Types of Joints

Question 1

What is a joint?

Answer 1

Site where rigid elements of the skeleton meet

Question 2

How are joints classified?

Answer 2

According to function or structure

Question 3

What are the functional classifications of joints based on?

Answer 3

The amount of movement that the joint allows

Question 4

What are the structural classifications of joints based on?

Answer 4

The material that binds the bones together and on the presence or absence of a joint cavity

Question 5

What are the classifications of joints according to structure and function?

Answer 5

Refer to Lecture 8 - Types of Joints PPT

Question 6

Functional Classification
Synarthroses

Answer 6

Immovable joints

Question 7

Functional Classification
Amphiarthroses

Answer 7

Slight movable joints

Question 8

Functional Classification
Diarthroses

Answer 8

Freely movable joints

Question 9

Functional Classification
Where can Synarthoses, Amphiarthroses and Diarthroses be found?

Answer 9

Synarthroses and Amphiarthroses = Axial Skeleton
Diarthroses = Limbs

Question 10

Structural Classification
What are fibrous joints?

Answer 10

Bones are connected by fibrous tissue
No joint cavity is present
Most fibrous joints are immovable

Question 11

Structural Classification
Fibrous Joints
Characteristics of Sutures

Answer 11

Bones are tightly bound by a minimal amount of fibrous tissue
Edges of the joining bones are wavy and interlocking
Occur only between bones of the skull

Question 12

Structural Classification
Fibrous Joints
Characteristics of Gomphoses

Answer 12

Conical process of one bone fits into the socket in another bone
Only example is tooth with its socket
Short periodontal ligament connects them

Question 13

Structural Classification
Fibrous Joints
Characteristics of syndesmoses

Answer 13

Bones are connected by ligaments (bands of fibrous tissue)
Amount of movement depends on length of connecting fibers

Question 14

Structural Classification
Fibrous Joints
Syndesmoses
How does the length of connecting fibers in syndesmoses affect the movement of bones?

Answer 14

Short Ligament = No movement. E.g.: Distal Tibio–Fibular Joint
Long Ligament = Large amount of movement. E.g.: Middle Radio–Ulnar Joint (Interosseous Membrane between radius and ulna)

Question 15

Structural Classification
What are cartilaginous joints?

Answer 15

The articulating bones are united by cartilage
Lack a joint cavity
Some are slightly movable

Question 16

Structural Classification
Cartilaginous Joints
Primary Cartilaginous Joints

Answer 16

Hyaline cartilage unites the bones
Synarthroses (immovable)
E.g.: Epiphyseal plates, Joint between first rib’s costal cartilage and manubrium

Question 17

Structural Classification
Cartilaginous Joints
Secondary Cartilaginous Joints

Answer 17

Fibrocartilage unites the bones
Slightly movable
Shock absorber
Provide strength and flexibility
Hyaline cartilage on articular surfaces of bones to reduce friction
E.g.: Intervertebral Discs and Pubic Symphysis

Question 18

Structural Classifications
What are synovial joints?

Answer 18

Include most of the body’s joints
All are diarthroses (freely movable)
All contain fluid-filled joint cavity

Question 19

Structural Classifications
Synovial Joints
Components of a Synovial Joint

Answer 19

Articular Cartilage
Joint/Synovial Cavity
Joint Capsule
Synovial Fluid
Ligaments

Question 20

Structural Classifications
Synovial Joints
Functions of Articular Cartilage

Answer 20

Reduces friction
Absorbs shock

Question 21

Structural Classifications
Synovial Joints
Characteristics of Joint Cavity

Answer 21

Potential space
Contains small amount of synovial fluid

Question 22

Structural Classifications
Synovial Joints
Characteristics of Joint Capsule

Answer 22

Surrounds joint
Made from two layers: Outer Fibrous Capsule and Inner Synovial Membrane

Question 23

Structural Classifications
Synovial Joints
Joint Capsule
What forms the Outer Fibrous Capsule?

Answer 23

Dense irregular connective tissue

Question 24

Structural Classifications
Synovial Joints
Joint Capsule
Characteristics of the Inner Synovial Membrane

Answer 24

Formed from loose connective tissue
Lines fibrous capsule
It secretes synovial fluid

Question 25

**Structural Classifications** **Synovial Joints** Characteristics of Synovial Fluid

Answer 25

Contains hyaluronic acid Slippery Cartilage’s nutrition

Question 26

**Structural Classifications** **Synovial Joints** Characteristics of Ligaments

Answer 26

Strengthen the capsule Includes *Extra-Capsular Ligaments* and *Intra-Capsular Ligaments (cruciate ligaments)*

Question 27

**Structural Classifications** **Synovial Joints** How can joints be classified according to number of bones?

Answer 27

**Simple** - 2 bones e.g. shoulder joint **Compound** - >2 bones e.g. knee **Complex** - Articular disc between, e.g. temperomandibular joint

Question 28

**Structural Classification** **Synovial Joints** How can joint be classified according to their axis of movement?

Answer 28

**Uniaxial** e.g., elbow joint **Biaxial** e.g., wrist joint **Multiaxial** e.g., hip joint

Question 29

**Structural Classifications** **Synovial Joints** Axis of movement *What are the potential axes of movement?*

Answer 29

**Flexion and extension** around the horizontal axis **Adduction and abduction** around the antero-posterior axis **Medial and lateral rotation** around the vertical axis

Question 30

**Structural Classifications** **Synovial Joints** How can joints be classified according to their shape?

Answer 30

**BISHEPP** Ball and socket synovial Saddle synovial Hinge synovial Condyloid/Ellipsoid synovial Plane synovial Pivot synovial

Question 31

**Structural Classifications** **Synovial Joints** Shape *Plane synovial joints*

Answer 31

Bone surfaces are flat Allow only gliding movements E.g. Inter-carpal, inter-tarsal joints, vertebrocostal joints

Question 32

**Structural Classifications** **Synovial Joints** Shape *Hinge synovial joints*

Answer 32

Convex cylindrical surface of one bone fits into concave surface of 2nd bone It allows flexion/extension movement It is uniaxial E.g. elbow joint

Question 33

**Structural Classifications** **Synovial Joints** Shape *Pivot synovial*

Answer 33

Rounded surface of bone rotates within ring formed by 2nd bone & ligament It allows rotation movement It is uniaxial E.g. proximal radio-ulnar joint, atlanto-axial joint

Question 34

**Structural Classifications** **Synovial Joints** Shape *Saddle synovial*

Answer 34

One bone saddle shaped, other bone fits in reciprocally It is biaxial It allows adduction/abduction & flexion/extension E.g. Trapezium and metacarpal bone of thumb (first carpo-metacarpal joint)

Question 35

**Structural Classifications** **Synovial Joints** Shape *Condyloid/Ellipsoid synovial*

Answer 35

Oval shaped projection fits into oval depression It is biaxial It allows adduction/abduction & flexion/extension E.g. wrist

Question 36

**Structural Classifications** **Synovial Joints** Shape *Ball and socket synovial*

Answer 36

Ball fitting into a cup like depression It is multi–axial It allows adduction/abduction & flexion/extension and medial/lateral rotation E.g. shoulder and hip joints