Joints Flashcards
Joint definition
Union between two or more rigid components (bone or cartilage) - can allow for articulation
What are joints needed for?
Growth + movement
Types of Joints
- Fibrous
- Cartilaginous
- Synovial
Fibrous joints (structure and properties)
Dense fibrous CT
Have high tensile strength with little movement in adults
3 Types oif fibrous joint
- Sutures - skull (cranial sutures)
- Gomphoses - immobile joints between the teeth and their sockets in the mandible and maxillae (periodontal ligament)
- Syndesmoses -slightly movable joints (amphiarthroses) - 2 parrellel bones joined (e.g. tibia and fibula - interosseus membranes)
Explain cartilaginous joints
Attached by cartilage (fibrous or hyaline)
What are the two types of cartilaginous joint called
- Synchondroses (primary)
- Symphyses (secondary)
Synchrondroses properties
No movement and dissapear in adults. Uses hyaline cartilage
What is the purpose of synchrondroses
Allow for bone growth - endochondral ossification
Symphyses
Don’t ossify with age, found in the midline of the body and have limited movement - ex inc. pubic symphysis, intervertebral discs
Properties of synovial joints
- greatest movement
- 6 Types
Parts of synovial joints
Synovial fluid, synovial (joint) cavity - other joints don’t have, fibrous capsule, synovial membrane, articular cartilage
What cartilage is found in synovial joints
Articular (hyaline) cartilage
What does the synovial membrane do?
Produce synovial fluid
What may synovial joints also contain
- Articular discs
*Ligaments
6 Types of synovial joint + example
- Hinge - elbow
- Pivot - between (C1 and C2) vertebrae
- Saddle - finger (trapezium carpal and 1st metacarpal bone)
- Condylar (ellipsoid) - radius and carpal bone of wrist
- Plane - between tarsal bones (ankle)
- Ball and socket - hip/shoulder joint
Joint stability
Joints need support - ligaments (/fibrous caspsules = protection) do this however, the tighter a ligament is (more stable), the less motion the joint has.
Why is flexation at elbow and knee in opposite directions?
Upper limb - lateral rotation in womb
Lower limb - medial rotaion (and more rotation)
briefly describe blood and nerve supply to joints
Joints have a rich blood and nerve supply (proprioception - where joint is). Anastomoses are common around joints. Hilton’s law is that the nerve supplying a muscle that crosses a certain joint will also innervate this joint.
What are symphyses made of
hyaline cartilage
Synchrondroses (primary/secondary and why)
Primary (like in kids) so endochondral ossification and gone in adults
