Ch. 8 - Joints

What are joints or articulations?

• Joints/articulations: Where 2 bones meet

What do joints allow for?

• Allow for mobility, while preserving bone strength

What is range of movement?

ROM

• Amount of motion allowed by anatomical structure

What is the SAD scale?

• Synarthrosis, amphiathrosis, diathrosis

  • mobility/function classification of joints

Describe synarthrosis joints? How strong are they?

• Synarthrosis: no movement (ROM)

  • strong/ very stable

Describe amphiarthrosis joints? How strong are they?

• Little movement (ROM) allowed

  • stronger/more stable than diathrosis

Describe diarthrosis joints? How strong are they?

• Freely movable (ROM)

  • weakest joints

What are sutures? What are their classification?

• Sutures; between cranial bones, made up of dense regular (fibrous)

• Synarthrosis joints

What is gomphosis? What are their classification?

• Gomphosis; tooth to socket, dense regular CT (fibrous)

• Synarthrosis joint

What is synchondrosis? What are their classification?

• Synchondrosis; costal cartilage, made up of hyaline (cartilage)

• Synarthrosis joint

What is synostosis? What are their classification?

• Synostosis; frontal bone fusing in infants, osteocytes (bone)

• Synarthrosis joint

What is syndemosis? What are their classification?

• Syndemosis; between ulna and humerus (forearm joint), fibrous

• Amphiathrosis joint

What is symphis? What are their classification?

• Symphis; pubic symphysis, fibrocartilage (cartilage)

• Amphiathrosis joint

What are synovial joints? What are their classification?

• Synovial joints; ends of long bones

• Diathrosis joint

What are the components of the synovial joint?

1. Articular cartilage

2. Joint capsule

3. Joint cavity

4. Synovial membrane and fluid

5. Ligament

What is articular cartilage? What is its function?

• Articular cartilage; covers bones at joints

  • Reduces friction, bone to bone contact

What is the joint capsule?

• Joint capsule; sacs closing toward eachother

  • continue from periosteum of bone

What is the function of the joint capsule?

• Function; adds strength and mobility to joint

What does the synovial membrane produce? What is its function?

• Synovial membrane: produces synovial fluid into joint cavity

  • Fluid: lubricates, cushions, prevents abrasion, and supports chondrocytes

Where is the synovial membrane found?

• Found; lining of interior joint capsule

What does the synovial percolate (pass through)? To do what?

• Articular cartilage

  • Provides oxygens and nutrients to chondrocytes

  • Carries away metabolic wastes

What are the functions of the synovial fluid?

1. Lubrication; reduces friction

2. Nutrient distribution; carry away wastes

3. Shock absorption; viscous fluid

What are the accessory structures of the knee?

1. Bursa

2. Fat pads

3. Meniscus

4. Patellar Ligament

5. Cruciate ligament

What are bursa? Their function?

• Bursa; synovial fluid filled pocket lined by synovial membrane

  • Function; reduce friction and absorb shock

What are fat pads?

• Masses of adipose tissue covered by synovial membrane

What are the functions of the fat pads?

• Protect articular cartilage/joints

• Fill in spaces

What is the meniscus? What is its function?

• Meniscus (articular disc); pad of fibrocartilage

  • Function; handles bone to bone compression, absorbs shock

What are extrinsic ligaments?

• Extrinsic ligaments; separate from joint capsule

  1. Extracapsular ligament

  2. Intracapsular ligaments

What are extracapsular ligaments? What is an example?

• Extracapsular ligaments: pass OUTSIDE joint capsule

  • Ex: patellar ligament

What are intracapsular ligaments? What is an example?

• Intracapsular ligaments; pass INSIDE joint capsule

  • Ex: cruciate ligament

What are the 3 articulations in the knee joint?

1. Medial condyle of tibia to medial condyle of femur

2. Lateral condyle of tibia to lateral condyle of femur

3. Between patella and patellar surface of femur

Is the fibula a part of the knee joint?

• Fibula; not a part of knee joint

What types of ligaments are the LCL and the MCL?

• Fibular/Lateral Collateral ligament; extracapsular

• Tibial/Medial Collateral ligament; extracapsular

What are the popliteal ligaments?

• Ligaments; posterior ligament on outside

  • extracapsular

What are medial and lateral meniscus on the knee joint?

• Fibrocartilage pads, cushions

  • on each side of knee joint

What is the ACL and PCL?

• Anterior cruciate ligament (ACL); originates from anterior side

• Posterior cruciate ligament (PCL); originates from posterior side

  • lock knee in extended postion

  • Intracapsular

What is disolation/luxation?

• Movement beyond normal range of motion

  • tearing ligaments

  • damaging synovial joint structures

What type of joints are the strongest?

• Synarthrosis joints; no ROM, STRONGEST

• Diarthrosis joints; highest ROM, WEAKEST

Where does the pain from dislocations come from?

• Pain; from nerves surrounding capsule/ligament

  • no receptors inside the joint

What does greater range of motion result in?

• Greater ROM; results in weaker joint