CHAPTER 8: JOINTS OF THE SKELETAL SYSTEM   (M.C. FLATH, Ph.D.)

 

KEY TO OBJECTIVES:

 

1.         Define the term articulation.

A joint (articulation) is the site where two bones come together.

 

2.         Distinguish between the structural and functional classification of joints, and relate the terms that are essentially synonymous.

Structural Classification

Functional Classification

fibrous

synarthoses

cartilaginous

amphiarthroses

synovial

diarthroses

 

3.         Compare and contrast the terms synarthroses, amphiarthroses and diarthroses and identify the examples of each in the diagrams below.

Functional Classification

Definition

Example

Synarthroses

Immovable joint

Suture (1stdiagram)

Amphiarthroses

Slightly moveable joint

Intervertebral disc (2nd diagram)

Diarthroses

Freely moveable

Elbow, shoulder, hip, and knee (3rd   diagram)

 

 

 

 

 

4.         Name the three types of fibrous joints, give an example of each, and identify each in the diagrams below.

Type of  Fibrous Joint

Example

Sutures

Coronal suture, etc. (1st diagram)

Syndesmoses

Tibiofibular joint (3rd diagram)

Gomphoses

Periodontal ligaments (2nd diagram)


5.         Identify the two differences between the epiphyseal plate and an intervertebral disc, and identify each in the diagrams below.

Example of Cartilaginous Joint

Difference 1 (hint:  Structural classification)

Difference 2 (hint:  Functional classification

Epiphyseal Plate (top right arrow of bottom diagram below)

Synchrondrosis

Synarthrosis

Intervertebral Disc (blue pad of fibrocartilage in b of first diagram)

Symphysis

Amphiarthrosis

 


6.      Label all structures associated with the typical synovial joint below, and provide the function of each of the labeled structures.

 

Structure Associated with Synovial Joint

Function

Articular cartilage

Resists wear and minimizes friction

Joint (articular) capsule

Attaches bone to bone; stabilizes joint

Synovial membrane

Lines joint cavity and reabsorbs fluid following injury or infection

Synovial fluid

 

Reduces friction between bones; weeping lubrication

Reinfocring ligaments

Reinforce joint capsule; join bone to bone; stabilize/prevent excessive movement by  joint

 

7.         Name the components and functions of synovial fluid.

Synovial Fluid Component

Function(s) of Synovial Fluid

Water

Lubrication and moisturizes cartilage

Phagocytes

Phagocytosis

N/A

Nourishes cartilage

 

8.         Define the terms fatty pads, articular discs, and bursae, name a key location for each, and identify each in the diagram below.

Synovial Joint Feature

Definition/description

Key location

Fatty pads

Pad of adipose tissue that cushions and protects

Hip and knee

Articular Discs

(Fibrocartilage)that separates the joint into two compartments (a meniscus)

Knee

Bursae

Flattened fibrous sacs with synovial fluid to prevent friction between bone and an adjacent structure

Acromion and skin

 

 

9.         List and discuss three factors that influence the stability of a synovial joint.

Shape of opposing bone surfaces

Reinforcing ligaments that enclose joint

Muscles that enclose joint

 

10.       Distinguish between the origin and insertion of a muscle, and identify each in the diagram below.

Origin

Insertion

Anchored, immoveable end of a muscle

Moveable end of a muscle

 

 

 

 

 

 

 

 

 

 

 

 

 

 

11.       Name the three general types of movements allowed by joints.

Gliding

angular

special

 


12.       List the angular movements allowed by synovial joints, provide a description of each, and review each movement in the diagrams below.

Angular Movement

Description

Flexion

Decreasing the angle between two bones

Extension

Increasing the angle between two bones

Abduction

Moving a bone/body part away from the midline

Adduction

Moving a bone/body part toward the midline

Circumduction

Moving a limb in a circular motion

Rotation

Turning movement of a bone along its long axis

 


13.       Identify the special movements allowed by the proximal radioulnar joint (i.e. between radius and ulna), by the sole, by the shoulders, by the jaw, and review each special movement in the diagrams above and below.

Special Movements of

Movement 1

Movement 2

Radius/Ulna

supination

pronation

Sole

eversion

inversion

Shoulders

elevation

depression

Jaw

protration

retraction

14.       Name the six types of synovial joints and provide an example of each.

Type of Synovial Joint

Movements Allowed

Example

Plane

Gliding

Intervertebral discs and within carpals

Hinge

Flexion and extension

Knee and elbow

Pivot

Rotation

First intervertebral disc

Condyloid

All angular movement except rotation

Carpals and knuckles

Saddle

Concave and convex bone surfaces that allow for free movement

Thumb

 

Ball-and-socket

Head of one bone surface fits into socket of other bone surface permitting all angular movement

Shoulder and hip

15.       Explain how an intervertebral disc can be all of the following:  an amphiarthrosis, cartilaginous joint, symphyses, gliding joint, and plane joint.

Intervertebral Disc as

How ?

Amphiarthosis

Allows for slight movement

Cartilaginous Joint

Composed of fibrocartilage

Symphyses

Composed of a pad of fibrocartilage

Gliding Joint

Allows for slight movement between body’s of vertebrae

Plane Joint

Allows for gliding movement


 

16.       Name all of the joint classifications that the sutures in the skull, elbows, and hip joints may satisfy.

 

Sutures of Skull

Elbow

Hip

Classifications that each may satisfy

Fibrous

Suture

Synarthroses

Synovial

Diarthrosis

Hinge

Synovial

Diarthrosis

Ball-and-socket

 

17.       Construct a table comparing the structural and functional classifications of joints, and draw arrows to show the relationships between the two.

Structural Classification

Functional Classification

Fibrous

Synarthroses

Cartilaginous

Amphiarthoses

Synovial

Diarthroses

 

18.       Discuss some important joint disorders.

Sprains, bursitis, osteoarthritis, rheumatoid arthritis, gout (see pages 271-274)