MUSCULAR SYSTEM

25問 • 1年前

問題一覧

• covers frontal bone • Runs from cranial aponeurosis to the skin of the eyebrows, where it inserts. • Allows us to raise eyebrows, wrinkle forehead

frontalis

• at posterior end of cranial aponeurosis. • Covers posterior aspect of skull and pulls scalp posteriorly.

occipitalis muscle

• Has fibers that run in circle around eye • Allows you to close eyes, squint, wink, blink

orbicularis oculi

• Kissing muscle • Circular muscle of lips • Close mouth, protudes lips

orbicularis oris

• Runs horizontally across cheek • Inserts into obicularis oris • Flattens cheek (whistling, blowing trumpet) • Chewing muscle-compresses cheek to hold food between teeth

buccinator

• Smiling muscle • Extends from corner of mouth to cheekbone • Raises corners of mouth upwards

zygomaticus

• Runs from zygomatic process of temporal bone • Covers angle of lower jaw • Closes jaw by elevating mandible

masseter

Fan shaped - Overlying temporal bone - Inserts into mandible - Acts as synergist of masseter in closing jaw

temporalis

• Single sheetlike • Covers anterolateral neck • Originates from connective tissue covering of chest muscles • Inserts into area around mouth inferiorly, producing downward sag of mouth • Single sheetlike • Covers anterolateral neck • Originates from connective tissue covering of chest muscles • Inserts into area around mouth inferiorly, producing downward sag of mouth

platysma

• Paired • Two-headed muscles on each side of neck • One arises from sternum and the other from the clavicle • Heads fuse before inserting into mastoid process of temporal bone • When both muscles contract, they flex your neck • Article sf bowing neck -"prayer • If just one muscle contracts, head is rotated toward shoulder on opposite side, tilts head to side

stenocleidomastoid

Move vertebral column most are posterior anti gravity muscles) Anterior thorax muscles, which move ribs, head, arms Muscles of abdominal wall, which help move vertebral column and form natural girdle of abdominal body wall

trunk muscles

- Large, fan-shaped - Covers upper chest - Origin is from sternum, shoulder girdle, and first 6 ribs - Inserts on proximal end of humerus - Forms anterior wall of axilla - Adduct and flex arm

pectoralis major

- Paired, straplike - Most superficial - Run from pubis to rib cage - Flex vertebral column - Compress abdominal contents during defecation and childbirth - Involved in forced breathing

rectus abdominis

- Paired, superficial - Lateral wall of abdomen - Fibers run downward and medially from last 8 ribs, insert into ilium - Flex vertebral column - Rotate trunk and bend it laterally

external oblique

- Most superficial - When seen together, they form diamond shaped muscle mass - Runs from occipital bone (skull) down to vertebral column to end of thoracic vertebrae - Flare laterally to insert on scapular spine and clavicle - extend the head - Antagonists of sternocleidomastoids - Elevate, depress, adduct, stabilize scapula

trapezius

• Two large, flat muscles • Cover lower back • Originate on lower spine and ilium • Sweep superiorly to insert into proximal end of humerus. • Extends and adducts humerus • Important when arm must be brought down in power stroke (swimming, striking i blow)

latissimus dorsi

- Prime mover of back extension - Paired, deep - Composite muscle consisting of three muscle columns (longissimus, iliocostalis, spinalis) that collectively span enture vertebral column - Act as powerful back extensors - Provide resistance that helps control action of bending over at waist

erector spinae

• Fleshy, triangle shaped • Form rounded shape of shoulder • Injection site when <5mL of medication must be given intramuscularly • Origin winds across shoulder girdle from spine of scapula to clavicle • Inserts into proximal humerus • Prime movers of arm abduction

deltoid

- first group includes muscles that arise from the shoulder girdle and cross the shoulder joint to insert into the humerus • Second group causes movement at elbow joint - Enclose humerus, insert on forearm bones • Third group includes muscles of forearm, which insert on hand bones and cause their movement. • Thin, spindle shaped.

muscles of the upper limb

• Bulges when elbow is flexed • Originates by two heads from shoulder girdle • Prime mover for flexion of forearm • Supinates forearm

biceps brachii

- Deep to biceps - Elbow flexion - lifts ulna as biceps lifts radius

brachialis

• Only muscle fleshing out posterior humerus • Three heads form shoulder girdle and proximal humerus • Inserts into olecranon process of ulna • Prime mover of elbow extension • Antagonist of biceps brachii • Boxer's muscle

triceps brachii

• Cause movement at hip, knee, foot joints • Among largest, strongest muscles in body • Specialized for walking and balancing body • Pelvic girdle is composed of heavy, fused bones—no special group of muscles is necessary to stabilize it • Muscles acting on thigh are massive - Help hold body upright against pull of gravity - Cause various movements at hip joint. • Muscles acting on leg form flesh of thigh - Leg muscles refers to whole lower limb, but anatomically only refers to part between knee and ankle • Thigh muscles cross knee and causes its flexion or extension. - Can cause movement at hip joint. • Muscles originating on leg cause assorted movements of foot and ankle

muscles of lower limb

• Fused, composed of 2 muscles - iliacus and psoas major • Runs from iliac bone and lower vertebrae deep inside pelvis • Insert on lesser trochanter of femur • Prime mover of hip flexion • Acts to keep upper body falling backwards when standing

iliopsoas

• Thin, straplike - Most superficial - Runs obliquely across thigh from anterior iliac crest to medial site of tibia - Weak thigh flexor • Tailor's muscle-synergist to bring about cross-legged position in which tailors are often shown

sartorius

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