Question | Answer |
What is a joint? 3 Main Classes | Where two different pieces of skeleton join
Cartilaginous, Synovial, Fibrous |
Fibrous Joints | skeletal only joined by ligaments
1. suture
2. syndesmosis |
Syndesmosis | Fibrous ligament with good-sized ligament joining skeletal elements
e.g.ligament at distal end of tibia and fibula
interosseous membranes, ligamentous sheets between ulna & fibula |
Synchondrosis | cartilaginous joint of hyaline cartilage
e.g. epiphyseal plates |
Symphysis | fibrocartilage holds bones together
ex. pubic symphysis & annulus fibrosus of intervetertebral discs
Allows some movement but not as much as synovial joint |
Synovial Joints | Highly movable joints (e.g.shoulder, knee, hip, wrist)
Have capsules and cavities |
Fibrous Articular capsule (joint capsule) | capsule is ligamentous (dense regular connective tissue). Keep joint from pulling apart
Acts as a bag that keeps fluid in joint cavity from bursting out |
Articular cartilage | absorb some of compressive stress.
Bounce back and re-expand
always film of synovial fluid between them |
Synovial membrane | inner layer of joint capsule,layer of connective tissue proper.
makes synovial fluid, derived from blood to maintain rich blood supply
No membrane on articular cartilage |
synovial fluid | slippery, viscous lubricant that fills joint cavity
consistency of raw egg white (synovial means "joint egg")
reduces friction
as slippery as ice on polished ice |
Articular disc (meniscus) | rings of fibrocartilage that occur in some synovial joints, subdivide joint cavity
uper shaped differently than lower
allow two distinct types of movement
allow bone-ends to fit together better
e.g. jaw joint, knee joint, etc. |
What also aids in relieving stresses in synovial joints? | Ligaments help
a. thicken fibrous walls of joint capsule
b. seperate ligaments internal to capsule
c. seperate ligaments outside of capsule |
What is it called when these ligaments/fibrous capsule is stretched or torn | sprained (e.g. sprained ankle) |
Why so many nerves in synovial ligaments and where? | very innervated
primarily to fibrous joint capsule
sensitive to position of joint capsule and how it is being stretched, for brain to maintain balance and coordinate movements |
Propriocetion | monitoring of joint stretch |
Where to blood vessels go? | not to the fibrous articular capsule (joint capsule) but to the synovial membrane that produces synovial fluid |
What does articular disc of temporo-mandibular joint allow? | hinge-like rotation and anterior gliding movement of mandibular head |
What kind of joints dislocate easily? | Shallow socketed joints dislocate easier than deep sockets like elbow and hig joints |