Flashcards in Chapter 9 - Articulations Deck (45):
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...
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
-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)
-More even weight distribution
-Nerve and blood supply
list the 6 types of synovial joints from least to most mobile.
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
describe the ball and socket joint
-Allows for a lot of movement and rotation
ex) Hip joint
define Range of Motion (ROM)
the range, measured in degrees of a circle, through which the bones of a joint can be moved.
what are the 4 factors that contribute to a joint's ROM?
1.Structure or shape of articulating bones
2.Strength and tension of muscles and ligaments
ex)Relaxin increases flexibility of pubic symphysis, loosen between sacrum and hip during pregnancy
4.disuse - results in:
-Accumulation of synovial fluid
simple back-and-forth and side-to-side movements.
-Limited in range of motion
-No significant alteration in angle between the bones
-At planner joints (intercarpal joins)
Increase or decrease the angle between bones
name and describe the 6 types of angular movements
1.Flexion- decrease in angle
2.Extension- increase in angle
3.Hyperextension - move beyond anatomical position
4.Abduction - movement away from midline
5. Adduction - movement towards the midline
6. Circumduction - moving in a circle
one bone moving around its own longitudinal axis
Ex) shaking your head “no”
Anterior surface of the bone moves towards midline of the body
name and describe the 2 types of rotational movement
1.Supination - movement of the forearm so the palm is upward (hold the soup)
2.Pronation movement of the forearm so the palm is turned downward (poor the soup)
describe elevation and depression. what types of movements are these?
1.Elevation - upward movement
ex) Close mouth
2.Depression - downward movement
describe protraction and retraction. what types of movements are these?
3. Protraction - movement anteriorly
4. retraction - movement posteriorly
describe inversion and eversion. what types of movements are these?
5. inversion - movement of the sole of the foot medially
6. eversion - movement of the sole of the foot laterally
describe dorsiflexion and plantar flexion. what types of movements are these?
7. Dorsiflexion - bending the foot at the ankle in an upward direction (toward the dorsum)
8.Plantar flexion - pointing the toes; foot at an angle in a downward direction (towards plantar surface)
describe opposition. what types of movement is this?
9. Opposition - movement of the thumb across the palm to touch other fingers
in a lever, what is a joints role?
weight of the body part opposes movement
when does movement occur?
effort exceeds load
mechanical advantages occur when....
load is closer to the fulcrum, and the effort is further away, only need small amount of effort
1st class lever
fulcrum is between the effort and the resistance (load)
-Few in the body
ex) Atlanto-occipital joint in the neck
2nd class lever
resistance is between the fulcrum and the effort
-Always producing a mechanical advantage
3rd class levers
effort is between the fulcrum and the load.
-Get more movement out of this arrangement
-most common in body
swollen, stiff, painful joits
-joint cartilage is lost through “wear and tear”
-Associated with aging, avoid it through exercising
autoimmune disease – body is breaking down cartilage in the joint linnings
-Uric acid buildup (byproduct of protein degeneration) or accumulation in joints.
-Hard to move joints because there is other “stuff” in the way
-inflammation affects joints in the vertebrae
-More common in men