Muscular System Chapter 4

What do our muscles do? Hold the body erect and make movement possible. Generate heat through movement; they supply nearly 85% of the heat that keeps the body warm.

Move food through the digestive system. Aids the flow of blood through the veins with muscle movement. Move fluids through ducts and tubes associated with other body systems.

The body has more than 600 muscles, which make up 40 to 45% of the body’s weight. Muscles are made up of fibers, are covered with fascia, and are attached to bones by tendons.

Word Parts: my/o = muscle fasci/o = fascia ten/o, tend/o, tendin/o = tendon.

Types of Muscle Tissue: skeletal muscles – also known as “striated” or striped muscles. These attach to the bones and make possible motions such as walking and smiling. They are also known as voluntary muscles, because we have control over them.

Smooth muscles – located in walls of internal organs such as the digestive tract, blood vessels and ducts leading from glands. They move and control the flow of fluids through these structures. They are unstriated or not-striped. They are involuntary muscles because they are not under voluntary control.

Cardiac muscle – also known as myocardial muscle or myocardium. Forms muscular wall of the heart. Is like striated muscle in appearance but like smooth muscle in its action. It is the contraction and relaxation of this muscle that causes the heartbeat.

Range of Motion Is the change of joint position that is produced by muscle movements. These muscle motions, which occur as pairs of opposites, are abduction, adduction, flexion, extension, rotation and circumduction, supination and pronation, inversion, eversion, dorsiflexion and plantar flexion.

Tendons: muscle to bone

How Muscles Are Named Origin and Insertion: Muscle origin is the place where the muscle begins (originates). This is the end of the muscle nearest the midline of the body.

The insertion is the place where the muscle ends (inserts). It is the portion of the muscle farthest from the midline of the body. For example: the sternocleidomastoid muscle: has 2 origins: the sternum, the clavicle (or cleido), and it inserts near the mastoid process behind the ear.

Muscles are also named for their action. Examples: flexor carpi muscles work with the extensor carpi muscles to make possible the flexion and extension motions of the wrist.

Muscles are also named for their location. If muscles have the word “pectoralis” in them, they relate to the chest. If muscle names have “lateralis” or “medialis”, they indicate “toward the side” or “toward the midline.”

Muscles are also named for their fiber direction: Rectus means straight. Oblique means “at an angle” or “slanted”. Transverse means crosswise. Sphincter is a ringlike muscle that tightly constricts the opening of a passageway.

Muscles are also named for number of divisions. Bi- means two divisions; example: biceps. Tri- means three divisions; example: triceps. Quadri- means four divisions; example: quadriceps.

Muscles are also named for their size. For example: the gluteus maximus is the largest muscle of the buttock, and maximus means large.

Muscles are also named for their shape. For example: the deltoid muscle is shaped like an inverted triangle or the Greek letter delta.

Let’s practice some terms and their definitions….. fasci/itis = inflammation of the fascia ten/algia = pain in a tendon tendin/itis = inflammation of a tendon

my/algia = muscle pain myo/malacia = abnormal softening of muscle tissue myo/rrhexis = rupture of a muscle myo/sclerosis = abnormal hardening of a muscle

fasci/otomy = incision into the fascia fasci/o/plasty = surgical repair of the fascia ten/ectomy = surgical removal of a tendon ten/otomy = incision into a tendon

ten/o/rrhaphy = suturing of a tendon my/ectomy = surgical removal of a muscle my/o/plasty = surgical repair of a muscle

Major Muscles of the Body As you start learning or reviewing the names of the major muscles, try to remember a clue about the name as to where it is, what it looks like, what body part it is near, etc., to help you remember.

New Suffices: -cele = hernia -ia = abnormal condition; same as –osis. -lysis = destruction -plegia = paralysis -paresis = partial or incomplete paralysis -desis = surgical fixation.

New Prefixes: brady- = slow. tachy- = fast. bi- = two; double. tri- = three.

Word Parts and their Meanings tax/o = coordination Words: a/tax/ia without coordinated movements dys/tax/ia difficulty in controlling movements

kinesi/o = movement Words: brady/kines/ia = slow movement tachy/kines/ia = fast movement hyper/kines/ia = abnormally increased movement hypo/kines/ia = abnormal decreased movement kinesi/ology = study of movement

ton/o = muscle tone Words: a/ton/ic = without muscle tone dys/ton/ia = condition of difficult or abnormal muscle tone hyper/ton/ia = excessive muscle tone hypo/ton/ia = decreased muscle tone

-desis to bind or tie together; to attach a part to another part. Example: ten/o/desis = attaching the end of a tendon to a bone.

Review of Word Parts: my/o: muscle fasci/o fascia ten/o, tend/o, tendin/o tendon -cele hernia

ia: abnormal condition of -lysis: destruction -plegia: paralysis -paresis partial or incomplete paralysis

-desis to tie, bind together, attach tax/o: coordination ton/o: muscle tone kinesi/o: movement

Pathology of the Muscular System Adhesion – a band of fibrous tissue that holds structures together abnormally; usually is the result of injury or surgery. Atrophy – a weakness or wasting away of muscle tissue, due to pathology or by disuse of the muscle over a long period of time.

Hernia – the protrusion of a part or structure through the tissues normally containing it. Myocele – the protrusion of muscle through its ruptured fascia. Atonic – lack of normal muscle tone (a- means without). Hypertonic – condition of excessive tone of the skeletal muscles with an increased resistance of muscle to passive stretching.

Hypotonia – condition of diminished tone of the muscles, with decreased resistance of muscle to passive stretching. Myotonia – delayed relaxation of a muscle after a strong contraction. Ataxia – an inability to coordinate the muscles during voluntary movement. Dystaxia – difficulty in controlling voluntary movement.

Contracture – an abnormal shortening of muscle tissues, making the muscle resistant to stretching. Spasm, or cramp – a sudden, violent, involuntary contraction of a muscle or group of muscles. Bradykinesia – extreme slowness in movement. Dyskinesia – distortion or impairment of voluntary movement, as in a tic or spasm.

Hyperkinesia – hyperactivity; abnormally increased motor function. Hypokinesia – abnormally decreased motor function or activity. Nocturnal myoclonus – the jerking or twitching of limbs that may occur normally as a person is falling asleep. Singultus – hiccups; myoclonus of the diaphragm that usually causes the hiccup sound with each spasm.

Muscular Dystrophy – a group of inherited muscle disorders that cause muscle weakness without affecting the nervous system. The most common forms, which affects only males, are Duchenne’s and Becker’s. Duchenne’s – appears from 2-6 years of age, and progresses slowly. Survival is rare beyond the late twenties. Becker’s – less severe; appears early adolescence or adulthood. Survival is into mid to late adulthood.

Fibromyalgia – a chronic disorder of unknown cause, causing aching pain, tender points, fatigue. Is not progressive, is not crippling. Ergonomics – the study of human factors that affect the design and operation of tools and the work environment.

Sprain – an injury to a joint; frequently caused by overuse; involves a stretched or torn ligament. Strain – an injury to the body of the muscle or attachment of the tendon. Usually involves a torn muscle or tendon attachment. Shin splint - pain caused by muscle tearing away from the tibia. Usually caused by repeated stress to the lower leg.

Spinal cord injury – often causes paralysis because nerve impulses cannot be carried below the level of the injury. Paraplegia – paralysis of both legs and the lower part of the body. Caused from an SCI below the cervical vertebrae. Quadriplegia – paralysis of all four extremities. Caused from an SCI involving the cervical vertebrae.

If an SCI occurs above C5, it also affects respiration. Hemiplegia – total paralysis of one side of the body. Usually associated with a stroke or brain damage.

Career Opportunities Orthopedic Surgeon – treats injuries and disorders involving bones, joints, muscles, tendons. Rheumatologist – treats disorders that involve the inflammation of connective tissues / muscles. Neurologist – treats the cause of paralysis and muscle disorders in which there is a loss of function.

Physical Therapist – provides treatment to improve mobility and prevent or limit permanent disability of patients with injuries or diseases. Physical Therapy Assistant - helps carry out plans of treatment prescribed by the Physical Therapist. Massage Therapist – uses therapeutic touch to provide pain relief and encourage healing.

Athletic Trainer – works to prevent and treat athletic injuries and provides rehabilitative services to athletes who have been hurt. Kinesiotherapist – works under the supervision of a physician to provide rehabilitative exercise programs designed to reverse or minimize the debilitation of patients undergoing medical treatment; aquatic therapy, prosthetics.

Occupational Therapist – treats people with mental, physical, developmental, and emotional disabilities, helping them develop or maintain daily living skills. Occupational Therapist Assistant – works under the supervision of an OT to help patients with prescribed exercises and activities.