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 lengthExtensibility-stretches when pulledElasticity-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 involuntary muscle muscle of the viscera

(e.g., in walls of blood vessels, intestine, & other 'hollow' structures and organs in the body)

Smooth muscle

Types of muscle cardiac

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

Attached to bone by tendons composed of connective tissue

The connective tissue surrounds the entire muscle and is called epimysium

Skeletal muscle

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 H-band 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__sarcomere_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_view0/chapter10/animation__breakdown_of_atp_and_cross-bridge_movement_during_muscle_contraction.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,

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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 (cross-bridges 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 high-energy 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.

StrainsAs 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-to-

person 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)

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

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)

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 diseaseThe 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 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 longer-lasting immunization.

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 congenitaMyotonic 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

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:

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), spinous processes of C1-T12

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 clavicleSternocostal 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 humerusSternocostal head: extends the humerusAs a whole, adducts and medially rotates the humerus It also draws the scapula anteriorly and inferiorly.

Latissimus dorsi spinous processes of thoracic T7-T12, 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 humerusmedial 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 at the wrist

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

Muscles of the Trunk

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

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 ilium2. dorsal surface of sacrum and coccyx3. sacrotuberous ligament

IT bend Gluteal tuberosity of femur

1. powerfully extends the hipLaterally rotates the thighUpper fibers aid to abduct the thighStabilizes a fully extended knee

Gluteus medius Outer aspect of illiumUpper fascia(gluteal aponeurosis

Superior aspect of greater trochanter

Abduct and medially rotate the thighStabilizes the pelvis and prevents free limb from sagging during gait

Tensor fasciae latae Anterior aspect of iliac crestAnterior superior iliac spine (ASIS)

Anterior aspect of iliotibilal (IT) bond below greater trochanter

Flexes the hipRotates and abducts a flexed thighTens 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 hipFlexes the thigh at the hipMay 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 hipFlexes the calf at the kneeMedially rotates tibia

Semimembranosus Ischial tuberosity Posterior medial aspect of medial tibial condyleFibers join to form most of obliquie popliteal ligament (and medial meniscus

Flexes the calf at the kneeExtends the thigh at the hipMedially rotates tibiaPulls medial meniscus posterior during flexion

semitendinosus Ischial tuberosity Medial aspect of tibial shaft Extends the thigh at the hipFlexes the calf at the kneeMedially rotates the tibia

Biceps femoris Long head: ischial tuberosityShort head: lateral lip of linea aspera and the lateral intermuscular septum

Head of fibula Flexes the calf a the kneeLaterally rotates thigh if flexed at the kneeExtends 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 patellar ligament

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 femurMedial 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 femurLateral 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