Ch. 2 Articular system Flashcards
What are articulations?
Where 2 bones meet
Body movements occurs at joints (articulations)
What does joint structure determine?
Direction
Distance of Movement (Range of Motion)
What is the relationship between joint mobility and joint stability?
There is an inverse relationship
Define degrees of freedom.
The number of axes (or planes) in which a joint can move
What are the 3 types of degrees of freedom that can occur in joints?
Uniaxial Joints: Movement along 1 axis (plane)
Biaxial Joints: Movement along 2 axes (planes)
Triaxial Joints: Movement along 3 axes (planes)
What does a greater degree of freedom lead to?
greater the mobility and less stability
What are nonaxial joints and examples?
Little movement
Movement is Gliding or Plane joints
Examples: Intercarpal Joints; Intertarsal Joints
What are the 2 classification methods for joints?
Functional classification
Structural classification
Describe the functional classification of joints?
Based on Joint Range of Motion
Synarthrosis (Immovable Joint)
Amphiarthrosis (Slightly Movable Joint)
Diarthrosis (Freely Movable Joint)
Describe the structural classification of joints?
Based on Anatomical Organization of the Joint
Fibrous
Cartilaginous
Bony
Synovial
What are synovial (diarthrodial) joints?
freely movable joints
What are number of axes that synovial (diarthrodial) joints can have?
Nonaxial Joints
Uniaxial Joints
Biaxial Joints
Triaxial Joints
What are the different classifications based on shape of the articulating surfaces of synovial joints?
Gliding (Planar) Joints
Hinge Joints
Pivot Joints
Condylar (Ellipsoidal) Joints
Saddle Joints
Ball and Socket
Describe Gliding (Plane) Joints
Flattened or slightly curved surfaces
Limited motion (Nonaxial Joint)
Movement tends to be linear instead of angular so surfaces glide across each other instead of one moving around the other
What are some examples of gliding (plane) joints?
Intercarpal Joints
Intertarsal Joints
Acromioclavicular Joint
Vertebrocostal Joints
Describe Hinge (Ginglymus) Joints
The convex surface on one bone fits into the concave surface of another bone
Angular Motion in a 1 Plane (Uniaxial Joint) - Flexion/Extension
What are some examples of hinge (ginglymus) joints?
Elbow Joint
Knee Joint (modified hinge)
Interphalangeal Joints
Describe Condyloid (Ellipsoid) Joints
The oval surface of one bone fits into the oval-shaped depression of another bone
Angular Motion in 2 Planes (Biaxial Joint):
- Flexion/Extension
- Abduction/Adduction
- Circumduction (Multiplanar)
What are some examples of condyloid (ellipsoid) joints?
Radiocarpal Joint
Metacarpophalangeal Joints 2 – 5
Describe saddle joints
The saddle-shaped surface of one bone articulates with the articular surface of the another bone that fits into the “saddle”
Angular Motion in 2 Planes (Biaxial Joint)
- Flexion/Extension
- Abduction/Adduction
- Circumduction (Multiplanar)
What are some examples of saddle joints?
Carpometacarpal Joint of the Thumb
Trapezium and the first metacarpal
Describe pivot joints
The rounded surface of one bone articulates with a ring formed partly by another bone and partly by a ligament
Angular Motion in a 1 Plane (Uniaxial Joint)
-Rotation
What are some examples of pivot joints?
Atlanto-axial Joint
Radio-ulnar Joints
Describe ball-and-socket joints
The ball-like surface of 1 bone rests within a cup-like depression of another bone
Angular Motion in 3 Planes (Triaxial Joint)
- Flexion/Extension
- Abduction/Adduction
- Internal and External Rotation
- Circumduction (Multiplanar)
What are some examples of ball-and-socket joints?
Shoulder (Glenohumeral) Joint
Hip Joint
What are the features of synovial joints (diarthodial)?
Articular Cartilage
Joint Cavity
Articular Capsule
Synovial Fluid
Reinforcing Ligaments
Nerves and Blood Vessels
What is articular cartilage?
The articulating surfaces of synovial joints are covered by articular cartilage (hyaline cartilage)
Prevents bones from touching
What is the joint cavity?
Joint space that contains synovial fluid
What is the articular capsule?
2 Layers:
- Outer Fibrous Capsule (dense irregular CT)
- Inner Synovial Membrane
Continuous with periosteum
Strengthens the joint so the bones are not pulled apart
Can there be more than one type of cartilage at a joint?
yes
What is the synovial membrane?
A connective tissue membrane
Lines moving, articulating joint cavities
Makes up the inner layer of the Articular Capsule
No epithelium
What does the synovial membrane consist of?
Connective Tissue:
- Areolar Connective Tissue
- Adipose Tissue
A Discontinuous Layer of Cells
-Synoviocytes: Cells of the synovial membrane
What are the 2 types of synovial cells in the synovial membrane?
Macrophage-like Synovial Cells (Type A Cells): Remove wear-and-tear debris from Synovial Fluid
Fibroblastic Synovial Cells (Type B Cells): Produce hyaluronan and Acts as a lubricant
Synovial fluid consist mainly of what?
Interstitial Fluid: Filtered from the blood plasma diffused from capillaries in the Synovial Membrane
Hyaluronan: Released by Fibroblastic Synovial Cells (Type B Cells)
What is synovial fluid?
Fluid within the joint cavity
Lubricates the joint to reduce friction
Provides nutrients and waste disposal
Provides shock absorption
What are reinforcing ligaments?
Ligaments that reinforce and strengthen the joint
What are the accessory structures of synovial joints?
cartilage
fat pads
ligaments
tendons
bursa(e)
synovial tendon sheath
labrum
What is cartilage?
Fibrocartilage pads that separate the articulating surfaces
Helps to cushion the joint
Example: Menisci (articular disc)
What are fat pads?
Localized masses of adipose tissue covered by a Synovial Membrane
Superficial to the Joint Capsule
Protect articular cartilages
What are ligaments?
Support and strengthen joints
What is occurring when a ligament sprains?
Ligaments with torn collagen fibers- fibers of ligaments are stretched beyond capacity
What are tendons?
Are not part of the joint
Pass across or around a joint
May limit joint ROM
Provide mechanical support for the joint
Anchor to other tissue including bone
What is occurring when a tendon strains?
injury to a muscle or tendon
What is a bursa(e)
Small fluid-filled (synovial fluid) sac
Reduce friction between tissues (typically between bones)
Cushions movement of these tissues against each other
What does a bursa sac consist of?
Outer Layer: Consists of dense connective tissue
Inner Layer: Consists of synovial membrane
What are bursa located?
between:
- Skin and Bones
- Tendons and Bones
- Muscles and Bones
- Ligaments and Bones
What is Synovial Tendon Sheath?
An elongated tube-like bursa (for when a regular bursa doesn’t fit)
Wraps around a tendon where it crosses bone surfaces
Protects all sides of a tendon from friction as the tendon slides back and forth
What is the labrum?
A fibrocartilaginous structure
Attaches to the rim of the Acetabulum and Glenoid Cavity
Helps to deepen the joint socket
Describe dislocation
Complete separation of the 2 articulating surfaces of a joint
Involves tearing of the capsule surrounding the joint and possibly tearing of tendons and ligaments
Associated with acute trauma
Describe subluxation
A partial dislocation of a joint
Can occur
- Over time
- Due to acute trauma
What is osteoarthritis also known as?
Also called Degenerative Joint Disease (DJD)
Known as “Wear-and-Tear” Arthritis b/c it occurs over a period of time
What is the most common type of joint disease?
osteoarthritis
What does osteoarthritis primarily affect?
synovial joints
What are the joint changes associated with OA?
Gradual loss of articular cartilage
Bony outgrowths or spurs (osteophytes)
Mild synovial inflammation
Thinning of joint space and thickening on end plates
What do the joint changes associated with OA result in?
Joint pain and stiffness
Limited ROM
Joint instability and deformity
Describe a sprain
Partial or complete tearing of ligament fibers
Describe a strain
Injury to a muscle or tendon
Resulting in an overstretching or tearing of the fibers of a Muscle or Tendon
What is tendonitis?
Inflammation of a tendon
Findings include
- Pain and burning in the affected area
- Decreased strength and flexibility
- Pain with activity
Due to an acute overload of the musculotendinous tissue
What is tendinosis?
Intratendinous degeneration (tendon starts to degenerate)
No significant inflammation
Due to chronic overuse
What is synovitis?
Inflammation of the synovial membrane
Can be due to inflammatory diseases (e.g., Rheumatoid Arthritis) and infection
What is tenosynovitis?
Inflammation of the tendon sheath
Can be due to inflammatory diseases (e.g., Rheumatoid Arthritis), infection and overuse
What is bursitis?
Inflammation of the bursa
Can be due to inflammatory diseases (e.g., Rheumatoid Arthritis), infection, trauma and overuse
What is capsulitis?
Inflammation of the joint capsule
Leads to joint stiffness and restriction of movement
What is capsular pattern?
When a joint capsule is inflamed for an extended period of time it begins to lose it extensibility and leads to loss of joint ROM
Each joint has a characteristic pattern of loss of ROM that occurs when capsular tightness is present
This pattern of loss of ROM is referred to as the Capsular Pattern of Motion Restriction
What is the common capsular pattern in the shoulder joint?
severe loss of lateral rotation
moderate loss of abduction
slight loss of medial rotation
What is the common capsular pattern in the wrist joint?
equal loss of flexion and extension
What is the common capsular pattern in the knee joint?
more loss of flexion than extension
