Joints

Question 1

What is a joint?

Answer 1

A union or junction between two or more bones or rigid parts of the skeleton

Question 2

Where do articular arteries (which nourish the joint) arise from?

Answer 2

They arise from the vessels around the joint

Question 3

Most articular nerves are branches of the nerves that supply the muscles surrounding the joint. T/F?

Answer 3

True

Question 4

What is the name of the sensation transmitted by joints which provides awareness of the movement and position of parts of the body?

Answer 4

Proprioception

Question 5

Joints can be classified according to their general morphology into three categories. These are…?

Answer 5

Fibrous joints
Cartilaginous joints
Synovial joints

Question 6

What are the three classification of joints according to their function?

Answer 6

Synarthrosis - joints which do not provide movement
Amphiarthrosis - joints which provide a small degree of movement
Diarthrosis - joints which provide free movement

Question 7

What kind of joints do not have a joint cavity?

Answer 7

Fibrous joints and cartilaginous joints

Question 8

What is a fibrous joint?

Answer 8

A joint which connects bones via fibrous tissue

Question 9

Fibrous joints can be classified according to the range of movement they permit as…?

Answer 9

Synarhtrotic or amphiarthrotic

Question 10

Give an example of a fibrous joint.

Answer 10

Sutures of the cranium

Question 11

What are cartilaginous joints and what range of motion do they offer?

Answer 11

These are joints without a joint cavity which are connected by cartilage. They can be syarthrotic or amohiarthrotic.

Question 12

What are the two types of cartilaginous joints?

Answer 12

Primary (synchondroses)

Secondary (symphases)

Question 13

What range of movement is offered by synovial joints?

Answer 13

Synovial joints are diarthrotic joints

Question 14

What is the general structure of a synovial joint?

Answer 14

Bones are united by a joint capsule which is formed from an outer fibrous membrane and an inner synovial membrane. The articular surfaces of the bones are lined with hyaline cartilage and are separated by synovial fluid.

Question 15

What is the synovial fluid and what is it composed of?

Answer 15

It is the viscous, clear fluid that exists within the capsule of a synovial joint and is secreted by the synovial membrane. Its main component is hyaluronic acid but it also contains macrophages.

Question 16

What is the synovial membrane composed of?

Answer 16

Loose areolar connective tissue with two types of cell: type A synoviocytes and type B synoviocytes

Question 17

What are the functions of the two types of cell within the synovial membrane?

Answer 17

Type A synoviocytes - modified macrophages
Type B synoviocytes - fibroblast-like cells responsible for secreting hyaluronic acid and other proteins of the synovial fluid.

Question 18

Synovial joints often have additional structures such as articular discs and fat pads associated with them. What are the purpose of these?

Answer 18

Articular discs - absorb compression forces, adjust to changes in the contours of joint interphases and increase range of movement

Fat pads - absorb compression forces

Question 19

What are bursae, where are the found and what is there function?

Answer 19

They are fibrous, slightly flattened sacks lined with synovial membrane and containing a thin film of synovial fluid.
They are usually found between bone and other tissues such as skin, tendons, ligaments and muscles.
They function to cushion the movement between these structures.

Question 20

What are tendon sheaths and what are there function?

Answer 20

Tendon sheaths are essentially elongated bursae which wrap around tendons which are particularly subjected to stress and protect them from frictional forces.

Question 21

What are the six sub-groups of synovial joints?

Answer 21

Plane joints
Hinge joints
Pivot joints
Ellipsoid/condyloid joints
Saddle joints
Ball and Socket

Question 22

Which synovial joints are uniaxial?

Answer 22

Plane joints
Hinge joints
Pivot joints

Question 23

Which synovial joints are biaxial?

Answer 23

Condyloid joints

Saddle joints

Question 24

Which synovial joint is multiaxial?

Answer 24

Ball and Socket

Question 25

Give an example of a plane joint.

Answer 25

Acromioclavicular joint between acromion of the scapula and the clavicle

Question 26

Give an example of a hinge joint.

Answer 26

Elbow joint

Question 27

Give an example of a pivot joint.

Answer 27

Superior radioulnar joint

Question 28

Give an example of an ellipsoid joint.

Answer 28

Metacarphophalangeal joints (knuckle joints)

Question 29

Give an example of a saddle joint.

Answer 29

Carpometacarpal joint at the base of the thumb

Question 30

Give an example of a ball and socket joint.

Answer 30

Hip joint. Spherical head of femur and socket formed by the acetabulum of the hip bone

Question 31

What kind of ligaments reinforce a synovial joint?

Answer 31

Accessory ligament

Question 32

What are the two main forms of ligament found inside the synovial joints?

Answer 32

Intracapsular accessory ligaments

Extracapsular accessory ligaments

Question 33

What limits the range if motion of a fibrous joint?

Answer 33

The length of the fibrous tissue of the joint. Longer tissue = greater range of motion

Question 34

Give a description of a synchondroses and provide an example of this type of joint.

Answer 34

It is a joint which unites bines via hyaline cartilage and is almost always synarthrotic. It can occur permanently (between first rib and manubrium) or temporarily ( between epiphyses and diaphyses of long bones in development)

Question 34

What us synovial fluid drained by?

Answer 34

Lymph vessels

Question 36

Describe a secondary cartilaginous joint and give an example of this type of joint.

Answer 36

Here the articulating surfaces of the bones of the joint are covered in hyaline cartilage but the bones are united by fibrocartilage. It usually occurs in the midline of the body (e.g. Pubic symphysis and intervertebral discs). They function well as shock absorbers

Question 37

What are the three sub-sets of fibrous joints? Give a description and provide an example for each

Answer 37

Syndesmosis - units bone with an interosseous filament (amphiarthrotic) e.g.joint between radius and ulna joined by ligamentum flavum
Gomphosis - peg-like process fits into socket between the root of the tooth and the alveolar process of the jaw and the joint is composed of a periodontal ligament (synarthrotic)
Suture - strong, synarthrotic joint in the skull held by a sutural ligament