ANATOMY - JOINTS Flashcards
What is a joint?
A normal interruption in the continuity of the skeleton
What is a simple joint?
Only 2 bones involved
What is a compound joint?
More than 2 bones involved
What are the 2 types of non-synovial joints?
- fibrous joints
- cartilaginous joints
What defines a non-synovial joint?
Doesn’t have a joint cavity
What defines a synovial joint?
Has a joint cavity
What is an example of a fibrous joint?
Sutures in skull
Fibrous attachments between teeth and jaws
Is movement possible at fibrous joints?
Very little movement is possible
Describe a fibrous joint
The bones are connected by fibrous connective tissue.
The bones are serrated and lock which gives them stability
Fibrous joints disappear with age as bones fuse
What are the types of cartilaginous joint?
Primary
Secondary
What is an example of a primary cartilagenous joint?
Epiphyseal plate
Is movement possible at primary cartaliganous joints?
Very little movement possible
What is Osgood-Schlatter disease?
A disease common in young athletes
Irritation at growth plate on tibia
Caused by tension on patellar ligament
What are examples of secondary cartilaginous joints?
Pubic symphysis
Intervertebral discs
Describe structure of secondary cartilaginous joint
- Hyaline cartilage covers the articulate surfaces
- there is a pad of fibrous cartilage in between
Are secondary cartilaginous joints flexible?
Yes. The thickness of the fibrous cartilage pad determines the relative movement of the bones
What is found at the ends of bones in synovial joints?
An articulate layer of hyaline cartilage
Why is any wear on articulate cartilage permanent?
It isn’t replaced after growth stops
Do synovial joints have any blood vessels?
No. They get nutrients from synovial fluid and blood vessels in the bones
What surrounds a synovial joint?
A fibrous capsule made of dense irregular connective tissue
What can happen to the fibrous capsule of synovial joints if there is prolonged inactivity of the joint?
- connective tissue shortens
- joints become stiff
What is the purpose of ligaments in a synovial joint?
Resist dislocation
Where is the synovial membrane located?
In synovial joints.
Lining the capsule
Not found on the articular cartilage, or any menisci
What is the function of synovial fluid?
Lubricate joints
What is joint effusion?
When there is increased amount of fluid in the joint cavity.
It can indicate joint disease
What are intra-articular discs/menisci ?
Pads of fibrocartilage
What are intraarticular discs / menisci attached to?
Joint capsule
What is the function of an intraarticular disc?
It completely subdivides the joint, so that different movements can occur in each section
What is the function of menisci in a joint?
- improve fit
- improve lubrication
- shock absorption
- distribution of pressure
What is a labrum in a synovial joint?
A fibrocartilagnous lip around the joint cavities
What is the function of a labrum in a synovial joint?
Increases the size of the socket
What are the function of fat pads in a synovial joint?
Occupy dead space
What are the types of synovial joints, classified on shape?
- plane
- hinge
- saddle
- pivot
- ellipsoid
- ball and socket
Describe a plane joint and give example.
- Flat surfaces
- Allow only a slight gliding movement
- acromioclavicular joint
Describe a hinge joint and give example
- Have a cylinder shaped surface fitting into a half-tube surface
- uniaxial
- elbow/ knee
Describe a saddle joint and give examples
- 2 saddle shaped bones coming together
- biaxial
- thumb
Describe a pivot joint and give examples
- a bony process rotating within a bone & ligament
- uniaxial
- radioulnar joints
Describe an ellipsoid joint and give examples
- egg shaped
- biaxial
- metacarpophalangeal joints
Describe a ball and socket joint and give examples
- multiaxial
- shoulder/hip
What does it mean if a joint has good congruity ?
The surfaces of the bones involve are similar and there is a good fit
What is the close packed position of a joint?
The joint position with the greatest congruity
What is the loose packed position of a joint?
Any joint position which isn’t the close packed position
Why are the close packed positions better?
E.g standing (KNEE JOINT)
- minimises muscle energy
- ligaments and capsule are taught
- bones are screwed together
- joint is highly stable
What causes osteoarthritis?
- cartilage on the ends of bones wears down over time .
- increased pressure on bones
- synovial fluid production increased in response
- joint cavity swells, capsule stretches, leading to pain
- bone underneath the damage thickened (BONE SPURS)
- joint movement leads to pain and inflammation
What body parts are normally affected by osteoarthritis ?
Knees and hips
