Copyright © 2005, Elsevier, Inc. All rights reserved. Slide 0 0 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved

Copyright © 2005, Elsevier, Inc. All rights reserved. Slide 11Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved.

Chapter 6Chapter 6

The Skeletal System

2Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved.

Learning ObjectivesLearning Objectives

• List and discuss the generalized functions of the skeletal system

• Identify the major anatomical structures found in a typical long bone

• Discuss the microscopic structure of bone and cartilage, including the identification of specific cell types and structural features

• Explain how bones are formed, how they grow, and how they are remodeled


Learning Objectives (cont’d.)Learning Objectives (cont’d.)

• Identify the two major subdivisions of the skeleton and list the bones found in each area

• List and compare the major types of joints in the body and give an example of each


Functions of BoneFunctions of Bone

What are five major functions of the skeletal system?


Functions of BoneFunctions of Bone

• Supports and gives shape to the body• Protects internal organs• Helps make movement possible• Stores calcium• Hematopoiesis


Types of BonesTypes of Bones

What are the four major types of

bones?


Examples of BonesExamples of Bones

• Long Humerus (upper arm)

• Short Carpals (wrist)

• Flat Frontal (skull)

• Irregular Vertebrae (spinal cord)


• Structural components Diaphysis or shaft Medullary cavity—hollow area inside

diaphysis containing yellow marrow Epiphyses or ends of the bone—spongy

bone contains red bone marrow

Structure of Long BonesStructure of Long Bones


Longitudinal Section of a

Long Bone

Structure of Long Bones (cont’d.)Structure of Long Bones (cont’d.)


Microscopic Structure of Bone and CartilageMicroscopic Structure of Bone and Cartilage

There are two major types of bone.

Who knows what they are?


Microscopic Structure of Bone and CartilageMicroscopic Structure of Bone and Cartilage

• Bone types Spongy

Texture results from needlelike threads of bone called trabeculae surrounded by a network of open spaces

Compact (Dense) Structural units are called osteons,

Haversian systems


Microscopic Structure of Bone and Cartilage (cont’d.)Microscopic Structure of Bone and Cartilage (cont’d.)

• Cartilage Cell type called chondrocyte Has the flexibility of firm plastic Matrix is gel-like and lacks blood vessels Has no blood vessels, so nutrients must

diffuse through the matrix to reach cells


Microscopic Structure of Bone

Microscopic Structure of Bone and Cartilage (cont’d.)Microscopic Structure of Bone and Cartilage (cont’d.)


Bone Formation and GrowthBone Formation and Growth

• The process of “remodeling” A newborn’s skeleton has many bones that

have not completely ossified. Cartilage models replaced by calcified bone

matrix• Osteoblasts form new bone• Osteoclasts resorb bone• As long as the epiphyseal plate remains

between epiphyses and diaphysis, growth continues

• The epiphyseal line marks where two centers of ossification have fused together


The SkeletonWhat are the two major divisions?

The SkeletonWhat are the two major divisions?


Divisions of the SkeletonDivisions of the Skeleton

• Skeleton: Two divisions and their subdivisions Axial skeleton

Skull Spine Thorax Hyoid bone

Appendicular skeleton Upper extremities, including shoulder

girdle Lower extremities, including hip girdle


Divisions of the Skeleton (cont’d.)Divisions of the Skeleton (cont’d.)

• Axial skeleton Skull Spine (Vertebral Column)

Consists of a series of separate bones called vertebrae

Sections called cervical, thoracic, lumbar, sacrum, coccyx

Curves of the spine give strength to support body


The Skull



The SpinalColumn




• Axial skeleton Thorax is formed by

12 pairs of ribs The sternum (breastbone) Thoracic vertebrae



Bones of the Thorax



• Appendicular skeleton Upper extremity formed by

Scapula (shoulder blade) Clavicle (collarbone)

o Attached by sternoclavicular joint Humerus Radius and ulna Wrist and hands—27 bones in all


Bones of the Arm, Elbow Joint, and Forearm



• Appendicular Skeleton Lower Extremity

Two coxal (pelvic) bones Femur; longest bone in the body

o Articulates proximally with coxal bone in socket called the acetabulum

Patella (kneecap) Tibia (shinbone) Fibula (slender bone in the lower leg) Phalanges are composed of metatarsals

and tarsals



Bones of the Thigh, Knee Joint, and Leg



Bones of the Right

Foot



Differences Between a Man’s and a Woman’s SkeletonDifferences Between a Man’s and a Woman’s Skeleton

• Size—male skeleton generally larger• Shape of pelvis—male pelvis deep and narrow,

female pelvis broad and shallow• Size of pelvic inlet—female pelvic inlet

generally wider, normally large enough for baby’s head to pass through

• Pubic angle—angle between pubic bones of female generally wider


Comparison of the Male and Female Pelvis

Differences Between a Man’s and a Woman’s SkeletonDifferences Between a Man’s and a Woman’s Skeleton


Joints (Articulations)Joints (Articulations)

• Kinds of joints Synarthrosis (no movement)

Fibrous connective tissue grows between articulating bones

Example: Sutures of skull Amphiarthrosis (slight movement)

Cartilage connects articulating bones Example: Symphysis pubis


Joints (Articulations) (cont’d.)Joints (Articulations) (cont’d.)

Diarthrosis (free movement)—most joints belong to this class Structures of freely movable joints—joint

capsule and ligaments hold adjoining bones together but permit movement at joint

Articular cartilage—covers joint ends of bones and absorbs jolts

Synovial membrane—lines joint capsule and secretes lubricating fluid

Joint cavity—space between joint ends of bones


Joints of the Skeleton



Types of Diarthrotic Joints



Skeletal Disorders

• Deficiency– Rickets

• Loss of bone minerals occurs in infants and

young children before skeletal maturity• Lack of bone rigidity causes gross skeletal

changes (bowing of legs)


Skeletal Disorders

• Deficiency– Osteomalacia

• First described by British surgeon Sir James Paget in

1882• Mineral content is lost from adult bones that have

already matured • Involves localized hyperactivity of osteoclasts and

osteoblasts• Faulty remodeling results in deformed bones that

fracture easily• May involve one or many bones—often appears in

spine, skull, and long bones of extremities


Skeletal Disorders

• Deficiency– Osteomalacia

• Unique symptoms (e.g., deafness, headache, facial paralysis) often caused by bone

deformity of skull bones pressing on nerves• Affects about 3% of people over age 50 (1% of cases may develop into osteosarcoma)• Cause may be genetic or triggered by viral

infections


Skeletal Disorders

• Bone infection– Osteomyelitis

• General term for bacterial (usually staphylococcal

infection of bone)• Bone infections may also be caused by viruses, fungi,

and other pathogens• Infection may be spread to bone via bloodstream,

adjacent soft tissue infection, open fractures, failed

surgical aseptic technique, or infected donor tissues or prostheses

• Symptoms caused by collection of pus and decreased

blood flow


Skeletal Disorders

• Deficiency

– Osteomyelitis• Treatment may involve surgery, drainage of

pus, and IV antibiotic treatment—often over prolonged periods

• Bone infection is often chronic and may

reappear long after an assumed cure


Skeletal Disorders

• Bone fractures – Open (compound) fractures pierce the skin and

closed (simple) fractures do not– Complete fractures involve total separation of

bone fragments, and incomplete fractures involve partially separated fragments; comminuted

fractures involve many fragments– Fracture lines can be classified by their angle

relative to a bone’s axis: linear, transverse, and oblique


Skeletal Disorders

• Joint disorders– Noninflammatory joint disorders—do not usually

involve inflammation of the synovial membrane. Symptoms tend to be local and not systemic

• Osteoarthritis or degenerative joint disease (DJD) – Most common noninflammatory disorder of movable

joints—often called “wear and tear” arthritis.– Characterized by bone spurs and degeneration of

articular cartilage– Hips, lumbar spine, and knees often involved


Skeletal Disorders

• Joint disorders– Noninflammatory joint disorders

• Osteoarthritis or degenerative joint disease (DJD)

– Symptoms include joint pain, morning stiffness, appearance of Bouchard’s nodes (at proximal interphalangeal joints), and

Heberden’s nodes (at distal interphalangeal joints) of the fingers

– Most common cause for partial and total hip and knee replacements


Skeletal Disorders


• Traumatic injury– Dislocation or subluxation—articular

surfaces of bones in joint are no longer in proper contact

– Sprain—acute injury to ligaments around

joints (e.g., whiplash type injuries)


Skeletal Disorders


• Traumatic injury– Strain—acute injury to any part of the

“musculotendinous unit” (muscle, tendon, junction

between the two, and attachments to bone)– Most strain injuries involve muscle tears – However, some strains may involve a weaker

component of the musculotendinous unit. In children avulsion and epiphyseal fractures may occur


Skeletal Disorders

• Joint disorders– Inflammatory joint disorders—arthritis is a

general name for several types of inflammatory joint diseases that may be caused by infection, injury, genetic factors, and autoimmunity. Inflammation of the synovial membrane occurs, often with systemic signs and symptoms.


Skeletal Disorders

• Joint disorders– Inflammatory joint disorders

• Rheumatoid arthritis – Systemic autoimmune disease—chronic

inflammation of synovial membrane with

involvement of other tissues such as blood vessels,

eyes, heart, and lungs– Pain, anemia, severe crippling, fever, fatigue, and

ulnar deviation of fingers are common symptoms– Juvenile rheumatoid arthritis, most common in girls

and often severe, may destroy growth cartilage and

arrest growth of long bones


Skeletal Disorders

• Joint disorders– Inflammatory joint disorders

• Gouty arthritis—synovial inflammation caused

by gout, a condition in which sodium urate

crystals form in joints and other tissues• Infectious arthritis—arthritis resulting from

infection by a pathogen, as in Lyme arthritis caused by the Lyme disease bacterium


Let’s Review!

Chapter 6


Slide 47

Question

A role of the skeletal system is to

A. Protect vital organsB. Produce blood tissueC. Enable movement of the bodyD. Provide a framework for the bodyE. All of these are correct


Slide 48

Question

The fatty material inside long bones is

A. Red bone marrowB. White bone marrowC. Yellow bone marrowD. Blood-producing tissueE. Made mostly of calcium


Slide 49

Question

The layers of bone material that build up to form cylindrical units of bone tissue are called

A. OsteonsB. LamellaC. LamellaeD. LacunaeE. Canaliculi


Slide 50

Question

Bone-making cells are called

A. OsteoblastsB. OsteocytesC. OsteoclastsD. FibroblastsE. Osteomalacia


Slide 51

Question

The acetabulum is located in the

A. SkullB. HipC. AnkleD. NeckE. Thoracic cage


Slide 52

Question

If you stand up, then bend your knee so that your leg is behind you, you have just ? the knee.

A. ExtendedB. FlexedC. AbductedD. AdductedE. Circumducted


Case Study Question

• Julie is a 14-year-old girl who is 5 feet 2 inches tall. She seems short compared to her tall parents. Julie’s mother is concerned, and she asks her daughter’s physician if Julie will grow any more. How can a healthcare provider tell if Julie has completed her growth?


Answer

• An x-ray study performed on her wrist. If it shows a layer of epiphyseal cartilage, then additional growth will occur. However, if it shows no epiphyseal cartilage, then her growth has stopped and she has attained adult height. This is because growth ceases when all epiphyseal cartilage is transformed into bone, and all that remains is an epiphyseal line that marks the location of where two centers of ossification have fused together.


Case Study Question

• Margie, who plays center on the women’s varsity basketball team, ended up at the bottom of a pile-up during a game. When she arrives at the doctor’s office, she complains that her knee is very sore. She mentions that she felt a “pop” at the time of the injury, and the knee buckles under her weight. What should be checked?


Answer

• Margie’s knee must be checked for strain on the collateral ligaments. Even though the knee is the largest joint, it is very vulnerable to forces applied from the wrong angle, particularly from the lateral side. If Margie’s collateral ligaments are sprained, she will likely need therapeutic exercise, ice packs to control pain and swelling, and use of a brace to support and stabilize the knee.

•


Fun Study Aid

• http://jeopardylabs.com/play/appendicular


QUESTIONS??

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Documents

Copyright © 2005, Elsevier, Inc. All rights reserved. Slide 0 0 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved