Joint Structure and Function
What are the movements around the AP axis in the coronal plane?
ABduction and ADduction
Name the 2 functions of interarticular disks and give 3 examples.
Functions: 1) improve fit between incongruous bones 2) increase ROM Ex: TMJ, SC joint, knee menisci
Give an example of an extracapsular ligament?
SC joint
What is the exception to the "little movement" rule of fibrous joints?
The interosseus membrane between the radius and ulna because it moves a lot through pronation and supination of the forearm
Name 3 examples of synovial joints.
There are a lot in your body, but some examples include the shoulder joint, knee joint, and joints between the ear ossicles.
What are the movements around the vertical axis in the horizontal plane?
medial and lateral rotation
Every plane has an axis that is BLANK to it.
perpendicular
The sagittal plane divides the body into...
right and left
Ligaments are working when they are....
Tight!
Give an example of capsular ligaments?
shoulder, hip
Give an example of an intracapsular ligament?
cruciate ligaments in the knee
What is the outer layer of the joint capsule made of?
dense CT
What is the inner layer of the joint capsule made of?
synovial membrane
The transverse plane divides the body into...
top and bottom
What are interarticular disks?
wedges of cartilage (usually fibrocartilage) that are within the joint capsule and surrounded by synovial fluid
What is Weeping Lubrication?
when stress is put on the joint (when it moves), synovial fluid gets squeezed out of cartilage and moves into the synovial joint cavity to increase lubrication.
What are the movements around the transverse axis in the sagittal plane?
flexion and extension
What movements cause circumduction?
flexion, extension, aBduction and ADduction
The coronal plane divides the body into...
front and back
Structure determines...
function!
What's the main job of ligaments?
limit unwanted movement in a certain direction
What are the characteristics of fibrous joints?
-bone-to-bone connection with dense CT -no joint cavity -usually very little movement (synarthrosis)
What are the characteristics of synovial joints?
-bones are united by a joint capsule -joint capsule is enclosed by a joint cavity -joint cavity is line by a synovial membrane -synovial membrane contains synovial fluid -articular surfaces are lined with hyaline cartilage - allows for free movement
What are the characteristics of cartilaginous joints?
-bones are united by cartilage: either hyaline or fibrocartilage -no joint cavity -slight movement - amphiarthrosis
What are bursae?
-closed sacs of synovial membrane -filled with synovial fluid
What are the strange movements of the foot and ankle?
-dorsflexion/plantarflexion -inversion/eversion
What is the purpose of synovial fluid?
-lubrication -nourishment
Are ligaments active or passive stabilizers?
Passive - because they don't contract
What's the difference between osteoarthritis and rheumatoid arthritis?
-osteoarthritis is normal wear and tear of a joint -rheumatoid arthritis is joint inflammation due to autoimmune disease - everything in the joint swells up
What's the purpose of bursae?
-reduce fiction
How do we classify joints by structure? (3)
1) Fibrous 2) Cartilaginous 3) Synovial
What are the competing needs of joints?
1) Stability - for strength/support 2) Mobility - to increase ROM
What are the 3 types of fibrous joints? Give an example of each.
1) Suture: skull bones 2) Gomphosis: periodontal membrane holds teeth down to mandible 3) Interossesus membrane: between radius and ulna
Name the multiaxial synovial joint(s) and give an example.
1) ball & socket -shoulder joint 2) saddle - thumb joint 3) gliding/plane - intercarpal joints
Name 5 factors that can limit joint movement
1) bone shape 2) ligaments 3) disease 4) apposition of muscle masses/soft tissue 5) tension in opposing muscles
Name the 3 types of ligaments.
1) capsula: thickenings of the joint capsule itself 2) extracapsular: located outside the joint capsule 3) intracapsular: located inside the joint capsule
Name the biaxial synovial joint(s) and give an example.
1) condyloid/ellipsoid - metacarpophalangeal joints
Give 2 examples of hyaline cartilaginous joints.
1) epiphyseal growth plate 2 costal cartlage
Name the uniaxial synovial joint(s) and give an example.
1) hinge - elbow joint 2) pivot - radioulnar joint
Give 2 examples of fibrocartilage cartilaginous joints.
1) intervertebral discs 2) pubic symphysis
What are the 3 different accessory structures?
1) ligaments 2) interarticular disks 3) bursae
How do we classify joints by freedom of movement? (3) Give an example of each.
1) synarthrosis - little to no movement (ex: skull) 2) amphiarthosis - slight movement (ex: joints between individual vertebral bones) 3) diarthrosis - free movement (ex: shoulder)
How many different shapes of synovial joints do we have?
6
Can we have both stability and mobility?
Nah - it's usually a tradeoff between the two
Extreme stretch or tear of a ligament is called a...
Sprain
