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-
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Structural
Classification
of Joints |
Functional
Classification |
Description |
Examples | |
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Fibrous
Joints: three types
(see
below) |
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The bones are joined by
fibrous tissues: There is no joint cavity;
Most are immovable |
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Suture |
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Syndesmosis |
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Gomphosis |
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Cartilaginous
Joints: Two type
below) |
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Articulating bones are
united by cartilage; Lack a joint
cavity |
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Synchon-drosis |
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Sym- physis |
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Synovial Joints |
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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 |
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Hinge |
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Pivot |
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Condyloid |
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Saddle |
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Ball and
Socket |
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Plane |
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Friction Reducing structures
1. Bursae-
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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
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Movements of Synovial Joints |
Description |
Examples | |
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Gliding |
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Angular Movements: |
Flexion |
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Extention |
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Dorsiflexion |
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Abduction |
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Adduction |
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Curcumduction |
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Rotation |
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Special Movements: |
Supination |
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Pronation |
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Inversion |
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Eversion |
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Protraction |
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Retraction |
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Elevation |
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Depression |
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Opposition |
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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
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