MSK Classification of joints Flashcards
How are joints classified according to the tissue type present? and give an example of each
- fibrous joints e.g. the skull bones
- cartilaginous joints e.g. pubic symphysis
- synovial joints e.g. elbow
How are joints classified according to their degree of movement? and give an example of each
- ‘Syn’ means ‘the same’ so synarthrosis means two bones making the same immovable joint e.g. skull
- ‘Amphi’ means ‘can be one or the other’ so amphiarthrosis is a slightly movable joint e.g. vertebral discs
- ‘Di’ means ‘different so diarthrosis means a freely moveable joint e.g. knee
What is a fibrous joint and how can it be further classified? (with examples)
Fibrous joints are strength joints that are bound by tough fibrous tissue
- Sutures are immovable joints ‘synarthrosis’ only found between flat bones of the skull (not fully fused until ~20)
- Gomphmoses are immovable joints found where the teeth articulate with their socket, the fibrous connection is the periodontal ligament
- Syndesmoses are slightly movable ‘amphiarthrosis’, they are composed of bones held together by an interosseous membrane e.g. middle radio-ulnar and middle tibia-fibular joint
What is a cartilaginous joint and how can it be further classified? (with examples)
The bones are attached by fibrocartilage or hyaline cartilage
Primary/synchondroses: Only hyaline, can be immovable or slightly movable e.g. the joint between the epiphysis and diaphysis of growing bone.
Secondary/symphyses: Can be hyaline or fibrocartilage, slightly movable e.g. pubic symphysis
What is a synovial joint and how can it be further classified? (with examples)
A joint filled with synovial fluid, fully moveable with a huge range of movement. They are classified by movement:
- Hinge: flexion and extension e.g. elbow
- Saddle: unites concave and convex surfaces e.g. metatarsophalangeal joint (toes)
- Plane: sliding movements e.g. acromioclavicular joint
- Pivot: rotation e.g. atlantoaxial joint
- Condyloid: flex, ext, add, abd & circumduction eg metacarpophalangeal joint
- Ball and socket: round head fits into concavity e.g. glenohumeral joint
What is the function of synovial fluid?
Lubrication
Nutrient distribution - vital for healthy cartilage as there is very poor blood supply
Shock absorption
What is the articular capsule of a synovial joint?
A fibrous capsule which is continuous with the periosteum
Outer fibrous layer - called the capsular ligament, holds together the bones and supports the synovium
Inner synovium - highly vascularised CT. Absorbs and secretes synovial fluid
What is the function of accessory ligaments of a joint?
Made up of bundles of dense regular CT
Highly adapted to resist strain
Prevent extreme movements that may damage the joint
e.g. the ischiofemoral ligament, pubofemoral ligament
What are bursa and how can they become damaged?
A small sac lined by synovial membrane - they are located at key points of friction is a joint, ensuring free movement
If the joint is overused they can become irritated and inflammed as a result of infection (bursitis). This results in pain swelling and tenderness. Common sites inc elbow, points where tendons run over the knee joint
What is Hiltons law?
States the nerves supplying a joint also supply the muscles that more the joint and the skin covering their distal attachments.
The nerves of a joint play a key role in proprioception (the ability of the body to know where parts of it are).
Describe the condition of osteoarthritis
The most common form of joint inflammation
Caused by heavy use of articular joints resulting in wearing away of articular cartilage and often erosion of the articular surfaces of bone.
Irreversible and degenerative
Symtoms - joint pain and stiffness
Arthritis can also come about as a result of infection, due to auto inflammatory causes (RheumatoidA) and as a result of infection not affecting the joint itself such as STIs and GI infections - reactive arthritis
