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By Dr MB Samarawickrama (MBBS MS) 31 th Batch July 2008 Muscles and Tendons.

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Presentation on theme: "By Dr MB Samarawickrama (MBBS MS) 31 th Batch July 2008 Muscles and Tendons."— Presentation transcript:

1 By Dr MB Samarawickrama (MBBS MS) 31 th Batch July 2008 Muscles and Tendons

2 Muscles Three types Skeletal Muscles Cardiac Muscles Smooth Muscles

3 Muscles Need to know Histology Gross Anatomy Physiology

4 Muscles Skeletal Muscles Formed by number of muscle fibers Non branching

5 Muscles-Histology Skeletal muscles Consist of unbranched fibres Banded by striations Small nuclei, placed peripherally on the surface of the fibres

6 Microscopic structure

7 Fiber’s size varies within a single muscle Hypertrophy of muscle results increase in size of the fiber The number remains the same

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9 These fibres are bound together by a loose areola tissue This envelope is known as epimysium

10 Muscles-Histology ENDOMYCIUM, PERIMYCIUM EPIMYCIUM

11 Cardiac muscle Also striated Fibres are branched Large nuclei placed centrally

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13 Smooth muscle Long spindle shaped cells Nucleus lies centrally

14 Parallel cells joined to form muscle fibres The fibres arrange Circularly, longitudinally or whorls & spirals with no demonstrable layers

15 The form of muscles Fibres in a muscle arrange in two ways Parallel to the line of pull –increase range of mobility

16 The form of muscles Oblique to the line of pull –range of mobility is less –Force of pull is maximum

17 The form of muscles E.g. muscles with Parallel fibers Sartorius Rectus abdominis Infrahyoid muscles Anterior & posterior fibres of the deltoid

18 Muscles with Parallel Fusiform

19 The form of muscles The muscles with oblique fibres One of 4 patterns –Unipinate muscles –Bipennate Muscles –Multipinate Muscles-two types

20 The form of muscles Unipinate muscle The tendon forms along one margin of the muscle All the fibres slope into one side of the tendon e.g. Flexor Policis Longus

21 The form of muscles Bipennate Muscles The tendon forms centrally muscle fibres slope into the two sides of the central tendon. –Like a feather e.g. Rectus Fumoris

22 The form of muscles

23 Multipinate Muscles Two varieties Series of bipinnate masses lying side by side e.g. Central part of the deltoid Subscapularies

24 The form of muscles Multipennate Muscles cylindrical muscle within which a central tendon forms Into the central tendon muscle fibres converge from all sides e.g. Tibialis anterior

25 Surface appearance of muscles Some more fleshy Some largely apponeurotic Some have a mixture of two

26 Surface appearance of muscles That reflect the function of the muscle If the muscle bears lot of pressure from adjacent structures – it is covered by an apponeurosis Where there is no pressure it is usually flesh

27 Origin and insertion of muscle No reality in these terms Origin – fixed end Insertion – moving end

28 Origin and insertion of muscle But vary depending on the circumstances Use the word attachment instead

29 Bone markings Fleshy origins leaves no marks on bones The area is flatten or depressed on the bone

30 e.g. Pec. Major on the clavicle

31 Bone markings Insertion of a pure tendon almost always leave a smooth mark on the bone e.g. Ligamentum patelle attachment

32 Bone markings Rough marks are made where there is admixture of flesh & tendon or where there is a lenthy insertion of aponeurosis e.g. Linear aspera femur

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34 Bone markings Flat muscles arise from-flat bone Muscle origin does not extend to the edge of the flat bone It origin from an edge of a curved line Between the origin and the edge of the bone is a bare area This area is occupied by a bursa Which may or may not be communicated with the adjacent joint e.g. subscapularis

35 Actions of muscles The action of muscles or muscle groups are often oversimplified Terms denoting action, in particular, emphasize only one of a number of habitual actions A given muscle may play different roles in different movements

36 Actions of muscles these roles may change if the movements are assisted or opposed by gravity Single muscle rarely contract alone The action is influence by its companions in contraction

37 Actions of muscles When a muscle crosses two joints It mainly act on distal joint to move it On proximal joint it act to steady the joint –e.g. Biceps long tendon –Triceps

38 Actions of muscles In such cases Position of the proximal joint changes the length of the muscles Thus affect the movement of the distal joint

39 Actions of muscles e.g. Action of long flexor tendons of the IPJ is affected by the position of the wrist Position of the knee affect the action of the Gastrocnemius on the ankle joint

40 Actions of muscles Synergic actions Muscles acting as a prime movers on a certain joint have a different action when a more distal segment of the limb is in motion. Then they act synergistically to stabilized the joint during the movement of the distal joint. e.g. short muscles of the shoulder estabilized the shoulder when – wrist fingers & elbow in movement

41 Actions of muscles Muscles act synergistically in another way This is to cancel out unwanted secondary effect. e.g. Tricep contract when the forearm is supinated while the elbow is flexed.

42 Actions of muscles This prevent the flexion of the elbow by the contraction of the biceps This will not oppose the supination action.

43 Assessment of Muscle Action Common sense Feeling of contraction Pullin tendons in dead Nerve stimulation of motor nerve Electromyography Comparative anatomy

44 Action of Paradox Multiplicity of common movements are aided by gravity In such movements opposing muscles contract to keep the limb against the force of gravity

45 Action of Paradox e.g. When the arm adduct from abducted position Deltoid muscle contract which is a muscle of abduction This is known as action of paradox

46 Blood supply Muscles have a rich blood supply Arteries and veins pierce the surface in company with the motor nerve From muscle belly artery supply the tendon Lymphatics run back with arteries

47 Large blood vessels enter the perimysium Branches of perimysial blod vesels ramify pass inbetween and surrounds the muscle fibers

48 Nerve supply of muscles Flat muscles of the body wall are pierced by cutaneous nerve They do not supply the muscles

49 Nerve supply of muscles In limbs If a nerve pierces a muscle that nerve supplies the muscle The motor branch leaves proximal to the muscle In limbs nerves passes between muscle planes This planes distinct morphological masses that have fused together

50 Nerve supply of muscles In limbs All the muscles are not supplied by plexus Flexor muscles are supplied by anterior divisions Extensor muscles are supplied by posterior divisions

51 Nerve supply of muscles Sensory supply In a nerve supply to a muscle contain 40% of sensory nerve fiber

52 Nerve supply of muscles Certain cranial nerves are purely motor (iii, iv, vi, vii, xii) supply ocular & facial muscles. Spinal accessory nerve also contain no sensory fibres Sensory supply to those muscles are derived from other adjacent nerves –e.g. trigemial V

53 Physiology of muscle All skeletal muscle in the body except heart is supplied by somatic nerves –Voluntary muscles Heart & all smooth muscles are supplied by autonomic nerves –Involuntary muscles

54 Physiology of muscle Smooth muscles can elongate to greater extend e.g. bladder Skeletal muscle cannot elongate 1/3 of their resting length

55 Naming of Muscles The names given to individual muscles are usually descriptive, based on their shape, size, number of heads or bellies Position, depth, attachments, or actions

56 Naming of Muscles The terms used according to the Shape Deltoid (= triangular) Quadratus (= square) Rhomboid (= diamond-shape) Teres (= round) Gracilis (= slender) Rectus (= straight) Lumbrical (= worm-like)

57 Naming of Muscles The terms used according to the Size Major(large) Minor (small) Longus (= long) Brevis (=short) Latissimus (= broadest) Longissimus (= longest)

58 Naming of Muscles The terms use according to the Number of heads or bellies Biceps (= 2 heads) Triceps (= 3 heads) Quadriceps (= 4 heads) Digastric (= 2 bellies)

59 Triceps Digastric

60 Naming of Muscles The terms used according to the Position Interosseus (= between bones) Supraspinatus (= above spine of scapula) Infraspinatus (= below spine of scapula) Dorsi (= of the back) Abdominis (= of the abdomen) Pectoralis (= of the chest) Brachii (= of the arm) Femoris (= of the thigh) Oris (= of the mouth) Anterior, posterior,

61 Naming of Muscles The terms used according to the Depth Superficialis (= superficial) Profundus (=deep) Externus (or external) Internus (or internal)

62 Naming of Muscles The terms used according to the Attachment sternocleidomastoid (from sternum and clavicle to mastoid process) coracobrachialis (from the coracoid process to the arm)

63 Naming of Muscles The terms used according to the Action Extensor, flexor Abductor, adductor Levator (= lifter), depressor Supinator, pronator Constrictor, dilator

64 Naming of Muscles These terms are often used in combination: E.G flexor digitorum longus (= long flexor of the digits) latissimus dorsi (= broadest muscle of the back).

65 Pathology Hypertrophy Atrophy Paralysis Ischaemia Necrosis

66 Tendons Tendons are tissues that connect muscles to bone, allowing the force of the muscles to move the joints. Tendons consist of longitudinally arranged collagen fibres Shape cylindrical or flat The aponeurosis of the abdominal wall muscles are wide sheats of tendons

67 Tendons Blood supply is by two main sources Descending vessels from the muscles Periosteal vessels from the bone of insertion

68 Tendons In long tendons an additional supply present From neighboring artery If you tear (rupture) or cut (sever) the tendon anywhere along its route unable to move the distal part Tendons are stretched tightly as they connect the muscle to the bone. If the tendon tears, the end must be sewn back together again (a surgical repair)

69 Tendons Synovial sheaths Enclose tendons where the range of movement is considerable e.g. the tendon in the fingers this is to reduce the friction

70 Tendons

71 Sheeth has two layers –Parietal –Visceral Parietal layer firmly attach to the surrounding structures Visceral layer firmly fixed to the tendon

72 Tendons In between Thin layer of fluid lubricate the two layers & facilitate movements The visceral & parietal layers fused each other on one side

73 Tendons They do not enclose tendon cylindrically Tendon looks pushed into double layers of enclosed sheath Blood vessels can enter the tendon between this space

74 Tendons


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