Synovial joint Flashcards
List the components of a synovial joint
Joint capsule
Synovium
Synovial fluid
articular cartilage
T or F: Capsular redundancy occurs in all joints
False - it only occurs in highly mobile joints and is a source of dysfunction
What is the joint capsule?
A cuff around the joint of Type I collagen fibers organized in parallel bundles that varies in thickness and attachment and completely encloses the joint, covering all surfaces EXCEPT articulating/contact surfaces
What are the 3 types of mechanoreceptors
Muscle
Skin
Joint
What are joint mechanoreceptors?
Sensory receptors on the joint capsule and articular ligaments that respond to velocity, position, and changes in movement (mechanical P or deformation)
List the 4 types of joint mechanoreceptors
Ruffini Corpuscles (Warm) Pacinian Corpuscles (Pressure) Golgi-type (length change) Nociceptors (pain)
Ruffini Corpuscles
A. Location?
B. Threshold, stim, adaptation?
C. Provide info on?
D. Responds by?
A. superficial jt capsules, ligaments and menisci
B. low threshold, easy stim, slow to adapt
C. Static or dynamic position (Postural Receptors), sense of velocity & direction and amplitude of movement
D. Increase tone in stretched mm, relaxing antagonistic mm
Pacinian corpuscles
A. Location?
B. Threshold, stim, adaptation?
C. Provide info on?
D. Responds by?
A. joint capsule, ligaments, fat pads and menisci
B. low threshold, oscillation to stim, rapidly adapting
C. Provide info on DYNAMIC sudden changes in movment or dynamic presssure changes in the joint (Accel/decl)
D. Increase tone in mm being stretched and relaxes antagonistic mm
Golgi-Type Endings
A. Location?
B. Threshold, stim, adaptation?
C. Provide info on?
D. Responds by?
A. joint capsule, ligaments, and menisci
B. High threshold, velocity stim, and slowly adapting
C. stim by stretch at end range –> DYNAMIC movement
D. Reflexively inhibits mm
Nociceptors
A. Location?
B. Threshold, stim, adaptation?
C. Provide info on?
D. Responds by?
A. Capsule, ligaments, articular fat pads, periosteum, walls of blood vessels
B. High threshold, movement stim, non adaptive
C. Burning, aching pain difficult to localize from excessive movement or pain (Static and dynamic)
D. Tonic receptors - respond by producing a tonic mm contraction to increase tone
Which two mechanoreceptors respond to both static and dynamic movement?
Which are static only?
Both: Nociceptors and Ruffini Corpuscles
Dynamic only: Golgi-type endings and Pacinian Corpuscles
Which joint mechanoreceptors need an outside stimulus to turn them off?(non-adapting)
Nociceptors
What are two types of joint capsule injury and what do they both have a potential to lead to?
Effusion
Capsular fibrosis
Adhesion formation
What is joint effusion (S/S)?
Signs: Joint moves to position of comfort
Symptoms: Tight in joint
What is capsular fibrosis?
Injury to capsule where it becomes thickened, and collagen fibers have decreased extensibility
Signs: Dec ROM in a capsular pattern
What pop is more prone to capsular fibrosis?
Elderly bc there is already not enough protein/water in joints so it all sticks together
What is adhesive capsulitis? (S/S)
Gradual loss of AROM and PROM w/capsular end feel and pain at the end range w/general aching around the hsoulder
What is frozen shoulder?
The most common type of adhesive capsulitis w/ ER > Abd > IR
T or F: Synovium covers all surfaces of joint capsule
False - it does not cover the weight bearing surfaces of the joint
What are synovicytes
A specialized layer of connective tissue cells that form the synovium
What are the two layers of the synovium
Intima and subsynovial tissue
What is the intima?
The inner synovial layer composed of specialized fibroblasts that contain macrophage and fibroblast cells which help lubricate the joint and secrete the matrix
What is the subsynovial tissue?
The second layer of the synovium that is fibrous, areolar, and adipose tissue that produces the collagen matrix and has lymph and blood vessels that vary w/in each joint
Which components of the subsynovial tissue have greater vascularity? Lowest?
Greatest: areolar and adipose
Lowest: fibrous subsynovial tissues
What are the functions of the synovium?
Joint lubrication (secretes GAG)
Transportation (nutrition)
Stability
May: regulate intra-articular temp and antimicrobial effect
What is the reaction to injury in the synovium?
- Proliferation of surface cells
- Increase in vascularization
- Gradual fibrosis of subsynovial tissues
- Granular surface appears
- Alteration in synovial fluid
List some common diseases and disorders of the synovium
- PT Synovitis
- Hemarthrosis
- Pigmented Villanodular Synovitis (PVNS)
- Rheumatoid Arthritis (RA)
What is Post-Traumatic Synovitis?
Pathophys and S/S
Patho: Intima increases to 8-15 layers (from 1-3) and an increase in lymphatics and protein synthesis occurs
S/S: joint effusion w/tight sensation around the joint
What is hemarthrosis? (S/S)
What do you need to rule out?
Rule out a fracture 1st
Signs: rapid swelling w/in 15 min - 2hrs after injury and dec. ROM from swelling (blood entering joint)
Symptoms: inc. pain and tight sensation (dec. ROM and swelling)
What is pigmented Villonodular Synovitis?
Possible autoimmune response or benign neoplastic process in which nodules are formed in synovial tissue due to attachment of blood clots that causes a lot of pain and discomfort and further hemorrhage during movements due to crushing of the nodules
What are s/s of PVNS and treatment?
Inflammatory s/s w/pain w/compression of joint surfaces
To treat it you do a synovectomy
Define RA
Chronic systemic inflammatory autoimmune disorder which causes symmetrical polyarthritis of large and small joints w/unknown etiology
Risk factors for developing RA?
Woman (lower if have kids or contraceptives)
Age 30-40
What is the key antibody present to dx RA
Anti Citrullinated Peptide Antibodies (ACPA) –> 80% have this
What are the symptoms of RA
- joint pain
- fatigue 4.5 hours after rising
- weakness unproportional to activity
- joint stiffer after inactivity and better w/activity
What are the signs of RA
- Swell in small jts of hands,wrists, and forefeet is most common
- palmar erythema is common
- cool, moist skin
- atrophy of hands and feet mm (late stages)
- joint contractures (late stages)
- symmetrical
How is RA dx?
W/lab tests, history, and phys exam
Treatment goals of RA (PT)?
- dec. pain
- maintain mobility
- min nstiffness and edema
- min jt destruction
- NOTHING AGGRESSIVE
What is synovial fluid
Blood plasma w/additions of proteins and hyaluronic acid
What is arthrocentesis
The surgical withdrawal of fluid from the joint cavity for analysis
What are the categories of arthrocentesis findings?
0: Normal I: Non-inflamm II: Inflamm III: Purulent (Pus) IV: Hemorrhagic
What happens to x of the fluid as you progress through the stages?
a. clarity
b. viscosity
c. WBC amount
a. from transparent to translucent to opaque
b. very high viscosity to very low
c. less than 200 to greater than 75,000