Lecture Medical assisting: Administrative and clinical procedures with anatomy and physiology (4/e) – Chapter 21

Chapter 21 - The skeletal system. After studying this chapter you will be able to: Describe the parts of a long bone, list the substances that make up bone tissue, list the functions of bones, identify bones by their classifications, describe how long bones grow, list and describe the skeletal structures and one location of each structure,…

The Skeletal

System

Learning Outcomes

21.1 Describe the parts of a long bone.

21.2 List the substances that make up bone

tissue.

21.3 List the functions of bones.

21.4 Identify bones by their classifications

21.5 Describe how long bones grow.

Learning Outcomes (cont.)

21.6 List and describe the skeletal

structures and one location of each structure.

21.7 List the bones of the skull, spinal

column, rib cage, shoulders, arms, hands, hips, legs, and feet Describe the location of each bone.

21.8 Define fontanels and explain their

importance

Learning Outcomes (cont.)

21.9 Describe the three major types of

joints and give examples of each.

21.10 Describe the structure of a synovial

joint.

21.11 Describe the causes, signs and

symptoms, and treatments of various diseases and disorders of the skeletal system

• Bones provide the

body with structure

and support

• 206 bones with joints

and connective tissue

• Arms and legs

• Pectoral girdle

• Pelvic girdle

The Skeletal System

Bone Structure (cont.)

• Compact bone looks solid

– Structures can be observed with a microscope

• All bones are made

up of both compact and spongy bone

Bone Structure (cont.)

Bone Structure (cont.)

• Flat bones – located in the skull and rib

• Male pelvic bones

– Heavier and thicker

– Obturator foramina and acetabula are larger and closer together

Gender Differences (cont.)

• Male pelvic cavity

– Narrower and longer

– Less roomy and more

less sharp posteriorly

• Male coccyx

– Less movable

Apply Your Knowledge

Match bone to classification.

Functions of Bones

• Give shape to body parts

• Support and protect soft structures

– Examples – brain, lungs, heart

• Allow body movement, because skeletal

muscles attach to them

– Allow for voluntary movement

Functions of Bones (cont.)

• Red bone marrow of

bone produces new

blood cells –

hematopoiesis

• Store calcium

Apply Your Knowledge

ANSWER: Every cell in the body needs calcium, so the

body must have a large supply readily available.

Why is it important for the bones to store calcium?

Correct!

– Bone-forming cells called

osteoblasts turn the membrane to bone (located in skull)

Bone Growth (cont.)

• Endochondral ossification

– Bones begin as cartilage

models

– Primary ossification center

• Bone formed in the diaphysis

– Secondary ossification center

• Epiphyses turn to bone

• Bones with some cartilage between an epiphysis and the diaphysis will continue to grow

– Medullary cavity and spaces in cancellous bone

form

• Cells that form holes in bone are called osteoclasts

Building Better Bones

• Teach healthy behaviors

– Bone-healthy diet with calcium and

Apply Your Knowledge

What are the two types of bone growth?

ANSWER: Intramembranous ossification, in which

bones begin as tough membrane and are turned to

bone by osteoblasts, and endochondral ossification, in

which primary ossification occurs in the diaphysis of

the bone and secondary ossification occurs in the

epiphysis.

Good Job!

Bony Structures

• Rigid foundation

• Projections and processes for muscle and

ligament attachment

• Depressions and hollows for articulations

– the connection of bones at joints

• Openings for blood vessels and nerves

Bony Structures (cont.)

Condyle A rounded process that usually articulates

with another boneCrest A narrow, ridge-like projection

Epicondyle A projection situated above a condyle

Foramen An opening through a bone that is usually

a passageway for blood vessels, nerves,

or ligaments Fossa A relatively deep pit or depression

Bony Structures (cont.)

Head An enlargement on the end of a bone

Process A prominent projection on a bone

Suture An interlocking line of union between

bonesTrochanter A relatively large process

Tubercle A small, knoblike process

Tuberosity A knoblike process, usually larger than a

tubercle

Apply Your Knowledge

Match the following:

_ Epicondyle A A relatively deep pit or depression

_ Fontanels B An interlocking line of union between bones _ Fossa C “Soft spots” felt on an infant’s skull

_ Process D A knoblike process, usually larger than a

tubercle _ Suture E A projection situated above a condyle

_ Tuberosity F A prominent projection on a bone

The Skull

• Two bone types:

– Cranial – form the top, sides, and back of the

Cranial Bones

• Frontal – anterior

• Parietal – top and

most of the sides

• Occipital – back

• Temporal – form the

lower sides of the

skull

• Sphenoid and

ethmoid bones – floor

• Ear ossicles are the smallest bones of the body

– Malleus– Incus– Stapes

The Skull (cont.)

• Mandible – forms the

lower jawbone

• Maxillae – form the upper

jawbone

• Zygomatic – form the

prominence of the cheeks

• Nasal bones – fuse

together to form the

bridge of the nose

• Palatine – form the anterior portion of the palate

• Vomer – a thin bone that divides the nasal cavity

Click to see 

The Skull (cont.)

Back

Apply Your Knowledge

Match the bones of the skull:

_ Occipital A Form the upper jawbone

_ Sphenoid B A thin bone that divides the nasal

cavity _ Mandible C Part of the floor of the skull

_ Maxillae D Form the prominence of the cheeks

_ Zygomatic E Back of skull

_ Vomer F Lower jawbone

The Spinal Column

The Spinal Column (cont.)

• Cervical vertebrae

– Smallest and lightest

– Located in the neck

region – First one is atlas

– Second one is axis

The Spinal Column (cont.)

– More commonly called the tailbone

Apply Your Knowledge

Identify the sections

of the spinal column

and give the

The Rib Cage

– Breastplate

– Forms the front

middle portion of the rib cage

– Joins with the

clavicles and most ribs

– Xiphoid process

• Cartilaginous tip

The Rib Cage (cont.)

• 12 pairs of ribs

– All are attached

posteriorly to thoracic vertebrae – True

• First seven pairs of ribs

– Floating

• Rib pairs 11 and 12

• Do not attach anteriorly to any structure

Apply Your Knowledge

True or False:

_ The sternum forms the front middle portion of the rib cage.

_ The xiphoid process is a boney tip of the sternum.

_ The true ribs are the first five pairs of ribs

_ False ribs attach to the costal cartilage of rib pair seven.

_ Floating ribs attach to the xiphoid process.

Bones of the Shoulders, Arms, and Hands

• Shoulders – pectoral girdles

– Clavicles – Scapulae

• Upper limb or arm bones

– Humerus – Radius – Ulna

• Hand

– 8 carpals per hand – 5 metacarpals per hand

– 14 phalanges per hand

• 3 in each finger

• 2 in each thumb

Apply Your Knowledge

Match the following:

_ Clavicle A Pectoral girdle

_ Radius B Arm bones

Bones of the Hips, Legs, and Feet

• Hipbones

– Coxal bones form

the pelvic girdle

• Ilium

• Ischium

• Pubis

Apply Your Knowledge

Match the following:

A Coxal bones B Leg bones C Foot bones

– Cartilaginous

joints

• Connected together with

a disc of cartilage

• Between vertebrae

• Covered with hyaline cartilage

• Held together by a fibrous joint capsule lined with synovial

Apply Your Knowledge

Match the following:

A Fibrous joints B Cartilaginous joints C Synovial joints

Between cranial bones and facial bones

Covered with hyaline cartilage

Common Diseases and Disorders

joint inflammation

– Osteoarthritis – degenerative joint

disease, primarily of weight-bearing joints

– Rheumatoid arthritis – chronic

systemic inflammatory disease of smaller joints and surrounding tissues

Common Diseases and Disorders (cont.)

• Bursitis – inflammation of a bursa

(fluid-filled sac that cushions tendons)

• Carpal tunnel syndrome – overuse of

wrist; the median nerve in the wrist

becomes compressed

• Ewing’s family of tumors (EFT) – a group

of tumors that affect different tissue types;

primarily bone

• Gout – a type of arthritis; deposits of uric

acid crystals in the joints

Common Diseases and Disorders (cont.)

• Kyphosis – abnormal curvature of the

spine (humpback)

• Lordosis – exaggerated inward curvature

of the lumbar spine (swayback)

• Osteogenesis imperfecta – brittle-bone

disease

• Osteoporosis – a condition in which

• Osteosarcoma – a type of bone cancer that

originates from osteoblasts, the cells that make

bony tissue

• Paget’s disease – causes bones to

enlarge and become deformed

and weak

• Scoliosis – an abnormal

S-shaped curvature of

the spine

Apply Your Knowledge

Osteosarcoma is a type of bone cancer that

originates from osteoblasts, the cells that make bony

tissue

The doctor has told your patient that he has an

osteosarcoma What do you know about this

disorder?

Nice Work!

In Summary

21.1 Bones consist of the following substances: Osteons or

Haversian systems, bone matrix between osteocytes (bone cells), collagen fibers and proteins, the lamella, and canaliculi

21.2 Diaphysis is the shaft of a long bone Epiphysis is an

end of a long bone Articular cartilage covers the end

of long bones The medullary cavity is lined by the endosteum The periosteum is the membrane

surrounding the diaphysis

21.3 Bone functions include giving shape to body parts,

protecting the soft structures of the body, and assisting in movement The red bone marrow is responsible for hematopoiesis Bones also store calcium

In Summary (cont.)

21.4 Long bones include the femur and humerus; short

bones include the carpals and tarsals; flat bones include the ribs and frontal bone; irregular bones include the vertebrae and bones of the pelvic girdle

21.5 Bones grow through the two types of ossification:

intramembranous ossification and endochondral ossification The cartilage plate between the diaphysis and epiphysis allows for growth of the long bone

21.6 Skeletal structures include the following: Condyles,

crests, epicondyles, foramens, fossas, heads, processes, sutures, trochanters, tubercles and tuberosities

In Summary (cont.)

21.7 The major bones of the skull are the frontal, parietal,

temporal, and occipital bones Within the skull are the mastoid processes, sphenoid, ethmoid, and ear

ossicles The facial bones include mandible, maxilla, zygomatic, nasal and palatine bones, and vomer The spinal column includes cervical, thoracic, and lumbar vertebrae and the sacrum and coccyx There are12 pair of ribs, a sternum, and xiphoid process An upper extremity includes the clavicle, scapula, humerus,

radius, ulna, carpals, metacarpals, and phalanges

The bones of the hip, leg, and foot include the coxal bones, femur, patella, tibia, fibula, metatarsals,

tarsals, and phalanges

In Summary (cont.)

21.8 The fontanels are the membranous structures that

connect the incompletely developed cranial bones

21.9 The three joint types are fibrous joints, cartilaginous

joints, and synovial joints

21.10 A synovial joint consists of hyaline-covered bones

held together by a fibrous joint capsule, which is lined by a synovial membrane that secretes synovial fluid Ligaments hold the bones of these joints

together

In Summary (cont.)

21.11 There are many diseases and disorders of bones

and skeletal system with varied signs, symptoms, and treatments found in the Pathophysiology section

of this chapter Some of the common diseases and disorders discussed include arthritis, bursitis, carpal tunnel syndrome, EFT, gout, kyphosis, lordosis, and scoliosis, as well as osteoporosis and osteosarcoma

Rigid, the skeleton of  habit alone upholds the  human frame.

~ Virginia Woolf

End of Chapter 21