Joints Flashcards
Classification of mobility of joints
- Mobility is the amount of movement at a joint; it is dependent on the type of materials joining bones and the articulating surfaces of the bones
- Joint classification based on mobility
- Synarthrosis
- Amphiarthrosis
- Diarthrosis
What is Synarthrosis?
Synarthrosis (syn = together, arthro = joint): immobile; mostly axial
What is Amphiarthrosis?
Amphiarthrosis (amphi = of both kinds): slightly moveable; mostly axial
What is Diarthrosis?
Diarthrosis (di = two): freely moveable; mostly appendicular
How are joints classified?
- Structural classification of joints is based on the type of material that binds the bones together and whether or not there is a joint cavity
1. Fibrous
2. Cartilaginous
3. Synovial
Which types of joints have joint cavities
-Synovial joints have joint cavities
- cartilaginous and fibrous do not have joint cavities
What is the construction of fibrous joint?
Dense regular CT connects bones
What is the construction of Cartilaginous joint?
Cartilage connects bones
What is the construction of Synovial joints?
Ligaments and articular capsule connect bones;
ends of bones covered with articular cartilage
What are sutures?
Fibrous Joints: Sutures
* Synarthrotic
* Connected with short dense regular CT fibers
* Example:
- Sutures (= “seams”) between bones of skull
* Allow for skull growth
* During middle age, skull bones fuse together
What are Syndesmoses?
Fibrous Joints: Syndesmoses
* Syndesmoses = “with ligament”
* Amphiarthrotic (most)
* If longer fibers, more movement
* Dense regular CT fibers, longer than with sutures
* Typically found between long bones
* Examples
-Ligament between distal tibia and distal fibula
- Interosseous membrane between radius and ulna
What are Gomphosis?
Fibrous Joints: Gomphoses
* Gomphosis = “bolt” (peg-in-socket
joint)
* Synarthrotic
* Periodontal ligaments attach tooth
to bone of socket
What are Synchondroses?
Cartilaginous Joints: Synchondroses
* Synchondrosis = “junction of cartilage”
* Synarthrotic - do not move
* Bones united by hyaline cartilage
* Examples
- Epiphyseal plates
- Joint between first rib’s costal cartilage and manubrium of sternum
What are Symphyses?
Cartilaginous Joint: Symphyses
* Symphysis = “growing together”
* Amphiarthrotic
* Bones united by fibrocartilage pad (both strong and flexible)
* Examples:
-Intervertebral discs
- Pubic symphysis
What are the general characteristics of Synovial Joints?
- Synovial = “joint eggs”
- Diarthrotic = freely movable
- Synovial joints have
- Ligaments
- Joint Cavity
- Articular capsule
- - Fibrous layer
- - Synovial membrane - Synovial fluid
- Nerves
- Blood supply
Synovial Joints - Ligaments
Ligaments connect bone to bone
* Made of dense regular CT
* Can be within or external to joint capsule
Synovial Joints- Joint Cavity
Joint Cavity
* Potential space with a small amount of
synovial fluid
Synovial Joints - Articular capsule
Articular capsule (joint capsule)
* Outer fibrous layer
* Inner synovial membrane
* Fibrous layer: dense irregular CT, continuous with periosteum
* Synovial membrane
* Inner lining of capsule and all other internal joint surfaces not covered in cartilage
* Loose CT, vascular
* Produces synovial fluid
* Synovial fluid is a lubricant within the capsule
Synovial Joints - Synovial Fluid
Synovial fluid
* Blood filtrate, is viscous
* Glycoproteins make fluid slippery, easing movement of joint
* Found in articular cartilages as well as in cavity
- Pressure placed on cartilages causes synovial fluid to move in and out of articular cartilages = weeping lubrication
- This nourishes the chondrocytes in the articular cartilage (important because it is avascular)
Nerves purpose in Synovial Joints?
Nerves
* Articular capsule has rich supply of sensory
nerve fibers
* Some detect pain
* Some detect amount of stretch of joint capsule
- Tells body about proprioception
Blood supply purpose for Synovial Joints?
Blood supply
* Most supply synovial membrane (for
producing synovial fluid)
What are synovial joints with an articular disk?
Some synovial joints have an articular disc
* Disc of fibrocartilage
* Helps improve the fit of articulating cartilages
* Example: meniscus (= “crescent”) of the knee (more on this later…)
What is the labrum?
- Labrum increases stability in joint
- Glenoid labrum: lip of fibrocartilage around glenoid cavity
- Acetabular labrum: circular rim of fibrocartilage around acetabulum of hip joint
What are Bursae?
Synovial Joints: Bursae
* Bursa (= “purse”): closed fibrous sac lined with synovial membrane and filled with synovial fluid
- Reduces friction as parts move over each other
- Often where ligaments, tendons overlie bone
What is Bursitis?
Inflammation & swelling of bursa
What are tendon sheaths?
Synovial Joints: Tendon Sheaths
* Tendon sheath is an elongated bursa that wraps around tendons in high friction areas
- Example, tendon sheaths encircle
tendons in the carpal tunnel of the
wrist
What is the mobility of synovial joints?
Synovial Joints: All are Diarthrotic
Synovial joints can be
* Nonaxial
* Uniaxial
* Biaxial
* Multiaxial
What is nonaxial?
Nonaxial: joint can move in multiple
Directions but only within one plane
What is Uniaxial?
Uniaxial: joint moves only around 1 axis
What is Biaxial?
Biaxial: joint moves around 2 axes
What is multiaxial?
Multiaxial: joint moves around 3 or more axes
What are Plane Joints?
Synovial Joints: Plane Joints
* Nonaxial
* Gliding movement (side to side, within one plane)
* Ex. Intercarpal joints, joints between vertebral
articular surfaces (facets), sacroiliac joint
What are hinge joints?
Synovial Joints: Hinge Joints
* Uniaxial
* Flexion and extension
* Ex. Elbow, interphalangeal joints (finger joints)
What are pivot joints?
Synovial Joints: Pivot Joints
* Uniaxial
* Rotational movements
* Ex. Radioulnar joints, atlantoaxial joint
(“No” motion of head)
What are Condylar Joints?
Synovial: Condylar Joint
* Biaxial
* Flexion/extension and abduction/adduction
* Ex. Metacarpophalangeal (knuckle) joints, carpals and radius joint, occipital condyles and atlas (“Yes” motion of head)
What is a Saddle Joint?
Synovial: Saddle Joint
* Biaxial
* Flexion/extension and abduction/adduction
* Ex. Carpometacarpal joint of thumb
What is a Ball-and-Socket Joint?
Synovial: Ball-and-Socket Joint
* Multiaxial
* Flexion/extension, adduction/abduction, and
rotation
* Ex. Shoulder and hip joints
What are the joints of the knee?
The knee:
* 2 joints that share ONE joint
capsule & cavity
1. Femoropatellar
2. Tibiofemoral
What is the Femoropatellar
Joint?
Femoropatellar
Joint
* Between patella and femur
* Plane joint gliding action
* Patella glides across femur as knee
bends
* Works with quadriceps femoris
muscles in leg extension
What is the Tibiofemoral Joint?
Tibiofemoral Joint
* Between tibia and femur
* Must withstand body
weight
What is the Bicondylar hinge joint?
Bicondylar hinge joint - Tibiofemoral Joint
* Articulations between both the
lateral and medial condyles
(femur) and the lateral and medial
condyles (tibia)
* Menisci is between the two bones
What is the movement of Tibiofemoral Joint?
Movement in 2 axes:
* Flexion and extension
* Medial and lateral rotation
What is purpose of Weight-bearing joint of Tibiofemoral Joint?
Weight-bearing joint that must
reconcile 2 different and dissimilar
needs
* Stability
* Mobility
How do articulating surfaces matched in Tibiofemoral Joint?
- In addition, articulating surfaces are
not well matched AND they meet
each other at an angle
How is stability achieved in Tibiofemoral Joint?
Tibiofemoral Joint
* Stability achieved through
* Ligaments
* Tendons
* Muscle tone puts tension on
tendons
* Menisci (fibrocartilaginous
discs)
What is the mobility of Tibiofemoral Joint?
- Mobility: the structures
surrounding joint allow
for enough flexibility in
joint so it can adapt to
(changing) surfaces while
walking and running
What are the layers of Articular capsule of Tibiofemoral Joint?
Articular capsule has
standard 2 layers
* Fibrous outer layer
* Inner synovial membrane
What do the ligaments of Tibiofemoral Joint do?
- Ligaments run through &
surround capsule to provide
strength & support
What are the ligaments of Tibiofemoral Joint?
Ligaments
* Tibial (medial) collateral
* Fibular (lateral) collateral
* Anterior cruciate ligament
* Posterior cruciate ligament
What is the Tibial (medial) collateral?
Tibial (medial) collateral
* Attaches tibia to femur
* Also attaches to medial meniscus
* Prevents medial movement of leg
* Stops leg extension, preventing hyperextension of knee
What is the Fibular (lateral) collateral?
Fibular (lateral) collateral
* Attaches fibula to femur
* Prevents lateral movement of leg
* Stops leg extension, preventing hyperextension of knee
What do Cruciate ligaments do?
- Cruciate ligaments allow you to
lock your knee
What is the Anterior cruciate ligament?
Anterior cruciate ligament
* Attaches to anterior part of
intercondylar area of tibia and
to the posterior surface of
lateral condyle of femur
What is the Posterior cruciate ligament?
Posterior cruciate ligament
* Attaches to posterior
intercondylar region of tibia
and medial condyle of femur
What does the Anterior cruciate ligament prevent?
Anterior cruciate ligament
* Prevents anterior sliding of
tibia
What does the Posterior cruciate ligament prevent?
Posterior cruciate ligament
* Prevents posterior sliding of
tibia
- = Prevents anterior sliding of
the femur
What is the Menisci?
Menisci
* Tibiofemoral Joint
* Horseshoe shaped fibrocartilaginous discs that sit on top of tibia (tibial plateau)
* Functions
- Enlarge contact area between tibia and femur
- Guide and support condyles
- Increase surface area across which weight is transferred
What is the tibial collateral
ligament attached to?
- The tibial collateral ligament has an attachment to the medial meniscus they are frequently torn together
What is a common knee injury?
A Common Knee Injury: The Triad of 3
What is the triad of 3?
- Tibial collateral ligament (torn)
- Medial meniscus (torn)
- Anterior cruciate ligament (torn)
What is a sprain vs strain?
Sprain = ligament stretched or torn
Strain = tendon/muscle stretched or torn
What is Rheumatoid Arthritis?
- Chronic inflammatory disorder
- Autoimmune: immune system attacks synovialmembranes
- Causes inflammation of synovial membranes
- Pain and swelling
What is the cause of Rheumatoid Arthritis?
- Inflamed synovial membrane forms a granular pannus
- Cartilage and bone are damaged by pannus
- Fibrous scar tissue gradually replaces pannus; this can cause fusion of bones
What is Osteoarthritis?
*Most common and mostly due to normal aging process
*Articular cartilage breaks down via normal enzyme activity or excessive use
*Resulting bone to bone contact further damages articular surface
What is Gouty Arthritis (Gout)?
*Uric acid is normal waste product produced by liver during purine metabolism
*High levels of uric acid in blood will precipitate out as crystals into synovial joints forming a tophus
– Body will initiate inflammatory response to digest crystals
What is Carpal Tunnel
Syndrome?
*Inflammation of tendon sheaths puts pressure on the median nerve passing through carpal tunnel
