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CHAPTER

Anatomy & Physiologyfor Health Professions: An Interactive Journey

Copyright ©2011 by Pearson Education, Inc.

All rights reserved.

Second Edition

Anatomy & Physiology for Health Professions: An Interactive Journey, Second Edition

Colbert • Ankney • Lee

The Skeletal System:

The Framework

6





I. Introduction

A. Function

1. The skeletal system provides support and allows us to move.

2. Protects the soft body parts, produces blood cells, and acts as a storage unit for minerals and fat.

3. There are 206 bones in the adult skeleton, along with cartilage, ligaments, and joints.





II. Bones

A. Although bones are composed of non-living minerals such as calcium and phosphorous, they are very much alive.

B. The word ‘skeleton’ comes from the Greek meaning “dried up body.”





C. Classified according to their shape:

1. Long bones – These bones are longer than they are wide and can be found in the arms and legs.

2. Short bones – These bones are fairly equal in width and length and are found mostly in the wrists and ankles.

3. Flat bones – These bones are thinner and can be either flat or curved (skull, ribs, and sternum).

4. Irregular bones – These bones are like parts of a jigsaw puzzle, odd in shape, and include the hip bone and vertebrae.





Figure 6-1 Various bone shapes.





D. Basic Bone Anatomy

1. Periosteum

a. Is an outer covering that is comprised of tough, fibrous connective tissue

b. Contains blood vessels, lymph vessels, and nerves

c. The periosteum acts as an anchor point for ligaments and tendons.





2. Epiphysis and Diaphysis

a. Both ends of a long bone increase in size to form the epiphysis

b. The region running between the two epiphyses is called the diaphysis.

c. The diaphysis is hollow (called the medullary cavity). It acts as a storage area for the yellow marrow.

i. Red marrow makes red blood cells

ii. Yellow marrow has a high fat content and can convert to red marrow in an emergency.





Figure 6-2 Basic bone anatomy.





E. Bone tissue

Bone can be composed of two types of tissue:

1. Compact

– Dense, hard tissue normally composing the shafts of long bones and the outer layer of other bones.

a. Mature bone cells form concentric circles around blood vessels.

b. The area around the bone cells is filled with bone matrix.





2. Spongy

a. Spongy bone is arranged in bars and plates (called trabeculae).

b. Irregular holes give the bone a spongy appearance and make the bone lighter in weight.





Figure 6-3 Comparison of compact and spongy bone.





F. Surface structure of bones

1. Bone is not perfectly smooth.

2. Projections act as points of attachment for muscles, ligaments, or tendons.

3. Grooves and depressions act as pathways for nerves and blood vessels.

4. Projecting structures and depressions can work together as joining or articulation points to form joints such as the ball and socket joint in your hip.





G. Bone growth and repair

1. Ossification is the term used to describe the formation of bone in the body.

2. Types of cells involved in bone formation and growth:

Osteoprogenitor cells

Osteoblasts

Osteocytes

Osteoclasts





Osteoblasts

• Osteoblasts are the cells that actually form bones.

• They arise from the non-specialized osteoprogenitor cells and are the cells that secrete the matrix of calcium with other minerals that give bone its typical characteristics.





Osteoclasts

• The osteoclasts’ job is to tear down bone material and help move calcium and phosphate into the blood.

• It is believed that osteoclasts originate from a type of white blood cell called a monocyte that is found in red bone marrow.





3. Bone development and growth – bone development begins when you are an embryo through ossification

4. Bone repair – for a bone fracture to heal, the ends of broken bone must be touching. A four stage procedure then follows:

a. Hematoma forms; inflammation

b. Soft callus forms (cartilage). Cartilage fills in the space between the bones.

c. Bony callus forms. Bone replaces the cartilage.

d. The bone is remodeled via the activity of osteoblasts and osteoclasts until the fracture is nearly undetectable.





Figure 6-4 Endochondral ossification of long bone.





III. Cartilage

A. Cells called chondrocytes.

B. Chondrocytes exist in holes in a gel-like matrix.

C. Location and functions1. The flexible part of your nose and ears are cartilage.2. Makes a flexible connection between bones, as between the ribs and sternum, allowing chest flexion during deep breathing3. Cartilage acts as a cushion between bones; articular cartilage is located on the ends of bones and acts as a shock absorber, preventing the ends from grinding together during movement..





Figure 6-5 Articular cartilage and synovial joint.





IV. Joints and Ligaments

A. When two or more bones join together, an articulation or joint is formed.

B. Many joints must be held together, yet still be movable, which is accomplished by special connective tissue called ligaments.

C. Tendons are cord-like structures that attach muscle to bone.





D. Joints can be classified by function or structure:

1. Function

a. Immobile

b. Move a little

c. Move freely

2. Structure

a. Fibrous: bones jointed by short connective tissue strands

b. Cartilaginous: bones united by cartilage





c. Synovial: bones united by fluid filled joint cavity

i. Pivot joint – turnstile movement in the neck and forearm

ii. Ball-and-socket joint – hip and shoulder

iii. Hinge joint – allow up and down movement in the knees and elbows

iv. Gliding joint – wrists and ankles

v. Saddle joint – shaped like a saddle found in the thumb

vi. Ellipsoidal joint – oval-shaped bone end fitting into an elliptical cavity in the other bone so there is movement from one plane to another but no rotation – fingers and toes





Figure 6-6 Types of joints.





E. Movement classification

1. Flexion – decreasing the angle of a joint

2. Extension – increasing the angle of a joint

3. Plantar flexion – pointing toes down

4. Dorsiflexion – bending the food up toward the body





5. Abduction – moving away from the body’s midline

6. Adduction – moving toward the midline of the body

7. Inversion – turning the foot inward toward other foot

8. Eversion – turning the foot outward away from opposing foot

9. Circumduction – circular arm movement

Movement classification cont.





Figure 6-7 Classification of joint movements.





V. Bones of the SkeletonA. Two main sections of the skeleton

1. Axial skeleton – Bones of the bony thorax, spinal column, hyoid bone, bones of the middle ear, and skull; they protect the body organs and total 80 bones

a. The skull – many bones forming a brain case and facial structures

b. The thorax – ribs and sternum (protects thoracic cavity)

c. The Spinal Columni. Also called vertebral column; houses the spinal cord; the

superhighway for information coming to and from the central nervous system

ii. The individual bones or vertebrae are numbered and classified according to the body region where they’re located





Figure 6-9 Bones of the skull.





Figure 6-9 (continued) Bones of the skull.





Figure 6-10 The bony thorax.





Figure 6-11 The spinal column.





V. Bones of the Skeleton

2. Appendicular skeleton – Bones of your arms, legs, hips, and shoulders and total 126 bones.

a. The appendicular region consists of the arms and legs.

b. Half the bones in the body are located in the hands and feet.





Figure 6-13 Bones of the upper and lower extremities.





VI. Common Disorders of the

Skeletal System

A. Aging affects the cartilage and bones. While this is a natural process, in some cases we can slow things down.

1. The composition of cartilage changes as we age, becoming more brittle and yellow due to calcification. This can lead to arthritis, an inflammatory process of the joints, reducing flexibility and decreasing range of motion.





There are two main types of arthritis:

1.Osteoarthritis:– degenerative condition

– result of simple “wearing out” of a joint from a sports injury, trauma, repetitive motion, obesity, or just the aging process.

2.Rheumatoid arthritis: – Autoimmune disease

– Result of your body’s cells mistaking your own proteins as a foreign intruder.





Osteoarthritis Rheumatoid





2. Bone mass decreases with age. In our 50’s the breakdown of bone is greater.

a. Osteoporosis: light, weak, porous bones. More common in women, but can be diagnosed in men.

b. Treatment and prevention of osteoporosis:

i. Healthy lifestyle

ii. Proper calcium intake

iii. Proper vitamin D,

iv. Weight bearing exercise

v. Drink less caffeine

vi. Quitting smoking

vii. Medication (treatment)





B. Bone fractures

1. A hairline fracture looks like a piece of hair on the x-ray. It is a fine fracture that doesn‘tcompletely break or displace the bone.

2. A simple or closed fracture is a break with minimal displacement and no tear in the skin.

3. A greenstick fracture is an incomplete break and is often found in children.





4. A spiral fracture is caused by a twistingmotion to the bone.

5. A comminuted fracture occurs when the bone fragments or splinters.

6. A compound or open fracture occurs when the bone protrudes through the skin, with the potential of infection from exposure.





Figure 6-14 (A) Femur, AP view, comminuted fracture.





Figure 6-14 (continued) (B) Tibia, simple, transverse fracture.





Figure 6-14 (continued) (C) Open fracture of the wrist.





Figure 6-14 (continued) (D) Displaced fracture of the distal radius. (Source: Charles

Stewart & Associates.)





Figure 6-14 (continued) (E) X-ray of complete fracture of the radius. (Source: James

Stevenson/Science Photo Library/Photo Researchers, Inc.)





Figure 6-14 (continued) (F) Fractured humerus. (Source: Charles Stewart & Associates.)





Figure 6-5 Articular cartilage and synovial joint.





Figure 6-3 Comparison of compact and spongy bone.





Figure 6-9 (continued) Bones of the skull.





Figure 6-8 The anterior and posterior human skeleton.





Test Your Knowledge (p. 124)

1. A term that can be used to describe the formation of bone is:

a. Ossification

b. Periosteum

c. Bonafide

d. Osteoclasts






2. These cells actually form bones:

a. Osteoclasts

b. Pericytes

c. Generator cells

d. Osteoblasts






3. Another name for the “growth plate” is:

a. Tectonic plate

b. Epiphyseal plate

c. Upper plate

d. Periostium plate






4. This connective tissue forms a cushion in joints:

a. Tendons

b. Ligaments

c. Cartilage

d. Cartridge






5. A skeleton is found buried in a land fill. Examination shows that the epiphysial plates are completely calcified. What was the age of the skeleton at time of death?

a. 5 years

b. 10 years

c. 15 years

d. 25 years






6. Riding his ATV one day, Jim falls and shatters his tibia, breaking it into many small pieces. At the hospital the surgeons use pins, plates, and screws to put pieces back in the right places. Why?

a. Bone must be touching to repair itself.

b. Bone cannot repair itself.

c. Inflammation is reduced by surgery.

d. The bone will never be strong enough to support weight after injury.






1. A movement that increases the angle of a joint is known as:

a. Flexion

b. Abduction

c. Rotation

d. Extension






2. A joint in which bones are connected by short connective tissue strands is known as a

a. Cartilaginous joint

b. Fibrous joint

c. Synovial joint

d. Freely moving joint






3. A joint in which flat bone surfaces move side to side past each other is known as a

a. Condyloid joint

b. Hinge joint

c. Saddle joint

d. Gliding joint






4. This lubricant helps to prevent wear in joints:

a. Pleural fluid

b. Synovial fluid

c. Mucus

d. Petroleum jelly






5. These structures attach bone to bone:

a. Ligaments

b. Tendons

c. Cords

d. Articulations






6. A young gymnast falls form the balance beam, rotating her knee. This is a problem because

a. The knee is a hinge joint and should not rotate

b. The knee should only rotate when standing

c. The knee joint is not a freely moving joint

d. There is no problem, knees are supposed to rotate






1. Which of the following bones is considered to be part of the axial skeleton?

a. Humerus

b. Patella

c. Femur

d. Sternum






2. The number of vertebra in the thoracic region is

a. 5

b. 7

c. 12

d. 120






3. The posterior skull bone is the

a. Parietal

b. Cervical

c. Occipital

d. Zygomatic






4. The last two pairs of ribs are

a. Vertebrosternal

b. Vertebrocostol

c. Vertebroclavical

d. None of the above






5. The shoulder blade is more technically known as the

a. Clavicle

b. Scapula

c. Sternum

d. Pelvis






6. Beth has fractured her humerus. What is in a cast?

a. Her leg

b. Her arm

c. Her neck is in a brace

d. Her entire body





End of Chapter

Review Questions

1. Your elbow is an example of what type of joint?

a. Hinge joint

b. Ball-and-socket joint

c. Gliding joint

d. Fibrous joint





End of Chapter

Review Questions

2. The sternum is the correct medical term for which bone?

a. Shin bone

b. Breast bone

c. Shoulder blade

d. Collarbone





End of Chapter

Review Questions

3. The end of a long bone is the:

a. Diplodicus

b. Epiphysis

c. Condylcorn

d. Perla





End of Chapter

Review Questions

4. The presence of a(n) ___________ in skeletal remains indicates the skeleton is a teenager or child.

a. Torquer center

b. Ossifier

c. Mantoux membrane

d. Epiphyseal plate





End of Chapter

Review Questions

5. The aging process, excessive caffeine, and cigarette smoking can each contribute to this bone disease:

a. Ligamental stenosis

b. Osteoporosis

c. Cartilentious dementia

d. Ossification





End of Chapter

Review Questions

6. Joe injured his elbow as a child and now, as an adult, his injured arm is much shorter than the other arm. Why?

a. Fractured bone is always shorter

b. His epiphyseal plate was damaged and the bone didn’t grow

c. He has arthritis in the joint, which decreases bone growth

d. He has a congenital problem that caused both the injury and the shorter bone





End of Chapter

Review Questions

1. Name three large appendicular bones femur, humerus & tibia.

2. List three places where cartilage is found in the body. nose, ears, & between ribs.

3. Synovial fluid is a liquid found in joints that keeps them lubricated.

4. The specialized cells that constantly rebuild bone are called osteoblasts.





End of Chapter

Review Questions

5. These specialized cells are needed to tear down bone: osteoclast.

6. Bone must be set to heal the fracture.





End of Chapter

Review Questions

1. Describe the difference between tendons and ligaments.

Tendons attach muscle to bone. Ligaments attach bone to bone.





Classroom Response System





Which of the following is NOT a bone

shape classification?

a. Long

b. Flat

c. Irregular

d. Concave





The tough, fibrous connective tissue

surrounding bone is:

a. Periosteum

b. Haversian

c. Osseus envelope

d. Pericardium





The end of a long bone is its:

a. Diaphysis

b. Epiphysis

c. Cleft

d. Terminal end





Storage of yellow marrow occurs in the:

a. Epiphysis

b. Clavicle

c. Sternum

d. Medullary Cavity





Which of the following is true of spongy

bone?

a. It is cancellous

b. It is arranged in bars and plates called trabeculae

c. It makes bones lighter and creates space for red bone marrow

d. All of the above





Which of the following is true of red

blood cells and RBC production?

a. It is known as hemopoiesis

b. The cells last about 120 days

c. There are approximately 25 trillion

d. All of the above





The following bone surface structure is a large

rounded knob, usually articulating with another

bone:

a. Condyle

b. Crest

c. Periostium

d. Foramen





Mature bone cells are known as:

a. Osteoprogenitor cells

b. Osteoblasts

c. Osteoclasts

d. Osteocytes





The cells that actually form bones are:

a. Haversian cells

b. Osteoblasts

c. Osteoclasts

d. Trabeculae





During endochondral ossification

a. A membrane turns to bone

b. Bone ends are brought into contact

c. Cartilage turns to bone

d. Bone is destroyed





A special dense form of connective tissue that often

provides shape and can withstand a fair amount of

flexing, tension, and pressure is:

a. Cartilage

b. Tendon

c. Ligaments

d. Muscle





The fluid that lubricates joints is:

a. Synovial

b. Cerebrospinal

c. Lymphatic

d. All of the above





An example of a hinge joint is the:

a. Hip

b. Wrist

c. Elbow

d. Neck





Movement that decreases the angle between

involved bones when bending a joint is:

a. Extension

b. Flexion

c. Protraction

d. Adduction





The thorax, spinal column, hyoid, skull,

and middle ear bones are part of the:

a. Appendicular skeleton

b. Axial skeleton

c. Columnar skeleton

d. Cytoskeleton





The manubrium, body, and xiphoid are

parts of the:

a. Cell

b. Neuron

c. Clavicle

d. Sternum





Hairline, simple, spiral, greenstick, and

comminuted are all:

a. Bone diseases

b. Types of cartilage

c. Types of fractures

d. Parts of the integument

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