Joints and Dislocations

Question 1

What is the skeleton made of?

Answer 1

Bones and cartilage

Question 2

What is bone made of?

Answer 2

Hard connective tissue

Question 3

What are the (4) main functions of bones?

Answer 3

Support & Protection
Calcium Metabolism
Red blood cell formation
Attachment (for skeletal muscles)

Question 4

What defines cartilages and where is it located?

Answer 4

Less rigid than bone

Located where mobility is required at articulation (joints)

Question 5

What are the three types of joints and their relative stability & mobility?

Answer 5

Fibrous - most stable / least mobile
Cartilaginous - moderate stability / mobility
Synovial - least stable / most mobile

Question 6

What are the subtypes of Fibrous joints and their features

Answer 6

Syndesmoses - unite bones with fibrous sheet (partially movable)
Sutures - highly stable

Question 7

What is an example of a Syndesmoses?

Answer 7

Interrousseous membrane between the fibula and tibia

Question 8

What is an example of a suture?

Answer 8

Coronal suture

Question 9

What are fontanelles?

Answer 9

Essentially precursors to sutures - found in neonatal skull - allow growing frontal, parietal, temporal and occipital bones to ‘slide’ over each other –> make’s baby’s head smaller for passage through birth canal

Question 10

What are the types of cartilaginous joints?

Answer 10

Primary and secondary

Question 11

What distinguishes primary cartilaginous joints?

Answer 11

Synchondroses: Bones joined by hyaline cartilage

Question 12

What is the function of synchondroses?

Answer 12

Permit growth in length of bone / ossification and fusion

Question 13

What distinguishes secondary cartilaginous joints?

Answer 13

Symphyses:

• strong
• slightly movable

Question 14

A slipped disc can compress which neural structures?

Answer 14

Spinal cord or spinal nerves

Question 15

What are the 8 typical features of synovial joints?

Answer 15

1. Two or more bones articulating with each other
2. Articular surfaces covered in hyaline cartilage
3. Capsule (wraps around joint)
4. Joint cavity (contains synovial fluid)
5. (Supported by) ligaments
6. Associated with skeletal muscle & their tendons
7. Associated with bursae
8. Often have special features (unique to each joint)

Question 16

What makes up a capsule in a synovial joint?

Answer 16

Superficial strong fibrous layer + deeper synovial membrane layer (secretes synovial fluid)

Question 17

What are ligaments?

Answer 17

Fibrous bands from bone to bone

Question 18

What is the function of ligaments?

Answer 18

Strengthen and improve stability of the joint

Question 19

In what way is hyaline cartilage involved in osteoarthritis?

Answer 19

Doesn’t grow back very well

Question 20

What is the function of bursae?

Answer 20

Prevent friction around the joint

Question 21

What are tendons?

Answer 21

Fibrous bands from muscle to bone

Question 22

What are the 5 subtypes of synovial joints?

Answer 22

Pivot, Plane, Hinge, Biaxial, Ball & Socket

Question 23

What is the range of movement of a pivot (synovial) joint?

Answer 23

> 45° of “shaking the head” rotation

E.g. Atlanto-axial joint

Question 24

What is the ROM of a ball & socket (synovial) joint?

Answer 24

Good ranges of multi-axial movement (e.g. circumduction)

E.g. Hip joint

Question 25

What is the ROM of a plane (synovial) joint?

Answer 25

Minimal movement in one plane | E.g. Acromioclavicular joint

Question 26

What is the ROM of a hinge (synovial) joint?

Answer 26

Reasonable movement in one plane | E.g. Elbow joint

Question 27

What ist the ROM of a biaxial (synovial joint)?

Answer 27

Reasonable ROM in one plane and less in another | E.g. Caropometacarpal joint

Question 28

What is mobility and stability determined by?

Answer 28

Joint type, i.e. shape & fit

Question 29

What is hypermobility?

Answer 29

Pathological or physiological increased mobility at joints

Question 30

What is subluxation?

Answer 30

Reduced area of contact between articular surfaces

Question 31

What is dislocation?

Answer 31

Complete loss of contact between articular surfaces

Question 32

What is the Temporomandibular joint?

Answer 32

Each TMJ is the synovial articulation between the mandibular fossa & the articular tubercle of the temporal bone superior and the head of the condylar process of the mandible inferiorly

Question 33

The articular disc of the TMJ divides the joint into ___?

Answer 33

superior & inferior cavity

Question 34

Muscles in the TMJ _____ to allow the mouth to open wide

Answer 34

naturally subluxes

Question 35

What happens in dislocation of the TMJ?

Answer 35

the head of the condylar process of the mandible becomes 'stuck' anterior to the articular tubercle of the temporal bone

Question 36

What is proprioception

Answer 36

Allows brain to sense where something (e.g. joint) is in space

Question 37

What are periarticular arterial anastomoses?

Answer 37

``` periarticular = around the joint anatomises = connection between arteries ```

Question 38

What is the purpose of anastomoses?

Answer 38

Prevents blood flow restriction to the joint when the muscle flexes - can be dangerously compromised during dislocation