JOINTS Chapter 7

Joints

A Joint is the articulation of two or more bones Knee, Elbow, hip, etc.

Functions Hold bones together Allow for mobility

Classification Structure and function

Joints - Structurally Fibrous Joints – bones are held together by

fibrous connective tissue that is rich in collagen fibers Lack synovial cavity (space between the bones)

Cartilaginous Joints – bones are held together by cartilage Lack synovial cavity

Synovial Joints – bones are united by irregular connective tissue and ligaments Synovial cavity present

Joints - Fuctionally

Synarthrosis – immoveable joint

Amphiarthrosis – slightly moveable joint

Diarthrosis – freely moveable joint All are synovial joints

Fibrous Joints Suture - hold together the bones of the skull

Functionally – synarthosis Syndesmosis – distal joint between the tibia

and fibulaFunctionally – amphiarthrosis (because it allows

some movement) Gomphosis – roots of the teeth articulating

with the mandible and maxillaFunctionally – synarthrosis (immovable)

Cartilaginous Joints

Synchondrosis – connecting material is hyaline cartilage (epiphyseal plate)Functionally – synarthrosis

Symphysis – End of the bones are covered by hyaline cartilage but are connected by a piece of fibrocartilage (pubic symphysis) Functionally – amphiarthrosis

Symphysis Joints

Features of Synovial Joints- Diarthroses

Slide 5.49Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

· Articular cartilage (hyaline cartilage) covers the ends of bones

· Joint surfaces are enclosed by a fibrous articular capsule

· Have a joint cavity filled with synovial fluid

· Ligaments reinforce the joint

Structures Associated with the Synovial Joint

Slide 5.50Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

· Bursae – flattened fibrous sacs

· Lined with synovial membranes

· Filled with synovial fluid

· Not actually part of the joint

· Tendon sheath

· Elongated bursa that wraps around a tendon

The Synovial Joint

Slide 5.51Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 5.28

Types of Synovial Joints

Planar joints – bones are slightly rounded which allows for bones to have a side-to-side or back-and-forth motionExample – wrist (between carpals) ankel

Hinge joint – convex surface of one bone fits into the concave surface of another bone which allows an open-close motionExample: Elbow, knee

Planar Joints Hinge Joint

Synovial Cont….

Pivot Joint – rounded or pointed surface of one bone articulates with a ring formed partly by another bone and partly by a ligament Example: Atlas and the axis articulate with

the dens to allow you to have the side-to-side motion

Condyloid joints – allows for the up-and-down motion and the side-to-side motion Knuckles

Still More

Saddle Joints – between the carpal and the thumb which gives the up-down and side-side motion (bones different shaped than condyloid)

Ball-and-socket Joint – ball-like structure of a bone fits into a cuplike depression on another bone. Example – shoulder

Knee Joint

Main Structures of the knee Patellar ligament –

extends from the patella to the tibia and strengthens the anterior surface of the joint

Oblique Popliteal ligament – strengthens the posterior surface of the joints

Posterior cruciate ligament (PCL) – extends anteriorly and medially from the tibia to the femur

Arcuate popliteal ligament – strengthens the posterior surface of the joint

Tibial collateral ligament – strengthens the medial aspect of the joint

Anterior cruciate liagment (ACL) – extends posteriorly and laterally from the tibia to the femur (70% of knee injuries)

More Meniscus –

fibrocartilage discs between the tibia and the femur Medial Meniscus –

semicircular disc on the medial side

Lateral meniscus – nearly circular piece found on the lateral side

Knee Injury

Inflammatory Conditions Associated with Joints

Slide 5.53Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

· Bursitis – inflammation of a bursa usually caused by a blow or friction

· Tendonitis – inflammation of tendon sheaths

· Arthritis – inflammatory or degenerative diseases of joints· Over 100 different types

· The most widespread crippling disease in the United States

Clinical Forms of Arthritis

Slide 5.54a

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

· Osteoarthritis· Most common chronic arthritis

· Probably related to normal aging processes

· Rheumatoid arthritis· An autoimmune disease – the immune system

attacks the joints

· Symptoms begin with bilateral inflammation of certain joints

· Often leads to deformities

Hip Replacement