Chapter 8 - Joints

Question 1

Joint

Answer 1

the area where two bones connect
- Help bind parts of the skeleton together
- Makes bone growth possible as there are more ends
- Allows for movement of bones

- 2 types of classifications; structural and functional

Question 2

Structural Classifications of Joints

Answer 2

• Fibrous: held by dense connective tissue
  
  • Cartilaginous: held by cartilage
    
    • Synovial: complex joint capsule structure

Question 3

Functional Classification of Joints

Answer 3

• Synarthrotic: immovable
• Amphiarthrotic: slightly movable
• Diarthrotic: freely moveable

Question 4

Fibrous Joints

Answer 4

• Held by dense connective tissue and lots of collagen fibers; provides close contact

includes:
- syndesmosis
- sutures
- gomphosis

Question 5

Fibrous Joints: Syndesmosis:

Answer 5

slightly moveable bones bound by a sheet of dense connective tissue(interosseous membrane or tissue)
○ e.g. between radioulnar and between tibia-fibula

Question 6

Fibrous Joint: Sutures

Answer 6

immovable thin layers of connective tissue between cranial bones
○ Margin of suture on cranial bones are like teeth which prevent movement
○ Sutural bones: bones created by sutures

Question 7

Fibrous Joints: Gomphosis

Answer 7

immovable cone shaped bony process in a socket
○ E.g. root of our teeth which are held in place by the periodontal ligament

Question 8

Cartilaginous Joints

Answer 8

• Connected by hyaline or fibrocartilage

includes:
- Synchondrosis
- Symphysis

Question 9

Cartilaginous Joints: Syndochondrosis

Answer 9

bands of hyaline cartilage which are immovable
○ Temporary ones like epiphyseal plates
Permanent ones like between the manubrium

Question 10

Cartilaginous Joints: symphysis

Answer 10

slightly moveable pads of fibrocartilage between bones
○ e.g. pubic symphysis, interverbal discs

Question 11

Synovial Joints

Answer 11

• all diarthrotic joints which have articular cartilage and joint capsules

includes:
- ball and socket
- condylar
- saddle
- pivot
- hinge
- plane/gliding

Question 12

Ball and Socket Joint

Answer 12

round head in a cup shaped cavity which has the widest range of motion
- e.g. Shoulder, hip
- allows for circumduction

Question 13

Condylar Joint:

Answer 13

oval condyle fits into the elliptical cavity allowing for circumduction, flexion/extension and abduction/adduction
○ Metacarpal-phalanges

Question 14

Plane/Gliding Joint

Answer 14

almost flat or slightly curved joints that allow for sliding motions
- radioulnar-carpal

Question 15

Hinge Joint

Answer 15

convex surface fits into concave surface of the other bone allowing for flexion/extension and slight rotation
- knee, elbow

Question 16

Pivot Joint

Answer 16

cylindrical surface rotates around a ring of another bone
- neck

Question 17

Saddle Joint

Answer 17

surfaces have both convex and concave surfaces which allows for biaxial movement
○ e.g. carpal-metacarpal

Question 18

How joints move?

Answer 18

• Movement of joints is determined by the shape of the joint and the muscles attached
  ○ Origin: relatively fixed end
  ○ Insertion: more moveable end
  
  • When a muscle contracts, the insertion is brought towards the origin

Question 19

Circumduction

Answer 19

movement of a part of the body in a circular path

Question 20

Dislocation

Answer 20

displacement of articulating surfaces

Question 21

Sprain

Answer 21

tearing of connective tissue in joint, without bone dislocation

- Torn Ligaments: resulting from overtwisting, overextension, lifting heavy objects and falling

Question 22

Structure of Synovial Joints

Answer 22

• Articular(hyaline) cartilage covers the ends of bones
• Joint capsule
  ○ Outer fibrous layer is composed of ligaments
  ○ Synovial membrane
  ○ Synovial cavity which secretes synovial fluid
  ○ Menisci
  ○ Bursa; sacs of synovial fluid which cushions ligaments going over bony processes

Question 23

Bursitis

Answer 23

inflammation of a bursa from overuse or stress

Question 24

Arthritis

Answer 24

inflammation, swelling, pain in a joint
- Rheumatoid arthritis: autoimmune
- Osteoarthritis: degenerative due to aging
- Lyme arthritis: caused by lyme disease
- Gout: build up of uric acid crystal in joint

Question 25

Joint Replacement

Answer 25

- Can use synthetic materials like steel, titanium for bigger joints and silicone or ceramic for smaller joint replacements - Most common are hip and knee joint replacements - New joint replacement tech also coats them with hydroxyapatite so that the body better receives it and grows over it

Question 26

Jaw Joint

Answer 26

- Consists of the mandible and temporal bone articulating between the mandibular condyle and mandibular fossa - An articular disc sits between the two surfaces and separates the synovial cavity in half - A modified hinge joint inferior to the articular disc allows depression/elevation while eating and the superior surface allows for gliding movements in grinding of food

Question 27

Shoulder Joint

Answer 27

- Consists of the glenoid cavity and head of the humerus protected by the coracoid and acromion processes as well as by dense connective tissue and muscle - Tendons of several muscles blend with the fibrous layer of the shoulder capsule forming the rotator cuff - The glenoid labrum composed of fibrocartilage helps deepen the cavity

Question 28

Elbow Joint

Answer 28

- Includes the hinge joint between the trochlea of the humerus and the trochlear notch of the ulna, and the plane joint between the capitulum of the humerus and the shallow depression on the head of the radius - Flexion extension occurs at the humerus-ulna connection while there is pronation/supination occurring due to the anular ligament at the head of the radius

Question 29

Hip Joint

Answer 29

- Consists of the head of the femur and the acetabulum - Ligamentum capitis attaches to the fovea capitis and connective tissue in the acetabulum and helps carry blood vessels - Acetabular labrum in a horseshoe shaped ring of fibrocartilage deepens the cavity and encloses the head of the femur

Question 30

Knee Joint

Answer 30

- Condyles of the femur and tibia are largely hinge joints but allow some rotation when the knee is flexed - Femur-patella joint is a plane joint - As the joint capsule is relatively weak the many ligaments and tendons strengthen it and cover the capsule anteriorly - C shaped menisci separate the articulating surface of the femur and tibia and help align them