Chapter 8 Joints J.F. Thompson, Ph.D. & J.R. Schiller, Ph.D. & G. Pitts, Ph.D.
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Chapter 8
Joints J.F. Thompson, Ph.D. & J.R. Schiller, Ph.D. & G. Pitts,
Ph.D.
Classification of JointsTable 8.1 - Summary of Joint ClassesStructural
Fibrous - bones joined by fibrous connective tissue; no joint cavity
Cartilaginous - bones joined by cartilage; no joint cavity
Synovial - bones separated by fluid filled cavity
Functional Synarthroses - non-movable Amphiarthroses - slightly movable Diarthroses - freely movable
Fibrous JointsSuture - wavy
border with dense fibrous connective tissue which penetrates into both bone
Syndesmosis - connected by a ligament
Gomphosis - peg in a socket (teeth)
Cartilaginous JointsSynchondroses
hyaline cartilage epiphyseal plate
• most limb bones most ribs to sternum
Symphyses fibrocartilage pelvis, vertebrae
Synovial JointsGeneral Structure
articular cartilage synovial (joint) cavity articular capsule synovial fluid reinforcing ligaments
meniscus – a fibrocartilage pad, e.g., at the tempero-mandibular joint (TMJ) and at the tibio-femoral (knee) joint
Synovial JointsBursae - flattened sacs filled with synovial fluidTendon sheath - elongated bursa which wraps
around a tendon
Synovial JointsGliding (plane)
joint
flat planes gliding over each other
intercarpal and intertarsal joints
Synovial JointsHinge
cylindrical projection fits into a notch
ulna and humerus
tibia and femur
interphalangeal joints
Synovial JointsPivot
rounded end of one bone protrudes into sleeve or ring of bone or ligaments
atlas (C1) and dens of the axis (C2)
proximal radio-ulnar joint
Synovial JointsCondyloid
rounded (convex) articulating surface of one bone fits into concave depression on the other bone
radio-carpal joints
metacarpal-phalangeal joints
Synovial JointsSaddle
each articular surface has both convex and concave areas
carpo-metacarpal joint of the thumb
special case of a condyloid joint
Synovial JointsBall and Socket
spherical or hemispherical head of one bone articulates with cuplike socket
provides greatest rotational flexibility
shoulder hip special case of a
condyloid joint which is capable of circumduction
Know the Terminology for Types of Motions in Your Lab Guide
GlidingRotationFlexion/ExtensionAbduction/AdductionCircumductionSpecial Movements
Reviewed in lab
Factors Influencing Joint StabilityArticular surfaces – shape and condition
are important for smooth functioning of the joint
Ligaments – dense regular fibrous connective tissue which will only stretch ~6% before tearing
Muscle Tone most important tone - resting activity – some minimal level of
contraction operating at all times muscles, tendons, and ligaments are supplied
with sensory nerve endings for feedback control of limb and body position and posture
Sagittal View of Knee Joint
The knee joint is a classic site for repeated injuries.
Since cartilage does not repair well, the cumulative effect of multiple traumas is to permanently weaken the joint.
Anterior view.
Knee joint relationships with some associated muscles
• Ligaments and tendons contribute to joint stability.
• Physical therapists and practitioners of sports medicine must become expert in the anatomy of the musculoskeletal system.
A common knee injury
A blow from the side forces the bones to move in a direction incompatible with the joint’s design. Ligaments are not flexible so they tear. They can repair with time. Cartilage repair will be minimal.
Anterior Cruciate Ligament (ACL) Injury
ACL torn above →& repaired below;screws stabilizethe repair.
ArthritisMore than 100 different types of
inflammatory or degenerative joint diseasesMost common crippling diseases in the U.S.
Symptoms – pain, stiffness, and swelling of joint(s)
Acute forms are caused by bacteria and are treated with antibiotics
Chronic forms include osteoarthritis (OA), rheumatoid arthritis, and gouty arthritis
After the End of Chapter 8,
You Will Find Some
Additional Slides with More
Detailed Information on Certain
Topics for Your Review
End Chapter 8
Gliding Movement
Figure 8.5a
Angular Movement
Rotational Movement
Special Movements
Ligaments and Tendons of Kneeall contribute to
stability
many contribute to fibrous capsule
SprainsThe ligaments reinforcing a joint are
stretched or torn
Partially torn ligaments slowly repair themselves
Completely torn ligaments require prompt surgical repair
Cartilage Injuries
The snap and pop of overstressed cartilage
Common aerobics injury
Repaired with arthroscopic surgery
Dislocations
Occur when bones are forced out of alignment
Usually accompanied by sprains, inflammation, and joint immobilization
Caused by serious falls and are common sports injuries
Subluxation – partial dislocation of a joint
Inflammatory and Degenerative Conditions
Bursitis An inflammation of a bursa, usually caused by a blow
or friction Symptoms are pain and swelling Treated with anti-inflammatory drugs; excessive fluid
may be aspirated
Tendonitis Inflammation of tendon sheaths typically caused by
overuse Symptoms and treatment are similar to bursitis
Developmental Aspects of Joints
By embryonic week 8, synovial joints resemble adult joints
Few problems occur until late middle age
Advancing years take their toll on joints: Ligaments and tendons shorten and weaken Intervertebral discs become more likely to
herniate Most people in their 70s have some degree of
OA
Prudent exercise (especially swimming) that coaxes joints through their full range of motion is key to postponing joint problems
End Chapter 8
End of extra review slides
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