[CN]CHAPTER 16



CHAPTER 16

The Bones and Soft Tissues

Preparation and Resources Needed

Materials: X-rays that show actual examples of different types of fractures; photographs of soft tissue injuries to teach students what to look for with each type of soft tissue injury dealt with in the chapter.

Equipment: Full-sized articulated skeletons (preferably real, but models are okay).

Personnel: An orthopedic surgeon to describe, perhaps with pictures or video, what he or she does; a radiologist to describe imaging techniques.

Recommended Time to Complete: Six days (based on two class periods per day, 170 school days per year). More activities are available through the textbook, workbook, and instructor’s manual than can be fit into the recommended time. The instructor should select activities that best suit his or her own teaching situation and training program duration.

Key Terms

abrasion An injury that occurs when several layers of skin are torn loose or totally removed.

acetylcholine The chemical released when a nerve impulse is transmitted.

action potential The electric change occurring across the membrane of a nerve or muscle cell during transmission of a nerve impulse.

afferent neuron A nerve that carries nerve impulses from the periphery to the central nervous system; also known as a sensory neuron.

angiogenesis The formation of new blood vessels.

antagonist A muscle whose action opposes the action of another muscle.

appendicular skeleton Bones of the pelvis and shoulder girdles, and limbs.

avulsion An injury in which layers of the skin are torn off completely or only a flap of skin remains.

axial skeleton The bones of the head and trunk (skull, spine, sternum, and ribs).

belly The central part of a muscle.

bursitis Inflammation of the bursa (a padded cavity around a joint that decreases the friction between two surfaces).

cardiac muscle Type of muscle that makes up the heart.

cellular dedifferentiation A form of wound healing in which mature cells produce new cells with the same function.

collagen fibers A protein substance found in bone and cartilage.

comminuted fracture A break in which the bone is shattered in many pieces.

compound fracture A complete break in the bone where the bone ends separate and break through the skin; also known as an open fracture.

connective tissue Cells whose secretions support and connect organs and tissues in the body.

contractibility The ability to shorten or reduce the distance between the parts.

contusion An injury resulting from a direct blow or force that does not interrupt the skin; typically, bruising is seen at the injury site.

delayed onset muscle soreness (DOMS) The presence of soreness in the muscles a day or two after overuse of the muscles or a traumatic injury.

diaphysis The shaft of a long bone.

ecchymosis Bruising.

efferent neuron A nerve that carries messages from the brain and spinal cord to muscles and glands; also known as a motor neuron.

elasticity The ability to return to original form after being compressed or stretched.

epiphyseal plate fracture A break in the bone at the growth plate (typically at the wrist or ankle).

epiphysis The end of a long bone.

excitability The ability to respond to stimuli; also known as irritability.

extensibility The ability to lengthen and increase the distance between two parts.

external fixation The use of a cast to maintain proper alignment of bones for the purpose of reduction.

extracellular matrix (ECM) Noncellular material that separates connective tissue cells.

greenstick fracture An incomplete break in the shaft of the bone; occurs in children.

hematoma The formation caused by pooling of blood and fluid within a tissue space.

inflammation Process that occurs when tissues are subjected to chemical or physical trauma; pain, heat, redness, and swelling occur.

insertion The part of the skeletal muscle that is attached to the movable part of a bone.

internal fixation Surgical alignment of bones for the purpose of reduction.

interneuron A nerve that carries messages from a sensory neuron to a motor neuron; also known as an associative neuron.

laceration An injury that results from a tear in the skin; also known as a cut.

leukocytes White blood cells.

lymphocytes A group of white blood cells of crucial importance to the body’s immune system.

medullary canal The center of the shaft of the long bone.

membrane excitability The ability of nerves to carry impulses by creating electrical charges.

monocyte Large, circulating white blood cells.

mononuclear phagocytes White blood cells that engulf and destroy waste material and foreign bodies in the bloodstream.

motor unit A motor nerve plus all of the muscle fibers it stimulates.

muscle fatigue The result of accumulation of lactic acid in the muscle.

muscle tone The state of partial contraction in which muscles are maintained.

myelin sheath The layers of cell membrane that wrap around nerve fibers; provide electrical insulation; and increase the velocity of impulse transmission.

myositis ossificans A calcification that forms within the muscle; results from an improperly managed contusion.

neuroma A ball-like growth of nerve fibers that creates a nerve scar.

neuromuscular junction The point between the motor nerve axon and the muscle cell membrane.

neutrophils White blood cells that engulf and kill bacteria.

origin The part of the skeletal muscle that is attached to the fixed part of a bone.

ossification The process of bone formation.

osteoblast Type of bone cell involved in the formation of bony tissue.

osteoclast Type of bone cell involved in the resorption of bony tissue.

osteocyte A bone cell.

periosteum The fibrous tissue that covers the bone.

prime mover Muscle that provides movement in a single direction.

puncture wound An injury caused by a sharp object that penetrates the skin.

reduction The process of putting broken bones back into proper alignment.

regeneration The act of wound healing (tissue rebuilding).

remodeling The process of absorbing and replacing bone in the skeletal system.

sarcolemma The muscle cell membrane.

sarcoplasm The material within the muscle cell, excluding the nucleus.

scar tissue Fibrous connective tissue that binds damaged tissue.

simple fracture A break in the bone that may be complete or incomplete, but does not break through the skin; also known as a closed fracture.

skeletal muscle Type of muscle, attached to a bone or bones of the skeleton, which aids in body movements; also known as voluntary or striated muscle.

smooth muscle Type of muscle that is not attached to bone, and is nonstriated and involuntary; also known as visceral.

sphincter muscle A type of circular muscle.

spongy bone Results from the breakdown of hard bone.

sprain An injury resulting from a fall, sudden twist, or blow to the body that forces a joint out of its normal position.

strain A muscle injury caused by the twisting or pulling of a muscle or tendon.

stress fracture A small, incomplete break in the bone that results from overuse, weakness, or biomechanical problems.

synapse The space between adjacent neurons through which an impulse is transmitted.

synergists Muscles that help steady a joint.

tendonitis Inflammation of the tendon (fibrous tissue connecting muscle to bone).

transdifferentiation A form of wound healing in which mature cells dedifferentiate and produce new cells that are then able to mature into cell types with a completely different function from the originating cells.

Lecture Outline

I. The Skeletal System

Key Concept

The skeleton has two main parts: the axial skeleton and the appendicular skeleton. The axial skeleton consists of the skull, spine, ribs, and sternum. The appendicular skeleton consists of the shoulder and pelvic girdles and the attached limb bones.

a. Functions:

i. Aids in body movement

ii. Supports and protects internal body organs

iii. Produces red and white blood cells

iv. Provides a storehouse for minerals

Key Concept

The functions of the skeletal system are:

• To aid in movement of the body

• To support and protect internal organs

• To produce red and white blood cells

• To provide a storehouse for minerals

II. Bones

a. Consist of osteocytes (mature bone cells)

b. Made of:

i. 35 percent organic material

ii. 65 percent inorganic mineral salts and water

c. Formation:

i. Initially consist of collagenous protein fibers secreted by osteoblasts

ii. During embryonic development, cartilage is deposited between fibers

iii. During the eighth week of embryonic development, ossification begins

. Mineral matter starts to replace previously formed cartilage, creating bone

III. Injury to Bones

a. Fractures

iv. Simple or closed

v. Compound or open

vi. Comminuted

vii. Stress

viii. Epiphyseal plate

Key Concept

Fractures can be classified by the degree of injury to the bone. There are six types. The simple fracture is a break in the bone that does not penetrate the skin; the compound fracture is a break in the bone that penetrates the skin; the greenstick fracture is an incomplete break; the stress fracture is the result of overuse or weakness; and the epiphyseal plate fracture is a break that occurs at or near the growth plate.

d. Fracture signs and symptoms

i. Swelling, deformity, pain, tenderness, and discoloration

e. Treatment

i. Bones must sometimes be put back in proper position (i.e., reduction)

ii. Immobilization through use of a cast

iii. Surgery

IV. Muscles

a. Principal types of muscles:

iv. Skeletal

. Under voluntary control

v. Smooth

. Involuntary

vi. Cardiac

. Only found in the heart

. Involuntary

Key Concept

There are three main types of muscle: skeletal muscle, which is under voluntary control and aids in movement; smooth muscle, which is not under voluntary control but is controlled by the central nervous system; and cardiac muscle, which is involuntary and makes up the heart.

V. Characteristics of Muscles

a. Four common characteristics:

vii. Contractibility

viii. Excitability

ix. Extensibility

x. Elasticity

VI. Muscle Attachments and Functions

a. More than 650 muscles in the body

xi. Muscles only pull, never push

f. Muscles attached to bones by tendons

i. Bones are connected at joints

g. Muscles are attached at both ends to bones, cartilage, ligaments, tendons, skin, or other muscles

h. Origin: part of a skeletal muscle that is attached to a fixed structure or bone

i. Insertion: attached to a movable part

j. Belly: central body of the muscle

k. Prime mover: movement in a single direction

i. Antagonist: movement in the opposite direction

VII. Sources of Energy and Heat

a. When muscles work, they move the body and produce heat

l. For muscles to contract and work, they need energy

i. Major source of energy is adenosine triphosphate

. Cell requires oxygen, glucose, and other materials

ii. When a muscle is stimulated, ATP is broken down, producing energy

VIII. Contraction of Skeletal Muscle

a. Muscle movement occurs as a result of:

iii. Myoneural stimulation

iv. Contraction of muscle proteins

m. Skeletal muscles must be stimulated by nerve impulses to contract

i. Begins with action potential, which travels along muscle fiber length

ii. Basic source of energy is glucose

IX. Muscle Fatigue

a. Caused by accumulation of lactic acid in muscles

n. During vigorous exercise, blood is unable to transport enough oxygen for complete oxidation of glucose in the muscles

i. Causes muscles to contract anaerobically (without oxygen)

X. Muscle Tone

a. Muscles should always be slightly contracted and ready to pull (muscle tone)

o. Muscle atrophy:

i. Wasting or loss of muscle tissue resulting from disease or lack of use

p. Hypertrophy:

i. Increase in the mass (size) of a muscle

XI. Injuries to Muscles

a. Strain:

ii. Caused by twisting or pulling a muscle or tendon

iii. Acute or chronic

. Symptoms: pain, muscle spasm, and muscle weakness

. Treatment: reduce swelling, anti-inflammatory drugs, surgery, rehabilitation

Key Concept

A strain is the result of twisting or pulling a muscle or tendon. It is characterized by pain, muscle spasm, and muscle weakness. Signs of a strain may include localized swelling, cramping, inflammation, and some loss of muscle function.

q. Sprain:

i. Caused by sudden twist, or a blow to the body

. Symptoms: pain, swelling, bruising, and loss of ability to move

. Treatment is similar to care for a strain

r. Tendonitis:

i. Inflammation of the tendon

. Symptoms: pain and inflammation along a tendon

. Treatment: avoidance of aggravating movements, medications, rehabilitation

s. Bursitis

i. Inflammation of a bursa

. Symptoms: joint pain (often mistaken for arthritis)

. Treatment: avoidance of aggravating movements, medications, rehabilitation

t. Contusion:

i. Direct blow that does not break the skin

. Symptoms: swelling, pain to the touch, redness, and ecchymosis

. Treatment: monitoring, ice, medications, compressive dressing

XII. Nerves

a. Nerve tissue consists of:

ii. Neuroglia

. Insulate, support, and protect neurons

iii. Neurons

. Sensory

. Motor

. Associative

u. Nerves carry impulses by creating electric charges through membrane excitability

i. A synapse is the space between adjacent neurons through which the impulse is transmitted

Key Concept

The function of nerve cells is to carry impulses by creating electrical charges. This is done by moving electrically charged ions across a membrane. Ions move from an area of higher concentration to an area of lower concentration.

XIII. Injury to Nerves

a. Nerves are fragile and can be damaged by pressure, stretching, or cutting

ii. Injury to a nerve can stop signals to and from the brain

. Causes muscles to become unresponsive and loss of feeling in the injured area

Key Concept

A nerve injury occurs because of pressure, stretching, or cutting of the nerve. Damage to a nerve interrupts its signals to the brain and can impair motor function and sensation as a result. Treatment for a cut nerve is to sew together the myelin sheath around both ends of the nerve. The goal is to save the cover so that new nerve fibers can grow.

XIV. Soft-Tissue Injuries

a. Classified as:

iii. Open

. Abrasions, lacerations, avulsions, and puncture wounds

iv. Closed

. Contusions, hematomas, ecchymoses, sprains, strains, tendonitis, bursitis, and stress-related injuries

Key Concept

The treatments for soft-tissue injuries vary by injury:

• Abrasions are treated by washing with soap and water, applying antibiotic ointment, and leaving them open to air if not bleeding or oozing.

• Lacerations are treated by cleaning them with soap and water and applying a bandage with pressure to stop the bleeding.

• Avulsions must be cleaned. Any remaining flap of skin should be replaced in its original position (completely detached skin can be placed on ice). This type of injury often requires treatment by a physician.

• Puncture wounds should be examined to determine if the object is still in the wound, if any underlying structures or organs were damaged, and if the object was contaminated and could increase the risk of infection. Puncture wounds should be checked by a physician.

• Contusions can be treated with ice, compressive dressings, and anti-inflammatory medications.

• Hematomas are treated with compression, cold packs, elevation, and rest.

• Ecchymosis usually does not require treatment unless severe.

XV. The Body’s Response to Injury

a. Inflammation:

v. Reaction to invasion by an infectious agent or physical, chemical, or traumatic damage

v. Regeneration:

i. Act of wound healing

w. Cellular dedifferentiation:

i. Regeneration

ii. Cells revert to an earlier stage of development

x. Transdifferentiation

i. Regeneration of cells with completely different functions than original

y. Tissue remodeling

i. Cells and molecules of tissue are modified and reassembled to yield a new composition of cell types and extracellular matrix

Key Concept

Inflammation is the body’s reaction to invasion by an infectious agent or physical, chemical, or traumatic damage.

XVI. Conclusion

a. The skeleton

ii. Provides support and protection to internal organs

iii. Foundation for muscle attachment

iv. Efficient factory for producing red blood cells

z. Many injuries associated with athletics are fractures

i. Other injuries involve muscles, attachments, and various surrounding tissues

Lesson Plans and Teaching Strategies

Follow the lecture outline to present material to students, using a variety of teaching strategies described in Instructional Strategies, such as modified lecture and cooperative/collaborative learning.

Answers to Student Exercises

Textbook Review Questions

1. The average adult skeleton has 206 bones. Infants have 270 because some of the bones have yet to fuse.

2. The skeleton plays an important part in movement, protects certain internal organs, produces blood cells in the red bone marrow, and stores minerals (such as calcium and phosphorus).

3. Compact bone provides strength commonly along the shaft of the bone. Spongy bone, found largely at the ends of the bone (epiphysis), provides strength along with lightness. Spongy bone responds to stress, producing bone where it is needed and removing it where it is not needed.

4. Answers will vary.

5. Red bone marrow, which is found in the spaces of spongy bone, is the site of blood cell production. Yellow bone marrow, found mostly in the medullary canal or cavity, is largely a storage area for fat.

6. The six fracture classifications are simple, compound, greenstick, comminuted, stress, and epiphyseal plate fractures.

7. External fixation uses devices such as casts to immobilize a bone, so that it can repair in proper alignment. Internal fixation refers to the use of surgery to align the bones, often using screws, pins, and plates to keep bones in place.

8. Whenever muscles are not used, they lose contractile materials within the cells (fibers) causing them to shrink in size and become weaker. This is a concern when certain body parts are immobilized for bone repair.

9. The first stage involves reducing swelling and pain, often using the RICE formula. The second stage is rehabilitation to improve the condition of the injured part and restore its function.

10. The neurons of the nervous system have the ability to transmit nerve impulses and stimulate other nerve cells. This ability creates a communication system within the body, whereby sensory neurons send signals to the brain in response to internal and external changes. The brain and spinal cord coordinate a response through motor neurons that control muscles or glands.

11. Neurons naturally have a difference in electrical charge from inside the cell to outside the cell. This difference, or voltage, can change in response to a stimulus; this change in voltage has the ability to travel along the length of the neuron.

12. The myelin sheath insulates nerve fibers so that the signal down one fiber is not affected by another signal in a nearby neuron. Nerve impulses can also jump from one end of a myelin sheath to the next, resulting in a much faster nerve impulse speed.

13. Neuron membranes redistribute ions internally and externally so that there is a difference in electrical charge from the inside to the outside of the cell (the inside is more negative). When the nerve is stimulated, the inside becomes more positive than the outside, again by the movement of specific ions across the membrane.

14. Soft-tissue injuries are injuries that affect skin, muscles, ligaments, and tendons. They can be classified as open or closed.

15. Abrasions occur when several layers of skin are torn loose or totally removed; a laceration is a tear in the skin; an avulsion is where layers of skin are either torn off or a flap remains; a puncture wound is caused by sharp, pointed objects that penetrate the skin; a hematoma is a pooling of blood and tissue fluid in a tissue space; and ecchymosis refers to an accumulation of blood in the skin (a bruise).

16. An inflammation is the reaction of the body to an infectious agent, or physical, chemical, or traumatic damage.

17. Blood vessels dilate, increasing the blood supply to the area; capillaries become more permeable, allowing specialized cells to reach the site of the injury; and leukocytes migrate into the tissues where they directly attack foreign invaders.

18. Cell regeneration is the act of wound healing. Mature cells actually regress to a more basic shape, divide to fill in the injured area; and then redifferentiate into specialized cells needed by the tissues.

19. If the wound is so severe that it cannot repair itself, connective tissue develops, which is scar tissue.

20. There are four components to this process: formation of new blood vessels spanning the wound; migration and proliferation of fibroblasts filling and bridging the wound; deposition of ECM; and tissue maturation and reorganization of the fibrous tissue into a scar.

Workbook Vocabulary Review

Matching

1. III

2. T

3. U

4. H

5. JJJ

6. KKK

7. E

8. G

9. J

10. K

11. L

12. A

13. B

14. D

15. M

16. N

17. O

18. Q

19. S

20. I

21. V

22. Z

23. CC

24. DD

25. EE

26. XX

27. YY

28. AAA

29. BBB

30. CCC

31. DDD

32. FF

33. HH

34. II

35. JJ

36. LL

37. NN

38. W

39. X

40. Y

41. QQ

42. RR

43. SS

44. TT

45. UU

46. WW

47. EEE

48. FFF

49. OO

50. PP

Workbook Quiz

1. C

2. A

3. B

4. A

5. D

6. A

7. B

8. B

9. A

10. C

Critical Thinking

1. Puncture wounds should be examined to determine if the object is still in the wound, if underlying structures are damaged, and if the object was contaminated, as this could increase the risk of infection. A physician should be consulted if the object penetrated deeply, and for advice on the need for a tetanus shot. Medical attention is necessary if signs of infection appear.

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