Joints

Question 1

What is a joint?

Answer 1

Meeting of two bones. Bones articulate at the joint

Question 2

What are joints classified by?

Answer 2

Function - range of movement

structure - what links the bones

Question 3

Functional classification of joints

Answer 3

Synarthrosis - immobile
Amphiarthrosis - Slightly mobile
Diarthrosis - Freely mobile

Question 4

Structural classifications of joints

Answer 4

Fibrous - Dense CT
Cartilaginous - Hyaline or Fibro-cart
Synovial - Ligaments
Synostosis - Bone

Question 5

Fibrous joint types

Answer 5

Suture and Syndesmosis

Question 6

Features of suture

Answer 6

Bones linked by thin layer of Fibrous CT, located in skull, immovable

Question 7

Features of Syndesmosis

Answer 7

Slightly moveable, forms interosseous membrane or ligament, more connective tissue linking bones than in sutures

Question 8

What are the cartilaginous joint types

Answer 8

Synchondrosis and Symphysis

Question 9

Synchondrosis

Answer 9

Hyaline cartilage links bones. Can facilitate growth of long bones

Question 10

Symphysis

Answer 10

Fibrocartilage joint

Compressible, strong and flexible. limited movement possible

Question 11

Synovial

Answer 11

Most common joint. Diarthroses.

Question 12

Features of synovial joint

Answer 12

➢ Articular cartilage
➢ Articular/fibrous capsule
➢ Synovial membrane
➢ Synovial cavity & synovial fluid
➢ Accessory structures (discs or ligaments) may also be
present.

Question 13

How can we classify synovial joints?

Answer 13

Axes of movement and shape

Question 14

Axes of movement

Answer 14

Nonaxial
Uniaxial
Biaxial
Multiaxial

Question 15

Shapes of synovial joint

Answer 15

Plane/Gliding
Hinge
Pivot
Condyloid
Saddle
Ball & Socket

Question 16

What are the 5 Synovial joints

Answer 16

Gliding
pivot/trochoidal
Condyloid/ellipsoid
Saddle
Ball and socket/spheroidal

Question 17

Gliding Synovial joint features

Answer 17

Articular surfaces are essentially flat.
➢ Allow short gliding movements (nonaxial).
➢ Some can be classified as amphiarthroses

Question 18

Hinge Synovial joint features

Answer 18

A cylindrical projection (convex) of one bone fits into
a trough-shaped surface (concave) of another bone.
➢ Motion is along a single plane (uniaxial) permitting
extension& flexion.

Question 19

Pivot / Trochoidal Synovial Joints

Answer 19

➢ The rounded end of one bone protrudes into a sleeve
composed of bone or ligaments.
➢ Allows rotation along the axis of the bone (uniaxial).

Question 20

Condyloid / Ellipsoid Synovial Joints

Answer 20

The oval-shaped (convex) articular surface of one bone fits into
complimentary depression (concave) on another bone.
➢ Permits movement in 2 planes (biaxial).

Question 21

Saddle / Sellar Synovial Joint

Answer 21

➢ Each articular surface has both concave & convex areas.

➢ Permits significant movement in different planes (multiaxial).

Question 22

Ball & Socket / Spheroidal Synovial Joints

Answer 22

➢ The spherical head of one bone articulates with a cupshaped socket of another bone.
➢ The most freely moveable of synovial joints (multiaxial).

Question 23

Explain the shoulder joint

Answer 23

Known as the glenohumeral or humeroscapular joint
➢ Ball & socket articulation
Head of humerus articulates with glenoid cavity
of scapula
➢ Relatively shallow & loose joint
➢ Most freely moveable joint in body
Joint supported by
➢ Ligaments (e.g. coracohumeral)
➢ Tendons of muscles (e.g. Biceps brachii)
➢ Rotator cuff muscles

Question 24

Explain the hip joint

Answer 24

Known as the coxal joint
➢ Ball & socket articulation (multiaxial).
Head of femur articulates with acetabulum of coxal
bone
➢ Acetabulum forms deep socket for head of femur
➢ Much more stable (but less moveable)
than shoulder joint.
Joint supported by
➢ Ligaments
➢ Tendons of thigh and hip muscles.

Question 25

What are the ligaments of the hip joint?

Answer 25

Iliofemoral, Ischiofemoral and pubofemoral ligament

Question 26

Explain the knee joint

Answer 26

``` Articulation between the femur, tibia and patella; ➢ One of the largest & most complex synovial joints in the body. Primarily a hinge joint; ➢ Joint capsule encloses posterior & medial aspects ➢ Extensions of quadriceps tendon cover anterior aspect. ```

Question 27

Knee joint Intracapsular ligaments

Answer 27

Intracapsular cruciate ligaments cross each other to form an X; ➢ Anterior cruciate ligament (ACL) ➢ Posterior cruciate ligament (PCL) Prevent forward or backward displacement of tibia.

Question 28

Knee joint Extracapsular ligaments

Answer 28

Fibular collateral ligament | Tibial collateral ligament

Question 29

What is the knee menisci?

Answer 29

The (knee) joint contains two crescent-shaped pads of fibrocartilage called lateral & medial menisci ➢ Absorb shock & prevent the femur rocking from side to side on the tibia

Question 30

3 features of the menisci

Answer 30

Lateral meniscus Synovial membrane Medial meniscus

Question 31

What is the "zero position"

Answer 31

Original anatomical position

Question 32

Flexion

Answer 32

Reduce angle between articulating elements

Question 33

Extension

Answer 33

Increases angle between articulating elements

Question 34

Abduction

Answer 34

= lateral movement; movement away from the longitudinal axis of the body.

Question 35

Adduction

Answer 35

medial movement; movement | towards the longitudinal axis.

Question 36

Circumduction

Answer 36

``` Conical movement; The shape of a cone is outlined by the pathway of the joint movement. ```

Question 37

Rotation

Answer 37

A circular movement along the longitudinal axis of a bone (s).

Question 38

What are two structures associated with synovial joints?

Answer 38

``` Bursae - —flattened fibrous sacs ▪ Lined with synovial membranes ▪ Filled with synovial fluid ▪ Not actually part of the joint Reducing friction during joint motion Tendon sheath- ▪ Elongated bursa that wraps around a tendon Secrete synovial fluid to promote movement ```

Question 39

Common injuries and disorders of the skeletal system are?

Answer 39

``` ▪ Fractures Breaks in bone Different classifications Stress fractures ▪ Osteoporosis Common in the elderly ▪ Female athlete triad Involves a combination of an eating disorder, amenorrhoea and osteoporosis ▪ Sprains and dislocations ```