What is an articulation?
An articulation, or joint, is the place where a bone meets another bone, cartilage, or teeth.
Articulations vary in stability and mobility, and are classified into categories. The most mobile joints are also the most unstable, while the most stable are immobile.
Rank the following in order of mobility and stability (#1 is the most mobile and least stable)
Glenohumeral joint (shoulder),
Elbow joint,
Hip joint,
Suture,
Intervertebral joints
Most mobile, least stable
Glenohumeral joint (shoulder)
Hip joint
Elbow joint
Intervertebral joints
Suture
Least mobile, most stable
What are synovial joints?
Joints in which the articulating bones are enclosed by a joint capsule with a fluid filled cavity. Examples are the shoulder, knee, and hip joints
What are the four categories of movement that can be made by synovial joints?
- Gliding:
The motion of bones sliding on one another - Angular:
A motion that changes a joint angle. These motions can be classified as:
- flexion: decreasing the angle between articulating bones (bending)
- extension: increasing the angle between articulating bones (straightening)
- abduction: movement away from the midline of the body
- adduction: movement towards the midline of the body - Rotation:
When a joint pivots around its own axis. Two types are:
- medial rotation: towards the midline
- lateral rotation: away from the midline - Special movements:
Three types are
- Supination and pronation
- Inversion and eversion
- Circumduction
(describe them in a separate cue card)
Describe the three special movements of synovial joints.
- Supination and pronation:
Rotation of the radius over the ulna (forearm bones). Supination occurs when the forearm rotates so the palm faces anteriorly, versus pronation which occurs when the forearm rotates so the palm faces posteriorly. This can be remembered as ‘supination’ helps you hold a bowl of soup - Inversion and eversion:
Twisting motion of the ankle. Inversion occurs when the ankle is twisted so the soles of the feet turn medially, versus eversion which occurs when the ankle is twisted so the soles of the feet turn laterally. - Circumduction (basically an example is going in a circle haha like CIRCumduction):
A continuous movement that combines flexion, abduction, extension, and adduction in succession.
What is hyperextension?
Happens when we extend past the anatomical position.
Occurs normally as a continuation of extension. However, it can occur as a result of an injury, or in people who have hypermobile joints (joints that can easily move beyond the typical range of motion).
