Chapter 8 Joints

 

Objectives:

1.  Define joint or articulation

2.  Classify joints both structurally and functionally

3.  Describe the general structure of fibrous joints and give examples.

4.  Describe cartilaginous joints and give examples.

5.  Describe the structural characteristics of a synovial joint.

6.  List three natural stabilizing features of synovial joints.

7.  Compare the structures and functions of bursae and tendon sheaths.

8.  Name and describe (or perform) the common body movements.

9.  Name and provide examples of 6 types of synovial joints based on movements.

10.  Describe the knee joint relative to articulating bones, anatomical characteristics of the joints, movements allowed, and joint stability.

11.  Name common joint injuries and discuss the symptoms and problems associated with each.

12.  Compare and contrast the common types of arthritis.

13.  Discuss joint replacement.

 

 

I.  Joints or articulations

 

            Weakest part of skeleton

 

            Articulation-

 

            Function of joints-

 

                        a..

 

 

                        b

 

II.  Classification of Joints: Structural

 

Structural classification focuses on the material binding bones together and

 whether or not a joint cavity is present

 

 

            The three structural classifications are:

 

                        a.

 

 

                        b.

 

                        c.

 

III.  Classification of Joints: Functional

 

            Functional classification is based on the amount of movement allowed by the joint

 

            The three functional classes of joints are:

 

                        a.  Synarthroses-

 

 

 

                        b.  Amphiarthroses

 

                        c.  Diarthrosis-

Nonaxial-

 

                                    Uniaxial-

 

                                    Biaxial-

 

                                    Multiaxial-

 

Structural

Classification of

Joints

Functional Classification

Description

Examples

Fibrous Joints: 

three types

(see below)

 

The bones are joined by fibrous tissues:

There is no joint cavity; Most are immovable

 

 

Suture

 

 

 

 

 

 

 

Syndesmosis

 

 

 

 

 

 

Gomphosis

 

 

 

 

 

 

Cartilaginous Joints:  Two type below)

 

 

 

 

 

 

 

Articulating bones are united by cartilage;

Lack a joint cavity

 

Synchon-drosis

 

 

 

 

 

 

Sym-

physis

 

 

 

 

Synovial  Joints

 

Those joints in which the articulating bones are separated by a fluid-containing joint cavity;

All are freely movable diarthroses

Examples – all limb joints, and most joints of the body;                         

 

Synovial joints have all of the following:

1.  Articular carilage (Hyaline cartilage)

2.  Joint Cavity

3.  Articular Capsule; (Two layered-the external layer is the fibrous capsule and the inner layer is the synovial memebrane

4.  Synovial Fluid  (viscous liquid inside the Joint Cavity)

 

 

5.  Reinforcing ligaments -intracapsular ligaments are inside the joint capsule and the extracapsular ligaments are outside the capsule

 

 

 

 

Hinge

 

 

 

 

 

 

 

 

Pivot

 

 

 

 

 

 

 

 

Condyloid

 

 

 

 

 

 

 

Saddle

 

 

 

 

 

 

Ball and Socket

 

 

 

 

 

Plane

 

 

 

 

 

 

 

 

 

 

 

 

 

 


           

 

 

 

 

 

 

 

           

 

 

 

 

 

 

 

 

 

                       

 

 

 

 

 

 

 

Friction Reducing structures

           

                                    1.  Bursae-

 

                                                .

 

                                    2.  Tendon Sheath-                  

 

 

                        Movement of Synovial Joints

 

                                    The two muscle attachments across a joint are:

 

Origin – attachment to the immovable bone

Insertion – attachment to the movable bone

 

Described as movement along transverse, frontal, or sagittal planes

 

                                   

                                               

 

                       

Movements of Synovial Joints

Description

Examples

Gliding

 

 

 

 

Angular Movements:

 

 

Flexion

 

 

 

 

Extention

 

 

 

 

Dorsiflexion

 

 

 

 

Abduction

 

 

 

 

Adduction

 

 

 

 

Curcumduction

 

 

 

 

Rotation

 

 

 

 

Special Movements:

 

 

Supination

 

 

 

 

Pronation

 

 

 

 

Inversion

 

 

 

Eversion

 

 

 

Protraction

 

 

 

Retraction

 

 

 

Elevation

 

 

 

Depression

 

 

Opposition

 

 

 

 

           

 

Selected Synovial Joint: Knee Joint

 

            Largest and most complex joint of the body

 

   Allows flexion, extension, and some rotation

 

   Three joints in one surrounded by a single joint cavity:

 

Femoropatellar

 

Lateral and medial tibiofemoral joints

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

           

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


Shoulder Joint (Glenohumeral Joint)

 

-Ball-and-socket joint in which stability is sacrificed to obtain greater freedom of movement

-Head of humerus articulates with the glenoid cavity of the scapula;  the glenoid    cavity is small, only 1/3 the size of the head of the humerous; like a golf ball sitting on a tee.

 

 

Know:

 

            Glenoid cavity

 

            Coracohumeral ligament

 

            Three glenohumeral ligaments

 

            Transverse humeral ligament

 

 

Hip (Coxal) Joint

 

-Ball-and-socket joint

-Head of the femur articulates with the acetabulum

-Good range of motion, but limited by the deep socket and strong ligaments; very  

  stable

 

 

 

Know:

 

            Acetuablular labrum

 

            Iliofemoral ligament

 

VII.  Joint Injuries

 

            1.  Herniated Disc

 

                        a.  The fibrocartilage between the vertebrae is made up of an outer part

                            (annulus fibrosis) and an inner part (nucleus puiposus)

 

b.  The annulus fibrosis ruptures and protrusion of the nucleus puiposus

   occurs and presses on the spinal cord or spinal nerves

 

c.  Numbness or excruciating pain results

 

d.  Treatment:  Moderate exercise, heat, painkillers, or surgery to remove

     the protruding disc and do a bone graft and fuse the vertebrae

 

 

            2.  Sprains

 

                        a.  The ligaments reinforcing a joint are stretched or torn

 

b.  Partially torn ligaments slowly repair themselves

 

c.  Completely torn ligaments require prompt surgical repair

 

 

            3.  Cartilage Injuries

 

                        a.  The snap and pop of overstressed cartilage

 

b.  Common aerobics injury

 

c.  Repaired with arthroscopic surgery

 

 

            4.  Dislocations

 

                        a.  Occur when bones are forced out of alignment

 

b.  Usually accompanied by sprains, inflammation, and joint

     immobilization

 

c.  Caused by serious falls and are common sports injuries

 

 

 

 

VIII. Joint Diseases

 

            1.  Bursitis

                       

                        a.  An inflammation of a bursa, usually caused by a blow or friction

 

b.  Symptoms are pain and swelling

 

c.  Treated with anti-inflammatory drugs; excessive fluid may be aspirated

 

 

                        d.  Bunion - enlarged bursa at the base of the big toe, swollen from

     rubbing of a  tight or poorly fitting shoe

 

            2.  Tendonitis

 

                        a.  Inflammation of tendon sheaths typically caused by overuse

 

b.  Symptoms and treatment are similar to bursitis

 

 

            4.  Arthritis

 

                        a.  More than 100 different types of inflammatory or degenerative diseases

                            that damage the joints

b.  Most widespread crippling disease in the U.S.

c.  Symptoms – pain, stiffness, and swelling of a joint

d.  Acute forms are caused by bacteria and are treated with antibiotics

e.  Chronic forms include osteoarthritis, rheumatoid arthritis, and gouty

    arthritis

 

 

                        Osteoarthritis

 

                                    Most common chronic arthritis; often called “wear-and-tear”

arthritis

Affects women more than men

85% of all Americans develop OA

More prevalent in the aged, and is probably related to the normal

aging process

OA reflects the years of abrasion and compression causing

 increased production of metalloproteinase enzymes that break

 down cartilage

As one ages, cartilage is destroyed more quickly than it is replaced

The exposed bone ends thicken, enlarge, form bone spurs, and

restrict movement

Joints most affected are the cervical and lumbar spine, fingers, knuckles, knees, and hips

OA is slow and irreversible

Treatments include:

Mild pain relievers, along with moderate activity

Magnetic therapy

Glucosamine sulfate decreases pain and inflammation

 

 

 

 

 

Rheumatoid Arthritis

 

                                    Chronic, inflammatory, autoimmune disease of unknown cause,

with an insidious onset

Usually arises between the ages of 40 to 50, but may occur at any

age

Signs and symptoms include joint tenderness, anemia, osteoporosis, muscle atrophy, and cardiovascular problems

The course of RA is marked with exacerbations and remissions

                                    RA begins with synovitis of the affected joint

Inflammatory chemicals are inappropriately released

Inflammatory blood cells migrate to the joint, causing swelling

Inflamed synovial membrane thickens into a pannus

Pannus erodes cartilage, scar tissue forms, articulating bone ends

connect

The end result, ankylosis, produces bent, deformed fingers

                                    Conservative therapy – aspirin, long-term use of antibiotics, and

physical therapy

Progressive treatment – anti-inflammatory drugs or immunosuppressants

The drug Enbrel, a biological response modifier, neutralizes the

harmful properties of inflammatory chemicals

 

 

 

 

                        Gouty Arthritis

                       

                                    Deposition of uric acid crystals in joints and soft tissues, followed

                                     by an inflammation response

Typically, gouty arthritis affects the joint at the base of the great

toe

In untreated gouty arthritis, the bone ends fuse and immobilize the

 joint

Treatment – colchicine, nonsteroidal anti-inflammatory drugs, and

glucocorticoids

 

 

 

IX.  Joint Replacements

 

            Most common joint replacements are the hip and knee.  They last about 10 to 15

           years if not excessively stressed. 

 

            Now available are fingers, elbows and shoulder joints

 

            New techniques include:

 

                        Osteochondral grafting:  healthy bone and cartilage remove from one part

of body and transplanted to the injured joint

 

                        Autologous chondrocyte implantation:  Healthy chondrocytes are removed

from body and cultivated in the lab and implanted in the damaged joint

 

                        Mesenchymal stem cell regeneration: Mesenchymal stem cells removed

from bone marrow and placed in gel, and packed into an area of eroded

cartilage