Chapter 7

Question 1

Articulation

Answer 1

• The point of contact between bone, bone and cartilage, or bone and teeth

Question 2

Two major classifications systems for joints

Answer 2

• Structural classification; is based on the presence or absence of a synovial (joint) cavity and the type of connecting tissue

1. Structurally, joints are classified as fibrous, cartilaginous, or synovial.

• Functional classification; of joints is based on the degree of movement permitted, from none to freely moveable.

Question 3

(CS) Synarthrosis

Answer 3

• An immobile or nearly immobile joint
• Immobile nature of these joints provide for a strong union between the articulating bones.
• This feature is important at locations where the bones provide protection for internal organs.
• For example: suture joints of the skull, immobile joints in adults

Question 4

(CS) Amphiarthrosis

Answer 4

• A joint that has limited mobility.
• ## For example: the cartilaginous joint that unites the bodies of adjacent vertebrae has an amphiarthrosis intervertebral disc

Question 5

(CS) Diarthrosis

Answer 5

• A joint that is freely mobile
• These types include all synovial joints of the body, which provide majority of body movements.
• For example: multiaxial joint like the hip joint allows movement from all three planes.

Question 6

Fibrous joints

Answer 6

• Lack synovial cavity, their articulating bones are held together by fibrous connective tissue, and they permit little or no movement.
• They form strong connections between bones

Question 7

Types of fibrous joints

Answer 7

1. Sutures
2. Syndesmoses
3. Interosseous membrane

Question 8

(FJ) Sutures

Answer 8

• Fibrous joint composed of a thin layer of dense fibrous connective tissue that unites skull bones

Question 9

Synostosis

Answer 9

• A suture joint that has ossified
• An example of a synostosis; is the frontal suture between the left and right sides of the frontal bone

Question 10

(FJ) Syndesmosis

Answer 10

• A fibrous joint with more fibrous connective tissue than in a suture

Question 11

(FJ) Interosseous membrane

Answer 11

• A sheet of dense irregular connective tissue joining two long bones (e.g., radius and ulna)

Question 12

Two types of cartilaginous joints

Answer 12

1. Synchondroses
2. Symphyses

Question 13

Cartilaginous joints

Answer 13

• Lacks a synovial cavity; its articulating bones are connected by either fibrocartilage or hyaline cartilage; and it allows little or no movement.

Question 14

(CJ) Synchdrondosis

Answer 14

• A cartilaginous joint in which the connecting material is hyaline cartilage

Question 15

(CJ) Symphysis

Answer 15

• A cartilaginous joint in which the connecting material is a disc of fibrocartilage.
• Examples of this joint are the intervertebral discs and the pubic symphysis

Question 16

Synovial joint

Answer 16

• A synovial joint (diarthrosis) has a synovial (joint) cavity between the articulating bones; this joint is freely movable.

-Articular cartilage covers the bones at synovial joints

• This cartilage reduces friction during movement, and helps to absorb shock
• The articular capsule surrounds a diarthrosis, encloses the synovial cavity, and unites the articulating bones.

1. Is composed of two layers - the outer fibrous capsule that may contain ligaments, and the inner synovial membrane that secretes a lubricating and joint-nourishing synovial

• The flexibility of the fibrous capsule permits considerable movement at a joint, whereas its great tensile strength helps to prevent bones from dislocating
• Synovial fluid, secreted by the synovial membrane, lubricates and reduces friction in the joint and supplies nutrients to and removes metabolic wastes from the joint.
• Ligaments help hold bone to bone
• Articular discs modify the shape of the joint surfaces of the articulating bones, help maintain the stability of the joint, and direct the flow of synovial fluid to areas of greatest friction.
• Nerves that supply a joint are the same as those that supply the skeletal muscles that move the joint

Question 17

Movements at synovial joints (four categories)

Answer 17

1. Gliding movements; occur when relatively flat bone surfaces move back and forth, and from side to side with respect to one another
2. Angular movements; involve an increase or a decrease in the angle between articulating bones, and can include: flexion, extension, hyperextension, abduction, adduction, and circumduction.
3. Rotation movements; involve a bone revolving around its own longitudinal axis
4. Special movement; occurs only at certain joints.

Question 18

Special movements that can occur at some joints

Answer 18

1. Elevation
2. Depression
3. Protraction
4. Retraction
5. Inversion
6. Eversion
7. Dorsiflexion
8. Plantar flexion
9. Supination
10. Pronation
11. Sprain
12. Strain

Question 19

(JM) Elevation

Answer 19

• Upward movement of a part of the body

Question 20

(JM) Depression

Answer 20

• Downward movement of a part of the body

Question 21

(JM) Protraction

Answer 21

• Movement of a part of the body anteriorly in the transverse plane

Question 22

(JM) Retraction

Answer 22

• Movement of a protracted part back to the anatomical position

Question 23

(JM) Inversion

Answer 23

• Movement of the soles medially at the intertarsal joints so that they face each other

Question 24

(JM) Eversion

Answer 24

• Movement of the soles laterally at the intertarsal joints so that they face away from each other

Question 25

(JM) Dorsiflexion

Answer 25

- Refers to bending of the foot at the ankle in the direction of the superior surface

Question 26

(JM) Plantar flexion

Answer 26

- Involves the bending of the foot at the ankle joint in the direction of the plantar surface

Question 27

(JM) Supination

Answer 27

- Movement of the forearm at the proximal and distal radioulnar joints in which the distal end of the radius crosses over to the distal end of the ulna, and the palm is turned posteriorly or inferiorly

Question 28

(JM) Sprain

Answer 28

- The forcible wrenching or twisting of a joint that stretches or tears its ligaments but does not dislocate the bone

Question 29

(JM) Strain

Answer 29

- A stretched or partially torn muscle

Question 30

Subtypes of synovial joints

Answer 30

1. Planar joints 2. Hinge joint 3. Pivot joint 4. Ellipsoidal joint 5. Saddle joint 6. Ball-and-socket joint

Question 31

(SJ) Planar joints

Answer 31

- Permit mainly side-to-side and back-and-forth gliding movements

Question 32

(SJ) Hinge joint

Answer 32

- The convex surface of one bone fits into a concave surface of another bone

Question 33

(SJ) Pivot joint

Answer 33

- A round or pointed surface of one bone fits into a ring formed by another bone and a ligament

Question 34

(SJ) Ellipsoidal joint

Answer 34

- An oval-shaped condyle of one bone fits into an elliptical cavity of another bone

Question 35

(SJ) Saddle joint

Answer 35

- Includes one bone whose articular surface is saddle-shaped, and another bone whose articular surface is shaped like a rider sitting in the saddle

Question 36

(SJ) ball-and-socket joint

Answer 36

- The ball-shaped surface of one bone fits into the cuplike depression of another

Question 37

Structure and function of the knee joint

Answer 37

- Knee joint is an example of a complex hinge joint, which we will examine in some detail *Know components of knee joint*