Unit 8 - Joints

Question 1

Fibrous Joints

Answer 1

• lack synovial cavity
• bones held closely together by fibrous connective tissue
• little or no movement
• 2 structural types
  
  • sutures (skull)
  • syndesmoses
  • gomphoses

Question 2

Sutures

Answer 2

• thin layer of dense fibrous connective tissue unites bones of skull
• immovable

Question 3

Syndemosis

Answer 3

• fibrous joint
• bones unites by ligament
• slightly moveable
• distal tibiofibular joint and interossoeous membrane
• everywhere except skull and teeth

Question 4

Gomphosis

Answer 4

• Teeth in alveolar processes
• ligament (periodontal) holds coneshaped peg in bony socket
• immovable

Question 5

Cartilaginous Joints

Answer 5

• lacks a synovial cavity
• allows little or no movement
• bones tightly connected by fibrocartilage or hyaline cartilage
• 2 types:
  
  • synchondroses (hyaline cartilage)
  • symphyses (fibrocartilage)

Question 6

Synchondrosis

Answer 6

• connecting material is hyaline cartilage
• epiphyseal plate or joints between ribs and sternum
• immovable

Question 7

Symphysis

Answer 7

• fibrocartilage is connecting material
• can withstand more stress
• intervertebral discs and pubic symphysis
• slightly moveable

Question 8

Synovial Joints

Answer 8

• synovial cavity separates articulating bones
• freely moveable
• articular cartilage reduces friction and absorbs shock
• articular capsule (2 layers):
  
  • outer fibrous capsule
  • thickening in fibrous capsule called ligaments
• synovial membrane
  
  • inner lining of capsule
  • secretes synovial fluid
  • brings nutrients to articular cartilage

Question 9

Other Special Features of synovial joints

Answer 9

• accessory ligaments
  
  • extracapsular ligaments outside joint capsule
  • intracapsular ligaments within capsule
• articular discs or menisci
  
  • attached around edges of capsule
  • allow 2 bones of different shape to fit tightly together
  • increase stability of joint

Question 10

Bursae

Answer 10

• fluid-filled structures between structures
• some are extensions of the joint capsule
• reduce friction between moving structures
  
  • skin and bone
  • ligament and bone
  • tendon and bone

Question 11

Tendon Sheaths

Answer 11

• tube-like bursae that wrap around tendons at wrist and ankle where many tendons come together in a confined space
• reduce friction

Question 12

Gliding Movement

Answer 12

• bone surfaces are flat or slightly curved
• slide side to side
• rotation prevented by ligaments
• examples
  
  • intercarpal or intertarsal joints
  • sternoclavicular joint
  • vertebrocostal joint

Question 13

Angular Movement: Hinge Joint

Answer 13

• convex surface of one bone fits into concave surface of another
• knee, elbow, ankle
• movement produced:
  
  • flexion: decreasing joint angle
  • extension: increasing joint angle
  • hyperextension: opening joint past anatomical position

Question 14

Abduction

Answer 14

-moving laterally… away from medial plane

Question 15

Adduction

Answer 15

-moving medially toward middle

Question 16

Rotation

Answer 16

• bone revolves around its own longitudinal axis
• medial rotation is turning of anterior surface in towards the midline
• lateral rotation is turning of anterior surface away from midline

Question 17

Circumduction

Answer 17

• movement of a distal end of a body part in a circle

- combination of flexion, extension, adduction and abduction

Question 18

Movements of Mandible

Answer 18

• elevation: upward
• depression: downward
• protraction: forward
• retraction: backward

Question 19

Hand and Foot Movements

Answer 19

• inversion: curving ankle medially
• eversion: curving ankle laterally
• dorsiflexion: flexed foot
• plantarflextion: pointed foot
• pronation: inward rotation of hand
• supination: outward rotation of hand

Question 20

Glenohumeral (shoulder) joint

Answer 20

• articular capsule from glenoid cavity to anatomical neck of humerus
• many nearby bursa
• rotator cuff provides support without restricted movement
• tendons of infraspinatus muscle
• tendon of teres minor muscle
• tendon of subscapularis muscle
• tendon of supraspinatus muscle
• subacromial bursa
• subscapular bursa

Question 21

Supporting Structures at Shoulder

Answer 21

• associated ligaments strengthen joint capsule
• tendons of muscle attachment
• coracoacromial ligament
• coracohumeral ligament
• transverse numeral ligament
• glenohumeral ligament
• tendon of biceps brachii muscle

Question 22

Hip Joint

Answer 22

• head of femur and acetabulum of hip bone
• ball and socket synovial joint
• bony support restricts movement