Articulations

Question 1

Definition of Articulation

Answer 1

-Place of contact between bones, bone & cartilage or bones & teeth

Question 2

Classifications of Articulations

Answer 2

1. Structurally;
   a) Fibrous: bones held together by dense regular CT
   b) Cartilagenous: bones joint by cartilage
   c) Synovial: fluid - filled cavity that separates cartilage-covered articulating surfaces of bones
2. Functionally;
   a) Synarthrosis: immobile joint
   b) Amphiarthrosis: Slightly mobile joint
   c) Diarthrosis: freely mobile joint

Question 3

Tradeoff between Mobility & Joint stability

-5 articulations from most mobile to lease mobile

Answer 3

*mobility and stability are inversely related

Glenohumeral joint -> Hip joint -> Elbow joint -> Intevertebral joints -> Suture (skull)

Question 4

Name the 3 types of fibrous joints

Answer 4

• Gomphoses
• Sutures
• Syndesmoses

Question 5

Gomphoses, Sutures & syndesmoses

-General shape, where found and level of mobility

Answer 5

Gomphoses: resembles peg in socket
-only one= articulation of roots of teeth w/ mandible & maxillae (held in place by periodontal membrane)
Sutures: immobile fibrous joints (synarthrosis)
-only b/w certain bones of skull
-have distinct, interlocking usu. irregular edges that increase strength & decrease no. of fractures
Syndesmoses: Articulating bones joined by long strands of dense regular CT only
-amphiarthorsis (e.g. ulna & radius; tibia & fibia)

Question 6

Name the 2 types of cartilaginous Joints

Answer 6

1. Synchondroses

2. Symphyses

Question 7

Synchondroses & Symphyses;

-Mobility, function and examples

Answer 7

• Synchondroses: joined by hyaline cartilage
  
  • all synarthroses
  • e.g. attachment of first rib to sternum by coastal cartilage, constochondrial joints (boints b/w bony ribs and coastal cartilage), spheno - occipital synchondrosis found b/w body of sphenoid & basilar part of occipital bone
• Symphyses: pad of fibrocartilage b/w articulating bones
  
  • resists compression & stresses
  • acts as shock absorber
  • amphiarthrosis
  • e.g. pubic symphsis

Question 8

Synovial Joints

Answer 8

• Are freely movable articulations that are separated by a space called the joint cavity (only type of articulation w/ it)
• Includes most commonly known joints (e.g. knee, elbow, glenohumeral)
• ARE ALL DIARTHROSIS

Question 9

Classification of Synovial joints (based on surfaces & types of movement they allow)

Answer 9

• Uniaxial: Bone moves in just one plane or axis
• Biaxial: Bone moves in 2 planes/axes
• Multiaxial: Bone moves in multiple planes/axes

Question 10

Name the 6 types of Synovial joints (least to most mobile)

Answer 10

1. Plane joint
2. Hinge joint
3. Pivot joint
4. Condyle joint
5. Saddle joint
6. Ball & socket joint

Question 11

Plane Joint

Answer 11

AKA planar or gliding joint

• simplest type
• only allows side to side movement
• articulates surfaces of bones that are flat or planar

e.g. Intercarpal and intertarsal joints

Question 12

Hinge Joint

Answer 12

• uniaxial
• convex surfaces of one bone fits into concave depression of other
• single axis

e.g. elbow joint (trochlea notch of ulna fits into troclea of humerous), knee & finger [interphalageal joint]

Question 13

Pivot Joint

Answer 13

• uniaxial
• 1 articulating bone w/ rounded surface fits into ring formed by ligament and another bone

e.g. proximal radionuclear joint, atlantoaxial joint

Question 14

Condyle Joint

Answer 14

AKA condyloid or ellipsoid
-biaxial w/ oval, convex surface on one bone concave on 2nd bone

e.g. metacarpphalngeal joints of fingers 2 to 5 (aka knucles

Question 15

Saddle joint

Answer 15

-convex & concav regions on articulate surfaces of bones (e.g. carpometacarple joint of thumb)

Question 16

Ball & socket Joint

Answer 16

• multiaxial joint
• spherical head of 1 fits into rounded, cuplike socket of other

e.g. hip joint and glenohumeral bone

Question 17

Name the 4 types of movements at Synovial Joints

Answer 17

1. Gliding motion
2. Angular Motion
3. Rotational Motion
4. Special movements

Question 18

Gliding motion

Answer 18

• 2 opposing surfaces slide slightly back and forth or side-to-side
• angle between bones doesn’t change
• typically occur along plane joints

Question 19

Anglular Motion (7 associated terms)

Answer 19

• either increases or decreases angles between 2 joints
• flexion: decrease angle (anterior-posterior plane)
• extension: increase angle (AP plane)
• hyperextension: extension of joint >180 degrees
• lateral flexion: trunk of body moves in coronal plane laterally
• abduction: Move away - body part moves away from trunk of body
• adduction: move towards - body part moves toward body midline
• circumduction: proximal end remains stationary while distal end makes circular motion

Question 20

Rotational motion

Answer 20

• pivoting motion in which bone turns on its own longitudinal axix
  e. g. atlantoaxial joint
• pronation: medial rotation of forearm so palm of hand is directed posteriorly or inferiorly
• superination: forearm rotates laterally so palm faces anteriorly and radius parallel w/ ulna

Question 21

Special movements

Answer 21

• Things that don’t fit into other categories

- e.g. elevation/depression, dorsiflexion & planatar flexion, protraction & retraction & opposition