Joint Structure Flashcards
1
Q
What are the classifications of joints?
A
- Diarthrosis (synovial/mobile joint)
- Synarthrosis (immobile joint)
- Amphiarthrosis (between)
2
Q
What are the subclassifications of diarthrosis/synovial joints based on movement?
A
- Uniaxial
- Biaxial
- Polyaxial
- Plane
3
Q
What type of joints are the ulnohumeral joint, and proximal and distal radioulnar joints?
A
Uniaxial diarthroses
4
Q
What type of joint is the radiocarpal joint?
A
Biaxial diarthrosis
5
Q
What type of joints are the shoulder and hip?
A
Polyaxial diarthsosis
6
Q
What type of joint are zygapophyseal joints, patellofemoral joint, and carpal/tarsal joints?
A
Plane (flat joint) diarthrosis
7
Q
What are five types of synarthroses?
A
- Symphysis
- Suture
- Synchondrosis
- Syndesmosis
- Synostosis
8
Q
What type of joints are the pubic symphysis and intervertebral discs?
A
Symphysis synarthrosis (technically amphiarthrosis)
9
Q
What is found within symphysis synarthrosis joints?
A
Fibrocartilage and ligaments
10
Q
What is found within suture synarthrosis joints?
A
Interdigitating bones with ligamentous connections
11
Q
Where can suture synarthrosis joints be found?
A
Skull
12
Q
What type of joint are manubriosternal and costochondral joints?
A
Synchondrosis synarthrosis
13
Q
What is found within synchondrosis synarthrosis joints?
A
Structures with cartilage ends, but no synovium
14
Q
What type of joint are interosseous membranes of tibiofibular and radioulnar joints?
A
Syndesmosis synarthrosis
15
Q
What is found within syndesmosis synarthrosis joints?
A
Fibrous connections between bones without cartilage
16
Q
What is a normal variant of synostosis synarthrosis?
A
5th toe synphalangism
17
Q
What is a pathological fusion of bones classified as synostosis synarthosis?
A
SI ankylosis in ankylosing spondylitis
18
Q
What is a unit load?
A
Compressive force expressed as kg/cm3
19
Q
What is the unit load threshold for cartilage injury?
A
20-26kg/cm3
20
Q
Excessive unit loads lead to ___
A
damage of articular cartilage
21
Q
What protects the joint cartilage from exceeding unit load?
A
- Mostly adjacent muscles, tendons
- Extra-articular ligaments
- Joint and bone deformation
- Intra-articular structures (ligaments and menisci)
22
Q
What are the external support structures of the knee?
A
Tendons: biceps femoris, patellar
Ligaments: medial and lateral collateral ligaments
Muscles: quadriceps
23
Q
What are the three types of articular cartilage?
A
- Hyaline cartilage
- Fibrocartilage
- Elastic cartilage
24
Q
What type of collagen is found in hyaline cartilage?
A
Type 2 collagen (resists compressive forces)
25
What type of collagen is found in fibrocartilage?
Type 1 collagen (resists tensile forces)
26
What type of collagen is found in elastic cartilage?
Type 2 collagen (and elastin)
27
What is the weakest type of cartilage?
Hyaline cartilage (susceptible to chondral fractures from tensile forces)
28
What type of cartilage is found in synovial joints and ribs?
Hyaline cartilage
29
What type of cartilage is found in the following?
* Menisci
* Triangular cartilage (wrist)
* Labrum (shoulder and hip)
Fibrocartilage
30
What is the strongest type of cartilage?
Fibrocartilage
31
Which type of cartilage is found in the pinna of the ear, nose, Eustachian tube, and epiglottis?
Elastic cartilage
32
What is the makeup of extracellular matrix of hyaline cartilage?
70-80% water
20-30% type II collagen and proteoglycans
33
How does hyaline cartilage appear?
Smooth and white, generally no thicker than 6mm
34
What is the function of hyaline cartilage?
* Shock absorption
* Low coefficient friction
35
What are the six zones of joint histology?
* Tangential zone
* Transitional zone
* Radial zone
* Tidal zone
* Calcified zone
* Subchondral bone plate
36
#joint histology
What is found in the tangential zone?
Flat chondrocytes, lots of type II collagen, aka skin of cartilage/armor plate
37
#joint histology
What is found in the transitional zone?
Round chondrocytes, lots of matrix
38
#joint histology
What is found in the radial zone?
Columns of chondrocytes, like in articular cartilage
39
#joint histology
What is found in the tidal zone?
Separation of vascular from avascular regions; base line for normal chondrocyte reproduction
40
#joint histology
What is found in the calcified zone?
Small chondrocytes, heavy calcification of matrix; chondrocyte reproduction in disease states (ie. acromegaly)
41
Layers of collagen have opposing grain directions.
What does this allow for?
Resistance to forces from different directions
42
#joint histology
What is the interface between mineralized and unmineralized cartilage?
Tide mark or blue line
43
#joint histology
What does the tide mark or blue line divide?
Nutritional source for chondrocytes:
* Articular side of line is diffusion
* Osseous side of the line is epiphyseal blood vessels
44
#joint histology
Above the tide mark or blue line, how do chondrocytes behave?
Replicate and migrate up towards surface above the line
45
#joint histology
Below the tide mark or blue line, how do chondrocytes behave?
Divide only if there is the appropriate chemical stimulus (ie. acromegaly)
46
Is articular cartilage vascularized?
No, avascular
47
Which part of the joint capsule is highly vascularized and innervated?
Fibrous layer of tissue
48
The internal portion of the joint capsule is lined by ___
synovial membrane
49
The synovial membrane is comprised of 2-3 layers of ___.
synoviocytes
50
#synoviocytes
What are type A cells?
Macrophages with lysosomal enzymes
51
#synoviocytes
What are type B cells?
Fibroblast like cells
52
Which synoviocytes produce synovial fluid components such as hyaluronate, collagens, fibronectin, and glycoproteins?
Type B cells
53
Synovial tissue is arranged in ___ and ___.
villi and microvilli
54
What are four functions of synovium?
1. Diffusion of nutrients and waste products
2. Ingestion of joint debris
3. Secretion of hyaluronate, immunoglobulins, lysosomal enzymes
4. Lubrication by secreting glycoproteins
55
Synovium provides lubrication by secreting ___.
glycoproteins
56
Besides glycoproteins, synovium secretes ___
hyaluronate, immunoglobulins, and lysosomal enzymes
57
How much synovial fluid is found in a joint?
1-4ml
58
How does synovial fluid act as a molecular sieve?
Hyaluronate molecules are large negatively charged molecules with high affinity for water
59
How is synovial fluid non-clotting?
No thromboplastin or fibrinogen
60
When interposed between hyaline cartilage surfaces, synovial fluid creates a coefficient of friction near ___.
zero
61
When interposed between hyaline cartilage surfaces, ___ creates a coefficient of friction near zero.
synovial fluid
62
___ is essential for joint development and maintenance.
Movement
63
Synovium and other vascularized structures require ___ to maintain optimal function.
regular activity
64
How does moderate exercise affect articular cartilage?
Decreases fibrillation and chondrocyte necrosis
65
How does immobilization affect articular cartilage?
Decreases proteoglycans and increases atrophy
66
___ helps maintain optimal diffusion of nutrients and wastes in articular cartilage.
| lifestyle
Activity
67
What is arthrogryposis?
* Multiple congenital joint contractures
* Abnormal connective tissue deposited around joints
| seen in utero
68
If there are multiple congenital joint contractures and lack of joint mobility in utero, what condition is present?
Arthrogryposis
69
What are some consequences of abnormal connective tissue deposited around joints by arthrogryposis?
* Stiffness
* Muscle weakness due to underdeveloped muscles and tendons
* Joint surface may become flattened and incongruent
70
What is the following law?
Every peripheral nerve supplying a muscle sends a branch to the joint moved by the muscle and to the skin overlying the joint.
Hiltons' law
71
What are the four types of nerve endings in a joint?
1. Encapsulated endings
2. Pacinian corpuscles
3. Golgi tendon organs
4. Free nerve endings
72
What is the function of encapsulated nerve endings in a joint?
Respond to mechanical stimuli such as pressure and stretch
73
What is the function of pacinian corpuscles in a joint?
Respond to initiation and cessation of movement
74
What is the function of golgi tendon organs in a joint?
A stretch receptor responding to the tension generated at the musculotendinous junction
75
What is the function of free nerve endings in a joint?
Mediate pain
76
What is the function of bursae?
Cushion and lubricate
77
What are bursae?
Connective tissue sacs lined with synovium
78
When do deep lying bursae develop?
Before birth
79
What can create new bursae (adventitial bursae)?
Excess friction
80
What is tendonitis?
How long is healing?
Acute tearing of the fibers creating an inflammatory reaction
Healing generally takes 6 weeks
81
What is tendinosis?
How long is healing?
Chronic overuse creates collagen degenerative microtears without inflammation
Healing takes 6 weeks to 6 months
82
Which tendons can have tenosynovitis?
Only those with tendon sheathes
83
Can the Achilles tendon have tenosynovitis?
No, it doesn't have a tendon sheath
84
What are tendon sheaths?
Tubes surrounding the tendons lined with synovium and filled with synovial fluid
85
What are the two layers of tendon sheaths?
Visceral and parietal with synovial fluid between
86
What is tenosynovitis?
Inflammation of tendon sheath synovium
87
Is tenosynovitis infectious or non-infectious?
Either
88
What are some causes of non-infectious tenosynovitis?
* Overuse (repetitive strain injuries)
* Autoimmune disease (rheumatoid arthritis, psoriatic arthritis)
* Idiopathic
89
Inflammation from tenosynovitis leads to increased ___ of synovial fluid thus increased ___.
**fibrin thickening** of synovial fluid thus increased **friction**
90
What pieces of evidence are present with an infectious case of tenosynovitis?
* Purulent exudate
* Necrosis of tendon sheath, tendon, and other structures
91
What are some clinical manifestations of tenosynovitis?
* Stiffness
* Pain
* Swelling, redness, warmth
* Decreased range of motion
* Increased symptoms with activity
* Decreased symptoms with rest
92
Which tendon is inflamed in De Quervain's tenosynovitis?
Abductor pollicis longus
93
Treatment of tendinosis and tenosynovitis depends upon ___.
cause
94
Infectious tendinosis/tenosynovitis can be treated with:
antibiotics
95
Which structure helps prevent excessive unit loads in joints?
Synovial villi
96
In synovial joints, what are the articulating ends of bone usually covered by?
Hyaline cartilage
