Chapter 9 - Joints Flashcards
Define a joint (articulation)
Any point where two bones meet, whether or not the bones are movable at that interface
Define arthrology
The science of joint structure, function, and dysfunction
Define kinesiology
The study of musculoskeletal movement
Kinesiology is a branch of biomechanics, which deals with what?
A broad variety of movements and mechanical processes
Define synarthrosis
- Type of joint which permits very little or no movement
- Most synarthroses joints are fibrous
Define amphiarthrosis and give examples
- A slightly movable joint
- Examples are symphyses and syndesmoses
Describe diarthrosis and give an example
- Freely movable joints (has a joint capsule)
- Synovial joints are diarthrotic
How are joints named?
Their names are typically derived from the names of the bones involved (example: radioulnar joint)
How are joints classified?
They’re classified according to the manner in which the bones are bound to each other
What are the four major joint categories based on structure?
- Bony joints
- Fibrous joints
- Cartilaginous joints
- Synovial joints
Describe synostosis (bony joint) and give examples
- When a joint becomes immobile because the gap between two bones ossifies (becomes one bone)
- Can occur in either fibrous or cartilaginous joints
- Examples: Left and right mandibular bones in infants, cranial sutures in elderly, attachment of first rib and sternum with old age
Define a fibrous joint
Bones bound by collagen fibers that emerge from one bone and penetrate into the other
What are the three types of fibrous joint?
1) Sutures
2) Gomphoses
3) Syndesmoses
Describe sutures
- A type of fibrous joint that’s immobile or slightly mobile
- Uses short collagen fibers
Describe gomphoses
- The attachment of a tooth to its socket
- Held in place by fibrous periodontal ligament (collagen)
- Allows the tooth to move a little under the stress of chewing
- A type of fibrous joint
Describe syndesmoses
- Two bones are bound by long collagen fibers
- Can be very mobile or less mobile
- A type of fibrous joint
Give an example of a very mobile syndesmosis and an example of a less mobile syndesmosis
- Very mobile syndesmosis: interosseus membrane joining radius to ulna (allows supination & pronation)
- Less mobile syndesmosis: joint between tibia to fibula
Define cartilaginous joints
Two bones that are linked by cartilage
What are the two types of cartilaginous joints?
- Synchondroses
- Symphyses
Define synchondroses and give examples
- Bones are joined by hyaline cartilage
- Examples: Epiphyseal plates in children (temporary joints), first rib attachment to sternum
Costal cartilages are joined to the sternum using what two mechanisms?
The first rib is attached with synchondroses, and other costal cartilages are joined to the sternum by synovial joints
Describe symphyses (singular symphesis) and give examples
- Defined as two bones joined by fibrocartilage
- Examples:
1) Pubic symphysis
2) Bodies of vertebrae joined by intervertebral discs, which allows for only slight movements between adjacent vertebrae. The collective effect of all 23 discs gives the spine considerable flexibility
Describe synovial joints (diarthrosis)
- Defined as two bones are separated by a joint cavity
- The most familiar and most structurally complex type of joint
- Most are freely mobile
- Most likely to develop painful dysfunction
- Most important joints for physical and occupational therapists, athletic coaches, nurses, and fitness trainers
- Their mobility makes them important to quality of life
Describe the general anatomy of synovial joints
1) Articular cartilage (usually 2 or 3 mm thick) made of hyeline cartilage absorbs shock
2) Joint (articular) cavity
3) Synovial fluid—slippery lubricant in joint cavity
Rich in albumin and hyaluronic acid
4) Joint (articular) capsule
-The outer fibrous capsule is continuous with periosteum
-The inner, cellular, synovial membrane has
fibroblast-like cells that secrete synovial fluid and macrophages that remove debris from the joint cavity
Describe synovial fluid
The slippery lubricant in synovial joint cavities; rich in albumin and hyaluronic acid
Describe the two parts of a joint (articular) capsule of synovial joints
1) Outer fibrous capsule: continuous with periosteum
2) Inner, cellular, synovial membrane:
fibroblast-like cells that secrete synovial fluid and macrophages that remove debris from the joint cavity
Describe the accessory structures of synovial joints
1) Articular disc between articulating bones
- Ex: temporomandibular joint
2) Meniscus: moon-shaped cartilage in each knee
- Absorbs shock and pressure
- Guide bones across each other and improve their fit together
- Stabilize the joints, reducing the chance of dislocation
Describe the meniscus of the knee
- A moon-shaped cartilage in each knee
- Absorbs shock and pressure for the synovial joint
- Guide bones across each other and improve their fit together
- Stabilize the joints, reducing the chance of dislocation
Ligaments attach ____ to ____, whereas tendons attach _____ to _____
Ligaments attach bone to bone, whereas tendons attach muscle to bone
Describe bursa and describe its purpose
- A fibrous sac filled with synovial fluid, located between muscles, where tendons pass over bone, or between bone and skin
- Cushions muscles, helps tendons slide more easily over joints, modifies direction of tendon pull
Describe a tendon sheath and where it’s found
- Elongated cylindrical bursa wrapped around a tendon
- In hand and foot
Describe how exercise can benefit your cartilage
- Exercise warms synovial fluid, which makes it become less viscous, and more easily absorbed by cartilage
- Cartilage then swells; becomes a more effective cushion
- Repetitive compression and decompression of cartilage (during exercise) moves synovial fluid in and out of the cartilage like a sponge.
- Oxygen and nutrients are brought to chondrocytes; wastes are taken away
- Without exercise, cartilage deteriorates more rapidly from inadequate nutrition and waste removal