Anatomy Chapter 8- Joints Flashcards
Joints
The site where two bones meet
General functions of joints
- Mobility- allows movement of various body parts
- Stability- holds the skeleton together (specifically axial)
General classification of joints
- Structural- type of tissue that connects bones at articulating surface
- Functional- amount of movement allowed by the joint
Synarthroses
No movement
Stability in axial skeleton (sutures)
Amphiarthrosis
Limited movement (still has stability function as well)
Stability in both skeletal systems (more in axial)
Diarthroses
Free movement (can move in 1 or more directions)
Appendicular skeleton
Fibrous Joints
Joints composed of collagen fibers of connective tissue
Types of fibrous joints
- Sutures
- Syndesmosomes
- Gomphoses
Sutures
“seams”
Found only between bones of the skull
Permits very little movement
Can ossify over time in adults to form syntoses
Syntoses
looks like bones straight across
replaced by bones over time
Syndesmosomes
Bones that are connected to one another only by ligaments
Ligaments
Bands of fibrous tissue that join bone to bone
Movement allowed by the joint depends on length of ligament bands
Gomphoses
Only joint type that does not join bone to another bone
Joins tooth to bony alveolar socket
Periodontal ligament
Joins the bone of the mandible/maxilla to the tooth
Fibers are short and provide little movement
Cartilaginous joints
Bones joined by cartilage
Types of cartilaginous joints
- Synchondroses
- Symphysis
Synchondroses
Bones united with a plate of hyaline cartilage
Epiphyseal plate
Occur in long bones
Type of synchondroses
Costal cartilage
Cartilage that moves the skin
Type of synchondroses
Symphysis
Fibrocartilage joins bone
Some movement allowed, but it is limited
Synovial Joints
Most complex because it allows for a lot of movement
Has a joint cavity - spaces between bones
Diarthroses
Six structures found in all synovial joints
- Articular cartilage
- Joint cavity
- Articular capsule
- Synovial fluid
- Reinforcing ligaments
- Innervation and vascularization
Articular cartilage
Hyaline cartilage covering bone ends
Prevents bone rubbing
Joint cavity
Small space between articulating bones
Stores the synovial fluid
Articular capsule
Two-layered capsule that encloses the joint cavity
Articular capsule parts
Fibrous Layer
Synovial membrane
Fibrous Layer of Articular capsule
The outer layer that is continuous with the periosteum of bones
Gives tough quality
Connects bone with the other bone it joins with - serves to reinforce the joint and holds the bones together even better
Synovial membrane of the Articular capsule
Inner layer that lines joint cavity
Produce and secrete fluid that’s important for joint function
Synovial fluid
Slippery fluid occupying space in joint capsule and articular cartilages
Viscous
When joint is not active, synovial fluid is…
Thins and becomes watery
When joint is active, synovial fluid…
Reinforcing ligaments
Bandlike ligaments that join articulating bones
Reinforce articular capsule
Where double-jointedness comes into play
Innervation and vasculariation
Joints supplied with sensory nerve fibers
Why is innervation to the joints so important?
- Pain
- Stretch
- Position
Strcutures that might be associated with synovial joints
- Bursae
- Tendon sheath
Bursae
flattened sacs that contain a small amount of synovial fluid
Reduces friction between adjacent structures
Tendon Sheath
Elongated bursa that craps completely around a tendon subjected to frequency friction
Articular surfaces
How well the two bones fit together
Golf ball sitting on a T
Ligaments
The more of these, the stronger the joint and the more stability
Muscle tone
Tendons attach muscle to bone and often wrap around or over joints
Most important
Any damage to the tendon that wraps around the joints will destabilize the joint
Movements allowed by synovial joints
- Nonaxial
- Uniaxial movement
- Biaxial movement
- Multiaxial
Nonaxial movement
no axis around which movement can take place
Bones that articulate have flat surfaces
Joint shape- plane joint
Movement- gliding
Ex: intercarpal & intertarsal joints (Wrists and ankles)
Uniaxial movement
Allows for movement of joint around a single axis
movement- flexion, extension, rotation
Uniaxial movement examples - joint shapes
Hinge joint (elbow joint)
Pivot joint (radius and ulna)
Biaxial movement
Allows for movement of a joint around 2 axes
Biaxial movement examples - joint shapes
Condylar joint (knuckle of finger)
Saddle joint (base of thumb)
Multiaxial movement
Allows for movement of a joint around multiple axes (at least 3)
Movement- flexion/extention, abduction/adduction, rotation
Multiaxial movement joint shape
Ball-and-socket joint (shoulder)
Temporomandibular joint
Where the mandible articulates with the temporal bone
Modified hinge joint
Superior (right to left) and inferior portions (up and down)
Glenohumeral joint
Where the humerus articulates with the scapula
Small amount of mobility
Ligaments part of the glenohumeral joint
Coracohumeral ligament
Glenohumeral ligament
Rotator cuff
Glenohumeral joint
4 muscles encircle this joint and hold the bone in place
Glenoid labrum
Rim of fibrocartilage around glenoid fossa some stability
Ring of cartilage tissue that serves to slightly deepen the sockets where the joint is formed
Elbow joint
Were the humerus articulates with the ulna
Stability of the ulna
- Close fit of trochlea and trochlear notch to make it more stable
- Muscle and tendon of arm muscles wrap around the elbow to provide further stability
- Ulnar collateral ligament and radial collateral ligament
Ulnar collateral ligament
Medial side
Radial collateral ligament
lateral side
Coxal joint
Where the head of the femur articulates with the os coxa
Stability provided by articular surfaces and strong ligaments
Acetabular labrum
The acetabulum of os coxa has this to further deepen the socket to stabilize the joint
Ligaments of the articular capsule
Iliofemoral ligament
Pubofemoral ligament
Ischiofemoral ligament
Ligamentum teres
Ligament of the head of the femur
Allows blood vessels to pass to the head of the femur
Knee joint
Single joint cavity shared by 3 separate joints
- 1 femoropatellar joint
- 2 tibiofemoral joint (1 medial, 1 lateral)
Menisci
Thin layer of fibrous cartilage at outer margins of tibiofemoral joints
Cruciate migaments
Intracapsular ligaments that secure articulating bones and prevent displacement
Anterior cruciate ligament
Prevents forward sliding of tibia and prevents hyperextension of the knee
Posterior cruciate ligament
prevents backward sliding of tibia and forward sliding of femur
Arthritis
Can be inflammatory (irritation of the joint tissue usually from bacteria or infection) or degenerative (issue that makes up the joint beaks down and disappears with time)
Acute Arthritis
Bacterial, inflammatory
Chronic Arthritis
usually degenerative and longlasting
Types of arthritis
Osteoarthritis
Rheumatoid arthritis
Osteoarthritis
Most common form
Caused by more articular cartilage being destroyed than being replaced and bones rub together forming bone spurs
Bone spurs
when exposed bone rubs together and bone ends deform, restricting movement at a joint
Spur will lock onto the glenoid labrum
Rheumatoid artitis
autoimmune chronic inflammatory disorder
Bilateral and degenerative
Invididuals will have flare ups when their immune systems are attacking their own joints
Progression of Rheumatoid arthritis
- Synovial membrane becomes inflamed
- Lymphocytes and macrophages flood area to destroy cause of inflammation
- synovial fluid accumulates and a pannus forms
Pannus
thickening of synovial membrane that breaks down cartilage tissue over time and bones will rub together
Ankylosis can occur
Ankylosis
Bones fuse together where cartilage/joints used to be
