Objectives

Classification of Joints1. Define joint or articulation.

2. Classify joints by structure and function.

Fibrous Joints3. Describe the general structure of fibrous joints. Name and give an example of each of

the three common types of fibrous joints.

Cartilaginous Joints4. Describe the general structure of cartilaginous joints. Name and give an example of

each of the two common types of cartilaginous joints.

Synovial Joints5. Describe the structural characteristics of synovial joints.

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

7. List three natural factors that stabilize synovial joints.

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

9. Name and provide examples of the six types of synovial joints based on the movement(s) allowed.

10. Describe the elbow, knee, hip, jaw, and shoulder joints in terms of articulating bones, anatomical characteristics of the joint, movements allowed, and joint stability.

Homeostatic Imbalances of Joints11. Name the most common joint injuries and discuss the symptoms and problems

associated with each.

12. Compare and contrast the common types of arthritis.

13. Describe the cause and consequences of Lyme disease.

Developmental Aspects of Joints14. Discuss factors that promote or disturb joint homeostasis.

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Classification of Joints (pp. 249–250; Figs. 8.1–8.3; Tables 8.1–8.2)

Joints (articulations):

Joints are classified by __________________________ and by ___________________________________.

The ____________________________________ classification focuses on the ______________________

binding the bones together and whether or not a joint ___________________ is present.

Structurally, there are three types of joints:

1. _______________________________________________________

2. _______________________________________________________

3. _______________________________________________________

The ___________________________________ classification is based on the amount of

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_________________________ allowed at a joint.

Synarthroses:

Amphiarthroses

Diarthroses:

Fibrous Joints (pp. 250–251; Fig. 8.1; Tables 8.1–8.2)

In fibrous joints, bones are joined together by ______________________ tissue and

_____________ a joint cavity, and provide little to no ___________________________________.

There are three types of fibrous joints:

1. ______________________________________________________

2. ______________________________________________________

3. ______________________________________________________

Sutures:

Syndesmoses:

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Gomphosis:

Figure 8.1 Fibrous Joints

Cartilaginous Joints (pp. 251–252; Fig. 8.2; Tables 8.1–8.2)

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In cartilaginous joints, the bones are joined together by _________________________________,

they ____________________a joint cavity, and have very __________________ mobility.

There are two types of cartilaginous joints:

1. ______________________________________________________

2. _____________________________________________________

Synchondroses:

Symphyses

Figure 8.2 Cartilaginous joints.

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Synovial Joints (pp. 252–269; Figs. 8.3–8.13; Tables 8.1–8.2)

Synovial joints have a structure that allows ___________________ movement about the joint.

General Structure

Figure 8.3 General Structure of a synovial joint.

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The general structure of a synovial joint contains six distinguishing features:

1. _______________________________ cartilage covers the ends of the articulating bones.

2. The joint (_____________________) cavity is a space that is filled with synovial fluid.

3. The two-layered __________________________capsule, consisting of a fibrous layer and a synovial membrane, encloses the joint cavity.

4. _________________________ fluid is a viscous, slippery fluid that fills all free space within the joint cavity.

5. Reinforcing ___________________ cross synovial joints to strengthen the joint.

6. There is a rich supply of _____________________ innervating the capsule that detect pain and stretch and _________________ vessels supplying the synovial membrane, giving rise to capillaries that provide filtrate that becomes synovial fluid.

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Bursae and Tendon Sheaths

Bursae and tendon sheaths contain _______________________________ that reduces friction at synovial joints.

Bursae :

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Tendon sheath:

Figure 8.4 Bursae and tendon sheaths.

Factors Influencing the Stability of Synovial Joints

Articular SurfacesThe shapes of the articular surfaces of bones found at a synovial joint determine the movements that occur at the joint, but play a minimal role in stabilizing the joint.

LigamentsLigaments at a synovial joint prevent excessive or unwanted movements and help to stabilize the joint; the greater the number of ligaments at the joint, the greater the stability.

Muscle ToneMuscle tone keeps tendons crossing joints taut, which is the most important factor stabilizing joints.

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Movements Allowed by the Synovial Joints

Skeletal muscles attach to bones or other connective structures at two points: the

___________________________, attached to the immovable bone; and the ____________________,

attached to the movable bone.

The movements can be described in ________________________ terms relative to the lines, or axes, around which the body part moves and the planes of space along which the movement occurs, that is along the transverse, frontal, or sagittal plane.

Range of motion allowed by synovial joints varies from:

Nonaxial movement:

Uniaxial movement:

Biaxial movement:

Multiaxial movement:

There are three general types of movements:

1. ___________________________________________________

2. ___________________________________________________

3. ___________________________________________________

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Figure 8.5 Movements allowed by synovial joints.

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Figure 8.5 (Continued)

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Gliding Movements

Gliding movements occur when one flat, or nearly flat, bone surface glides or slips over another.

Angular Movements

Angular movements increase or decrease the angle between two bones.

Flexion ______________________________ the angle of the joint and brings the articulating bones closer together.

Extension ______________________________ the angle between the articulating bones.

Abduction is the movement of a limb (or fingers) ____________________ from the midline body (or of the hand).

Adduction is the movement of a limb (or fingers) ____________________ the midline of the body (or the hand).

Circumduction is moving a limb so that it describes a ________________ in the air.

Rotation

Rotation is the turning of a bone along its own long axis.

Medial Rotation:

Lateral Rotation:

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Special Movement

Supination is rotating the forearm _______________________ so that the palm faces anteriorly or superiorly.

Pronation is rotating the arm _______________________ so that the palm faces posteriorly or inferiorly.

Dorsiflexion ____________________________ the angle between the top of the foot (dorsal surface) and the anterior surface of the tibia.

Plantar flexion decreases the angle between the sole of the foot (plantar surface) and the posterior side of the tibia.

Inversion occurs when the sole of the foot turns ________________________.

Eversion occurs when the sole faces ____________________________.

Protraction non-angular anterior movement in a transverse plane.o Example: when you jut your jaw out.

Retraction non-angular posterior movement in a transverse plane.o Example: when you retract your jaw to bring it back in.

Elevation involves lifting a body part _______________________.

Depression involves moving the elevated part ______________________________.

Opposition is the action taken when you touch your ________________ to the tips of the other fingers on the same hand.

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Figure 8.6 Special body movements.

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Types of Synovial Joints

Figure 8.7

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Plane joints have flat articular surfaces and allow gliding and transitional movements.

Hinge joints consist of a cylindrical projection that nests in a trough-shaped structure, and allow movement along a single plane.

Pivot joints consist of a rounded structure that protrudes into a sleeve or ring, and allow uniaxial rotation of a bone around the long axis.

Condylar joints consist of an oval articular surface that nests in a complementary depression, and permit all angular movements.

Saddle joints consist of each articular surface bearing complementary concave and convex areas, and allow more freedom of movement than condylar joints.

Ball-and-socket joints consist of a spherical or hemispherical structure that articulates with a cuplike structure. They are the most freely moving joints and allow multiaxial movements.

Selected Synovial Joints

Knee Joint

The single cavity of the knee joint is actually three joints in one: the femoropatellar joint, the lateral and medial joints between the femoral condyles, and the menisci of the tibia, known collectively as the tibiofemoral joint.

The tibiofemoral joint is a hinge joint, allowing mostly flexion and extension, although limited rotation is possible when the knee is bent.

The femoropatellar joint is a plane joint that allows the patella to glide across the knee when the knee is flexed.

Three types of ligaments stabilize and strengthen the capsule of the knee joint: capsular and extracapsular ligaments prevent hyperextension and rotation when the knee is extended, and intracapsular ligaments, the cruciates, keep the articulating bones of the knee aligned.

The knee capsule is reinforced by muscle tendons such as the strong tendons of the quadriceps muscles and the tendon of the semimembranosus.

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Figure 8.8 The knee joint

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Figure 8.8 (Continued)

Figure 8.9 A common knee injury

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