Download Muscles - Mentor High

Muscles of the Human Body
Science Olympiad
Anatomy and Physiology
2009-2010
Muscles
 Definition: a type of tissue composed of
contractile cells (or fibers) which effect
movement of an organ or part of the
body
 Male and female body contains
approximately 640 muscles.
Skeletal Muscles
 vary considerably in size, shape, and
arrangement of fibers.
 range from extremely tiny strands such as the
stapedium muscle of the middle ear to large
masses such as the muscles of the thigh.
 may be made up of hundreds, or even
thousands, of muscle fibers bundled together
and wrapped in a connective tissue covering.
Characteristics of muscle
 Excitability-responds to a stimuli (eg
nerve impulse
 Contractility-able to shorten in length
 Extensibility-stretches when pulled
 Elasticity-tends to return to original
shape and length after contraction or
extension
Functions of muscle
 Motion: provide levers for muscles
 The stimulation of individual muscle fibers
maintains a state of muscle contraction known as
tonus (muscle tone).
 Important in maintaining the movement of blood
and lymph through out the body.
 When muscle is cut off from nerve supply, a
condition that occurs when spinal nerves are
severed, the muscles lose tonus and become
flaccid and eventually atrophies (shrinks)
 Heat production
 Muscle metabolism produces heat as an end
product.
 Because muscles constitute about 40-45% of the
body’s weight and are in a constant state of fiber
activity, they are the primary source of body heat.
 The rate of heat production rises with increased
muscle activity.
 Emaciated and elderly people, who have reduced
muscle mass have difficulty staying warm.
 Support: form the framwork that suports the
body and cradles soft organs
Maintenance of posture
 Skeletal muscles maintain posture, stabilize the
joints and support the viscera.
 Skeletal muscles have muscle tone (remain partly
contracted), which helps maintain body posture.
 Ongoing signals from the nervous system to the
muscle cells help maintain tone and readiness for
physical activity

Postural muscles of the head, neck and trunk are
working even when you think you are relaxed.
 The head, in particular is constantly being held at
the atlanto-occipital joint up by the muscles of the
neck.
 When you start to get drowsy, these muscles will
relax and your head nods forward.

 Protection: provide a protective case
for the brain, spinal chord, and vital
organs
 Mineral storage-reservoir for minerals
especially calcium and phosphorus
 Blood cell formation: hematopoiesis
occurs within the marrow cavities of
bones
Muscles
 skeletal muscles will not contract unless
stimulated by neurons
 smooth & cardiac muscle will contract
without nervous stimulation but their
contraction can be influenced by the
nervous system.
Types of muscle
 skeletal:
 attached to bones &
moves skeleton
 also called striated
muscle (because of
its appearance under
the microscope, as
shown in the photo
to the left)
 voluntary muscle
Skeletal muscle
(striated muscle)
Types of muscle
Smooth
muscle
 smooth
 involuntary muscle
 muscle of the viscera
(e.g., in walls of
blood vessels,
intestine, & other
'hollow' structures
and organs in the
body)
Types of muscle
 cardiac


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
muscle of the heart
Involuntary
Myofibrils in the two
interlocking muscle cells
are firmly anchored to the
membrane at the
intercalated disc.
Because their myofibrils
are essentially locked
together, the two muscle
cells can "pull together"
with maximum efficiency.
Cardiac muscle
Muscle attachments
 Tendons: are dense connective tissue
that attaches the muscle to bone.
 When
a muscle contracts, it shortens and puts
tension on the tendon andthe bone.
 The muscle tension causes movement of the
bone at a synovial joint.
 Belly:
 the fleshy thick part of the muscle. Also called
the gaster.
 Origin
 The less moveable attachment of the muscle
 At the girdles and appendages the most proximal
muscle attachment is the origin.
 Insertion
 The more moveable bony attachment of the
muscle is called the insertion.
 In muscles associated with girdles and
appendages the more distal attachment is the
insertion.
Muscle Groups based on their actions
 Synergistic:
 Muscle
groups that contract together to
accomplish a particular movement.
 large movements of the body require
several synergistic muscles to accomplish
the task.
 Muscles that are primarily responsible for a
movement are called prime movers.
Muscle Groups based on their actions
 Antagonistic:
 muscles that have opposing actions and
are located on opposite sides of a joint
 are needed because the fibers in a
contracted muscle are shortened and need
to be elongated (stretched) before they can
cause movement via contraction again.
Structures of the skeletal muscles
Skeletal muscle
 Attached to bone by tendons composed of
connective tissue
 The connective tissue surrounds the entire
muscle and is called epimysium
 Each muscle is surrounded by a connective
tissue sheath called the epimysium.
 Fascia, connective tissue outside the
epimysium, surrounds and separates the
muscles.
 Portions of the epimysium project inward to
divide the muscle into compartments.
 Each compartment contains a bundle of
muscle fibers.
 Generally, an artery and at
least one vein accompany
each nerve that penetrates
the epimysium of a
skeletal muscle.
 Branches of the nerve and
blood vessels follow the
connective tissue
components of the muscle
of a nerve cell and with
one or more capillary
skeletal muscle
 Skeletal muscles consist of many bundles called
fascicles which are surrounded by connective tissue
called Perimysium
 Each fascicles is composed of numerous muscle
fibers (or muscle cells)
 The fascicles are surrounded by connective tissue
called endomysium
Muscle cell
 The cell plasma
membrane of a muscle
cell is called the
sarcolemma,



maintains a membrane
potential.
Forms a physical barrier
against the external
environment
Mediates signals
between the exterior and
the muscle cell
 impulses travel along muscle cell
membrane (sarcolemma)
 the 'function' of impulses in muscle cells
is to bring about contraction.
 Sarcoplasm
 Specialized cytoplasm of a muscle cell
 Contains subcellular elements an the Golgi
apparatus
 Abundant with myofibrils
 Has a modified endoplasmic reticulum
known as the sarcoplasmic reticulum (SR)
 Also has myoglobin and mitochondria
 Transverse tubules (t-
tubules)
Extends through the
sarcolemma, through
the muscle cell to the
opposite side
sarcolemma
 Allows impulses to
penetrate the cell and
activate the SR
(sarcoplasmic reticulum)
 2 tubules are in each
sarcomere

 Sarcoplasmic
reticulum
A form of
endoplasmic
reticulum
 Forms a network
around the myofibrils
 Stores and provides
the Ca2+ that is
required for muscle
contraction

 Myofibrils
 Contractile units of the muscle cell
 In an ordered arrangement of longitudinal
myofilaments
 Myofilaments are thick (myosin) or thin
filaments (actin)
Muscle striations
 The sarcomeres are what give skeletal and cardiac
muscles their striated appearance.
 A sarcomere is defined as the segment between two
neighboring Z-lines (or Z-discs, or Z bodies).
 Sarcomere’s line up end to end and work together
for muscle contraction
Muscle striations
 Surrounding the Z-line is the region of the I-band (for
isotropic)

Area of thinner (lighter) filaments
 A-band (for anisotropic)

Area of darker filaments
 Within the A-band is
a paler region called
the H-band (from
the German "Heller",
bright)..
 Finally, inside the Hband is a thin M-line
(from the German
"Mittel", middle of
the sarcomere).
Myofibrils
 Composed of 2 types of
myofilaments


Thick-myosin
Thin-actin
 Arranged in a very
regular, précis pattern
 Thick myofilaments are
usually surrounded by 6
thin myofilaments
 Anchoring structure is
nebulin for the actin and
titin for the myosin
 http://highered.mcgraw-
hill.com/sites/0072495855/student_view0/chapter10/animation__sarco
mere_contraction.html
Myosin (thick filament)
 Mysoin head
 Has ATP binding
sites in which ATP is
housed
 Has actin binding
sites which fit
molecules of ACTIN
 Has a hinge at the
point where it leaves
the core of the thick
filament, it swivels
and actually causes
muscle contraction
Actin (thin filament)
 Composed of 3 types of protein: Actin,
troponin, and tropomyosins wrapped around
each other
 http://highered.mcgraw-
hill.com/sites/0072495855/student_view
0/chapter10/animation__breakdown_of_
atp_and_crossbridge_movement_during_muscle_contr
action.html
 DVD
Nerve-muscle connection
 The nervous system 'communicates' with
muscle via neuromuscular junctions.
chemical transmitter is released from vesicles
(each of which contains 5,000 - 10,000 molecules
of acetylcholine) and diffuses across the
neuromuscular cleft,
 the transmitter molecules fill receptor sites in the
membrane of the muscle & increase membrane
permeability to sodium,
 sodium then diffuses in & the membrane potential
becomes less negative,
 if the threshold potential is reached, an action
potential occurs, an impulse travels along the
muscle cell membrane, and the muscle contracts.

Steps in contraction of a muscle
1. Impulse is transferred from a neuron to the
sarcolemma of a muscle cell
2. Impulse travels along the sarcolemma and
travels down the T-tubules into the
sarcoplasmic reticulum
3. impulse travels along the sarcoplasmic
reticulum, opening the calcium gates in the
membrane of the SR and allowing the
calcium to diffuse out of the SR and among
the myofilaments
Muscle contraction
Steps in contraction
4. Calcium fills the binding sites in the Troponin
molecules which then alters the shape and
position of the troponin and causes
movement of the attached Troopomyosin
molecule
5. Movement of the tropomyosin permits the
myosin head to contact ACTIN
6. Contact with actin causes the myosin head
to swivel
8. During the swivel, the MYOSIN HEAD is
firmly attached to ACTIN. So, when the HEAD
swivels it pulls the ACTIN (and, therefore, the
entire thin myofilament) forward.. Many
MYOSIN HEADS are swiveling
simultaneously, or nearly so, and their
collective efforts are enough to pull the entire
thin myofilament).
8. At the end of the swivel, ATP fits into the binding site
on the cross-bridge & this breaks the bond between
the cross-bridge (myosin) and actin. The MYOSIN
HEAD then swivels back. As it swivels back, the ATP
breaks down to ADP & P and the cross-bridge again
binds to an actin molecule.
9. As a result, the HEAD is once again bound firmly to
ACTIN. However, because the HEAD was not
attached to actin when it swiveled back, the HEAD
will bind to a different ACTIN molecule (i.e., one
further back on the thin myofilaments). Once the
HEAD is attached to ACTIN, the cross-bridge again
swivels,
 youtube.com
Muscle fatigue
 Under most circumstances, calcium is the "switch"
that turns muscle "on and off" (contracting and
relaxing).
 When a muscle is used for an extended period, ATP
supplies can diminish.
 As ATP concentration in a muscle declines, the
MYOSIN HEADS remain bound to actin and can no
longer swivel.
 This decline in ATP levels in a muscle causes
MUSCLE FATIGUE. Even though calcium is still
present (and a nervous impulse is being transmitted
to the muscle), contraction (or at least a strong
contraction) is not possible.
Types of muscle contractions
 Isotonic- Contraction leads to shortening of the
muscle.


involves movement against resistance and is a dynamic
contraction.
Lifting free weights is primarily isotonic. and biceps curls are
isotonic.
 Isometric- is a static contraction in which the muscle
remains the same length.


There is no shortening of the muscle
Usually performed against a resistance that can’t be moved
Twitch
 The response of a skeletal muscle to a single
stimulation (or action potential)
 Steps
latent period - no change in length; time during
which impulse is traveling along sarcolemma &
down t-tubules to sarcoplasmic reticulum, calcium
is being released, (muscle cannot contract
instantaneously!)
 contraction period - tension increases (crossbridges are swivelling)
 relaxation period - muscle relaxes (tension
decreases) & tends to return to its original length

Muscle fibers exercise and “twitch
 Exercise may increase muscle fiber size, but
muscle fiber number generally remains
constant.
 Skeletal muscles take up about 40% of the
body's mass, or weight.
 They also use a great deal of oxygen and
nutrients from the blood supply.
 Skeletal muscles have two types of muscle
fibers: fast-twitch and slow-twitch.
Slow twitch
 Slow twitch
 also called "red," muscle fibers
 contract more slowly, have better blood
supplies, operate aerobically, and do not
fatigue as easily.
 slow muscle fibers are used in movements
which are sustained such as maintaining
posture
 Other aerobic exercises include activities that
are prolonged and require constant energy.
 Long distance running and cycling are
examples of aerobic exercise.
 In aerobic exercise, the muscle cell requires
the same amount of oxygen that the body
supplies.
 The oxygen debt is slashed and lactic acid is
not formed
Anaerobic exercise uses fast-twitch
fibers.
 Fast twitch
 also called "white," muscle fibers
 contract rapidly, have poor blood supply,
operate anaerobically
 fatigue rapidly.
 Such exercise includes activities that
are fleeting and require brief highenergy expenditure.
 Weightlifting, sprinting, and push-ups
are examples of anaerobic exercise.
 Because all cells require oxygen to produce
energy, anaerobic exercise depletes oxygen
reserves in the muscle cells quickly. The
result is an oxygen debt.
 To repay the debt, humans breathe deeply
and rapidly, which restores the oxygen level.
 Anaerobic exercise creates excess lactic acid
(a waste product). By increasing oxygen
intake, the liver cells can convert the excess
lactic acid into glucose, the primary food
molecule used in cellular metabolism.
Disorders of the muscle
Strains and sprains
 Sprain. A sprain is a stretching or tearing
of ligaments.

Common locations for sprains are your ankles
and knees.
 Strain. A strain is a stretching or tearing of
muscle or tendon.

People commonly call strains "pulled"
muscles. Hamstring and back injuries are
among the most common strains.
Treatment for sprains and strains
depends on the severity

Sprains can cause rapid swelling. Generally, the greater the pain and
swelling, the more severe the injury.
 Mild.
• ligament stretches excessively or tears slightly.
• The area is somewhat painful, especially with movement.
• You can put weight on the joint.
 Moderate.
• The fibers in the ligament tear, but they don't rupture completely.
• The joint is tender, painful and difficult to move.
• The area is swollen and may be discolored from bleeding in the
area.
• You may feel unsteady when you try to bear weight on your joint.
 Severe.
• One or more ligaments tear completely.
• The area is painful.
• You can't move your joint normally or put weight on it. If the
sprain occurs in the ankle or knee, when you try to walk, your leg
feels as if it will give way.
• The joint becomes very swollen and also can be discolored.
• The injury may be difficult to distinguish from a fracture or
dislocation, which requires medical care.
 Strains
As with sprains, signs and symptoms of
strains will vary depending on the severity of
the injury.
 Common signs and symptoms include:
Pain
 Stiffness
 Swelling
 Bruising

 With a severe strain, the muscle or tendon is
torn apart or ruptured.

There may be significant bleeding, swelling and
bruising around the muscle,.
 Properly warming up before vigorous
physical activity loosens your muscles
and increases joint range of motion,
making the muscles less tight and less
prone to trauma and tears.
Poliomyelitis
 Poliomyelitis is a disease caused by
infection with the poliovirus.
 The
virus spreads by direct person-toperson contact, by contact with infected
mucus or phlegm from the nose or mouth,
or by contact with infected feces.
 The virus enters through the mouth and nose,
multiplies in the throat and intestinal tract,
and then is absorbed and spread through the
blood and lymph system.
 The time from being infected with the virus to
developing symptoms of disease (incubation)
ranges from 5 - 35 days (average 7 - 14
days)
 In about 1% of cases the virus enters
the central nervous system ,
preferentially infecting and destroying
motor neurons, leading to muscle
weakness and acute flaccid paralysis.
 Different types of paralysis may occur,
depending on the nerves involved
Three patterns of polio
 SUBCLINICAL INFECTION symptoms last up
to 72 hours
General discomfort or uneasiness (malaise)
 Headache
 Red throat
 Slight fever
 Sore throat
 Vomiting

NONPARALYTIC POLIOMYELITIS
(lsymptoms last 1-2 weeks)
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Back pain or backache
Diarrhea
Excessive tiredness, fatigue
Headache
Irritability
Leg pain (calf muscles)
Moderate fever
Muscle stiffness
Muscle tenderness and spasm in any area of the body
Neck pain and stiffness
Pain in front part of neck
Pain or stiffness of the back, arms, legs, abdomen
Skin rash or lesion with pain
Vomiting
PARALYTIC POLIOMYELITIS
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Abnormal sensations (but not loss of sensation) in an area
Bloated feeling in abdomen
Breathing difficulty
Constipation
Difficulty beginning to urinate
Drooling
Fever 5 - 7 days before other symptoms
Headache
Irritability or poor temper control
Muscle contractions or muscle spasms in the calf, neck, or back
Muscle pain
Muscle weakness, asymmetrical (only on one side or worse on one side)

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
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
Location depends on where the spinal cord is affected
Progresses to paralysis
Rapid onset
Sensitivity to touch; mild touch may be painful
Stiff neck and back
Swallowing difficulty
Treatment
 Vaccine to prevent the disease
 The goal of treatment for the disease is
to control symptoms while the infection
runs its course.
 People with severe cases may need
lifesaving measures, especially
breathing help.
 Which US president contracted polio
before he was in office?
 FDR
 Does muscle function return completely
with CNS polio?
Abbreviated polio timeline
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1941 - The United States enters World War II. Most of the best medical
researchers, including Jonas Salk , either enter the military or work on
military-related projects.
1945 - World War II ends. Large epidemics of polio in the U.S. occur
immediately after the war with an average of more than 20,000 cases a
year from 1945 to 1949.
1947 - Jonas Salk accepts a position in Pittsburgh at the new medical
laboratory funded by the Sarah Mellon Scientific Foundation..
1952 - There are 58, 000 cases of polio in the United States, the most ever.
Early versions of the Salk vaccine , using killed polio virus, are successful
with small samples of patients at the Watson Home for Crippled Children
and the Polk State School, a Pennsylvania facility for individuals with
mental retardation.
1953 - Amid continued "polio hysteria," there are 35, 000 cases of polio in
the United States..
1955 - A nationwide vaccination program is quickly started.
1957 - After a mass immunization campaign promoted by the March of
Dines, there are only about 5600 cases of polio in the United States.
1958 and 1959 - Field trials prove the Sabin oral vaccine, which uses live,
attenuated (weakened) virus, to be effective.
1962 - The Salk vaccine is replaced by the Sabin oral vaccine, which is not
only superior in terms of ease of administration, but also provides longerlasting immunization.
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1964 - Only 121 cases of polio are reported nationally.
1977 - The National Health Interview Survey reports that there are 254,000
persons living in the United States who had been paralyzed by polio. Some
estimates place the number at more than 600, 000.
1979 - The last indigenous transmission of wild polio virus occurs in the
U.S. All future cases are either imported or vaccine-related.
1981 - Time Magazine reports that many polio survivors are experiencing
late effects of the disease.
1988 - With approximately 350, 000 cases of polio occurring worldwide, the
World Health Organization passes a resolution to eradicate polio by the
year 2000.
1993 - The total number of reported polio cases worldwide falls to about
100, 000. Most of these cases occur in Asia and Africa.
1994 - China launches its first National Immunization Days, immunizing 80
million children! The entire Western Hemisphere is certified as "polio
free."
1995 - India follows China's lead and organizes its first National
Immunization Days. More than 87 million children are immunized!
1999 - More than 450 million children are vaccinated, including nearly 147
million in India. In the 11 years since the World Health Assembly Initiative,
the number of reported cases worldwide has fallen to approximately 7 000.
 2000 - Wars, natural disasters, and poverty in
about 30 Asian and African nations prevent the
complete eradication of polio. There is even a
polio outbreak in Haiti and the Dominican
Republic, which along with the rest of the western
hemisphere had been polio free since the early
1990s. A new target date for worldwide
eradication of 2005 is now set by the Global Polio
Eradication Initiative.
 2001 - 575 million children are vaccinated in 94
countries.
 2005 - Polio spreads from Nigeria to the Sudan, with 105
confirmed cases. This latest outbreak illustrates "the high
risk posed to polio-free areas by the continuing epidemic in
west and central Africa
Muscular Dystrophies
 Muscular dystrophy is a group of
disorders that are characterized by
progressive skeletal muscle weakness,
defects in muscle proteins, and the
death of muscle cells and tissue
Causes
 Many diseases called muscular dystrophies
(MD) are inherited disorders, such as:
 Becker’s muscular dystrophy
 Duchenne muscular dystrophy
 Emery-Dreifuss muscular dystrophy
 Facioscapulhumeral muscular dystrophy
 Limb-girdle muscular dystrophy
 Myotonia congenita
 Myotonic dystrophy
 Signs may include:
 Scoliosis
 Joint contractures
 Low muscle tone (hypotonia)
 Some types of muscular dystrophy involve
the heart muscle, causing cardiomyopathy
or disturbed heart rhythm arrhythmias
Prognosis
 The severity of disability depends on the type
of muscular dystrophy. All types of muscular
dystrophy slowly get worse, but how fast this
happens varies widely.
 Some types of muscular dystrophy, such as
Duchenne muscular dystrophy, are deadly.
Other types cause little disability and people
with them have a normal lifespan.
Prevention
 Genetic counseling is advised when
there is a family history of muscular
dystrophy
Myastenia gravis
 Myasthenia gravis is
a chronic
autoimmune
neuromuscular
disease
characterized by
varying degrees of
weakness of the
skeletal (voluntary)
muscles of the body
 In myasthenia gravis, antibodies block,
alter, or destroy the receptors for
acetylcholine at the neuromuscular
junction which prevents the muscle
contraction from occurring.
 The hallmark of myasthenia gravis is muscle
weakness that increases during periods of
activity and improves after periods of rest.
 Certain muscles such as those that control
eye and eyelid movement, facial expression,
chewing, talking, and swallowing are often,
but not always, involved in the disorder.
 The muscles that control breathing and neck
and limb movements may also be affected.
 The thymus gland may play a role in
MG
 Scientists believe the thymus gland may
give incorrect instructions to developing
immune cells, ultimately resulting in
autoimmunity and the production of the
acetylcholine receptor antibodies,
thereby setting the stage for the attack
on neuromuscular transmission.
 A special blood test can detect the
presence of immune molecules or
acetylcholine receptor antibodies.
 Most patients with myasthenia gravis
have abnormally elevated levels of
these antibodies. However, antibodies
may not be detected in patients with
only ocular forms of the disease
Treatment
 several therapies available to help reduce
and improve muscle weakness.
Medications: anticholinesterase agents such as
neostigmine and pyridostigmine, which help
improve neuromuscular transmission and increase
muscle strength.
 Immunosuppressive drugs: prednisone,
cyclosporine, and azathioprine may also be used.

• These medications improve muscle strength by
suppressing the production of abnormal antibodies.
Treatments
 Thymectomy, the surgical removal of the thymus
gland (which often is abnormal in myasthenia gravis
patients),

reduces symptoms in more than 70 percent of patients
without thymoma and may cure some individuals, possibly
by re-balancing the immune system.
 Other therapies


plasmapheresis, a procedure in which abnormal antibodies
are removed from the blood
high-dose intravenous immune globulin, which temporarily
modifies the immune system and provides the body with
normal antibodies from donated blood
The MUSCLES
Types of joint movements:
 Flexion: is the bending at the joint.
 Extension: the opposite of flexion. It is straightening of the joint
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to a 180º angle.
The joint angle is increased to 180º. Extension returns a body
part to the anatomical
position.
Hyperextension: occurs when a part of the body is extended
beyond the anatomical position so that the joint angle is greater
than 180º.
Abduction: movement of a body part away from the axis of the
body, away from the midsagittal plane in a lateral direction.
Adduction: The opposite of abduction. it moves a body part
towards the main
axis of the body.
Rotation: is a circular motion that occurs in joints that have a
rounded or oval articular surface that corresponds to a
depression in another bone..
Muscles are named by:
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Shape: rhomboideus, triceps, biceps
Location: pectoralis, brachia, intercostal
Attachment: zygomaticus, temporalis
Size: maximus, longus, brevis, minimus
Orientation of fibers: rectus (straight), transverse,
oblique
 Relative position: lateral, medial, internal, external
 Function: adductor, flexor, extensor, pronator,
levator
Muscle table
Head and Neck
Muscle
Origin
Insertion
Function
Frontalis
Galea aponeurotica
Mastoid process
Wrinkles eyebrow
Orbicularis oris
Maxilla and mandible
Skin around the lips
Puckers the lips
Orbicularis oculi
Frontal bone; medial papebral
ligament; lacrimal bone
Lateral papebra raphe
Closes the eyelid
Occipitofrontalis
2 occipital bellies and 2 frontal
bellies
Galea aponeurotica
Raises eyebrows, wrinkles forehead
Zygomaticus major
Anterior of zygomatic process
Modiolus of mouth
draws angle of mouth upward and
laterally
Masseter
Zygomatic arch and maxilla
Coronoid process and ramus of
mandible
Elevation (as in closing of the mouth) and
retraction of mandible
Temporalis
Temporal lines on the parietal
bone of the skull.
Coronoid process on the
mandible
Elevation and retraction of the mandible
Sternocleidomastoid
Manubrium sterni, medial
portion of the clavicle,
Mastoid process of the
temporal bone, superior nuchal
line
Acting alone tilts head to its own side and
rotates it so the face is turned towards the
opposite side.
Acting together, flexes the neck, raises
the sternum and assists in forced
inspiration
Trapezius
external occipital protuberance,
along the medial sides of the
superior nuchal line, gamentum
nuchae (surrounding the
cervical spinous processes),
posterior, lateral 1/3 of
clavicle, acromion, superior
spine of scapula
elevates scapula , upward rotation of the
scapula (upper fibers), downward rotation
of the scapula (lower fibers), retracts
scapula
Muscles of the upper extremities
Muscles
Origin
Insertion
Action
Pectoralis Major
Clavicular head: anterior surface of
the medial half of the clavicle
Sternocostal head: anterior surface of
the sternum, the superior six costal
cartilages and the aponeurosis of the
external obliquie muscle
Intertibercular groove of the
humerus.
Clavicular head: flexes the humerus
Sternocostal head: extends the humerus
As a whole, adducts and medially rotates the
humerus It also draws the scapula anteriorly and
inferiorly.
Latissimus dorsi
spinous processes of thoracic T7T12, thoracolumbar fascia iliac crest
and inferior 3 or 4 ribs, inferior angle
of scapula
floor of the intertubercular groove of
the humerus
adducts, extends and internally rotates the arm
Deltoid
adducts, extends and internally
rotates the arm
Deltoid tuberosity of humerus
Shoulder abduction, flexion, and extension
Teres major
posterior aspect of the inferior angle
of the scapula
medial lip of the intertubercular
sulcus of the humerus
Internal rotation (medial rotation) of the humerus
Biceps brachii
Short head: coracoid process of the
scapula. long head: superglenoid
tubercle
Racial tuberosity and bicipittal
aponeurosis into deep fascia on
medial part of forearm
Flexes elbow and supinates forearm
Triceps brachii
long head: infraglenoid tubercle of
the scapula
lateral head: posterior humerus
medial head: posterior humerus
olecron process of ulna
Extends forearm, caput longum adducts shoulder
Brachialis
anterior surface of the humerus,
particularly the distal half
Coronoid process and the tuberosity
of the ulna
Flexion of the elbow joint
Brachioradialis
Lateral supracondylar ridge of the
humerus
Radial styloid process
Flexion of forearm
Palmaris longus
medial epicondyle of humerus
(common flexor tendon)
palmar aponeurosis
wrist flexor
Flexor carpi radialis
medial epicondyle of humerus
(common flexor tendon)
Bases of second and third
metacarpal bones
Flexion and abduction at wrist
Flexor digitorum superficialis
Median epicondyle of the
humerus (common flexor tendon)
as well as parts of the radius and
ulna.
phalanges
flexor of fingers (primarily at proximal
interphalangeal joints)
Extensor carpi radialis
lateral supracondylar ridge
2nd metacarpal
extensor at the wrist joint, abducts the hand
Extensor carpi radialis
lateral supracondylar ridge
2nd metacarpal
extensor at the wrist joint, abducts the
hand at the wrist
Extensor digitorum
lateral epicondyle (common
extensor tendon)
2nd and 3rd phalanges
extension of hand and fingers
Extensor digiti minimi
the anterior portion of the lateral
epicondyle of the humerus
(common extensor tendon)
extensor expansion, located at
the base of the proximal
phalanx of the finger on the
dorsal side
extends the little finger at all joints
Extensor carpi ulnaris
Common extensor tendon
(lateral epicondyle), ulna
5th metacarpal
extends and adducts the wrist
External oblique
Lower 8 costae
Crista iliaca, ligamentum
inguinale
Rotates torso
Internal oblique
Inguinal ligament, Iliac crest
and the Lumbodorsal fascia
Linea alba, Xiphoid process and
the inferior ribs.
Compresses abdomen and rotates
vertebral column.
Transverse abdominus
ribs and the iliac crest
inserts into the pubic tubercle
via the conjoint tendon, also
known as the falx inguinalis
compress the ribs and viscera, providing
thoracic and pelvic stability
Infraspinatus
infraspinous fossa of the scapula
middle facet of greater tubercle of
the humerus
Lateral rotation of arm and stabilizes humerus
Rectus abdominus
pubis
Costal cartilage of ribs 5-7,
xiphoid process of sternum
flexion of trunk/lumbar vertebrae
Serratus anterior
fleshy slips from the outer
surface of upper 8 or 9 ribs
costal aspect of medial margin
of the scapula
protract and stabilize scapula, assists in
upward rotation
Muscles of the Trunk
Thoracolumbar fascia
(aponeurosis)
The thoracolumbar fascia is an extensive
fascial sheet that splits into anterior and
posterior layers, thereby enclosing the deep
back muscles. It is thin and transparent where
it covers the thoracic parts of the deep muscles
but is thick and strong in the lumbar region.
The lumbar part of the thoracolumbar fascia,
extending between the 12th rib superiorly and
the iliac crest inferiorly, is a point of origin for
the internal oblique and transverse abdominal
muscles
Move the Lower extremities
Illiopsoas: Combination of 3
muscles: psoas major, psoas
minor, and illiacus
Inner surface of the upper iliac
fossa, T12-L4, superior pubic
ramus
Tendon of the lesser trochanter of
the femor to just below the lesser
trochanter on the posterior aspect
of the femur
Flexes the thigh at the hip, externally rotates
the femur
Sartorius
ASIS anterior superior iliac
spine
Upper medial surface of body
of tibia
Flexes the thigh and the calf at the hip and
knee, laterally rotates the thigh if flexed at
the hip
Gluteus maximus
1. outer rim of ilium
2. dorsal surface of sacrum and
coccyx
3. sacrotuberous ligament
IT bend
Gluteal tuberosity of femur
1. powerfully extends the hip
Laterally rotates the thigh
Upper fibers aid to abduct the thigh
Stabilizes a fully extended knee
Gluteus medius
Outer aspect of illium
Upper fascia(gluteal
aponeurosis
Superior aspect of greater
trochanter
Abduct and medially rotate the thigh
Stabilizes the pelvis and prevents free
limb from sagging during gait
Tensor fasciae latae
Anterior aspect of iliac crest
Anterior superior iliac spine
(ASIS)
Anterior aspect of iliotibilal
(IT) bond below greater
trochanter
Flexes the hip
Rotates and abducts a flexed thigh
Tens medially to support femur on the
tibia during standing
Adductor longus
Anterior surface of pubis, just
inferior to the pubic tubercle
Medial lip of linea aspera on
middle half of femur
Adducts the thigh at the hip
Flexes the thigh at the hip
May laterally rotate the thigh at the hip
Gracilis
Body of pubis and inferior
pubic ramus
Medial surface of proximal
tibia, inferior to tibial condyle
Adducts the thigh at the hip
Flexes the calf at the knee
Medially rotates tibia
Semimembranosus
Ischial tuberosity
Posterior medial aspect of
medial tibial condyle
Fibers join to form most of
obliquie popliteal ligament
(and medial meniscus
Flexes the calf at the knee
Extends the thigh at the hip
Medially rotates tibia
Pulls medial meniscus posterior during
flexion
semitendinosus
Ischial tuberosity
Medial aspect of tibial shaft
Extends the thigh at the hip
Flexes the calf at the knee
Medially rotates the tibia
Biceps femoris
Long head: ischial tuberosity
Short head: lateral lip of linea
aspera and the lateral
intermuscular septum
Head of fibula
Flexes the calf a the knee
Laterally rotates thigh if flexed at the
knee
Extends thigh at the hip
Rectus femoris
Anterior inferior iliac spine
(aIIs), lateral lip of linea
aspera, lateral intermuscular
septum
Common quadriceps tendon
into patella, tibial tuberosity via
patellar ligament
Extends the calf at the knee, flexes the
thigh at the hip
Vastus lateralis
Greater trochanter, lateral lip of
linea aspera
Common quadriceps tendon
into patella, tibial tuberosity via
Extends the calf at the kneed (may
abnormally displace the patella)
Vastus intermedium
Anterior lateral aspect of the
femoral shaft
Common quadriceps tendon
into patella, tibial tuberosity via
patellar ligament
Extends the calf at the knee
Vastus medialis
Intertrochanteric line of femur
Medial aspect of linea aspera
Common quadriceps tendon
into patella, tibial tuberosity via
patellar ligament
Extends the calf at the knee
Tibialis anterior
Lateral tibial condyle, proximal
2/3 of the anterolateral surface
of tibia, interosseaous
membrane, anterior
intermuscular septum and
crural fascia
Medial and plantar surface of
base of first metatarsal, medial
and plantar surface of the
cuneiform
Powerfully dorsiflexes the foot , inverts
and adducts the foot
Gastrocnemius
Medial head just above the
medial condyle of the femur
Lateral head just above lateral
condyle of femur
Calcaneus via lateral portion of
calcaneal tendon
Plantar flexes the foot at the ankle, flexes
the calf at the knee when not weight
bearing, stabilizes ankle and knee when
standing
Soleaus
Upper fibula, soleal line of
tibiae
Calcaneus via cataneal tendon
Plantar flexes the foot
Peroneus longus
Head of the fibula, proximal
2/3 of later fibula, adjacent
intermuscular septum
Plantar surface of cuboid, base
of first and second metatarsal,
plantar surface of medial
cuneiform
Evers and abducts the foot, Weakley
plantar flexes the foot
Peroneus brevis
Distal 2/3 of lateral fibula,
posterior and anterior
intermuscular septum
Tuberosity on lateral aspect of
base of 5th metatarsal
Evers and abducts the foot, Weakley
plantar flexes the foot