Factors Affecting Joint Stability

Question 1

What is the joint mobility-stability trade-off?

Answer 1

Joints are connections between bones that need to be both mobile and stable
When mobility is emphasised, stability is reduced
When stability is emphasised, mobility is reduced

Question 2

Define shape of articulating surfaces and provide an example

Answer 2

Refers to the shape of two bones creating a joint e.g. the ball-shaped head of the femur articulating with ball-shaped socked on the coxal bone

Question 3

Define ligaments and provide an example

Answer 3

Made of tissue properties and connects bones together providing joint stability e.g. knee

Question 4

What is the role of a ligament?

Answer 4

Restricts undesirable movements
Offers support and stability
Susceptible to injury

Question 5

Define muscle arrangement and provide an example

Answer 5

Muscle tendons that cross the joint are important stabilises, especially when bone articulations are poor e.g. shoulder

Question 6

What is muscle tone?

Answer 6

Low level of contractile activity in a relaxed muscle that enables muscle to react to any postural changes or movement

Question 7

Define skin and fibrous connective tissue

Answer 7

Forms a sheath around muscles and joints offering greater stability

Question 8

Define atmospheric pressure and provide an example

Answer 8

A vacuum within a joint is created when joint surfaces are being separated further improving a joint’s stability e.g. if a muscle or ligament surrounding the hip joint are cut, the head of the femur would remain in place

Question 9

What are the factors affecting joint stability?

Answer 9

Shape of articular surfaces, ligaments, muscle arrangement, skin and fibrous connective tissue (fascia), atmospheric pressure