2Vocab development Calat- something inserted Erg- work Fasc- bundle -gram- something writtenHyper- over, moreinter;- betweenIso-equalLaten- hiddenMyo- muscleReticul- a netSarco- fleshSyn- togetherTetan- stiff-tonic- stretched-troph- well fedVoluntar- of one’s free will
3IntroductionMuscles are organs made of cells that use chemical energy stored in nutrients to exert a force on the structures they are attached to.Muscle actions provide:Muscle tonePropel body fluids and foodGenerate the heartbeatDistribute heat
4Introduction 3 types of muscle Skeletal Smooth Cardiac We are going to focus mostly on skeletal muscle in this chapterSkeletal muscle attaches to bones and to the skin of the face and is under conscious control
5Structure of Skeletal Muscle Composed mostly of skeletal muscle tissue, nervous tissue, blood, and other connective tissuesLayers of connective tissue enclose and separate all parts of a skeletal muscle allowing the parts to move somewhat independently.
6Skeletal Muscle: Connective Tissue Coverings FasciaSeparates a muscle from its adjacent muscles; covers the whole muscleTendonConnect a muscle to a boneAponeurosesconnects muscle to bone and other muscles
7Skeletal Muscle: Connective Tissue Coverings EpimysiumClosely surrounds a skeletal musclePerimysiumExtends inward from epimysium & separates the muscle tissue into small sections called fasciclesEndomysiumEach muscle fiber within a fascicle is covered by this
8Skeletal Muscle Fibers Each muscle fiber forms from many undifferentiated cells that fuse togetherEach muscle fiber is multinucleateShaped like a long, thin cylinder with rounded endsSarcolemma- just beneath the muscle cell membraneSarcoplasm- cytoplasm of the fiber
9Skeletal Muscle Fibers MyofibrilsBundles of threadlike structures found within muscle fibersFundamental in the muscle contraction mechanismConsist of 2 types of proteinsMyosin- thick filamentsActin- thin filamentsAlternating of the myosin & actin causes the striations found in skeletal muscleSarcomeres- repeating patterns of striations along each muscle fiberAlternating of myosin and actin produce the dark and light striations that you see in skeletal muscles
10Skeletal Muscle Fibers Striation PatternHas 2 main partsI band (light bands) made of actin filaments connected to z linesA bands (dark bands) made of myosin filaments overlapping thin actin filamentsInclude an H zone which consists of only thick filaments (myosin)
12Skeletal Muscle Fibers Sarcoplasmic reticulumWithin the sarcoplasm of a muscle fiberNetwork of channels that surrounds each myofibrilMuscle fibers and the connective tissues associated with them are flexible but if they are overstretched they tear. The is commonly called a muscle strain.
13Skeletal Muscle Contraction Complex interaction of cellular and chemical piecesThe result is movement within the myofibrils where the filaments of actin and myosin slide past each other causing the sarcomere to shorten
14Skeletal Muscle Contraction Energy SourcesATPMuscle fiber only has enough ATP to contract briefly so it must be able to regenerate ATPCreatine PhosphateInitial source of energy to regenerate ATPMuch more abundant in muscle fibers than ATP, but it cannot supply energy directly to the cellCellular RespirationATP is decomposed to ADP, the energy from creatine phosphate molecules is transferred back to these ADP molecules, quickly phosphorylating them back into ATP .The amount of ATP and creatine phosphate is ususally not enough to support maximal muscle activity for more than 10 seconds…as a result the muscle fibers in an active muscle soon use cellular respiration of glucose to synthesize ATP
15Skeletal Muscle Contraction 10 steps to muscle contraction1. An action potential is conducted down a motor neuron axon2. The motor neuron terminal releases the neurotransmitter acetylcholine (ACh)3. ACh binds to ACh receptors on the muscle fiber4. The sarcolemma is stimulated, an action potential is generated, and the impulse is conducted over the surface of the muscle fiber and deep into the fiber through the transverse tubules.
16Skeletal Muscle Contraction 5. The impulse reaches the sarcoplasmic reticulum, and calcium channels open. 6. Calcium ions diffuse from the sarcoplasmic reticulum into the sarcoplasm and bind to tropin molecules. 7. Tropomyosin molecules move and expose specific sites on actin. 8. Actin and myosin link, forming cross-bridges. 9. Thin (actin) filaments are pulled toward the center of the sarcomere by myosin cross-bridges increasing the overlap of the thin and thick filaments. 10. The muscle fiber contracts.
17Skeletal Muscle Relaxation 1. Acetylcholinesterase decomposes acetylcholine, and the muscle fiber membrane is no longer stimulated.2. Calcium ions are actively transported into the sarcoplasmic reticulum.3. ATP breaks linkages between actin and myosin filaments without breakdown of ATP itself4. Breakdown of ATP “cocks” the myosin heads.5. Troponin and tropomyosin molecules inhibit the interaction between myosin and actin filaments.6. Muscle fiber remains relaxed until it is stimulated again.
18Muscle Fatigue Caused by Decreased blood flow Ion imbalances due to repeated stimulationPsychological loss of desire to continueLactic acid accumulationOxygen debtAccumulates in the muscles when ATP production goes from aerobic to anaerobic
19Muscular Responses Threshold Stimulus A muscle fiber remains unresponsive until a certain strength of stimulation is reached, once this is reached an action potential is generated and the process of muscle contraction beginsWhen an isolated muscle fiber is exposed to a series of stimuli of increasing strength, the fiber remains unresponsive until a certain strength of stimulation called the threshold stimulus is applied. Once the threshold is reached, an action potential is generated, resulting in an impulse that spreads throughout the muscle fiber, releasing enough calcium ions from the sarcoplasmic reticulum to activate cross-bridge formation and contract the fiber. A single action potential conducted down a motor neuron normally releases enough Ach to bring the muscle fibers to threshold, generating an impulse in the muscle fiber.
20Muscular Responses Recording a Muscle Contraction Twitch- contractile response of a single muscle fiber to a muscle impulseA twitch consists of a period of contraction, during which the fiber pulls at its attachments, followed by a period of relaxation, during which the fiber pulls at its attachments, followed by a period of relaxation, during which the pulling force declines. These events can be recorded in a myogram. A twitch has a brief delay between the time of stimulation and the beginning of contraction. This latent period, which in human muscle may be less than 2 milliseconds.The length to which a muscle fiber is stretched before stimulation affects the force it will develop. If a skeletal muscle fiber is stretched well beyond its normal resting length the force will decrease. This is because the sacaromeres of that fiber become so extended that some myosin heads cannot reach binding sites on the thin filamnets and cannot contribute to contraction. Conversely at very short fiber lengths, the sarcomeres become compressed, and further shortening is not possible. During normal activities muscle fibers contract at optimal lengths.
21Muscular Responses Summation The force that a muscle fiber can generate is not limited to the maximum force of a single twitch. A muscle fiber exposed to a series of stimuli of increasing frequency reaches a point when it is unable to completely relax before the next stimulus in the series arrives. When this happens, the individual twitches begin to combine, and the contraction becomes sustained. In such a sustained contraction, the force of individual twitches combines by the process of summation. At higher frequencies of stimulation, as the time spent in relaxation becomes very brief, a condition called incomplete tetanus or partial tetany. When the resulting forceful, sustained contraction lacks even partial relaxation, it is called complete tetanus or complete tetanic contraction.
22Muscular Responses Types of Contractions Isotonic Contractions (equal force –change in length)—allow you to move thingsConcentric-muscle contracts with greater force than resistance and shortensEccentric- muscle contracts with less force than resistance and lengthensIsometric Contractions – (equal length- change in force) – allow you to sit and hold your postureIn an isotonic contraction the length of the muscle changes but the amount of force does not…in an isometric contraction the length of the muscle doesn’t change but the muscle still contractsMost body movements require both isotonic and isometric contractions. In walking for example certain leg and thigh muscles contract isometrically and keep the limb stiff as it touches the ground, while other muscles contract isotonically bending and lifting the opposite limb.
23Muscular Responses Fast & Slow Twitch Muscle Fibers 3 types Slow twitch fibers (red fibers)Produce ATP from oxygen making them more resistant to fatigueThese fibers can contract for long periods of time without fatigueFast twitch fibers (white fibers)Produce ATP primarily through glycolysisCan contract rapidly but also fatigue rapidly as lactic acid accumulates in themIntermediate Fibers (white fibers)Can contract rapidly and also have a larger respiratory capacity so they don’t fatigue like fast-twitch fibersMuscle fibers vary in contraction speed and in whether they produce ATP oxidatively or glycolytically. There are atleast three types of muscle fibers found in humans.Slow Twitch Fibers- called red fibers because they contain the red, oxygen storing pigment called myoglobin. These fibers are well supplied with oxygen carrying blood. In addition red fibers, contain more mitochondria, which is an adaptation for the aerobic reactions of cellular respiration. These fibers have a high respiratory capacity and can generate ATP fast enough to keep up with the ATP breakdown that occurs when they contract.Fast twitch fibers- White fibers because they have less myoglobin and have a poorer blood supply than red fibers. These fibers have fewer mitochondria and so the have a reduced respiratory capacity.Intermediate Fibers - A type of white fiver, the fast twitch fatigue resistant fibers. These fibers have the fast twitch speed associated with white fiber with substantial amount of oxidative capacity more characteristic of red fibers
24Smooth Muscles Smooth muscles lack striations Cells have only one nucleus2 major types of smooth musclesMultiunitVisceralSmooth muscle cells are shorter than the fibers of skeletal muscle and they have a single centrally located nucleus. Remember skeletal muscle cells are multinucleate.
25Smooth Muscles Multiunit Smooth Muscle Muscle fibers function as separate unitsFound in the irises of the eyes & walls of large blood vesselsContract after stimulation by neurons or certain hormonesThe muscle fibers are less well organized and function as separate units, independent of their neighboring cells. Typically contracts only after stimulation by neurons or certain hormones.
26Smooth Muscles Visceral Smooth Muscle Fibers respond as a single unit Found in the walls of hollow organs (intestines, stomach, bladder, uterus)Two features- conduction of impulses and rythmicity produce peristalsisPeristalsis- wavelike motion of contractionPeristalsis is what help your body move food from organ in the digestive system to the nextVascular smooth muscleFound in the walls of small blood vessels where it helps control blood pressure and blood flowComposed of sheets of spindle shaped cells held close together by gap junctions.Fibers respond as a single unit, when one fiber is stimulated, the impulse conducted over its surface may excite adjacent fibers that stimulate others.Peristalsis consists of alternate contractions and relaxations of the longitudinal and circular muscles. These movements help force the contents of a tube along its length. In the intestines, for example, peristaltic wves move masses of partially digested food and help to mix them with digestive fluids. Peristalsis in the ureters moves urine from the kidneys to the urinary bladder.
27Cardiac Muscle Found only in the heart Composed of striated cells joined end to endOpposite ends of cardiac cells are connected by intercalated discsHelp join cells, transmit the force of contraction, & diffuse ions from cell to cellIt is composed of striated cells joint end to end, forming fibers interconnected in branching, three-dimensional networks. Each cell contains a single nucleus and many filaments of actin and myosis similar to those in skeletal muscle. A cardiac muscle cell also has a well-developed sarcoplasmic reticulum, a system of transverse tubules, and many mitochondria.
28Skeletal Muscle Actions Skeletal action depends onType of joint it is associated withThe way the muscle is attached on either side of the joint
29Skeletal Muscle Actions Body MovementWhen a body part moves bones and muscles interact as a lever3 types of levers1st class- resistance-fulcrum, force (seesaw; when the arm straightens at the elbow)2nd class- fulcrum- resistance- force (wheelbarrow; when you chew something up)3rd class- resistance-force-fulcrum (tweezers- when the arm bends at the elbow)4 basic components of a leverA rigid bar or rodA fulcrum or pivot on which the bar turnsAn object moved against resistanceA force that supplies energy to move the bar
30Skeletal Muscle Actions Origin and InsertionOrigin- less moveable end of the muscleInsertion- more moveable end of the muscleWhen a muscle contractsInsertion is pulled toward its originHead of the muscle is the part closest to its originOne end of a skeletal muscle is usually fastened to a relatively immovable or fixed part on one side of a joint, and the other end is connected to a moveable part on the other side of the joint
32Skeletal Muscle Actions Interaction of Skeletal MusclesAgonist- muscle that causes an actionSynergists- muscles that work togetherPrime mover- muscle that does most of the work during an actionAntagonists- muscle that opposes actionMost skeletal muscles function in groups.A muscle that causes an action is called an agonist for that action. While an agonist is acting, other nearby muscles may also contract and help with the action. Muscles that work together are called synergists. The agonist can also be the prime mover. The antagonist is a muscle that works to oppose an action. These muscles can cause movement that acts in the opposite direction.
33Major Skeletal Muscles Muscles of Facial ExpressionInnervated by the facial nerve (CN VII)Lack of symmetry in facial expression may indicate nerve damage
34Muscles of Facial Expression Orbicularis oculiorbicular= circularOculi= eyeOrigin: orbital rim, frontal & maxillary bonesInsertion: lateral region of eye, some encircle the eyeAction: closing the eyelidExpression: form’s crows feet
35Muscles of Facial Expression CorrugatorOrigin: frontal boneInsertion: eyebrowAction: draws eyebrow medially & inferiorlyExpression: frowning & sufferingRuns from the bridge of the nose to eyebrows
36Muscles of Facial Expression ProcerusOrigin: fascia covering the lower nasal bone & upper lateral nasal cartilageInsertion: skin between and above the eyebrowsAction: causes transverse wrinkles over the bridge of the noseExpression: squintingRuns from the bridge of the nose to the medial corner of the eyebrow
37Muscles of Facial Expression NasalisCircles the opening of the nostrilsHas 2 parts:Dilator narisCompressor narisAction: dilates & compresses nostrilsWiggles your nostrils
38Muscles of Facial Expression EpicraniusOrigin: occipital boneInsertion: skin around the eye & orbicularis oculiAction: elevates eyebrows, moves scalp forward & backwardExpression: surprise2 bellied muscle connected with an aponeurosis
39Muscles of Facial Expression Orbicularis OrisOribicular= circleoris = mouthOrigin: encircles mouthInsertion: angle of mouthAction: encloses & protrudes up; helps keep food on occlusal surfaces during chewingExpression: closing or pursing lips
40Muscles of Facial Expression Quadratus Labii Superioris4 muscles of the upper lipLevator labii superioris alaeque nasiLevator labii superiorisZygomaticus minorZygomaticus majorAllow you to frown and smile
43Muscles of Facial Expresssion Quadratus Labii Superioris Cont…Zygomaticus minorOrigin: zygomatic boneInsertion: upper lipAction: raises upper lipExpression: scornZygomaticus majorInsertion: angle of mouthAction: elevates the corner of the mouthExpression: smiling
44Muscles of Facial Expression Levator Anguli OrisOrigin: canine fossa (on the maxilla)Insertion: orbicularis orisAction: elevates the angle of the mouthExpression: smiling (laughing)
45Muscles of Facial Expression SmilingProduced by the contraction of 2 facial muscles:Zygomaticus majorOribicularis oculi
46Muscles of Facial Expression RisoriusOrigin: fasica superficial to masseter muscleInsertion: angle of the mouthAction: pulls angle of the mouth laterallyExpression: smiling widely; grinning
47Muscles of Facial Expression Depressor labii inferiorisOrigin: mandibleInsertion: lower lipAction: depresses the angle of the mouthExpression: sadness; grief
48Muscles of Facial Expression Depressor Anguli OrisA.K.A triagularisOrigin: mandibleInsertion: angle of the mouthAction: depresses angle of the mouthExpression: frowning
49Muscles of Facial Expression MentalisOrigin: mandible near the incisive fossaInsertion: skin of the chinAction: pulls skin of chin upward; protrudes lower lip; raise lower lipExpression: doubt; disdainAlso called the lip fighter muscle like at the dentist when they have to keep holding down your lip so that they can get at your lower teeth.
50Muscles of Facial Expression Buccinator2 origins:Pterygomandibular rapheAlveolar process of the mandible & maxillaInsertion: orbicularis orisAction: draws the corners of the lips laterally, compresses cheek, helps keep food on occlusal surface during chewingPlays and important role in chewingMakes up the musculature of the cheek
51Muscles of Facial Expresion LaughterMuscle that form the core of the laughter of exhilartion:Zygomatic majorOribicularis oculiMuscles used to enhance laughter:Levator labii superiorisRisoriusMentalisDepressor anguli orisOrbicularis oris
52Muscles of Facial Expression Auriculares3 small muscles around the auricle of the earNot well developed in manAllow you to wiggle your ears
53Muscles of Facial Expression PlatysmaBroad, thin, superficial muscleOrigin: fascia below clavicleInsertion: lower border of mandible from canine to second molarAction: depresses angle of the mouth, wrinkles the skin of the neck & upper chestExpression: dejection, horror, grimacing
54Muscles of Mastication 4 pairs of muscles attached to the mandible3 pairs close the lower jaw1 pair lowers the jaw & allows side to side movement
55Muscles of Mastication MasseterOrigin: zygomatic archInsertion: lateral surface of the mandibleAction: elevates the mandible
56Muscles of Mastication TemporalisOrigin: temporal fossaInsertion: coronoid fossa of the mandibleAction: elevates the mandible; retraction
58Muscles of Mastication Medial PterygoidOrigin: sphenoid, palatine, & maxillaInsertion: medial surface of the mandibleAction: elevates mandible; moves it from side to side
59Muscles That Move the Head and Vertebral Column SternocleidomastoidOrigin:sternum & collar boneInsertion: temporal boneAction: pulls head to one side, flexes neck or elevates the sternum
60Muscles That Move the Head & Vertebral Column Splenis CapitisOrigin: spinous process of lower cervical & upper thoracic vertebraeInsertion: occipital boneAction: rotates head, bends head to one side, or extends neck
61Muscles That Move the Head & Vertebral Column Semispinalis capitisOrigin: processes of lower cervical & upper thoracic vertebraeInsertion: occipital boneAction: elevates head & rotates the head
62Muscles that Move the Head & Vertebral Column Quadratus lumborumOrigin: iliac crestInsertion: upper lumbar vertebrae & twelfth ribAction: aids in breathing, extends lumbar region of vertebral column
63Muscles That Move the Head & Vertebral Column Erector SpinaeOrigin & Insertion at many locations on the axial skeletonAction: extend & rotate the head & maintain the erect position of the vertebral column
64Muscles That Move the Pectoral Girdle Work closely with the muscles that move the armConnect the scapula to near by bones & help move the scapula up, down, forward, & backward
65Muscles That Move the Pectoral Girdle TrapeziusOrigin: occipital bone & spines of the cervical & thoracic vertebraeInsertion: clavicle, spine, & acromion process of scapulaAction: rotates scapula; shrugs shoulders
66Muscles That Move the Pectoral Girdle Rhomboid MajorOrigin: spines of upper thoracic vertebraeInsertion: medial border of the scapulaAction: retracts, elevates, & rotates the scapula
67Muscles That Move the Pectoral Girdle Rhomboid MinorOrigin: spines of the lower cervical vertebraeInsertion: medial border of the scapulaAction: retracts & elevates the scapula
68Muscles That Move the Pectoral Girdle Levator ScapulaeOrigin: transverse process of the cervical vertebraeInsertion: medial margin of the scapulaAction: elevates scapula
69Muscles That Move the Pectoral Girdle Serratus AnteriorOrigin: outer surfaces of upper ribsInsertion: ventral surface of scapulaAction: pulls scapula anteriorly & downward
70Muscles That Move the Pectoral Girdle Pectoralis MinorOrigin: sternal ends of upper ribsInsertion: coracoid process of scapulaAction: pulls scapula forward and downward to raise ribs
71Muscles That Move the Forearm Most forearm muscle movements are produced by muscles that connect the radius or ulna to the humerus or pectoral girdle.Muscles that move the forearm are grouped into three categories:Flexors-ExtensorsRotators
72Muscles That Move the Forearm Flexor:Biceps BrachiiOrigin: above the glenoid cavity of the scapulaInsertion: radiusAction: flexes elbow & rotates the hand laterally(turning a doorknob or screw driver)
73Muscles That Move the Forearm FlexorBrachialisOrigin: anterior shaft of the humerusInsertion: coronoid process of ulnaAction: Flexes elbowStrongest flexor of the elbow
74Muscles That Move the Forearm Flexor:BrachioradialisOrigin: distal lateral end of humerusInsertion: lateral surface of the radius above the styloid processAction: flexes elbow
75Muscles That Move the Forearm ExtensorTriceps BrachiiOrigin: below glenoid cavity & lateral & medial surfaces of the humerusInsertion: olecranon process of the ulnaAction: extends elbowThis is the only muscle on the back of the arm.
76Muscles That Move the Forearm Rotators:SupinatorOrigin: lateral epicondyle of humerus & ulnaInsertion: lateral surface of radiusAction: rotates forearm laterally and supinates the hand (palm facing upward)
77Muscles That Move the Forearm Rotators:Pronator teresOrigin: medial epicondyle of humerus and the ulnaInsertion: lateral surface of radiusAction: rotates forearm medially and pronates the hand
78Muscles That Move the Forearm Rotator:Pronator QuadratusOrigin: anterior distal end of ulnaInsertion: anterior distal end of radiusAction: rotates forearm medially and pronates hand
79Muscles That Move the Hand Movements of the hand include movements of the wrist and fingers.2 major groups of musclesFlexors- on anterior side of the forearmExtensors- on the posterior side of the forearm
80Muscles That Move the Hand FlexorsFlexor carpi radialisOrigin: medial epicondyle of the humerusInsertion: base of the 2nd & 3rd metacarpalsAction: flexes wrist & abducts hand
81Muscles That Move the Hand FlexorFlexor carpi ulnarisOrigin: medial epicondyle of the humerusInsertion: carpals & metacarpalsAction: flexes the wrist & adducts the hand
82Muscles that Move the Hand FlexorsPalmaris longusOrigin: medial epicondyle of humerusInsertion: fascia of the palmAction: flexes wrist; like you are telling someone to come here
83Muscles That Move the Hand FlexorsFlexor Digitorum ProfundusOrigin: anterior surface of the ulnaInsertion: bases of distal phalanges in fingers 2-5Action: flexes distal joints of fingers
84Muscles that Move the Hand FlexorFlexor digitorum superficialisOrigin: humerusInsertion: tendons of fingersAction: flexes the fingers and wrist
85Muscles that Move the Hand ExtensorExtensor Carpi Radialis LongusOrigin: distal end of the humerusInsertion: base of 2nd metacarpalAction: extends wrist and abducts the hand
86Muscles that Move the Hand ExtensorExtensor carpi radialis brevisOrigin: lateral epicondyle of the humerusInsertion: base of 2nd & 3rd metacarpalsAction: extends wrist & abducts hand
87Muscles that Move the Hand ExtensorsExtensor carpi ulnarisOrigin: lateral epicondyle of humerusInsertion: base of the 5th metacarpalAction: extends wrist & adducts hand
88Muscles that Move the Hand ExtensorExtensor DigitorumOrigin: lateral epicondyle of the humerusInsertion: posterior surface of phalanges in fingers 2-5Action: extends fingers
89Muscles that Move the Arm FlexorsCoracobrachialisOrigin: coracoid process of the scapulaInsertion: shaft of the humerusAction: flexes & adducts the arm
90Muscles that Move the Arm FlexorPectoralis majorOrigin: clavicle, sternum, & costal cartilages of upper ribsInsertion: humerusAction: flexes, adducts, and rotates arm medially
91Muscles that Move the Arm ExtensorTeres MajorOrigin: lateral border of scapulaInsertion: humerusAction: extends, adducts, and rotates the arm medially
92Muscles that Move the Arm ExtensorLatissimus DorsiOrigin: spines of scral, lumbar, & lower thoracic vertebrae, iliac crest, & lower ribsInsertion: humerusAction: extends, adducts, and rotates the arm medially, or pulls the should downward & back
93Muscles that Move the Arm AbductorsSupraspinatusOrigin: posterior surface of scapula above spineInsertion: humerusAction: abducts the arm
94Muscles that Move the Arm AbductorsDeltoidOrigin: acromion process, spine of the scapula, & clavicleInsertion: humerusAction: abducts, extends, & flexes the arm
95Muscles that Move the Arm RotatorsSubscapularisOrigin: Anterior surface of scapulaInsertion: humerusAction: rotates arm medially
96Muscles that Move the Arm RotatorsInfraspinatusOrigin: posterior surface of scapula below spineInsertion: humerusAction: rotates arm laterally
97Muscles that Move the Arm RotatorsTeres MinorOrigin: lateral border of scapulaInsertion: humerusAction: rotates arm laterally
98Muscles of the Abdominal Wall Muscles of the abdominal wall connect the rib cage & vertebral column to the pelvic girdleLinea alba- band of tough connective tissue that extends from the xiphoid process of the sternum to the pubic symphysis & provides attachment for some of the abdominal musclesContraction of these muscles helps move air out of the lungs during forceful exhalation & other everyday functions of the bodyThe walls of the chest and pelvic regions are supported directly by bone, but those of the abdomen are not. Instead, the anterior and lateral walls of the abdomen are composed of layers of broad, flattened muscles. These muscles connect the rib cage and vertebral column to the pelvic girdle
99Muscles of the Abdominal Wall External obliqueOrigin- outer surfaces of the lower ribsInsertion- Outer lip of iliac crest & linea albaAction- Tenses abdominal wall & compresses abdominal contents
100Muscles of the Abdominal Wall Internal ObliqueOrigin- crest of ilium & inguinal ligamentInsertion- cartilages of the lower ribs, linea alba, & crest of the pubisAction- Tenses abdominal wall & compresses abdominal contents
101Muscles of the Abdominal Wall Transversus abdominisOrigin- costal cartilages of the lower ribs, processes of the lumbar vertebrae, lip of iliac crest, & inguinal ligamentInsertion- linea alba & crest of pubisAction- tenses abdominal wall & compresses abdominal contents
102Muscles of the Abdominal Wall Rectus AbdominisOrigin- Crest of the pubis & pubic symphysisInsertion- xiphoid process of sternum & costal cartilageAction- tenses the abdominal wall & compresses abdominal contents & also flexes the vertebral column
103Muscles that Move the Thigh Muscles that move the thigh are attached to the femur & to part of the pelvic girdleImportant exceptions: sartorius & rectus femorisMuscles can be separated into 2 groups:Anterior- primarily flexes the thigh; advance the lower limb when walkingPosterior- primarily extends, abducts, or rotates the thigh
104Muscles that Move the Thigh: Anterior Group Psoas majorOrigin: lumbar intervertebral discs; bodies and transverse processes of lumbar vertebraeInsertion: lesser trochanter of the femurAction: flexes the thigh
105Muscles that Move the Thigh: Anterior Group IliacusOrigin: Illiac fossa of iliumInsertion: lesser trochanter of the femurAction: Flexes thigh
106Muscles that Move the Thigh: Posterior Group Gluteus maximusOrigin: sacrum, coccyx, & posterior surface of the iliumInsertion: posterior surface of the femur & fascia of the thighAction: extends hip; helps straighten the lower limb at the hip when you walk, run, or climb
107Muscles that Move the Thigh: Posterior Group Gluteus minimusOrigin: lateral surface of the iliumInsertion: greater trochanter of the femurAction: abducts & rotates the thigh medially
108Muscles that Move the Thigh: Posterior Group Gluteus mediusOrigin: lateral surface of the iliumInsertion: greater trochanter of the femurAction: abducts & rotates thigh medially
109Muscles that Move the Thigh: Posterior Group PiriformisOrigin: anterior surface of the sacrumInsertion: greater trochanter of the femurAction: abducts & rotates the thigh medially ; stabilizes the hip
110Muscles that Move the Thigh: Posterior Group Tensor fasciae lataeOrigin: anterior iliac crestInsertion: greater trochanter of the femurAction: abducts, flexes, & rotates thigh medially
111Muscles that Move the Thigh: Adductors PectineusOrigin: spine of the pubisInsertion: femur distal to lesser trochanterAction: Flexes & adducts thigh
112Muscles that Move the Thigh: Adductors Adductor brevisOrigin: pubic boneInsertion: posterior surface of femurAction: adducts & flexes thigh
113Muscles that Move the Thigh: Adductors Adductor longusOrigin: pubic bone near the pubic symphysisInsertion: posterior surface of the femurAction: adducts & flexes the thigh
114Muscles that Move the Thigh: Adductors Adductor magnusOrigin: Ischial tuberosityInsertion: posterior surface of the femurAction: adducts thigh, posterior portion extends & anterior portion flexes thigh
115Muscles that Move the Thigh: Adductors GracilisOrigin: Lower edge of pubic symphysisInsertion: medial surface of the tibiaAction: adducts thigh & flexes knee
116Muscles that Move the Leg Connect the tibia or fibula to the femur or pelvic girdle.Two major groups:FlexorsExtensors
117Muscles that Move the Leg Hamstring GroupBiceps femorisOrigin: ischial tuberosity & linea asperaInsertion: head of fibula & lateral condyle of tibiaAction: flexes knee, rotates leg laterally & extends thigh
118Muscles that Move the Leg Hamstring GroupSemitendinosusOrigin: ischial tuberosityInsertion: medial surface of the tibiaAction: flexes knee, rotates leg medially & extends thigh
119Muscles that Move the Leg Hamstring GroupSemimembranosusOrigin: ischial tuberosityInsertion: medial condyle of tibiaAction: Flexes the knee, rotates the leg medially & extends the thigh
120Muscles that Move the Leg SartoriusOrigin: anterior superior iliac spineInsertion: medial surface of tibiaAction: flexes knee & hip, abducts & rotates thigh laterally
121Muscles that Move the Leg Quadriceps GroupRectus FemorisOrigin: spine of the illium & margin of the acetabulumInsertion: patella by tendon, which continues as the patellar ligament to the tibiaAction: extends knee, flexes thigh
122Muscles that Move the Leg Quadriceps GroupVastus LateralisOrigin: greater trochanter & posterior surface of the femurInsertion: patella by tendon, which continues as patellar ligament to the tibiaAction: extends knee
123Muscles that Move the Leg Quadriceps GroupVastus medialisOrigin: medial surface of the femurInsertion: patella by tendon, which continues as patellar ligament to the tibiaAction: extends knee
124Muscles that Move the Leg Quadriceps GroupVastus intermediusOrigin: anterior & lateral surfaces of femurInsertion: patella by tendon, which continues as patellar ligament to the tibiaAction: extends knee
125Muscles that Move the Foot Movements of the foot include movements of the ankle & toesAttach to the femur, tibia, & fibula to bones of the footMove the foot upward (dorsiflexion) or downward (plantar flexion) and turn the foot so the plantar surface faces medially (inversion) or laterally (eversion)4 types: dorsal flexors, plantar flexors, invertor, evertor
126Muscles that Move the Foot Dorsal FlexorTibialis AnteriorOrigin: lateral condyle & lateral surface of the tibiaInsertion: tarsal bone & first metatarsalAction: dorsiflexion & inversion of foot
127Muscles that Move the Foot Dorsal FlexorFibularis TertiusOrigin: anterior surface of the tibiaInsertion: dorsal surface of the 5th metatarsalAction: dorsiflexion & eversion of the foot
128Muscles that Move the Foot Dorsal FlexorExtensor Digitorum LongusOrigin: lateral condyle of tibia & anterior surface of the fibulaInsertion: dorsal surfaces of 2nd & 3rd phalanges of the 4 lateral toesAction: dorsiflexion & eversion of the foot, extends toes
129Muscles that Move the Foot Dorsal FlexorExtensor Hallucis LongusOrigin: anterior surface of the fibulaInsertion: distal phalanx of the big toeAction: extends big toe, dorsiflexion & inversion of foot
130Muscle that Move the Foot Plantar FlexorGastrocnemiusOrigin: lateral & medial condyles of femurInsertion: posterior surface of calcaneusAction: plantar flexion of foot, flexes knee
131Muscles that Move the Foot Plantar FlexorSoleusOrigin: head & shaft of fibula & posterior surface of the tibiaInsertion: posterior surface of the calcaneusAction: plantar flexion of the foot
132Muscles that Move the Foot Plantar FlexionPlantarisOrigin: femurInsertion: calcaneusAction: plantar flexion of foot, flexes knee
133Muscles that Move the Foot Plantar FlexorFlexor Digitorum LongusOrigin: posterior surface of the tibiaInsertion: distal phalanges of four lateral toesAction: plantar flexion & inversion of foot, flexes four lateral toes
134Muscles that Move the Foot InvertorTibialis PosteriorOrigin: lateral condyle & posterior surface of tibia & posterior surface of fibulaInsertion: tarsal & metatarsal bonesAction: plantar flexion & inversion of foot
135Muscles that Move the Foot EvertorFibularis LongusOrigin: lateral condyle of tibia & head & shaft of the fibulaInsertion: Tarsal & metatarsal bonesAction: plantar flexion & eversion of foot, supports arch