Joint Notes
From the anatomy and physiology web-site,
choose Skeletal System
Upload 7.20 Joint Homework to eBackpack.
View the powerpoint (you have the app) on
one partner’s ipad and complete the
homework on the other partner’s ipad. Make
sure you save and share when you are done.
Definition
• functional junction
between bones,
also known as an
articulation
The knee joint
Purpose
• enable the body to
move
• bind parts of the
skeletal system
• permit parts of the
skeleton to change
shape during childbirth
• allow for bone growth
Structural Classification
1. Fibrous
• Fibrous dense connective tissue joins the bones
• very little to no movement (synarthrotic)
• example: joints of skull (sutures)
As you can see on this child’s
cranium, the frontal bone is
divided into two pieces. This
extra joint makes the skull
more flexible during the birth
process.
2. Cartilaginous
• disks of fibrocartilage or hyaline
cartilage connect the bone
• allow limited movement
(amphiarthrotic)
• example: intervertebral disks
There are a total of 23 intervertebral discs
in the spine. Together they account for
approximately 25% of the total height of
the vertebral column (this decreases with
age as disc height is lost). Click on the
picture to learn about herniated discs.
3. Synovial
• more complex
- ends of bone covered with
hyaline cartilage
- held together by a capsule of
dense connective tissue
- filled with synovial fluid that
lubricates the joints
- some have menisci (shock
absorbing pads)
• free moving- (diarthrotic)
Study this picture and then label the picture
found on the homework sheet.
Dislocations
Look at the pictures
of dislocations shown
in this and the next 3
slides. What type of
joint (synarthrotic,
amphiarthrotic, or
diarthrotic) is most
likely to dislocate?
Why?
Answer:
synovial joints
Reason:
synovial joints
allow the most
movement
therefore they
are more likely to
dislocate
Torn ACL
Click here to watch an ACL repair.
This is not gross or bloody.
Use the illustration on the
right to find the structures of
the knee on the MRI.
Types of Synovial Joints
Look at the picture and
decide which type of
synovial joint is illustrated.
Word Bank
Ball and Socket
Condyloid
Gliding
Hinge
Pivot
Saddle
Hinge- bones may only move in one
direction, allows for extension and
flexion, found in the knee and elbow
Try It! Swing your knee back
and forth in one plane.
Word Bank
Ball and Socket
Condyloid
Gliding
Hinge
Pivot
Saddle
Ball and Socket- allows for radial
movement in almost any direction, found
in the hips and shoulders.
Try It! Do an arm circle.
Word Bank
Ball and Socket
Condyloid
Gliding
Hinge
Pivot
Saddle
Gliding joint- nearly flat bones slide
past each other, the thoracic cage has
many gliding joints for breathing,
wrists and ankles are gliding joints
Try it: Hold your arm upright and
wave side to side.
Word Bank
Ball and Socket
Condyloid
Gliding
Hinge
Saddle joint- allows movement back and forth and
Pivot
up and down, but does not allow for rotation, think
Saddle
of one bone being the saddle and the other bone
being the rider- carpal to thumb metacarpal is the
only example
Try It!
1. Spread all five digits out, then bring them all together sideby-side
2. Cross the thumb over the palm of your hand toward your
little finger.
Word Bank
Ball and Socket
Condyloid
Gliding
Hinge
Pivot Joint- allows rotation around an axis. The neck
and forearms have pivot joints. In the neck the atlas
Pivot
spins over the top of the axis. In the forearms the
Saddle
radius and ulna twist around each other.
Try It! 1. Turn your head side to side as if you
are saying no. 2. Twist your forearm.
Word Bank
Ball and Socket
Condyloid
Gliding
Hinge
Pivot
Condyloid joint- An oval shape condyle fits into
Saddle
an oval shaped depression. Look at the occipital
condyle and facet above. Hint: If there is a
condyle, there is a condyloid joint.
Try It! Nod yes.
Label each picture of synovial joints found in the
homework.
Joint Movement
Because of joints, the muscles can move the
bones in various directions.
These directions are given names.
These names will be used throughout the rest of
the course so commit them to memory.
Watch this video to learn the joint movements.
Link: Anatomical Terms of Movement
Fill out your notes as you watch the video.