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The Muscular System Structural and functional organization of muscles The system of the little mouse.

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Presentation on theme: "The Muscular System Structural and functional organization of muscles The system of the little mouse."— Presentation transcript:

1 The Muscular System Structural and functional organization of muscles The system of the little mouse

2 Structural and Organization of Muscles 600 Human skeletal muscles –Also smooth & cardiac muscles General structural & functional organization –functions of muscle –connective tissues of muscle –general anatomy of skeletal muscles –muscle shape and function –coordinated actions of muscle groups –intrinsic and extrinsic muscles –muscle innervation

3 The Functions of Muscles Movement of body parts and organ contents Maintain posture and prevent movement Communication - speech, expression & writing Control of openings and passageways Body heat production

4 Non-Verbals

5 Interspecies non-verbals

6 Connective Tissues of a Muscle Perimysium Epimysium Endomysium Tendon Deep fascia

7 Connective Tissues of a Muscle Epimysium –covers whole muscle belly –blends into connective tissue that separates muscles Perimysium –slightly thicker layer of connective tissue –surrounds a bundle of cells called a fascicle Endomysium –thin layer of areolar tissue surrounding each cell –allows room for capillaries and nerve fibers

8 Fascicle, c.s. Fascicles, Perimysium & Endomysium Endomysium


10 Location of Fascia Superficial Fascia Deep Fascia Deep fascia –found between adjacent muscles Superficial fascia (hypodermis) –found between skin and muscles –contains adipose tissue

11 Muscle Attachments Direct (fleshy) attachment to bone –epimysium is continuous with periosteum –intercostal muscles Indirect attachment to bone –epimysium continues as tendon or aponeurosis that merges into periosteum as perforating fibers –biceps brachii or abdominal muscle Attachment to dermis Stress will tear the tendon before pulling the tendon loose from either muscle or bone

12 Parts of a Skeletal Muscle Origin –attachment to stationary end of muscle Belly –thicker, middle region of muscle Insertion –attachment to mobile end of muscle

13 Skeletal Muscle Shapes Fusiform muscles –thick in middle & tapered at ends –biceps brachii m. Convergent muscle –broad at origin and tapering to a narrower insertion Parallel muscles –parallel fascicles –rectus abdominis m.

14 Skeletal Muscle Shapes (2) Circular muscles –act as sphincters –ring around body opening –orbicularis oris Pennate muscles –fascicles insert obliquely on a tendon –unipennate, bipennate or multipennate –palmar interosseus, rectus femoris & deltoid

15 Biceps Tendon Rupture: As a result of chronic tendonitis or truama, the long head of the biceps may rupture. When this occurs, the biceps muscle appears as a ball of tissue and there is a loss of function.

16 Healthy Bicep

17 In september 2005 Maria Sharapova from Russia withdrew from the China Open due to a pectoral injury

18 Healthy Pectorals

19 Top European Golfer: David Howell Ranked 30 th in the world one of England’s best withdrew from the U.S. Open in June of He suffered a rip To the left oblique

20 You can hit these abdominals with a pike and that pike will shatter

21 Ptosis Ptosis is a drooping of the entire upper eyelid. It can be due to trauma, disorders (IE: neurological, myasthenia, auto- immune), surgery, and medication.


23 Terrell Owens, leaving the field and wincing in pain after suffering a regular season ending, lower leg injury against the Cowboys.

24 Terrell Owens has been kicked 800 feet up in the air by the lower leg of Chuck Norris ↑

25 Coordinated Muscle Actions Prime mover or agonist –produces most of force Synergist aids the prime mover –stabilizes the nearby joint –modifies the direction of movement that occurs Antagonist –opposes the prime mover –preventing excessive movement and injury Fixator –prevents movement of bone that prime mover is attached to Example

26 Muscle Actions during Elbow Flexion Prime mover (agonist) = biceps brachii m. Synergist = brachialis m. Antagonist = triceps brachii m. Fixator = muscle that holds scapula firmly in place such as rhomboideus m. Definitions

27 Methods used to diagnose structural muscle disorders Myopathies: Muscle disorders –Can be confused with skeletal/nervous disorders Physical tests – Can you lift against gravity? –Can you lift against resistance? –Can you lift repeatedly? Physicians judge the amount of force and assign a grade; percentage, verbal grade, or numeric


29 Myometers/Dynometers measure the amount of force a muscle exerts MRIs distinguish soft tissues making them more useful than X-Rays Electromyography records electrical activity of a muscle Biopsies: remove a small tissue sample

30 Blood and Urine tests Show muscle enzymes that have leaked into blood –Creatine Kinase –Lactate Dehydrogenase –Aldolase –Aspartate transaminase Changes in conc. of electrolytes which are usually more conc. in skeletal muscle than blood. How much muscle myoglobin is in the urine.

31 Creatine kinase (CK) Its function is the catalysis of the conversion of creatine to phosphocreatine. –Where do you think the phosphorous comes from? Creatine/Phosphocreatine help buffer fluctuations in ATP usage. Studies suggest taking creatine can improve muscle performance under high energy aerobic training –Creatine use is not considered doping and is not banned by sport-governing bodies. In some countries however, like France, creatine is banned.

32 Structural Disorders of Skeletal Muscle Rhabdomyolysis the breakdown of muscle due to injury, either mechanical, physical or chemical. The principal result of this process is acute renal failure due to accumulation of muscle breakdown products in the bloodstream, several of which are injurous to the kidney. Treatment is with intravenous fluids, and dialysis if necessary.

33 Photomicrograph of muscle biopsy sample shows swollen and necrotic muscle fibers without any inflammatory infiltrate

34 Caution Things get gross from here on out. Feel free to look at something calming.

35 Edema is the medical term for swelling as a result of fluid in the skin or muscle. A hematoma is a collection of blood under the skin. It can occur in any soft tissue such as skin or muscle. A hematoma is caused when blood leaks from an injured vessel.

36 Contracture: Abnormal shortening of muscles Dupuytren's contracture is a fixed flexion contracture of the hand where the fingers bend towards the palm and cannot be fully extended.

37 Myositis Muscle inflammation Viral, bacterial, or parasitic infection Trichinois: Larva of parasitic rounworms Tricinella get encysted in muscles. Caused by eating undercooked pork or bear ~ 12 cases a year in US ~500 cases a year in Thailand

38 Polymyositis Degenerated skeletal muscle fibers (amorphous pink) with infiltrating macrophages and regenerating fibers with multiple nuclei and more lavender cytoplasm.

39 Crush injuries are associated with significant mechanisms of injury. If a force is great enough, soft tissue (muscles, vessels, skin) can be crushed leading to extensive tissue damage and subsequent swelling and pain. Crush injuries in the lower extremities and forearm can lead to compartment syndrome that generally takes a few hours to develop.

40 In the eyes of a ranger, The unsuspecting stranger, Had better know the truth of wrong from right, 'Cause the eyes of a ranger are upon you, Any wrong you do, he's gonna see, When you're in Texas, look behind you, 'Cause that's where the rangers gonna be.

41 Intrinsic and Extrinsic Muscles Intrinsic muscles are contained within a region such as the hand. Extrinsic muscles move the fingers but are found outside the region.

42 Skeletal Muscle Innervation Cranial nerves arising from the brain –exit the skull through foramina –numbered I to XII Spinal nerves arising from the spinal cord –exit the vertebral column through intervertebral foramina

43 How Muscles are Named Nomina Anatomica –system of Latin names developed in 1895 –updated since then English names for muscles are slight modifications of the Latin names. Table 10.1 = terms used to name muscles digiti = of a finger levator = elevates a body part profundus = deepest quadriceps = having 4 heads

44 Learning Strategy Explore the location, origin, insertion and innervation of 160 skeletal muscles using the tabular information in this chapter. Increase your retention & understanding by: –examining models and photographic atlases –palpating yourself using the images in Atlas B –observe an articulated skeleton –say the names aloud and check your pronunciation

45 The Muscular System

46 Muscles of Facial Expression Small muscles that insert into the dermis Innervated by facial nerve (CN VII) Paralysis causes face to sag Found in scalp, forehead, around the eyes, nose and mouth, and in the neck

47 Occipitofrontalis is found in the scalp. Frontalis m. raises the eyebrows while Occipitalis m. fixes the galea aponeurotica Muscles of the Scalp and Forehead Frontalis Occipitalis

48 Corrugator supercilii Muscles around the Eyes Nasalis Orbicularis oculi closes the lips. Corrugator draws the eyebrows together. Procerus pulls down the skin of forehead. Nasalis widens nostrils. Procerus Orbicularis Oculi

49 Orbicularis oris encircles mouth & other mm blend into it Levator & depressor of labii (lip) & anguli (angle of mouth) Risorius & zygomaticus curl corner of mouth up in smile Buccinator keeps food on top of teeth, blowing & sucking Muscles around the Mouth Orbicularis oris Risorius Depressor labii inferioris Buccinator Zygomaticus major Depressor anguli oris Levator labii superioris

50 Some of the Muscles used in Facial Expression


52 Musculature of the Tongue Intrinsic muscles = vertical, transverse & longitudinal Extrinsic muscles connect tongue to hyoid, styloid process, palate and inside of chin Tongue shifts food onto teeth & pushes it into pharynx Intrinsic tongue muscles Extrinsic tongue muscles

53 Muscles of Mastication 4 Major muscles Arise from skull & insert on mandible Temporalis & Masseter elevate the mandible Medial & Lateral Pterygoids help elevate, but produce lateral Swinging of jaw used to grind with molars Temporalis Masseter Lateral pterygoid Medial pterygoid

54 Suprahyoid Muscles and Swallowing Digastric and Mylohyoid = open mouth Geniohyoid = widens pharynx during swallowing Stylohyoid = elevates hyoid Thyrohyoid (an infrahyoid m.) = elevates larynx, closing glottis Digastric Mylohyoid Stylohyoid Thyrohyoid

55 Triangles of the Neck

56 Other Muscles involved in Swallowing Pharyngeal constrictors push food down throat Infrahyoid muscles pulls the larynx downward Intrinsic laryngeal muscles used to control speech Pharyngeal constrictors

57 Muscles of Respiration Breathing requires the use of muscles –diaphragm –external intercostal muscles –internal intercostal muscles Contraction of the first 2 produces Inspiration Contraction of the last produces Forced Expiration Normal Expiration requires little muscular activity –elastic recoil of tissues and gravity collapsing the chest –only inspiratory muscles active in braking action, so exhalation is smooth

58 Muscles of Respiration -- Diaphragm Muscular dome between thoracic and abdominal cavities Muscle fascicles extend to a fibrous central tendon Contraction flattens it –increases the vertical dimension of the thorax drawing air into the lungs –raises the abdominal pressure to help expel urine, feces and facilitating childbirth Central tendon

59 Muscles of Respiration -- Intercostals External intercostals –extend downward and anteriorly from rib to rib –pull ribcage up & outward during inspiration Internal intercostals –extend upward and anteriorly from rib to rib –pull ribcage downward during forced expiration

60 Muscles of Respiration - Serratus Serratus posterior superior –elevates ribs 2-5 during inspiration Serratus posteriori inferior –depresses ribs 9-12 during inspiration

61 Muscles of the Abdomen 4 Pairs of sheetlike muscles –external oblique –internal oblique –transverse abdominis –rectus abdominis Functions –support the viscera –stabilize the vertebral column –help in respiration, urination, defecation & childbirth

62 Rectus Abdominis & External Oblique External oblique –superficial –downward –anteriorly –inguinal ligament Rectus abdominis –vertical, straplike –tendinous intersections –rectus sheath –linea alba External oblique Rectus abdominis

63 Internal Oblique -Transverse Abdominis Internal oblique –anteriorly –upwards Transverse abdominis –horizontal fiber orientation –deepest layer Transverse abdominis Internal oblique

64 Superficial Muscles of the Back Trapezius Latissimus dorsi Semispinalis Splenius Levator scapulae Rhomboideus Supraspinatus Infraspinatus Teres major Gluteus maximus Gluteus medius

65 Muscles of the Back Erector spinae group –3 columns muscle –extends from sacrum to ribs –extends vertebral column Semispinalis group –vertebrae to vertebrae –extends neck Multifidis –vertebrae to vertebrae –rotates vertebral column Quadratus lumborum –ilium to 12th rib –lateral flexion Multifidis Erector spinae Quadratus lumborum Semispinalis

66 Muscles of the Pelvic Floor 3 Layers of muscles span pelvic outlet –support pelvic viscera Region is called perineum –diamond-shaped region bounded by pubic symphysis, coccyx and ischial tuberosities –penetrated by anal canal, urethra & vagina –anteriorly = urogenital triangle; posteriorly= anal triangle 3 Layers or compartments of the perineum –superficial layer = Superficial perineal space –middle layer = Urogenital diaphragm & Anal sphincter –deep layer = Pelvic diaphragm

67 Muscles in Superficial Perineal Space 3 Muscles found just deep to the skin Ischiocavernosus = arises from ischial & pubic ramus Bulbospongiosus = covers bulb of penis or encloses vagina Superficial transverse perineus = extends from the ischial tuberosities to the central tendon of the perineum Function during sexual intercourse & voiding of urine Bulbospongiosus Ischiocavernosus Superficial transverse perineus

68 Muscles of the UG diaphragm Middle layer of pelvic floor contains Urogenital diaphragm and External anal sphincter Urogenital diaphragm = 2 muscles –deep transverse perineus m. supports pelvic viscera –external urethral sphincter m. inhibits urination External anal sphincter Urogenital diaphragm

69 Muscles of the Pelvic Diaphragm Deepest compartment of the perineum Pelvic diaphragm = 2 muscles –levator ani m. supports viscera & functions during defecation –coccygeus m. supports and elevates pelvic floor Levator ani Coccygeus

70 Hernias Protrusion of viscera through muscular wall of abdominopelvic cavity Inguinal hernia –most common type of hernia (rare in women) –viscera enter inguinal canal or even the scrotum Hiatal hernia –stomach protrudes through diaphragm into thorax –overweight people over 40 Umbilical hernia –viscera protrude through the navel

71 Muscles Acting on the Pectoral Girdle Originate on axial skeleton & insert onto clavicle or scapula Anterior muscle group = 2 muscles Posterior muscle group = 4 muscles Scapular movements produced include –medial and lateral rotation of the scapula –elevation and depression of the scapula –protraction and retraction of the scapula Clavicle braces the shoulder & limits movement

72 Anterior Scapular Muscle Group Pectoralis Minor –ribs 3-5 to coracoid process of scapula –protracts & depresses scapula –lifts ribs during forced expiration Serratus Anterior –ribs 1-9 to medial border of scapula –abducts & rotates or depresses scapula –throwing muscle

73 Muscles Acting on the Scapula

74 Posterior Scapular Muscle Group 4 Muscles –superficial = Trapezius –deep = Rhomboids & Levator scapulae Trapezius –rotate scapula upward –retract scapula –depress scapula With Levator scapulae & Rhomboids elevates scapula With Serratus anterior depresses scapula

75 Rhomboideus mm. –medial border of scapula to C7-T1 Posterior Scapular Muscle Group Levator scapulae –from superior angle of scapula to C1-C4

76 Muscles Acting on the Humerus 9 Muscles cross the shoulder joint to the humerus –2 axial muscles arise from axial skeleton –prime movers of humerus in flexion & extension –arise from sternum & clavicle OR T7-L5 & ilium Pectoralis major Latissimus dorsi

77 7 scapular muscles arise from scapula –Deltoid is prime mover flexion, extension and abduction of humerus –Coracobrachialis assists in flexion – Teres major assists in extension –Remaining 4 form the rotator cuff muscles that reinforce the shoulder joint capsule Muscles Acting on the Humerus

78 Posterior View of Chest in Cadaver

79 Rotator Cuff Muscles Extending from posterior scapula to humerus –supraspinatus –infraspinatus –teres Minor Extending from anterior scapula to humerus –subscapularis All 4 help reinforce joint capsule. Supraspinatus Infraspinatus Teres minor Subscapularis

80 Anterior View of Chest in Cadaver

81 Muscles Acting on the Elbow Principal flexors –biceps brachii inserts on radius –brachialis inserts on ulna Synergistic flexor –brachioradialis Prime extensor –triceps brachii inserts onto ulna

82 CS Through Upper Limb & Forearm

83 Supination & Pronation of the Forearm Supination Supinator muscle Palm facing anteriorly Pronation Pronator teres and Pronator quadratus mm. Palm faces posteriorly

84 Muscles of the Anterior Forearm Flex/extend wrist and fingers, adduct/abduct wrist Digitorum = inserts into fingers Carpi = inserts onto carpal bones Pollicis = inserts into thumb

85 Muscles of the Posterior Forearm Extension of wrist and fingers, Adduct/abduct wrist Extension and abduction of thumb (pollicis) Brevis = short, Ulnaris = on ulna side of forearm Extensors

86 Thenar group = fleshy base of thumb muscles Hypothenar group = base of little finger muscles Midpalmar group = Interosseus mm. & Lumbrical mm. Intrinsic Hand Muscles Interosseus Lumbrical

87 Carpal Tunnel Syndrome repetitive motions causes inflammation and pressure on median nerve

88 Anterior Muscles Acting on the Hip Iliopsoas muscle –crosses anterior surface of hip joint & inserts on femur –iliacus portion arises from iliac fossa –psoas portion arises from lumbar vertebrae –major hip flexor Iliopsoas

89 Posterior Muscles Acting on the Hip Gluteus maximus –forms mass of the buttock –prime hip extensor –provides most of lift when you climb stairs Iliotibial band –band of fascia lata attached to the tibia Gluteus maximus Gluteus medius Iliotibial band

90 Deep Gluteal Muscles Most laterally rotate femur Except: Gluteus minimus medially rotates femur Important in walking to shift body weight when foot is lifted Quadratus femoris is adductor of hip Piriformis & Gluteus minimus are abductors of hip Quadratus femoris Piriformis Gluteus minimus

91 Adductors of the Hip Joint 5 muscles act as adductors Adductor magnus is also an extensor of hip joint Gracilis also is flexor of knee Pectineus, Adductor brevis and Adductor longus adduct the femur Adductor longus Adductor brevis Pectineus Adductor magnus

92 Muscles Acting on the Knee 4 headed muscle attaches to tibial tuberosity –extends knee joint rectus femoris arises from ilium so flexes hip joint quadriceps femoris tendon attaches to patella patellar ligament attaches to tibia

93 Anterior Thigh Muscles in Cadaver

94 Muscles of the Leg Crural muscles are separated into 3 compartments. –anterior compartment (green) –fibular (lateral) compartment (blue) –posterior (superficial = brown) (deep = purple)

95 Anterior Compartment of the Leg Extensor digitorum longus = extension of toes & ankle Extensor hallucis longus = extension of big toe & ankle Fibularis tertius = dorsiflexes and everts foot Tibialis anterior = dorsiflexes and inverts foot Extensor digitorum longus Peroneus tertius Extensor hallucis longus Tibialis anterior

96 Posterior Compartment of the Leg Superficial Group of Plantar Flexors Gastrocnemius = flexes knee and plantar flexes ankle Soleus = plantar flexes ankle Plantaris = flexes knee and plantar flexes ankle Gastrocnemius Soleus Plantaris

97 Posterior Compartment of the Leg Deep Group of Plantar Flexors Tibialis posterior, Flexor digitorum longus, and Flexor hallucis longus and are plantar flexors. Popliteus unlocks the knee joint for knee flexion.

98 Lateral Compartment of the Leg 2 muscles in this compartment Both plantar flex and evert the foot Provides lift and forward thrust Fibularis brevis Fibularis longus

99 Leg Muscles in the Cadaver

100 Intrinsic Muscles of the Sole Four muscle layers Support for the arches –abduct & adduct the toes –flex the toes One dorsal muscle –extensor digitorum brevis extends toes Dorsal view

101 Athletic Injuries Vulnerable to sudden and intense stress Proper conditioning and warm-up is needed Common injuries –shinsplints –pulled hamstrings –tennis elbow Treat initially with rest, ice, compression and elevation “No pain, no gain” is a dangerous misconception.

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