Joints/ Tendons Flashcards
Components of Joint
- Articular cartilage -White, smooth, glistening
- Bone synovial membrane
- Synovial fluid
How does articular cartilage obtain nutrients?
- No nerves, blood, or lymph
- Obtain nutrients from synovial fluid & subchondral vessels
Articular capsule is composed of…
Outer layer = CT
Inner layer = Synovial membrane
-A cells = Macrophages (activated by IL15)
-B cells = Fibroblasts –> produce synovial fluid
Articular cartilage response to injury
- Limited response due to lack of blood flow
1. Cartilage erosion (not reaching subchondral bone) –possible recovery
2. Cartilage Ulceration (complete loss) –> repair w/ fibrocartilage!
Pathogenesis of injured cartilage
- Lack of compression/relaxation cycle –> atrophy
- Roughened –> fibrillation –> erosion –> Eburnation (ulceration)
Eburnation
Complete loss of cartilage
-exposed subchondral bone
Pathogenesis of Inflammatory joint degeneration
A cells secrete IL1 & TNFalpha –> stimulate B cells to produce PG & NO & collagenases –> inhibit proteoglycan synth –> articular cartilage degeneration
Which hormones have an anabolic effect on joints?
- IL6
- IGF
- TNF beta
Synovial membrane response to injury
- Hyperplasia of synoviocytes
- Pannus
- Joint Mice
- Osteophytes
- Inflammatory leukocytes
Response of Subchondral bone to injury
- Sclerosis (decrease resorp/increased production)
2. Eburnation
Pannus
Granulation tissue –> Ankylosis
Ankylosis = adhesion between to bones –> stiffen/immobilize joint
Joint Mouse
Fragment of chondral/ osteochondral material, free in joint cavity
Osteophytes
Chondro-osseous proliferations at synovial membrane / perichondrial jnx
Joint ( portal of entry / Defense mechanisms )
- -Direction inoculation &/or extension by adj tissue
- -hematogenous
Defense = limited regeneration –> degenerative joint dz
Tendons ( portal of entry / Defense mechanisms )
- -Lacerations or punctures
- -extension from adj infection
Defense = similar inflammatory rxn to other tissue
Arthrogryposis
- contracture of the joint
- congenital
- sporadic
- viral (BLUETONGUE)
- hereditary
- ***CNS lesion –> degeneration/atrophy of muscles –> contraction of limbs
- non-neurologic form
- Alkaloids –lupine/ poison hemlock
- -> fetal paralysis
Hip dysplasia
-Heritable –Dogs, Hereford cattle
Synovitis
Inflammation of synovial membrane
Arthritis
Inflammation of articular cartilage
Osteoarthritis
NONinflammatory Jt Dz
aka DJD
Arthropathy
Any type of Jt Dz
Outcome of inflammation in Jt
- Resolution
2. DJD
Synovial fluid response (Acute/subacute/chronic)
Acute
-Reduced viscosity
Subacute
-WBCs &fibrin in fluid
Chronic
- granulation tissue
- fibrosis
- ulceration/hypertrophy of synovial lining
“Rule of thumb” for bacterial arthritis
Gram + –> Pyogenic
Gram - –> Fibrinous
Rare viral arthritis
Reovirus - Chickens
CAE - Goats
Rheumatoid arthritis
- Autoimmune
- non-infectious
Gout
Deposit of urates in /around joint
- -> acute/chronic granulomatous synovitis
- -> degeneration of articular cartilage
Pseudogout
Deposits of Ca & Phos in soft tissue of synovial capsule & ligaments
-young dogs
Outcome of IVDD
- Disk herniation
2. Spondylosis –lateral & ventral –> decrease mobility/stabilztes
Joint neoplasm
Synovial sarcoma
-neoplasia of synovial cells in joints/tendons
A-cells = higher chance of mets B-cells = lower change to metastasize
