סקירה של שרירי שלד עיקריים

Frontalis

O: galea aponeurotica I: eyebrows

F: raise eyebrows, pull scalp anteriorly

Occipitalis

O: occipital & temporal bones I: galea aponeurotica

F: pull scalp posteriorly

Orbicularis oculi

O: frontal, maxillary bones I: eyelids

F: close eyes

Orbicularis oris

O: muscles around mouth I: lips

F: close, purse lips

Buccinator

O: maxilla & mandible I: orbicularis oris

F: compress cheek

Temporalis

O: squamous portion of temporal bone I: mandible

F: elevate mandible

Muscles of mastication

•Temporalis –O: temporal fossa–I: coronoid process

of mandible–Action: elevate and

retract mandible

(11.7a)

Masseter

O: zygomatic arch I: angle of mandible

F: elevate mandible

Muscles of mastication

•Masseter –O: zygomatic arch–I: angle & ramus of

mandible–Action: elevate

mandible

(11.7a)

Zygomaticus

O: zygomatic I: corner of mouth

F: smile

Sternocleidomastoid

O: sternum & clavicle I: mastoid of temporal bone

F: flex and rotate head

Muscles of neck & throat

•Sternocleidomastoid

–O: manubrium & medial clavicle

–I: mastoid process of temporal bone

–Action: head & neck flexion, rotate head

contralaterally

(11.8a)

Muscles of neck & throat

•Sternocleidomastoid

Platysma

O: fascia over Pec. major, Deltoid I: mandible & skin

F: depress lip & mandible

Shoulder muscles

•Pectoralis major

–O: medial clavicle, sternum, cartilage of ribs 1-6, aponeurosis

of external oblique–I: greater tubercle of

humerus–Action: arm-flexion,

medial rotation, adduction, elevation

of rib cage (11.13a)

Superficial thorax muscles

•Pectoralis minor• O:anterior surface

of ribs 3-5–I: coracoid process

of scapula–Action: with ribs

fixed, pulls scapula anterior & inferior; with scapula fixed,

pulls ribs superiorly (11.13a)

Subclavius•Small, round muscles

•O: 1st rib at costal cartilage•I: Middle third of clavicle

•A: Anchors and depresses clavicle

•Protects subclavian artery if clavicle fractures

Superificial thorax muscles

•Trapezius –O: occipital bone,

ligamentum nuchae, C7-T12 spinous processes

–I: acromion, spine of scapula, lateral third of

clavicle–Action: stabilize, elevate,

adduct, depress scapula, extend head

(11.13b)

Latissimus dorsi

Origin: ribs, thoracic & lumbar vertebra, iliac crest of coxal bone

Insertion: humerus

Action: humerus extension, adduction, medial rotation

Levator scapulae

O: cervical vertebrae I: scapula

F: elevate scapula, rotate neck

Shoulder muscles

•Deltoid –O: lateral clavicle,

acromion & spine of scapula (compare to

insertion of trapezius)–I: deltoid tuberosity

of humerus–Action: arm-

abduction, flexion, extension, medial &

lateral rotation

(11.13ab)

Abdominal wall muscles

•Rectus abdominis –O: pubic crest & symphysis–I: xiphoid process and

costal cartilages of ribs 5-7–Action: flex & rotate lumbar

vertebrae, fix & depress ribs, stabilize pelvis during

walking, increase intraabdominal pressure

–Note: 3 tendinous insertions, aponeurosis &

linea alba

(11.11ab)

External oblique

Origin: lower ribs

Insertion: linea alba; iliac and pubic crests of coxal bone

Action: abdomenal compression, vertebral flexion, trunk rotation, lateral vertebral flexion

Muscles of Anterior Abdominal Wall•External Obliques

–O: lower 8 ribsI: aponeurosis to linea albaFunction: Flex trunk, compress abd. wall (together)

Rotate trunk (separate sides)

•Internal Obliques–O: Lumbar fascia, iliac crest, inguinal ligament–I: Linea alba, pubic crest, last 3-4 ribs, costal margin–Function: Same as External obliques

•Transversus AbdominisO:same as Internals, plus last 6 ribs

–I: Xiphoid process, costal cart. 5-7–Function: Compress abdomen

•Rectus Abdominis–O: Pubic crest, pubic symphysisI: Xiphoid, cost cart 5-7–Function: Flex, rotate trunk, compress abdomen, fix ribs

Hip & knee muscles

•Gluteus muscles–O: ilium, sacrum,

coccyx–I: shaft & greater

trochanter of femur–Action: extend

thigh (climb stairs, running), lateral &

medial rotate thigh, abduct thigh,

steadies pelvis

(11.20ab)

Gluteus maximus

Origin: saccrum, coccyx, and ilium of coxal bone

Insertion: femur & iliotibial tract

Action: femur extension & lateral rotation

Hip & knee muscles•Quadriceps femoris

–O: anterior inferior

iliac spine, superior margin of acetabulum,

greater trochanter, shaft of femur

–I: patella and tibial tuberosity via patellar

tendon–Action: extend knee,

flex thigh11.19a

Hip & knee muscles•Hamstrings

–O: ischial tuberosity, shaft of femur

–I: lateral & medial condyles and shaft of

tibia, head of fibula, lateral condyle femur

–Action: extend thigh, flex knee

–Makes touching toes hard (11.20a)

Biceps Femoris

Extends Thigh & Flexes Lower Leg

Elbow muscles

•Biceps brachii –O: short head-coracoid

process, long head-tubercle above glenoid

cavity and lip of glenoid cavity (intertubercular

groove)–I: radial tuberosity–Action: flex elbow,

supinate forearm, weak arm flexor

(11.14c)

Brachialis

O: humerus I: coronoid process of ulna

F: flex forearm

Elbow muscles

•Triceps brachii

• O: long head-infraglenoid tubercle,

lat. & med. heads-posterior shaft of

humerus–I: olecranon process

of ulna–Action: extend

forearm, assist adduction of arm

(11.14b)

Leg muscles

•Tibialis anterior

–O: lateral condyle and shaft of tibia

–I: tarsal and first metatarsal bones

–Action: dorsiflexion

(11.21ab)

Anterior Compartment of the Leg

•Extensor digitorum longus = extension of toes & ankle•Extensor hallucis longus = extension of big toe & ankle•Fibularis tertius = dorsiflexes and everts foot

•Tibialis anterior = dorsiflexes and inverts foot

Extensor digitorum longus

Peroneus tertius

Extensor hallucis longus

Tibialis anterior

Leg muscles

•Gastrocnemius –O: medial & lateral

condyles of femur–I: calcaneus via Achilles

tendon–Action: plantar flexion,

flex knee(11.23a)

Posterior Compartment of the LegDeep Group of Plantar Flexors

•Tibialis posterior, Flexor digitorum longus, and Flexor hallucis longus and are plantar flexors.

Forearm muscles

•Flexor carpi (radialis & ulnaris)

–O: medial epicondyle of

humerus, ulna–I: metacarpals and

carpals–Action: wrist

flexion, abduct & adduct hand

–Carpal tunnel syndrome p. 184 (11.15a)

Anterior view

Forearm muscles

•Extensor carpi–O: lateral epicondyle of

humerus–I: base of metacarpals –Action: extend, abduct,

and adducts wrist–Palpate forearm

muscles

11.16a Posterior View