)
• I: Posterior, medial aspect of proximal Tibia
• A: Flexes, abducts, and laterally rotates thigh; flexes knee
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Medial Compartment of the Thigh
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Gracilis
• O: Body of pubis• I: Medial surface of
Tibia• A: Adducts thigh; flexes
thigh; medially rotates thigh
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Anterior Compartment of the Thigh
![Page 86: Muscular System](https://reader035.vdocuments.us/reader035/viewer/2022070402/568138ff550346895da0b6d2/html5/thumbnails/86.jpg)
Quadriceps Femoris
• Four Heads– Rectus Femoris– Vastus Lateralis– Vastus Medialis– Vastus Intermedius
![Page 87: Muscular System](https://reader035.vdocuments.us/reader035/viewer/2022070402/568138ff550346895da0b6d2/html5/thumbnails/87.jpg)
Rectus Femoris
• O: Anterior Inferior Iliac Spine (AIIS)
• I: Patella and tibial tuberosity
• A: Extends knee; flexes thigh at hip
![Page 88: Muscular System](https://reader035.vdocuments.us/reader035/viewer/2022070402/568138ff550346895da0b6d2/html5/thumbnails/88.jpg)
Vastus Lateralis
• O: Greater trochanter• I: Patella and tibial
tuberosity• A: Extends and
stabilizes knee
![Page 89: Muscular System](https://reader035.vdocuments.us/reader035/viewer/2022070402/568138ff550346895da0b6d2/html5/thumbnails/89.jpg)
Vastus Medialis
• O: Linea aspera, intertrochanteric line
• I: Patella and tibial tuberosity
• A:Extends knee; inferior fibers stabilize patella
![Page 90: Muscular System](https://reader035.vdocuments.us/reader035/viewer/2022070402/568138ff550346895da0b6d2/html5/thumbnails/90.jpg)
Vastus Intermedius
• O: Anterior and lateral surface of proximal femur
• I: Patella and tibial tuberosity
• A: Extends knee
![Page 91: Muscular System](https://reader035.vdocuments.us/reader035/viewer/2022070402/568138ff550346895da0b6d2/html5/thumbnails/91.jpg)
Tensor Fascia Latae
• O: Iliac crest, ASIS• I: Iliotibial tract• A: Flexes and abducts
thigh; pulls iliotibial tract taut
![Page 92: Muscular System](https://reader035.vdocuments.us/reader035/viewer/2022070402/568138ff550346895da0b6d2/html5/thumbnails/92.jpg)
Posterior Muscles
![Page 93: Muscular System](https://reader035.vdocuments.us/reader035/viewer/2022070402/568138ff550346895da0b6d2/html5/thumbnails/93.jpg)
Gluteus Maximus
• O: Dorsal ilium, sacrum, coccyx
• I: Gluteal tuberosity of femur, ITB
• A: Extends thigh
![Page 94: Muscular System](https://reader035.vdocuments.us/reader035/viewer/2022070402/568138ff550346895da0b6d2/html5/thumbnails/94.jpg)
Gluteus Medius & Minimus
• O: Surface of ilium• I: Greater trochanter of
femur• A: Abducts and
medially rotates thigh
![Page 95: Muscular System](https://reader035.vdocuments.us/reader035/viewer/2022070402/568138ff550346895da0b6d2/html5/thumbnails/95.jpg)
Lateral Rotators
![Page 96: Muscular System](https://reader035.vdocuments.us/reader035/viewer/2022070402/568138ff550346895da0b6d2/html5/thumbnails/96.jpg)
Piriformis
• O: Anterolateral surface of sacrum
• I: Greater trochanter of femur (superior border)
• A: Laterally rotates thigh
![Page 97: Muscular System](https://reader035.vdocuments.us/reader035/viewer/2022070402/568138ff550346895da0b6d2/html5/thumbnails/97.jpg)
Posterior Compartment of the Thigh
![Page 98: Muscular System](https://reader035.vdocuments.us/reader035/viewer/2022070402/568138ff550346895da0b6d2/html5/thumbnails/98.jpg)
Hamstrings
• Biceps femoris (two heads)• Semitendinosus• Semimembranosus
![Page 99: Muscular System](https://reader035.vdocuments.us/reader035/viewer/2022070402/568138ff550346895da0b6d2/html5/thumbnails/99.jpg)
Biceps Femoris
• O: Ischial tuberosity• I: Head of fibula and
lateral condyle of tibia• A: Extends thigh; flexes
knee; laterally rotates leg
![Page 100: Muscular System](https://reader035.vdocuments.us/reader035/viewer/2022070402/568138ff550346895da0b6d2/html5/thumbnails/100.jpg)
Semitendinosus
• O: Ischial tuberosity• I: Medial aspect of
Tibia• A: Extends thigh; flexes
knee; medially rotates leg
![Page 101: Muscular System](https://reader035.vdocuments.us/reader035/viewer/2022070402/568138ff550346895da0b6d2/html5/thumbnails/101.jpg)
Semimembranosus
• O: Ischial tuberosity• I: Medial condyle of
tibia; lateral condyle of femur
• A: Extends thigh; flexes knee; medially rotates leg
![Page 102: Muscular System](https://reader035.vdocuments.us/reader035/viewer/2022070402/568138ff550346895da0b6d2/html5/thumbnails/102.jpg)
Muscles of the Leg
![Page 103: Muscular System](https://reader035.vdocuments.us/reader035/viewer/2022070402/568138ff550346895da0b6d2/html5/thumbnails/103.jpg)
Anterior Compartment
![Page 104: Muscular System](https://reader035.vdocuments.us/reader035/viewer/2022070402/568138ff550346895da0b6d2/html5/thumbnails/104.jpg)
Tibialis Anterior
• O: Upper 2/3 of tibia, interosseus membrane
• I: Medial cuneiform and 1st metatarsal bone
• A: Dorsiflexion of foot
![Page 105: Muscular System](https://reader035.vdocuments.us/reader035/viewer/2022070402/568138ff550346895da0b6d2/html5/thumbnails/105.jpg)
Extensor Digitorum
• O: Proximal ¾ of fibula; interosseous membrane
• I: Middle and distal phalanges of toes 2-5
• A: Toe extension; dorsiflexes foot
![Page 106: Muscular System](https://reader035.vdocuments.us/reader035/viewer/2022070402/568138ff550346895da0b6d2/html5/thumbnails/106.jpg)
Extensor Hallucis
• O: Fibula; interosseous membrane
• I: Distal phalanx of great toe
• A: Extends great toe; dorsiflexes foot
![Page 107: Muscular System](https://reader035.vdocuments.us/reader035/viewer/2022070402/568138ff550346895da0b6d2/html5/thumbnails/107.jpg)
Lateral Compartment
![Page 108: Muscular System](https://reader035.vdocuments.us/reader035/viewer/2022070402/568138ff550346895da0b6d2/html5/thumbnails/108.jpg)
Peroneus (Fibularis)
• 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.
![Page 109: Muscular System](https://reader035.vdocuments.us/reader035/viewer/2022070402/568138ff550346895da0b6d2/html5/thumbnails/109.jpg)
Posterior Compartment
![Page 110: Muscular System](https://reader035.vdocuments.us/reader035/viewer/2022070402/568138ff550346895da0b6d2/html5/thumbnails/110.jpg)
Triceps Surae
• Gastrocnemius (Two heads)• Soleus
![Page 111: Muscular System](https://reader035.vdocuments.us/reader035/viewer/2022070402/568138ff550346895da0b6d2/html5/thumbnails/111.jpg)
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
![Page 112: Muscular System](https://reader035.vdocuments.us/reader035/viewer/2022070402/568138ff550346895da0b6d2/html5/thumbnails/112.jpg)
Soleus
• O: Superior tibia and fibula; interoesseous membrane
• I: Calcaneus• A: Plantar flexes foot
![Page 113: Muscular System](https://reader035.vdocuments.us/reader035/viewer/2022070402/568138ff550346895da0b6d2/html5/thumbnails/113.jpg)
Flexor Digitorum Longus
• O: Posterior Tibia• I: Distal phalanges 2-5• A: Plantar flexion of
foot and flexion of the toes.