Joints 1

Question 1

What is a joint?

Answer 1

Union between two or more rigid components (bone or cartilage)

Articulation- another term for joint

Question 2

Why do we need joints?

Answer 2

movement of body
growth - at certain types of joints new bone is formed

Question 3

What are the three categories of joints?

Answer 3

Fibrous
Cartilaginous
Synovial

Question 4

Characteristics of fibrous joints?

Answer 4

-dense fibrous connective tissue- densely packed collagen fibres
-high tensile
-little movement
-difficult to pull bones apart

Question 5

Examples of fibrous joints?

Answer 5

-Cranial sutures - joints between skull bones
-Periodontal ligament - tooth root and tooth rocket
-Interosseus membrane- fore arm

Question 6

Characteristics of cartillaginous joints?

Answer 6

-layers of cartillage

Question 7

What are the two types of cartillaginous joints?

Answer 7

Synchondroses (primary)
Symphyses (secondary)

Question 8

Sychondroses characteristics?

Answer 8

Allow for bone growth (endochondral ossification)
Disappear in adults
No movement
-hyaline cartillage only

Question 9

Symphyses ( plural) characteristics?

Answer 9

Do not ossify with age
Found in midline of body
Limited movement
two types of cartillage

Question 10

Example of sympheses joints?

Answer 10

-joint between two adjacent vertebrae bodies
-invertebral disc (fibrocartillage) AND layer of hyaline cartillage (cover bone surfaces)

Question 11

Synovial joints characteristics?

Answer 11

-These joints allow for greatest movement
-Joints include a fibrous capsule
-On inner side of membrane there is synovial membrane which produces synovial fluid (found within synovial cavity)
-Sinovial fluid important for lubrication of the joint

Question 12

What other features do you find in synovial joints?

Answer 12

Articular discs
Ligaments

Question 13

Examples of synovial joints?

Answer 13

Hinge - in elbow
plane - allows for sliding and gliding (limited)
ball and socket - hip or shoulder
condylar - medium movement
saddle - looks like saddle - medium movement. In thumb origin
pivot- rotation of movement around one long axis. Atlas and axis

Question 14

What ensures joint stability?

Answer 14

Shape of articulating surfaces
Fibrous capsule & ligaments
Muscles

Question 15

Example of joint stability?

Answer 15

Shoulder joint
Shallow socket- large range of movement
Fibrous capsule and ligaments around joint
muscles provide stability (rotator cuff muscles)

Question 16

Limb rotation during embryonic development?

Answer 16

Both limbs undergo a rotation , upper limbs rotate laterally and lower limbs rotate medially. At week 8 upper limbs stop rotation and lower limbs twist for longer and this is reason flexion at knee is different to flexion at elbow.

Question 17

Blood and nerve supply to joints?

Answer 17

Joints have a rich blood & nerve supply
Anastomoses
(Branches of blood vessels reconnect)

Question 18

What does flexion mean?

Answer 18

To bring two ventril surfaces together.

Question 19

Why do we need limb rotation?

Answer 19

Thanks to limb rotation we do not need to walk like lizard. Lizards need lots of vertebral column movement. In lizards, forelimb and hindlimb both stick outwards. Opposite for humans.

Question 20

Why are anastomoses important?

Answer 20

The blood flow can take alternative routes as extreme joint motion - compression of individual blood vessels is prevented. For e.g. severe flexion

Question 21

Hilton’s Law?

Answer 21

The nerve supplying a muscle that crosses a certain joint, also innervates this joint.

Question 22

Nerve supply to joints?

Answer 22

Proprioception- proprioceptors are also located in joint capsules, joints important in proprioception.

Question 23

What is proprioception?

Answer 23

Proprioception is the body’s ability to sense its location, movements, and actions.