Anatomy and Physiology - Muscles



Introduction- 650 muscles in body (40% body weight)Functions:A. Voluntary movement including speech and breathingB. In addition to external motion of the arms and legs, the muscular system also moves things inside the body( Internal motion includes the movement of the digestive system, the cardiovascular system, and the respiratory system)C. PostureD. Heat production* Different types of muscles allow for both external and internal movement.II. OverviewExcitability-capacity to generate electrical impulsesContractility- capacity to shorten in lengthA. Muscle is a general term for all contractile tissueB. The contractile property of muscle tissue allows it to:1. Become short and thick in response to a nerve impulse2. Relax once the nerve impulse is removedC. This alternating contraction and relaxation causes movementIII. 3 Types of muscles1. Skeletal musclelefttopOrigin- attachment to stationary end of muscle. (Ceps)Belly- thicker , middle region of muscle Insertion- attachment end of muscle(tail) Attaches to the skeletonTendons – Fibrous tissues that attach skeletal muscle to bones (attach to periosteum of bone)? Aponeurosis – a broad sheet of connective tissue that attaches certain muscles to bones and soft tissues Tendon of orgins: Called the “ceps” Attach to less movable structures (biceps, triceps, quadriceps) Tendon of insertion: The tail of the muscle Attachment to the more moveable structure ii. Ligaments attach bone to boneb. Is under conscious control (is voluntary muscle)c. Composed of fibers with a striped appearance (therefore called striated muscle) Functions: Performs external movements of the body (running, lifting, etc.) Maintains body posture Helps with heat generationFascia of muscle-A. Epimysium – fibrous connective tissue sheath that encloses the entire belly of the muscleB. Perimysium- loose connective tissue sheath that surrounds only a bundle (fascile) of muscle fibersC. Endomysium-loose connective tissue sheath that surrounds each individual muscle fiber.Blood supply and nerve supply (innervation) of muscle:A. blood vessels and nerve fibers in the connective tissue fascia of the muscle branch to the individual muscle fibersB. Innervation of muscle fibers – 1. Proprioceptors- sensory neurons that supply muscles 2. Somatic neurons- motor neurons that permit voluntary excitation of skeletal muscle fibers. Each somatic motor neuron innervates (supplies) several hundred skeletal muscle fibers (called a microunit)2. Smooth muscle Found within internal organs, blood vessels, and airways (also called visceral muscle) Is not under conscious control (is involuntary muscle) Does not have a striped appearance Functions include: The internal movement of food in the digestive organs (peristalsis) Facilitating blood distribution by changing the diameter of blood vessels (vasoconstriction and vasodilation) Facilitating the movement of air by changing the diameter of the airways found in the lungs3. Cardiac Found only in the heart (makes up the heart walls) Is not under conscious control (is involuntary) Is striated Contraction of cardiac muscle causes your heart to beat Clinical Application – Muscle tone Normally, all muscles exhibit muscle tone (tonus), which is the partial contraction of a muscle with resistance to stretching Increased muscle tone (hypertrophy) – seen in athletes Loss of muscle tone (atrophy) is seen in patients who do not use their musclesa. Atrophied muscle tissue may become flaccid (soft and flabby)b. Examples of situations where atrophy may develop:i. In a bedridden patientii. In a patient who’s arm or leg has been in a cast for several weeksc. One reason hospitalized patients are encouraged to get out of bed ASAP is to prevent atrophyWhile skeletal muscle can regenerate from damage, extensive damage results in scarring Pathology Connection – myopathy, strains, and tears1. Myopathy- A general term for muscle disease or disorder Causes can include: Injury, Genetics, Nervous system disorders, Medication, Cellular abnormalities Symptoms: Weakness, Cramping, Stiffness, Spasm Treatment depends on the cause2. Strains and tears Cause: Strains are caused by overstretching the tendons or muscles Severity of injury can range from mild to severe ? Mild - pulled muscle (a slight overstretch of the muscle) ? Severe - complete muscle tear or complete tendon ruptureInjuries can be acute or chronic? Acute – usually resulting from trauma? Chronic – usually resulting from overuse or disease Signs and symptoms – vary depending on severity of injury Mild strain (no tear of muscle or tendon fibers) – mild pain and possibly stiffness Moderate strain (some tearing of muscle or tendon fibers) – more intense pain, bruising, obviousweaknessSevere strain (complete tear of muscle or tendon) – severe pain, swelling, extensive bruising, and oftenComplete loss of movement Diagnosis: Medical history, Physical examination, Imaging (MRI, X-ray, ultrasound) Treatment – varies with severity of injury Strains? In the first 72 hours: PRICE therapy- Protection- Rest- Ice- Compression- Elevation? After the first 72 hours- Gradual increase in activity and/or physical therapy- Application of heat? Pain relievers (like acetaminophen or ibuprofen)**Strains are often slow to healTears – treated surgically at the time of diagnosis ? Skeletal muscle and dense regular connective tissue have only moderate ability to repair themselvesTendinitis/Tendinosis Cause: A degenerative disease leading to breakdown and scarring of tendonsAppears to be caused by the failure of tendons to repair themselves after injuryCommonly seen related to overuse/repetitive motion or untreated acute injuries Risk factors Some tendons are more prone to tendinosis:- Rotator cuff- Achilles tendon- Tibialis posterior tendon- Tendons of lateral elbowOther risk factors : Age, Gender, Skeletal anatomy, Types of occupational equipment used, Systemic disease (like diabetes mellitus, because of poor wound healing)b. Signs and symptoms include pain, tenderness, and stiffnessc. Treatment: PRICE Physical therapy Steroids (short term only) Lasers Ultrasound and extracorporeal shock wave therapy Surgery is a last resort** Unfortunately, treatments are not very effective, and prognosis is not as good as for acute tendon injuries Shin Splints A common inflammatory injury of the lower leg extensor muscles and surrounding tissues Related to running Can be treated with rest, reduction of exercise intensity, ice, anti-inflammatory medication, and modification of footwear. Amazing Body Factsa. Muscles make up almost half the weight of the entire bodyb. The size of your muscles depends on how much you use them and how big you arec. The little muscles around the eye can contract 100,000 times a dayd. Individual muscle cells can be up to 12 inches (30 cm) in lengthe. At about age 40, the number and diameter of muscle fibers begin to decrease By age 80, 50% of the muscle mass may be lost Exercise helps to decrease this loss Muscle tears – sometimes they are beneficial When you exercise a muscle group, it develops small tears The healing process leads to increased muscle growth and mass Process works best if you give the muscle group a rest after exercise Major skeletal muscle groups/ skeletal muscles of specific regions Facial skeletal muscles Muscle Location Functiona. Orbicularis oculi Encircles eye Closes eyelidb. Masseter Jaw or mandible Closes jawc. Sternocleidomastoid From sternum (breast bone) Flexes neck forward and rotates head and clavicle (collar bone) to temporal bone (lower sides of skull)***See facial Muscle work sheet. Anterior and posterior trunk skeletal muscles Muscle Location Functiona. Pectoralis major Chest Flexes the chest areab. Intercostals Between ribs Lifts and lowers the ribs to assist breathingc. Diaphragm Floor of thoracic cavity Primary muscle of normal breathing Diaphram a unique muscle that is under both voluntary and involuntary control:? You do not need to think every time you breathe? However, you can voluntarily change the way your breathe Skeletal muscles of the arm and shoulder Muscle Location Functiona. Biceps brachii Anterior upper arm Flexes arm (flexes elbow)b. Triceps brachii Posterior upper arm Extends arm (extends elbow)c. Deltoid Shoulder Moves arms (at the shoulder); also an IM injection site Skeletal muscles of the legs Muscle Location Functiona. Gluteus maximus Buttocks Abducts and rotates thigh; IM injection siteb. Quadriceps Anterior portion of thigh Extends lower leg (extends knee)c. Vastus lateralis Upper outer thigh Extends knee (part of quadriceps)d. Hamstrings Posterior portion of thigh Flexes lower leg (flexes knee)e. Tibialis anterior Front of lower leg Dorsiflexes footf. Gastrocnemius Main muscle of calf Flexes foot (plantarflexes foot) Learning Hint – Muscle namesMuscles can be named by several criteria1.Muscle location Example – Biceps brachii; brachii = arm2.Number of origins Example – Biceps brachii; biceps = two heads3.Action Example – Adductor longus; adducts the thigh4.Size- Example - Gluteus maximus; maximus = biggest5. Location of attachments Example – brachioradialis; radialis refers to the radius6. Shape Example – Deltoid is a triangular muscle; delta =triangle7. Combination- Example – Pectoralis major; pectoral = shoulder,major = big Pathology Connection – Fibromyalgia syndromeMyalgia – pain or tenderness in a muscleFibromyalgia syndrome – a chronic pain syndromeCharacterized by: Pain of three months duration Bilateral tenderness Fatigue Sleep disorders Depression Anxiety Exercise intolerance Epidemiology – more common in women Cause – unknownThere does not seem to be any inflammation involved May be caused by hyperactive stress response May also be caused by sensory or neurological problem leading to increased sensitivity to pain DiagnosisPain in 11 of 18 designated tender points for fibromyalgiaTreatment There is no definitive treatment Symptoms can be managed with antidepressants, antiepileptics, exercise, and/or pain relievers However, symptom management is often inadequate at relieving pain completelySkeletal muscle movementContraction and relaxationa. Movement of the body is the result of contraction (shortening) of certain muscles while there is relaxation of othersb. Primary mover (or agonist) – the chief muscle causing a movement As the muscle contracts, it pulls the bone, causing movement Most muscles attach to at least two bones One bone is stationary, and one bone moves with muscle contraction ? Point of origin – the end of the muscle that is attached to the stationary bone ? Point of insertion – the muscle end attached to the moving bonec. Synergistic muscles assist the primary moverd. Antagonist muscles cause movement in the opposite direction of the agoniste. All movement is a result of contraction of primary movers and relaxation of opposing musclesMovement terminologya. Rotation describes circular movement that occurs around an axis Ex. – turning head from left to rightb. Abduction means to move away from the midline of the bodyc. Adduction is a movement toward the midlined. Extension means increasing the angle between two bones connected at a joint The muscle that straightens a joint is called the extensor musclee. Flexion is the opposite of extension, decreasing the angle between two bones The muscle that bends the joint is called the flexor muscle***Actions of a Skeletal Muscle:Extensor - increases the angle at a jointFlexor - decreases the angle at a joint Abductor - moves limb away from the midline of the bodyAdductor - moves limb toward midline of the bodyLevator - moves insertion upwardDepressor - moves insertion downwardRotator - rotates a bone along its axis Sphincter - constricts an opening Abnormal muscle movement Ataxia – a condition of irregular muscle movement and lack of muscle coordinationMovement at the cellular level Muscle cells1. Muscle is made of elongated cells called muscle fibers2. Each muscle fiber contains several subunits called myofibrilsInternal anatomy of a muscle cell1. Muscle cells contain structures called sarcomeresa. Sarcomeres are the functional contractile units of each cell2. Each sarcomere has two types of threadlike structures called thick and thin myofilamentsa. Thick myofilaments are made up of the protein myosinb. Thin myofilaments are made up of the protein actin3. The sarcomere has the actin and myosin filaments arranged in repeating unitsa. These repeating units are separated from each other by dark bands called Z lines, which give the striated appearance to skeletal muscle Muscle contraction1. Muscle cell contraction occurs when the two types of myofilaments slide toward each othera. This shortens each sarcomere, and therefore the entire muscle2. The sliding of these filaments is made possible by the formation of temporary connections (called crossbridges) between actin and myosina. Once these connections are made, myosin “heads” rotate and pull the actin towards the center of the sarcomere3. When the muscle cell relaxes, the filaments return to their resting or relaxed positionZ lines are places where actin filaments are anchored and define the limits of the sarcomere I bands are lighter bands where actin fibres do not overlap with myosin A bands are darker bands where myosin filaments are located M lines are the sites where myosin filaments are anchored During contraction, actin filaments slide along the myosin filaments. This involves accessory proteins and the expenditure of energy. As a result of the sliding action, the sarcomere is shortened (Z lines move closer and I bands shorten).Pathology Connection – Muscular dystrophy (MD) Duchenne’s muscular dystrophy A genetic, incurable myopathy Caused by an error in the dystrophin protein gene Dystrophin’s function is to hold muscle fibers together during contraction Without functional dystrophin, muscle fibers degenerate All types of muscle are affected (smooth, cardiac, and skeletal) Carried on the X-chromosome, so it is seen much more often in boysSymptoms: Muscle weakness As disease progresses, more muscle fibers disappear. Muscle becomes progressively weaker, scarred, and filled with fatty deposits Smooth muscle and cardiac abnormalities often develop as well Disease course:A progressive diseaseUsually diagnosed around age 4 By age 10, usually child is wheelchair bound Average life span is 17 years Death is usually due to respiratory or cardiac failure Diagnosis: Physical examination, including evaluation for gait abnormality and pseudohypertrophy of the calves Biochemical tests for muscle enzymes Genetic testing Electromyogram:? A test where the muscle group is stimulated with an electrical impulse? The impulse triggers a muscle contraction, and the strength of contraction is measuredTreatmentThere is no effective treatment for DMD, so focus is on symptom management, assistive devices, andpalliative carePhysical therapy is not used, because it increases the breakdown of muscle fibersThere are some experimental treatments under investigation* Current research is focusing on increasing muscle repair to keep pace with muscle damage Becker’s muscular dystrophy A milder form of MDHas a later onset; usually diagnosed in 20s or 30sLeads to debilitating myopathy, but progresses more slowlyNeuromuscular system:1. Contraction of skeletal muscle requires the coordination of both the muscular and nervous systems2. Initiation of a skeletal muscular contraction requires an impulse from a motor neuron of the nervous system a. This impulse causes the neuron to release a chemical called acetylcholine b. The acetylcholine binds to receptors on the muscle cell called ligand gated sodium channels i. Binding of acetylcholine causes these sodium channels to open ii. Sodium flows into the muscle cell, causing intracellular calcium to be released iii. Once calcium is released, the muscle contracts3. This all occurs at the neuromuscular junction – the place where a nerve cell touches a muscle cell4. After the nerve cell has finished sending its signal, acetylcholine must be removed from the neuromuscular junction a. Acetylcholinesterase – the enzyme that cleans up acetylcholineATP and calcium1. Energy is needed for contraction and relaxation; this energy comes from ATP (adenosine triphosphate), which helps the myosin heads form and break the crossbridges with actin2. Calcium is needed to help actin, myosin, and ATP interact with each othera. During muscle relaxation, calcium is stored away from the actin and myosin in the sarcoplasmic reticulum (SR) b. During muscle contraction, calcium is released from the SR i. The released calcium causes actin, myosin, and ATP to interact, resulting in muscle contraction; ii. When calcium returns to the SR, the crossbridge attachments are broken and the muscle relaxes3. Sequence of muscle contraction (including calcium and ATP) a. The nervous system tells a muscle to contract by releasing acetylcholine b. Acetylcholine binds to the muscle cell, causing sodium channels to open c. Sodium ions flow into the muscle cell, causing the cell to become excited d. This causes calcium to be released from the SR e. The calcium, now free in the cytoplasm, helps myosin form cross-bridges with actin f. ATP helps myosin heads repeatedly pivot, let go, and reattach to the actin g. This causes the actin filaments to slide along the myosin filaments h. The sarcomere shortens, and therefore shortens the muscle (muscle contraction) i. When the contraction is done, the calcium is pumped back into the SR ii. The muscle relaxes & Calcium is returned to storage for the next contraction. Amazing Body Facts - Rigor mortis1. When a body dies, stored calcium cannot be pumped back into the sarcoplasmic reticuluma. Excess calcium remains in the muscles throughout the body and causes muscle fibers to shorten and stiffen2. When a body dies, ATP can no longer be produced a. Without ATP, the actin-myosin cross-bridges cannot be broken3. Together, the excess calcium and lack of ATP result in stiffening of the entire body. This stiffening is called rigor mortis.. Pathology Connection – Myasthenia gravis and tetanus Myasthenia gravis An autoimmune disorder where the immune system attacks and destroys a large number of acetylcholine receptors at the neuromuscular junctionSigns and symptoms:i. When motor neurons release acetylcholine, the muscle cell cannot respondii. This results in muscle weakness, which characteristically worsens with activity and improves with restiii. The eye muscles are typically affected first, though some patients initially experience difficulty chewing,swallowing or talkingCourse of disease: A progressive disease Course varies widely from person to person Epidemiology: Most common in women under 40 and men over 50Diagnosis Characteristic fluctuating weakness Blood tests for acetylcholine receptor antibodies Electromyography TreatmentAcetylcholinesterase inhibitors? Slows the breakdown of acetylcholine? Allow increased activity of acetylcholineCorticosteroidsImmunosuppressant drugsPlasma exchange Tetanus (also known as “lock jaw”)Caused by an untreated bacterial wound infectionThe bacteria responsible is Clostridium tetani, which lives in the soilThis bacteria produces a toxin that causes the disease b. Signs and symptomsMuscle spasms (involuntary, sudden and violent muscle contractions)In tetanus, major muscle spasms may be triggered by minor stimuli (like loud noises, turning on a light)ii. Rigid paralysisiii. Stiffnessiv. Pain Course of disease Symptoms usually begin in the jaw Symptoms progress over time Eventually, the diaphragm may become paralyzed TreatmentCleaning of the wound Injection of IV tetanus anti-toxin Sedation Ventilator support Pain management Recovery takes several weeks, and many patients have long term problemsPrevention is possible through vaccinationInitial tetanus series given in childhoodBooster shots given every 10 years to adults Smooth muscle (Visceral muscle) Found in: The organs (except for the heart) The blood vessels The bronchial airways Function – helps with internal body processes 1. Smooth muscle in the blood vessels – affects blood pressure * When the vessels get larger in diameter (vasodilate), there is less resistance to flow and blood pressure drops *When smooth muscle contracts, the vessels get smaller in diameter (vasoconstrict), resulting in increased blood pressure 2. Smooth muscle in the airways – affects breathing in asthmatics *During an asthma attack, smooth muscle in the airways constricts. It becomes difficult to get air in and out of the lungs. And the patient begins to wheeze 3. Other smooth muscles - sphincters* Sphincter – a donut-shaped muscle that can act like a doorway (opening and closing)* Found in several parts of the digestive system (as well as other places in the body) Rectum, pyloric in stomach. Smooth muscles are involuntary muscles and don’t contract as rapidly as skeletal muscles, which contract 50 times faster Smooth muscle receives a smaller blood supply than skeletal muscle, resulting in poorer repair of injured tissueCardiac muscle Cardiac muscle creates the walls of the heart Contraction forces blood from the heart, causing it to circulate through the blood vessels in the body Cardiac muscle is involuntary Cardiac muscle fibers are shorter and receive a richer supply of blood than any other muscle in the body Cardiac muscle fibers are connected by intercalated disks 1. Because of this connection, when one fiber contracts so do the adjacent fibers 2. This creates a domino effect; the wave of motion squeezes blood out very efficiently Cardiac muscle does not repair itself after damage1. If damage occurs, it leads to scarring2. Scar tissue doesn’t contract like normal tissue because it is rigid3. If the scar tissue is extensive enough, it can decrease cardiac output, leading to disability and/or death Muscular fuelA. Muscles, like all tissue, need fuel (in the form of nutrients) and oxygen to survive and functionB. The body stores glycogen in the muscle; when needed, glycogen is converted to glucose, which releases energyC. Muscles with very high demands also store fat and use it as energyD. Muscle blood supply and color 1. Higher demand muscles have a rich blood supply to carry much needed oxygen a. These muscles are needed for endurance (like long distance running) b. The rich blood supply gives them a darker color 2. Muscle with fewer heavy demands needs only a small supply of blood a. These muscles do not have much endurance b. They have lighter color (due to their smaller blood supply)Example – Light meat and dark meat in chickena. Since chickens do not fly, the breast and wing are not heavily used; these areas contain white meatb. Legs endure constant use; they contain dark meatMuscles and body temperature1. Not only do muscles produce movement, they also help maintain posture, stabilize joints, and produce heat2. Producing heat is important in maintaining body temperature3. As the energy-rich ATP is used for muscle contraction, three fourths of the energy escapes as heat4. This process helps to maintain body temperature by generating heat when muscles are used a. When you exercise, your temperature rises b. If you become too cold, your body uses muscle contractions to generate heat (through shivering)Applied Science – Botulism Botulism is a potentially deadly disease resulting from food poisoning with the Clostridium botulinum bacteria The bacteria produce a toxin that paralyzes muscle Science can utilize botulinum toxins for medical and cosmetic treatment Small amounts of botulinus toxin are injected into facial muscles to stop previously untreatable facial twitching by paralyzing the muscles Toxin also is used to treat wrinkles without surgery; known as Botox injectionsDiseases and Conditions of the Muscular System Strains (tears)Etiology – Acute injury or chronic overuse or diseaseSigns and Symptoms – Varies with severity, pain, stiffness,bruising, weakness, loss of functionDiagnostic Tests – Examination, radiologic studies, patient historyTreatments – Acute injury: depends on severity, PRICE, pain relievers, heat, PT, surgery. Chronic: PRICE, PT, anti-inflammatory drugs, lasers, ultrasound, shock waves Tendinitis1. Etiology – Acute injury or chronic overuse or disease2. Signs and Symptoms – Varies with severity, pain, stiffness, bruising, weakness, loss of function3. Diagnostic tests – Examination, radiologic studies, patient history4. Treatments – Acute injury: depends on severity, PRICE, pain relievers, heat, PT, surgery. Chronic: PRICE, PT, anti-inflammatory drugs, lasers, ultrasound, shock waves Shin splints1. Etiology – Repetitive lower body exercise such as running. Can be due to faulty foot mechanics or footwear2. Signs and symptoms – Pain in the tibia region3. Diagnostic tests – Patient history and physical exam4. Treatments – Ice packs, anti-inflammatory medications, decrease the intensity of exercise and avoid hills and hard surfaces, modify footwear Cramps/Spasms1. Etiology – Can be result of prolonged physical activity, excessive fluid/electrolyte loss, menstruation2. Signs and symptoms – Sudden, severe involuntary muscle contraction3. Diagnostic tests – Patient history and physical exam. Blood work for electrolyte levels4. Treatments – Rest from specific task, rehydration, passive stretching, dietary electrolyte replacementFibromyalgia Syndrome Etiology – Unknown, but may be neurologicalSigns and Symptoms – Chronic pain, bilateral tenderness, fatigue, sleep disorders, depression, exercise intoleranceDiagnostic tests – Location of pain confined to “tender points”Treatments – Symptom management, not very effective, some helped by antidepressants, exercise, pain relievers, antiepilepticsDuchenne muscular dystrophy (MD)Etiology – Genetic defect in muscle protein, causes disintegration of muscle fibersSigns/ symptoms – Muscle weakness in early stages, later, significant progressive muscle weakness including skeletal, cardiac and smooth musclesDiagnostic tests – Physical exam, biochemical and genetic tests, Electromyogram (EMG), muscle biopsyTreatments – No real treatment, disease is invariably fatal in adolescence or young adulthood. Symptom Management and palliative care. Some experimental treatments in developmentMitochondrial myopathyEtiology – Defect in ATP production in mitochondriaSigns and symptoms – Progressive muscle weakness, often accompanied by hearing loss, diabetes mellitus, heart problems, nervous system disorders and other biochemical abnormalitiesDiagnostic tests – Genetic tests, biochemical tests, EMG, muscle biopsy (for ragged red fibers)Treatments – No consensus on treatment, some drugs can decrease symptoms but nothing can stop progressionMyasthenia gravisEtiology – Autoimmune attack at neuromuscular junctionSigns /symptoms – Progressive, fluctuating muscle weakness, often starting with facial or eye musclesDiagnostic tests – Blood tests, EMGTreatments – Steroids, immunosuppressant drugs, plasma exchange, acetylcholinesterase inhibitors Tetanus (Lock jaw) Etiology – Bacterial infection; Clostridium tetani Signs and symptoms – Progressive descending muscle spasm, paralysis, stiffness and pain, esp. jaw Diagnostic tests – Physical exam, lab tests to rule out other disorders, history of wound Treatments – Wound hygiene, tetanus antitoxin, sedation, ventilator support, pain management Pharmacology Corner – Skeletal muscle drugs Non-steroidal anti-inflammatory drugs (NSAIDs) Relieve inflammation, but do not have the negative side effects of steroids Examples – ibuprofen (Advil), naproxen (Aleve) Pain medications Aspirin Acetaminophen (Tylenol) Muscle relaxants Help muscles rest in order to heal themselves Help relieve musculoskeletal spasms Examples – Flexeril, Parafon Forte Paralytic medications Used in situations where paralysis is desired (like during surgery) Cut off communications between the brain and the muscles Examples – succinylcholine (Anectine), pancuronium (Pauvulon) Must be closely monitored, because too much medicine can cause the heart or breathing to stop Do not affect consciousness or relieve pain; therefore in surgery, they must always be given with sedative/pain relieving drugsFacial Muscle WorksheetMuscleLocationFunctionOriginInsertionFacial musclesOribicularis Oculi NasalisZygomatic MinorMasseterZygomatic MajorTemporalisLevator Labii SuperiorBuccinatorOribcularis OrisLevator Anguli OrisPlatysmaDepressor Anguli OrisMentalisDepressor Labii InferiorisOccipitalisAponeurosis tendonSternocleidomastoid FrontalisFrontalis & Occipitalis raises eyebrows and wrinkles to foreheadFrontalis attached by a tendon Aponeurosis to occipitalisTemporalis over temporal bone assists with chewing and wiggling ears.Orbicularis oculi (circular muscle around eye / ocular- closes eyelid, winking, blinkingOrbicularis oris (circular muscle /oral )pucker lipsZygomaticus (major and minor) attachment to zygomatic bone and insertion to corner of lips; SmilingBuccinator (under zygomaticus muscles) sucking, blowing, fish face, keeps food against teeth,& whistling.Masseter (masticating food) assists chewing Sternocleidomastoid neck muscle attach to (insertion site) mastoid process to clavicle and sternum – shake head no or back and forthPlatysma- allows head to move forwardTrapezius hyperextends neckLevator Labii Superior raises lip (Elvis look) Levator Anguli Oris works with zygomatic muscles (synergists) to smileFrown:Depressor Labii Inferioris depresses lower lip pouting /frowningDepressor Anguli Oris main muscle of frowning Mentalis deeply perplexed face (chin)Procerus muscle in-between eyes wrinkle skin in between eyes Leg muscles:The largest muscle masses in the leg are present in the thigh and the calf.The muscles that make up the quadriceps are the strongest and leanest of all muscles in the body. These four muscles at the front of the thigh are the major extensors (help to extend the leg straight) of the knee. They are:Vastus lateralis: On the outside of the thigh, this is the largest of the quadriceps. It extends from the top of the femur to the kneecap, or patella. Vastus medialis: This teardrop-shaped muscle of the inner thigh attaches along the femur and down to the inner border of the kneecap. Vastus intermedius: Between the vastus medialis and the vastus lateralis at the front of the femur, it is the deepest of the quadriceps muscles. Rectus femoris: This muscle attaches to the kneecap. Of the quadriceps muscles, it has the least affect on flexion of the knee.The hamstrings are three muscles at the back of the thigh that affect hip and knee movement. They begin under the gluteus maximus behind the hipbone and attach to the tibia at the knee. They are:Biceps femoris: This long muscle flexes the knee. It begins in the thigh area and extends to the head of the fibula near the knee. Semimembranosus: This long muscle extends from the pelvis to the tibia. It extends the thigh, flexes the knee, and helps rotate the tibia. Semitendinosus: This muscle also extends the thigh and flexes the knee.The calf muscles are pivotal to movement of the ankle, foot, and toes. Some of the major muscles of the calf include:Gastrocnemius (calf muscle): One of the large muscles of the leg, it connects to the heel. It flexes and extends the foot, ankle, and knee. Soleus: This muscle extends from the back of the knee to the heel. It is important in walking and standing. Plantaris: This small, thin muscle is absent in about 10 percent of people. The gastrocnemius muscle supersedes its function.Possibly the most important tendon in terms of mobility is the Achilles tendon. This important tendon in the back of the calf and ankle connects the plantaris, gastrocnemius, and soleus muscles to the heel bone. It stores the elastic energy needed for running, jumping, and other physical activity. Arm Muscles:The arm’s curved shape comes from its major exterior muscles. These bulky muscles also give the arm its strength.The muscles of the arm that can be seen easily on the surface include:Biceps: This large muscle of the upper arm is formally known as the biceps brachii muscle, and rests on top of the humerus bone. It rotates the forearm and also flexes the elbow. Triceps: This large muscle in the back of the upper arm helps straighten the arm. It is formally known as the triceps brachii muscle. Brachioradialis: This muscle, located at the top of the forearm near the elbow, helps rotate the forearm both outwardly and inwardly. It also flexes the forearm at the elbow.Extensor carpi radialis longus: This muscle next to the brachioradialis is one of five major muscles that help to move the wrist in multiple directions. When you clench your fist, this muscle bulges out from the skin. Deltoid: Although technically part of the shoulder, the deltoid muscle controls the majority of the shoulder’s movements and thus enables the arm to have increased range of motion.These muscles work together to move the forearm. The biceps is the agonist, and it inserts on the radius. Contraction of the biceps flexes the arm, moving it toward the humerus and shoulder. The triceps does the opposite. It's the antagonist, and it inserts on the ulna. Contraction of the triceps brings the arm back down, extending it away from the humerus.Strength training exercises are common ways to increase the size and overall strength of the major muscles in the arms. Common exercises to build up arm muscles include curls, presses, pushdowns, and extensions using weights.Pain can occur anywhere in the arm. The most common cause of arm pain is overexertion of a muscle or injury to it. Twisting, pulling, or falling are common ways muscles in the arms become painful. Although repetitive injuries affect the deep muscles more often, pulled muscles from lifting something too heavy or overexerting can also create pain and soreness, but this usually subsides in a few days.Arm muscle pain can usually be easily treated with resting the affected muscle and icing, elevating, and compressing the area. The deltoid is this muscle here, right at the shoulder joint. You could say that this is the muscle that gives your shoulder that rounded shape that it has. It stabilizes and moves the shoulder and arm. The deltoid is the main abductor muscle of the shoulder, meaning it moves the arm away from the center of the body. The deltoid has three origin points along the scapula and the clavicle - these bones here. The origin points are stable and do not move, unlike the insertion point of the muscle, here, which moves the humerus bone of the upper arm. The antagonist (or opposing muscle) to the deltoid is the pectoralis major. This muscle is located on the upper chest area and is kind of fan-like in shape. Similar to the deltoid, the pectoralis major has multiple origin points, but just one insertion point. The origin points are here, along the clavicle, sternum and abdomen, while the insertion point is here, on the humerus. Muscles that support the deltoid and pectoralis major So you can see, together the deltoid and pectoralis major work to move the upper arm because both have insertion points on the humerus. And, as you may have guessed, since the pectoralis major is the opposite of the deltoid, its function is to adduct the arm, moving it closer to the center of the body. Both of these muscles are aided by other muscles around the shoulder, like the pectoralis minor, latissimus dorsi and the teres muscles, helping them raise, lower and rotate the arm. The pectoralis major and deltoid muscles ................
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