joints

Question 1

Structural classification of joints

Answer 1

Fibrous = held together by dense collagen fibers (dense regular connective tissue)
Cartilaginous = bones held together by cartilage
synovial = bones held together by ligaments

Question 2

Functional classification of joints

Answer 2

Synarthrosis = immovable
Amphiarthrosis = slightly movable
Diarthrosis = freely movable

Question 3

Types of Fibrous joints

Answer 3

1. Sutures = occur b/t bones of skull –> synarthrosis (synostosis)
2. Syndesmoses = interosseous membrane –> b/t tibia/fibula and radius/ulna –> amphiarthrosis
3. Gomphoses = cone-shaped peg fits into socket –> teeth in mandible/maxilla –> synarthrosis

Question 4

Cartilaginous joints

Answer 4

1. Synchondroses = hyaline cartilage at epiphyseal growth plate and first rib/manubrium –> synarthrosis
2. Symphyses = discs of fibrocartilage –> pubic symphysis and intervertebral discs –> amphiarthrosis

Question 5

Articular Capsule

Answer 5

• sleeve-like capsule enclosing synovial cavity
• composed of 2 layers: outer fibrous (continuum of periosteum) and inner synovial membrane (synoviocytes)

NO EPITHELIUM

Question 6

Synovial Fluid

Answer 6

• Secreted by synovial membrane
• reduces friction
• transports oxygen, nutrients, and waste to and from cartilage

Question 7

Accessory ligaments and articular discs

Answer 7

• Anterior and posterior cruciate ligaments
• medial and lateral (tibial and fibular) collateral ligaments
• menisci = pads of fibrocartilage that allow bones to fit better

Question 8

Nerve and blood supply to joints

Answer 8

• nerve endings respond to degree of movement and stretch at a joint
• arterial branches from several different arteries merge around joint before penetrating the articular capsule

Question 9

bursae

Answer 9

• sac like structures with fluid similar to synovial fluid
• b/t tendons and ligaments
• cushions movement of body parts

Question 10

Tendon sheath

Answer 10

Wraps around tendons to reduce friction

• prominent in wrists
• Ganglion cyst = tendon sheath bubbles up at wrist and fills with synovial fluid

Question 11

4 types of synovial joint movement

Answer 11

1. Gliding = simple side-to-side movement w/ limited range at intercarpal joint
2. Angular movements = change angle between articulating bones –> flexsion/extension, ab/adduction, lateral flexsion, circumduction
3. Rotation = bone revolves around its own longitudinal axis –> shaking head no, rotating humerus, turning knee inward (hip)
4. Special movement = elevation/depression, protraction/retraction, inversion/eversion, dorsiflexion/plantar flexion, supination/pronation, opposition

Question 12

Range of Motion (ROM)

Answer 12

refers to range, measured in degrees of a circle through which bones of a joint can be moved

Question 13

Things that affect range of motion

Answer 13

• shape of bones
• strength/tension of ligaments
• arrangement/tension of muscles
• contact of soft parts
• hormones (relaxin)
• disuse (movement stimulates production of synovial fluid)

Question 14

How are joints affected with age?

Answer 14

• decrease in synovial fluid
• articular cartilage thins
• osteoarthritis could happen
• stretching and aerobics helps to minimize these effects

Question 15

osteoarthritis

Answer 15

• “degenerative arthritis”
• damage to articular cartilage
• usually from wear and tear of weight-bearing joints and distal finger joints
• sometimes a gene codes for weaker collagen
• bone spurs could develop around area of friction
• restricts movement
• main reason for hip and knee replacements

Question 16

Rheumatoid arthritis

Answer 16

• unknown cause
• affects smaller joints (fingers, wrists, ankles, feet)
• affects synovial membrane –> swollen and inflamed –> thickens with time and clings to articular cartilage
• cartilage breaks down (more lysosomal enzymes)
• fibrous tissue forms at end of bones
• ossification and bone fusion

Question 17

Intervertebral disc anatomy

Answer 17

• outer fibrocartilage = anulus fibrosis

- inner elastic gelatinous material = nucleus pulposus

Question 18

slipped disc

Answer 18

• anulus fibrosis is pushed into vertebral foramen

- due to weakened posterior longitudinal ligaments (which connect vertabrae bodies)

Question 19

herniated disc

Answer 19

nucleus pulposus breaks through anulus fibrosus into vertebral forament