Joints

Question 1

What are joints?

Answer 1

Regions of the skeleton where bones meet and articulate with each other

Supported by a variety of soft tissues

Question 2

What is the function of joints?

Answer 2

Function is either to allow movement or growth

Question 3

How are joints classified?

Answer 3

There is no single best way to classify joints but classification is usually based on either the degree of movement possible or the nature of the soft tissues involved

Question 4

What are the classifications of joints?

Answer 4

Fibrous- bones are only separated by connective tissue with negligible movement

Cartilage

• primary cartilaginous (synchondrosis)
• secondary cartilaginous (symphysis)

Synovial
-Characterized by 6 criteria

Question 5

Explain fibrous joints as a classification

Answer 5

Sutures

• Immovable
• Dense irregular connective tissue between bones

Syndesmosis

• slight movement
• greater distance
• More connective tissue
  
  • Gomphosis- teeth

Interosseous membrane

Question 6

Explain Cartilaginous joints

Answer 6

Synchondrosis

• bone and hyaline cartillage meet
• immobile
• very strong
• Epiphyseal growth plate

Symphysis

• Articular surfaces lined with hyaline cartilage with a fibrocartilage disc in between
• Limited amount of movement
• pubic symphysis
• intervertebral joints

Question 7

Explain synovial joints

Answer 7

• Articular surfaces covered with hyaline cartilage
• Has a joint cavity
• has a joint capsule
• Has a synovial membrane
• Reinforced by ligaments internally, externally or both
• Capable of varying degrees of movement

Question 8

What are the classes of synovial joints?

Answer 8

• plane joint
• hinge joint
• pivot joint
• condyloid joint
• saddle joint
• ball-and-socket

Question 9

What is a plane joint?

Answer 9

Type of synovial joint that is between navicular and second and third cuneiforms of tarsus in foot

Question 10

What is a hinge joint?

Answer 10

Synovial joint between trochlea of humerus and trochlear notch of ulna at the elbow

Question 11

What is the pivot joint?

Answer 11

Synovial joint between head of radius and radial notch of ulna

Question 12

What is the condyloid joint?

Answer 12

Synovial joint between radius and scaphoid and lunate bones and carpus (wrist)

Question 13

What is the saddle joint?

Answer 13

Synovial joint between trapezium of carpus (wrist) and metacarpal of thumb

Question 14

What is a ball-and-socket joint?

Answer 14

Synovial joint between head of femur and acetubulum of hip bone

Question 15

Describe gliding movements

Answer 15

• flat bone surfaces
• limited in range
• no significant alteration in angle

Question 16

Describe angular movements

Answer 16

-change in angle

-described in terms f the body planes
Flexion-extension

Abduction-adduction

Lateral flexion, hyper extension , curcumduction

Question 17

Describe rotational movement

Answer 17

• a bone revolves around its own longitudinal axis
• Ususlly requires “fixing” another joint before rotation can be achieved
• At limbs this is defined in relation to the midline
• Medial/internal rotation

Question 18

What is the temporomandibular joint?

Answer 18

Classification: -atypical synovial joint

-modified hinge/condylar

Articular surfaces:
-Condyle of the mandible

• Articular tubercle of temporal bone
• Mandibular fossa

Question 19

What is the Glenohumeral joint ?

Answer 19

Articulation between
-head of humerus and glenoid cavity

Highly mobile at expense of stability

The factors increasing stability:
-Bony arch

• Rotator cuff
• Ligaments both intra- and extra-capsular

Question 20

What is a dislocation?

Answer 20

Dislocation usually occur inferno-anteriorly in the absence of fracture - shoulder joint is weakest inferiorly. It’s very painful.

Once dislocated, can reoccur

Question 21

What bodily prevents dislocation for the shoulder?

Answer 21

Superior support
-bony arch

Anterior and posterior support
-Ligaments

• biceps long head tendon
• rotator cuff muscles- mainly during movement

Question 22

Describe the hip joint

Answer 22

• More stable than shoulder and somewhat less mobile
• weight-bearing joint
• femur neck features often in elderly
  
  • osteoporosis
  • can be devastating

Question 23

What are the age related changes?

Answer 23

• decreased production of synovial fluid
• Articular cartilage becomes thinner
• Mainly on weight-bearing joints
  
  • knees and hips

-osteoarthritis