Articulations CH 8
Outline Joint Cavity Components Selected articulations Joint capsule Articular cartilage Synovial membrane Joint accessory components Selected articulations Intervertebral articulations Glenohumeral joints Tibiofemoral joint Talocrural joint
Synovial Joint Space Space contents Degree of motion Example Yes! Joint cavity Space contents Synovial fluid Held together w/ bands of dense regular CT- ligaments Degree of motion Freely moveable Least stable- high motility Example Knee, elbow, fingers, shoulder
Synovial Joint “fluid filled joint” No direct bone- bone contact Joint cavity- persistent space between bones Diarthrosis- high degree of mobility
Joint Cavity Components Joint capsule Articular cartilage Synovial membrane Joint accessory components Accessory Capsular ligaments Extracapsular ligaments Intracapsular ligaments Bursae Menisci Fat pads Stabilizing bones & muscles
Joint Capsule Dense irregular CT encloses cavity Function Adds joint stability Refines joint motility Defines joint cavity border
Joint Capsule
Joint Capsule
Articular Cartilage Structure Function Modification Hyaline cartilage Reduces friction Shock absorption Modification Synovial fluid storage Porous allows synovial fluid to be released during compression (joint motion)
Articular Cartilage
Clinical- Chondromalacia
Synovial Membrane Structure Function Nourishes articular cartilage Membrane lining articular capsule Stops at articular cartilage Function Synovial fluid secretion Provides lubrication/ reduces friction Efficient motion w/out wear on bones Nourishes articular cartilage Chondrocytes acquire nutrition thru synovial fluid Why? Shock absorption Absorbs and distributes shock across articular cartilage
Synovial Membrane
Joint Accessory Components Accessory capsular ligaments Extracapsular ligaments Intracapsular ligaments Articular discs – menisci Bursae Fat pads Muscles Bones
Accessory Capsular Ligaments Distinct localized thickenings of articular capsule Work to add strength, refine motion & stabilize joints Component of capsule
Capsule Pubofemoral Ligament
Extracapsular ligaments “outside” capsule Fibers comprise the layer of CT that is on the outside of the articular capsule Ulnar Collateral Ligament
Extracapsular Ligaments Medial Collateral Ligament (knee)
Intracapsular ligaments Fibers located within the articular capsule
Intracapsular Ligaments Anterior Cruciate Ligament- Knee
Articular Discs – Menisci Structure Fibrocartilage discs Function Change the shape of the articulating surface Refine joint movement- stabilize koint Absorb shock Channel & distribute synovial fluid Location Articulating bones of knee
Menisci
Menisci Provide better bone-bone fit
Menisci Refine movement- stability
Menisci Channel & distribute synovial fluid
Bursae “Fluid filled pouch” Structure Function Location CT sacs filled with synovial fluid Lined with synovial membrane Connected or separated from joint cavity Form where ligaments or tendons rub against other tissue Function Reduce friction Absorb shock Location Areas of friction
Suprapatellar Bursa
Fat Pads Pads of fat Structure Function Location Adipose loose connective tissue proper Function Reduce friction Fill space Location Areas of friction
Infrapatellar Fat Pad
Stabilizing Bones & Muscles Add stability to joint
Clinical Applications Synovial joint dislocation Sprain Strain Bursitis
Synovial Joint Dislocation Luxation- Full dislocation Subluxation- Partial dislocation Articulating surfaces forced out of position Displacement can cause joint structure damage Cartilage, ligaments, menisci
Synovial Joint Dislocation
Synovial Joint Dislocation
“Double Jointed” Weakly stabilized joints Permit greater range of motion More prone to luxation
Strain Overstretching or tearing of muscle or muscle connective tissue Results from joint over extension Repair ~ 3-4 weeks
Sprain Overstretching or tearing of ligament or capsule Result from joint overextension Repair- ~3-4 weeks
Bursitis Inflammation of the bursa Result from A direct fall or blow Overuse Infection
Bursitis
Bursitis