Chapter 9 - Articulations Flashcards
functional classification is based on…
the degree of movement permitted
name and describe the 3 functional classifications of joints.
synarthroses - immovable (btw skull bones)
amphiarthroses - slightly movable
diarthroses - move freely
structural classification is based on…
anatomy
name and describe the 3 structural classifications of joints.
fibrous joints - bones held together by dense irregular CT
cartilaginous joints - bones held together by cartilage
synovial joints - have synovial cavity, bones held together by ligaments
Describe fibrous joints
lacking cartilage and synovial cavity, usually synarthroses (little movment)
what are 3 examples of fibrous joints?
Ex #1) Suture joints in skull
Ex #2) Syndesmoses- greater distance btw bones, more dense irregular CT than suture joints (btw radius and ulna)
Ex #3) Interosseous membranes – binds neighboring long bones
Describe cartilaginous joints.
- consist of a bar of cartilage between two bones
- Usually amphiarthroses – little to no movement
(ex) pubic symphasis, intervertebral discs
Describe synovial joints
- Ligaments hold bones together
- Forms a synovial cavity composed of an outer fibrous capsule and inner synovial membrane
- *Always diarthroses (free moving)
- Articular cartilage on the ends of the bones
describe synovial fluid and what secretes this.
- dense viscous fluid
- secreted by synovial membrane
purpose of synovial fluid.
- reduces friction by lubricating the joint
- Absorbs shock
- Supplies oxygen and nutrients
- removes waste from cartilage
name and describe the 2 accessory structures of synovial joints
ligaments –> considered to be outside joint
Bursae –> fluid filled structure to minimize friction (similar to synovial) but it is only found where there may be increased friction (extra padding) only where there is bone on bone
define menisci and their purpose
- pads of dense fibrocartilage btw articular surfaces
- Provides additional strength and stability
- Fits bones of different space (fills space creating a tighter fit)
- Shock absorber
- More even weight distribution
- Nerve and blood supply
list the 6 types of synovial joints from least to most mobile.
- planar joint
- hinge joint
- pivot joint
- condyloid joint
- saddle joint
- ball-and-socket joint
describe the planar joint
- Flat bones sliding
ex) between carpals
describe the hinge joint
- Looks like a hinged door
ex) Elbow joint
describe the pivot joint
ex) atlas rotates around the axis
describe the condyloid joint
- Convex oval structure
ex) Between radius and carpal joints
describe the saddle joint
- Looks like a rider in a saddle
ex) Between thumb, metacarpal, and carpal