Health Occupations

Muscular System – Unit 1

Muscle Location FunctionFrontalis Above nose & eyes Raises eyebrows

Temporalis Temples Closes the jawOrbicularis Occuli Around eye Closes eyeMasseter Jaw Clenches teethOrbicularis Oris Around lips Closes lips, kissesTrapezius Upper back & neck Extends head, shoulderSternocleidomastoid side of neck Turns & flexes headDeltoid Shoulder Abducts arm, injectionPectoralis Upper chest Adducts & flexes armTriceps Upper arm Extends lower armSerratus Ventral lower ribs Moves scapulaAnterior biceps Upper arm Flexes lower armLattisimus dorsi Spine around to chest Extends, adducts arm

Rectus abdominis Ribs to pubis Compresses abdExterior oblique Lower abd/pelvis (lat) Bends/rotates vertebrae

Sartorius Front of thigh Abducts & flexesRectus femoris Front of thigh Extends legVastus lateralis Lateral thigh Extends kneeVastus medialis Medial thigh Extends kneegastrocnemius Back of lower leg Flexes sole of footTibialis anterior Front of lower leg Flexes & inverts foot

Bicep femoralis Back of thigh Flexes knee, lat rotate thigh, extendshipGluteus maximus buttocksExtends thigh, injection

Achilles tendon Back of calf Allows calf to function

Frontalis

SternocleidomastoidTrapezius

DeltoidPectoralisTricepsSerratusBiceps

Latissmus dorsiRectus abdominusExterior oblique

Gluteus maximusSartoriusRectus femoris

Vastus lateralisVastus medialis

Gastrocnemius

Tibialis anterior

Achilles tendon

Muscular System

Made up of over 600 muscles Organs – bundles of muscle fibers held

in place by connective tissue Contraction

– Movement of muscles when stimulated Tonus

– Muscle’s ability to maintain slight & continuous contraction

Muscular System

Types of stimulation– Electrical– Mechanical– Chemical

When not contracted, muscles are FLACCID or soft

Properties of muscles

Excitability– Irritability, ability to respond to a stimulus such as

a nervous impulse Contractility

– Ability to shorten forcefully when stimulated Extensibility

– Ability to be stretched Elasticity

– Ability to recoil to its resting length when relaxed

Functions of muscle

Aids in movement Provides & maintains posture Protects internal organs Provides movement of blood, food, &

wastes through the body Opens & closes body openings Produces heat

Types of muscle tissue

Muscle type Appearance Manner of control

Skeletal Striated Voluntary

Visceral Smooth Involuntary

Cardiac Indistinctly striated

involuntary

Skeletal Muscle

>40% of body weight Increases in size & weight with exercise Decreases in size & weight with inactivity Variety of sizes & shapes due to genetics,

nutrition, & exercise Tendons – attach muscles to bone

– Narrow strips of dense connective tissue– Gastrocnemius

• Calf muscle attaches with the Achilles tendon to the heel

Skeletal Muscle

Fascia – – Tough, sheetlike membrane– Covers & protects tissue

• Deep muscles of back & trunk are surrounded by lumbodorsal fascia

Named by:– Location– Related bones– Shape– Action– Size

Skeletal Muscle

Appearance– Striated under microscope– Made up of bundles of fine fibers– Number of fibers doesn’t increase much

after birth– Muscle mass increases due to increase in

fiber SIZE not number

Actions & Movements of skeletal muscles Adduction – toward midline Abduction – away from midline Flexion – decreasing angle between 2 bones Extension – increasing angle between 2 bones Rotation – turning a part around its own axis Circumduction – moving in a circle @ a joint Pronation – turning hand or foot downward or

backward Supination – turning hand or foot upward or

forward

Flexion

ExtensionRotation

Abduction

Adduction Supination Pronation

Sarcomere

Basic unit of muscle fibers causing muscular contraction

Made up of actin & myosin myofibrils Most contract under voluntary control 3 parts to skeletal muscle

– Origin – the end of muscle attaching to less moveable part of bone

– Action or body – thick, middle part of muscle– Insertion – the end of muscle attaching to most

moveable part of bone

Sarcomere (cont)

Movement occurs by pulling bones, working in PAIRS– One muscle contracts– Counteracting muscle relaxes

Prime mover – AGONIST– Pulls to contract muscle

Antagonist muscle –– Relaxes when agonist contracts

Synergists & fixators– Keep muscle & bone stable during movement

Skeletal Muscle Tissue

Origin

Action or body

Insertion

Contracted

Relaxed

Relaxed

Contracted

Sarcomere (cont)

Atrophy – Shrinking in size & loss of strength of

muscle– Occurs when muscle is not used over time

Contracture– Severe tightening of a flexor muscle– Results in bending of a joint– Foot drop is common

Visceral Muscle

Smooth, NO striations like skeletal muscle Contracts when stimulated Controlled by autonomic nervous system Lines various organs

– Makes up walls of blood vessels– Found in tubes of digestive system– Sphincter muscles (circular)

• Opens & closes pupils• Urinary bladder

Cardiac muscle

Found only in heart Indistinctly striated Involuntary control Has specialized cells that provide a

stimulus for contraction - PACEMAKER

Range of Motion (ROM)

Standards– Move each joint slowly, gently, smoothly– Support each joint during movement– Don’t move joint past its present level of

movement– If pain occurs, stop movement & report– Watch face, especially eyes, for signs of pain– Discuss exercise plan with charge nurse– Perform ROM on one side of body at a time– Move each joint 5 times

ROM Procedure

Wash hands Identify client Explain procedure & ask permission to

perform skill Provide privacy

ROM

Shoulder– Hold wrist & elbow– Flexion & extension– Abduction & adduction– Horizontal abduction & adduction (hand to

opposite shoulder, then back out to shoulder level)

– Rotation of elbow, up & down like hand signal

ROM

Elbow– Hold wrist & elbow– Flexion & extension– Rotation of hand, up & down towards face

& feet

ROM

Wrist– Hold wrist & fingers– Flexion & extension– Hyperextension of hand– Abduction & adduction of wrist– Tilt Hand towards toes, bring hand, thumb

side up, towards nose

ROM

Fingers/Thumbs– Hold hand– Make fist to flex fingers– Straighten fist by extending fingers– Abduction, adduction of all fingers– Thumb abduction, adduction– Thumb opposition

ROM

Hip & Knee– Hold knee & ankle– Flexion knee & hip, extend knee, return to

resting position– Abduction & adduction– Rotation of leg, inward & outward

ROM

Ankle– Hold ankle & foot– Flexion & extension of foot– Foot abduction & adduction

ROM

Toes– Hold foot– Flexion & extension of toes– Abduction & adduction of toes

To finish– Position comfortably– Bed lowest position– Side rails up, call light in place– Wash hands