The Muscular System

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 Tendon Deep fascia Epimysium Perimysium Endomysium

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

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

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. Ranked 30th in the world one of England’s best withdrew from the U.S. Open in June of 2005. He suffered a rip To the left oblique Top European Golfer: David Howell

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 Example • 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

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

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

49. Muscles around the Mouth • 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 Levator labii superioris Zygomaticus major Buccinator Risorius Depressor anguli oris Orbicularis oris Depressor labii inferioris

50. Some of the Muscles used in Facial Expression