Types of Joints Flashcards
What is a joint?
Site where rigid elements of the skeleton meet
How are joints classified?
According to function or structure
What are the functional classifications of joints based on?
The amount of movement that the joint allows
What are the structural classifications of joints based on?
The material that binds the bones together and on the presence or absence of a joint cavity
What are the classifications of joints according to structure and function?
Refer to Lecture 8 - Types of Joints PPT
Functional Classification
Synarthroses
Immovable joints
Functional Classification
Amphiarthroses
Slight movable joints
Functional Classification
Diarthroses
Freely movable joints
Functional Classification
Where can Synarthoses, Amphiarthroses and Diarthroses be found?
Synarthroses and Amphiarthroses = Axial Skeleton
Diarthroses = Limbs
Structural Classification
What are fibrous joints?
Bones are connected by fibrous tissue
No joint cavity is present
Most fibrous joints are immovable
Structural Classification
Fibrous Joints
Characteristics of Sutures
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
Structural Classification
Fibrous Joints
Characteristics of Gomphoses
Conical process of one bone fits into the socket in another bone
Only example is tooth with its socket
Short periodontal ligament connects them
Structural Classification
Fibrous Joints
Characteristics of syndesmoses
Bones are connected by ligaments (bands of fibrous tissue)
Amount of movement depends on length of connecting fibers
Structural Classification
Fibrous Joints
Syndesmoses
How does the length of connecting fibers in syndesmoses affect the movement of bones?
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)
Structural Classification
What are cartilaginous joints?
The articulating bones are united by cartilage
Lack a joint cavity
Some are slightly movable
Structural Classification
Cartilaginous Joints
Primary Cartilaginous Joints
Hyaline cartilage unites the bones
Synarthroses (immovable)
E.g.: Epiphyseal plates, Joint between first rib’s costal cartilage and manubrium
Structural Classification
Cartilaginous Joints
Secondary Cartilaginous Joints
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
Structural Classifications
What are synovial joints?
Include most of the body’s joints
All are diarthroses (freely movable)
All contain fluid-filled joint cavity
Structural Classifications
Synovial Joints
Components of a Synovial Joint
Articular Cartilage
Joint/Synovial Cavity
Joint Capsule
Synovial Fluid
Ligaments
Structural Classifications
Synovial Joints
Functions of Articular Cartilage
Reduces friction
Absorbs shock
Structural Classifications
Synovial Joints
Characteristics of Joint Cavity
Potential space
Contains small amount of synovial fluid
Structural Classifications
Synovial Joints
Characteristics of Joint Capsule
Surrounds joint
Made from two layers: Outer Fibrous Capsule and Inner Synovial Membrane
Structural Classifications
Synovial Joints
Joint Capsule
What forms the Outer Fibrous Capsule?
Dense irregular connective tissue
Structural Classifications
Synovial Joints
Joint Capsule
Characteristics of the Inner Synovial Membrane
Formed from loose connective tissue
Lines fibrous capsule
It secretes synovial fluid
Structural Classifications
Synovial Joints
Characteristics of Synovial Fluid
Contains hyaluronic acid
Slippery
Cartilage’s nutrition
Structural Classifications
Synovial Joints
Characteristics of Ligaments
Strengthen the capsule
Includes Extra-Capsular Ligaments and Intra-Capsular Ligaments (cruciate ligaments)
Structural Classifications
Synovial Joints
How can joints be classified according to number of bones?
Simple - 2 bones e.g. shoulder joint
Compound - >2 bones e.g. knee
Complex - Articular disc between, e.g. temperomandibular joint
Structural Classification
Synovial Joints
How can joint be classified according to their axis of movement?
Uniaxial e.g., elbow joint
Biaxial e.g., wrist joint
Multiaxial e.g., hip joint
Structural Classifications
Synovial Joints
Axis of movement
What are the potential axes of movement?
Flexion and extension around the horizontal axis
Adduction and abduction around the antero-posterior axis
Medial and lateral rotation around the vertical axis
Structural Classifications
Synovial Joints
How can joints be classified according to their shape?
BISHEPP
Ball and socket synovial
Saddle synovial
Hinge synovial
Condyloid/Ellipsoid synovial
Plane synovial
Pivot synovial
Structural Classifications
Synovial Joints
Shape
Plane synovial joints
Bone surfaces are flat
Allow only gliding movements
E.g. Inter-carpal, inter-tarsal joints, vertebrocostal joints
Structural Classifications
Synovial Joints
Shape
Hinge synovial joints
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
Structural Classifications
Synovial Joints
Shape
Pivot synovial
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
Structural Classifications
Synovial Joints
Shape
Saddle synovial
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)
Structural Classifications
Synovial Joints
Shape
Condyloid/Ellipsoid synovial
Oval shaped projection fits into oval depression
It is biaxial
It allows adduction/abduction & flexion/extension
E.g. wrist
Structural Classifications
Synovial Joints
Shape
Ball and socket synovial
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
