joint test Flashcards
bones must be ________ together in order to function
joined
the science of joints
arthrology
involves the joints
arthroscopic surgery
there are many kinds of joints, ad they can be classified by the types of tissue binding the joint at each junction
- Fibrous joints (connective tissue)
- Cartilaginous joints (fibrocartilage)
- Synovial joints (synovial membrane)
have just a little fibrous connective tissue between bones
are immovable
example: sutures of cranial bones
fibrous joints
have fibrocartilage between bones
examples: intervertebral discs, pubic symphysis
cartilaginous joints
most body joints are of this type
allow free movement
have synovial membrane that secretes synovial fluid- the consistency of raw egg white
examples: humerus articulates with the glenoid cavity of the scapula, femur articulates with the acetabulum of the hipbone
synovial joints
characteristics of synovial joints
- articular cartilage (hyaline cartilage) at the end of the two articulating bones
- synovial membrane surrounds joint and produces synovial fluid which fills the synovial cavity
- joint capsule (heavy connective tissue) surrounds the entire joint
- bursae (outpockets of membrane)
functions of parts making up synovial joints
- synovial fluid
- reduces friction
- moistens cartilage
- nourishes cartilage
- joint capsule provides stability and protection
- bursae cushion joint
Why is it important for synovial fluid to nourish cartilage
cartilage has no blood vessels
a functional junction between bones
joint
synovial joints can be classified according to shape and movement
- hinge joint
- ball and socket joint
- pivot joint
- saddle joint
convex surface of one bone fits the concave surface of another bone
functions to increase or decrease an angle
has movement in one plane only
examples:
-elbow
-knee
hinge joint
head of one bones fits into the depression of another bone
provides the most movement (movement in all planes plus rational movement around a central axis)
examples:
hip (femur in acetabulum)
shoulder (humerus in glenoid cavity)
ball and socket joint
Provides rotation around a central axis
Examples:
Head of radius round ulna
Atlas around the axis
Pivot joints
Concave surface of one bone articulates with concave surface of another bone
Both bones have concave and convex surfaces (saddle-shaped)
Provides movement in two planes
Examples:
1st metacarpal with carpal bone
Saddle joint
What happens when you pop your knuckles?
Bones of the joint pull apart
Joint capsule is stretched
Volume of synovial cavity is increased, which decreases pressure within cavity
Decreased pressure leads to gases once dissolved in synovial fluid forming bubbles- a process known as cavitation
If pressure in cavity drops enough, these bubbles burst, producing the pop associated with knuckle cracking
Takes 25-30 minutes for gas to redissolve
Joint movement
Goes on every time we move, walk, write, or go about our everyday activities… Flexion Extension Adduction Abduction Circumduction
Functions to decrease an angle
Example: biceps contracting decrease the angle of the elbow
Flexion
Functions to increase an angle
Example: triceps contracting increase the angle of the elbow
Extension
Functions to bring a limb toward the midline
example : adductor muscle in thigh is medial
adduction
Functions to move a limb away from the midline
Example: deltoid contracts to take arm away from midline
Abduction
Functions to make a circular motion
Example: arm moving in a chair
Circumduction
Joint disorders
Arthritis (osteoarthritis and rheumatoid arthritis)
Bursitis
Gout
Sprains
