Introduction And Classification Of Joints Based On Structural Flashcards
What is a joint?
A connection between 2 or more bones
What are the primary functions of joints?
Movement and stability
Examples include movement of limbs and stability found in the bones of the skull.
What are the characteristics of fibrous joints?
Bone ends united by fibrous tissue, immovable, no joint cavity
List the subtypes of fibrous joints.
- Sutures
- Syndesmoses
- Gomphosis
What are sutures?
Immovable joints peculiar to the skull
Name the types of sutures based on the shape of bony margins.
- Serrate suture
- Denticulate suture
- Plane suture
- Squamous suture
- Wedge and Groove suture
What is the anterior fontanelle used for in infants?
To judge the hydration of the infant
What happens to fontanelles by 18 months?
They become bone
What are synostoses?
Fused skull bones in middle age
What characterizes syndesmoses?
Permits slight movement
Give an example of an interosseous membrane.
Between the tibia and fibula in the leg, or between radius and ulna in the forearm
What are gomphoses?
Immovable joints where a cone-shaped peg fits into a socket by fibrous tissue
What are the two types of cartilaginous joints?
- Synchondroses
- Symphyses
Describe primary cartilaginous joints (synchondroses).
Connecting tissue is hyaline cartilage, immovable and strong
Provide an example of a primary cartilaginous joint.
Epiphyseal (growth) plate
What defines secondary cartilaginous joints (symphyses)?
Slightly movable, ends covered with hyaline cartilage and united by a disc of fibrocartilage
List examples of secondary cartilaginous joints.
- Pubic symphysis
- Intervertebral joints
- Manubriosternal joint
What is a synovial joint?
A joint that allows for free movement
What is the function of the synovial cavity?
Allows a joint to be freely movable
What covers the articular surfaces in a synovial joint?
Articular cartilage
What is the composition of the articular capsule?
- Inner synovial membrane
- Outer fibrous capsule
What does the synovial membrane secrete?
Synovial fluid
What are the functions of synovial fluid?
- Reducing friction
- Absorbing shocks
- Supplying oxygen and nutrients
- Removing carbon dioxide and metabolic wastes
What are the classifications of synovial joints according to the number of articulating bones?
A. Simple - only 2 bones enter in articulation.
B. Complex - joint is divided into 2 compartments by articular disc or meniscus.
C. Compound - more than 2 bones enter in articulation.
What are the classifications of synovial joints according to the axis of movements?
A. UNIAXIAL - around one axis.
B. BIAXIAL - around two axes.
C. MULTIAXIAL - around three axes.
What are the types of synovial joints according to the shape of articulating surfaces?
Hinge joints, Pivot joints, Bicondylar joints, Ellipsoid joints, Saddle joints, Ball-and-socket joints, Plane joints.
What are the characteristics of hinge joints?
Articular surfaces are pulley-shaped.
Examples: elbow, ankle, interphalangeal joints.
UNIAXIAL – transverse axis.
Movements: Flexion, Extension.
What defines a pivot joint?
Rounded surface of bone articulates with the ring formed by the 2nd bone ligament.
Examples: proximal radioulnar joint, atlanto-axial joint.
UNIAXIAL - around vertical axis.
What are the characteristics of condylar joints?
Articular surfaces include two distinct condyles fitting into reciprocally concave surfaces.
Modified hinge joint.
Examples: knee joint, TMJ.
What defines an ellipsoid joint?
One articular surface is convex & elliptical, the other is concave & reciprocally curved.
Examples: Radiocarpal joint, Metacarpophalangeal joints.
Movements: Flexion, extension, adduction, abduction & circumduction.
What are the characteristics of saddle joints?
Articular surface of one bone is saddle-shaped, and the other fits into the saddle.
Examples: 1st carpometacarpal joint, Sternoclavicular joint.
Movements: Flexion, extension, adduction, abduction & circumduction.
What defines a ball-and-socket joint?
Articular surfaces include a globular head fitting into a cup-shaped socket.
Examples: Shoulder joint.
Multiaxial - around transverse, vertical & AP.
What are the characteristics of plane (gliding) joints?
Articular surfaces are more or less flat.
Examples: Intercarpal & Intertarsal joints, joints of articular processes of vertebrae.
