Chapter 4 Medical Terminology
and
Chapter 7 Body Structures
THE MUSCULAR SYSTEM
Functions of the Muscular
System
Hold the body erect
Make movements possible
Keeps the body warm
Moves food through digestive system
Aids in the flow of blood through veins
– muscle movements such as walking
Moves fluids through ducts and tubes
associated with other body systems
Structure of the Muscular
System
Muscle fibers: long, slender cells that
make up muscles
Fascia: sheet of connective tissue
that covers a muscle
Tendons: nonelastic, dense,
connective tissue that functions to
attach muscle to bone
– Example: Achilles tendon (gastrocnemius
muscle in the calf)
Tendons attach muscle to
bone
Ligaments join bone to
bone
Aponeurosis: flat sheet of
connective tissue that connects
muscle to bone OR to other tissues
Types of Muscle Tissue
Skeletal Muscles
Smooth Muscles
Cardiac Muscles
Skeletal Muscle: AKA striated
- alternating dark and light bands creating a striped effect
Attach to the 206
bones of skeleton
Function to allow
body motions such
as walking and
smiling
Voluntary muscles
Smooth Muscles: AKA
unstriated/visceral
Located along the walls of internal organs
Function to move and control the flow of fluids
through structures such as the digestive tract, blood
vessels, and ducts leading from glands
Involuntary: under the control of the autonomic
nervous system
Found in large internal organs and in hollow
structures
Cardiac Muscles: AKA
myocardial muscle
Forms the wall of the heart
Specialized tissue often referred to as the
myocardium that has a striated appearance, but
functions like smooth muscle
Contraction/relaxation of myocardium =
heartbeat
Characteristics of Muscles
Kinesiology: the study of muscular
activity and the resulting movement
of body parts
Antagonistic: to work in opposition
to each other
– One muscle works in one direction
(contracts)
– The other muscle in the pair, works in
the opposite direction (relaxes)
Contraction and Relaxation
Specialized cells within muscle tissue can change
shape/length by contracting or relaxing =
movement
Contraction: tightening of a muscle – shorter and
thicker
– The muscle bulges in the center (belly)
– Stimulated by Muscle Innervation –
transmitted by a motor nerve
Relaxation: when a muscle returns
to it’s original form
– Longer and thinner and the belly is no
longer enlarged
– Cease of Muscle Innervation
(stimulation)
Muscle Tone: tonus –
normal state of balanced
muscle tension required to
hold the body in an awake
position
Neuromuscular: pertaining to the relationship
between nerve and muscle
- if the nerve impulse is interrupted
due to injury or pathology, the
muscle becomes paralyzed
Range of Motion
The change in
joint position
produced by
muscle
movements
–
–
–
–
–
Flexion/Extension
Elevation/Depression
Rotation/Circumduction
Supination/Pronation
Dorsiflexion/Plantar
Flexion
– Abduction/Adduction
Abduction/Adduction
Abduction:
movement away from
midline
– abductor: the muscle
responsible for moving
a part away from
midline
Adduction:
movement toward the
midline
– adductor: the muscle
responsible for moving a
part toward midline
Flexion/Extension
Flexion: decreasing
the angle between two
bones or bending a
limb at a joint
– flexor: the muscle
responsible for bending a
limb at a joint
Hyperextension:
extreme/overextension of
limb or body part
Extension: increasing
the angle between two
bones or straightening
out a limb
– extensor: muscle
responsible for
straightening a limb at a
joint
Elevation/Depression
Elevation: the act of
raising or lifting a
body part
– levator: the muscle
responsible for raising a
body part
Depression: the act
of lowering a body
part
– depressor: the muscle
responsible for lowering
a body part
Rotation/Circumduction
Rotation: circular
movement around an
axis
– rotator muscle: the
muscle responsible for
turning a body part on
its axis
Circumduction:
circular movement of
a limb at the far end
Supination/Pronation
Supination: rotation
of the arm or leg so
the palm of the hand
or sole of the foot is
turned forward or
upward
Pronation: rotation of
the arm or leg so the
palm of the hand or
sole of the foot is
turned downward or
backward
Dorsiflexion/Plantar Flexion
Dorsiflexion: bends the
foot upward at the ankle
– narrows the angle
between the top of the
foot and the front of the
leg
Plantar Flexion: bends
the foot downward at the
ankle
– Increases the angle
between the top of the
foot and the front of the
leg
– Plantar: refers to the sole
of the foot
How Muscles are named
Origin and
Insertion
Action
Location
Fiber Direction
Number of
Divisions
Size
Shape
Origin and Insertion
Muscle Origin:
point where muscle
begins
– More fixed
attachment
– Closest end to
midline
 Muscle Insertion:
point where muscle ends
(inserts)
- more moveable end
- farthest end away from
midline
Sternocleidomastoid: muscle that helps flex neck and rotate head –
originates near midline (sternum and clavicle) – inserts away from midline
into the mastoid process of the temporal bone
Action of Muscles
Action that a
particular muscle is
responsible for is
often used to
describe (name) a
muscle
Example:
– Flexor carpi muscles:
flex the wrist
– Extensor carpi muscles:
extend the wrist
Location of Muscles
Muscles are also
named according to
their location on body
or near-by organ
– Inferior/superior
– Lateral/medial
– Pectoral: relating
to the chest
– Internal/external
– Anterior/posterior
Muscle Fiber Direction
Muscles can be
named according
to the direction of
their fibers
Rectus: means straight (Rectus Abdominus)
Oblique: means slanted or at an angle (external
abdominal oblique)
Transverse: means in a crosswise direction
(transverse abdominus
Sphinctor: a ringlike muscle that tightly constricts
the opening of a passageway (anal sphinctor)
Muscle Divisions
Muscles may be named
according to the
number of divisions
forming them
Examples:
– Biceps brachii: formed
from 2 divisions
(bi = 2
ceps = head)
– Triceps brachii: formed
from 3 divisions
(tri = 3
ceps = head)
– Quadriceps femoris:
formed from 4 muscle
divisions
(quadri = 4 ceps = head)
Muscle Size
Some muscles are
named according to
their size
– Broad or narrow
– Large or small
Example:
– Gluteus
Maximus: largest
muscle in the
buttock
Muscle Shape
Muscles are named
according to their
shape related to a
familiar object
– Deltoid muscle: shaped
like an inverted triangle
or the Greek letter delta
– Trapezius: shaped like
a trapezoid
– Rhomboideus major:
shaped like a rhomboid
Medical Specialties Related to
the Muscular System
Skeletal Muscle Disorders
– Orthopedic surgeon: bones, joints, muscles, and
tendons
– Rheumatologist: inflammation of connective tissue,
including muscles
– Neurologist: cause of paralysis, muscular disorders with
loss of function
– Sports Medicine: sports-related injuries of bones, joints,
and muscles
Smooth Muscle Disorders
– Specialists who treat a particular body system, also treats
any involved muscles
Cardiac Muscle Disorders
– Cardiologist: cardiac muscles
Fibers, Fascia,
and Tendons
Fasciitis:
inflammation of a
fascia
Tenalgia:
pain in a tendon
Tendinitis:
inflammation of the
tendons caused by
excessive or
unusual use of the
joint
www.podiatryinfo.c
om/
vphtml/heel.html
Muscles
Adhesion: band of fibrous
tissue that holds structures
together abnormally
Atrophy: weakness and
wasting away of muscle
tissue
Polymyositis: chronic,
progressive disease
affecting the skeletal
muscles that is
characterized by muscle
weakness and atrophy
Myomalacia: abnormal
softening of muscle tissue
www.ohiorepromed.com/ illustrations.htm
Muscle fatigue
– Caused by an accumulation of lactic acid
in the muscles due to not receiving
enough oxygen during vigorous activity.
– Causes cramps
– Reversed when enough oxygen is taken
in while resting
Hernias
Hernia: the
protrusion of a part
or structure through
the tissues normally
containing it
Myocele: the
protrusion of a
muscle through its
ruptured sheath or
fascia
www.tusalud.com.mx/ 120110.htm
Muscle Tone
Atonic: lack of normal
muscle tone
Hypertonia: condition
of excessive tone of the
skeletal muscles –
increased resistance to
stretching
Hypotonia: diminished
tone of the skeletal
muscles – decreases
resistance to stretching
tmcr.usuhs.mil/tmcr/chapter4/ esophagus.htm
Voluntary Muscle
Movement
Ataxia: inability to
coordinate the muscles
in the execution of
voluntary movement
Spasm: (cramp)
sudden, violent,
involuntary contraction
of a muscle or a group
of muscles
Spasmodic torticollis:
(wryneck) stiff neck due to
spasmodic contraction of the
neck muscles that pull the
head toward the affected side
www.dystonia-support.org/ la-pain%20in%20spasm...
Muscle Function
Kinesia: kines = movement
ia = condition
– Bradykinesia: slowness in movement
– Dyskinesia: distortion or impairment in
voluntary movement
– Hyperkinesia: (hyperactivity),
abnormally increased motor function or
activity
– Hypokinesia: abnormally decreased
motor function or activity
Muscular Dystrophy
A group of inherited muscle disorders that cause muscle
weakness without affecting the nervous system
– Most common affecting only males = Duchenne’s muscular
dystrophy (DMD) & Becker’s muscular dystrophy (BMD)
Fibromyalgia Syndrome
Chronic disorder of
unknown cause
characterized by
widespread aching pain ,
tender points, and fatigue
Tender points: abnormal
localized areas of soreness,
important in diagnostic
measures of FMS
www.chiro.cc/health_info/ fibromyalgia.htm
Repetitive Stress Disorders
Have symptoms caused by repetitive
motions that involve muscles, tendons,
nerves, and joints
Ergonomics: study of human factors that
affect the design and operation of tools and
the work environment
www.igo4mac.com/ ergonomics.html
Rotator Cuff Injuries
www.medicalmultimediagroup.com/.../
Rotator cuff tendinitis:
inflammation of the tendons
of the rotator cuff (pitcher’s
shoulder)
Impingement syndrome:
occurs when the tendons
become inflamed and get
caught in the narrow space
between the bones within
the shoulder joint
Calcium deposits
Torn Tendon
www.eatonhand.com/ img/14522.htm
Carpal Tunnel
Syndrome
www.everybody.co.nz/docsa_c/ carpaltunnel.htm
Carpal Tunnel: Narrow bony
passage under the carpal
ligament located ¼ inch below
the inner surface of the wrist
– median nerve and the
tendons that bend the fingers
pass through this tunnel
Carpal Tunnel Syndrome:
occurs when the above
tendons are chronically
overused and become
inflamed and swollen, creating
pressure on the median
nerve, pain, burning, an
paresthesia (tingling) in the
fingers and hand
Sports Injuries
Sprain: injury to a joint, frequently
caused by overuse, involving a
stretched or torn ligament
Strain: injury to the body of the
muscle or attachment of the tendon,
usually associated with overuse
injuries that involve a stretched or
torn muscle or tendon attachment
Paralysis
The loss of sensation and voluntary muscle
movements through disease or injury to its nerve
supply
– Frequently caused by a spinal cord injury
 Paraplegia: paralysis of both legs and the lower
part of the body
 Quadriplegia: paralysis of all four extremities
 Hemiplegia: total paralysis of one side of the
body
 Cardioplegia: paralysis of the muscles of the
heart
Treatment Procedures of the
Muscular System
Medications
Physical Therapy
– Range of Motion Exercises (ROM)
– Activities of Daily Living
Fascia – fasciotomy, relieves tension
Tendons
– Carpal Tunnel Release
Muscles
– Myectomy, myoplasty, myorrhaphy
removal
repair
suture