classification of joints Flashcards
joint cavity
Space enclosed by the articular capsule of a synovial joint that is filled with synovial fluid and contains the articulating surfaces of the adjacent bones.
functional classifications
describe the degree of movement available between the bones, ranging from immobile, to slightly mobile, to freely moveable joints. The amount of movement available at a particular joint of the body is related to the functional requirements for that joint.
structural classification of joints
based on whether the articulating surfaces of the adjacent bones are directly connected by fibrous connective tissue or cartilage, or whether the articulating surfaces contact each other within a fluid-filled joint cavity.
3 structural classification
-fibrous joint
-cartilaginous joint
-synovial joint
fibrous
is where the adjacent bones are united by fibrous connective tissue
cartilaginous joint
bones are joined by hyaline cartilage or fibrocartilage.
synovial
the articulating surfaces of the bones are not directly connected, but instead come into contact with each other within a joint cavity that is filled with a lubricating fluid. Synovial joints allow for free movement between the bones and are the most common joints of the body.
3 functional classifications
-synarthrosis
- amphiarthrosis
- diarthrosis
synarthrosis
- immobile
- provides for a strong union between the articulating bones
- provide protection for internal organs
- examples: sutures, the fibrous joints between the bones of the skull that surround and protect the brain
amphiarthrosis
- limited mobility
- An example of this type of joint is the cartilaginous joint that unites the bodies of adjacent vertebrae. Filling the gap between the vertebrae is a thick pad of fibrocartilage called an intervertebral disc
diarthrtic
-mobile
These types of joints include all synovial joints of the body, which provide the majority of body movements. Most diarthrotic joints are found in the appendicular skeleton and thus give the limbs a wide range of motion.
multiaxal diarthrotic
- allows for movement along 3 axes
- shoulder and hip bone
- allow the upper or lower limb to move in an anterior-posterior direction and a medial-lateral direction
- limb can also be rotated around its long axis. This third movement results in rotation of the limb so that its anterior surface is moved either toward or away from the midline of the body
intervertebral disc
An intervertebral disc unites the bodies of adjacent vertebrae within the vertebral column. Each disc allows for limited movement between the vertebrae and thus functionally forms an amphiarthrosis type of joint. Intervertebral discs are made of fibrocartilage and thereby structurally form a symphysis type of cartilaginous joint.
three types of fibrous joints
- suture
- Syndesmosis
- Gomphosis
ligament
Strong connective tissue bands that hold the bones at a moveable joint together
suture
all bones in skull except for mandible are held together by suture fibrous joints
skull sutures are functionally classified as
synarthrosis
interosseous membrane
Wide sheet of fibrous connective tissue that fills the gap between two parallel bones, forming a syndesmosis; found between the radius and ulna of the forearm and between the tibia and fibula of the leg
syndesmosis purpose and mobility
- serves to unite parallel bones and prevent separation
- no movement between bones- amphiarthrosis
gomphosis
the specialized fibrous joint that anchors the root of a tooth into its bony socket within the maxillary bone (upper jaw) or mandible bone (lower jaw) of the skull
periodontal ligament
dense connective tissue between the bony walls of the socket and the root of the tooth
functional classification of gomphosis
synarthrosis- no mobility
cartilaginous joints
adjacent bones are united by cartilage, a tough but flexible type of connective tissue.
- lack a joint cavity, joined by hyaline cartilage or fibrocartilage
synchondrosis
- cartilaginous joints
- joined by hyaline cartilage
- Also classified as a synchondrosis are places where bone is united to a cartilage structure, such as between the anterior end of a rib and the costal cartilage of the thoracic cage
- hyaline cartilage: smooth and made of short collagen fibers embedded in a chondroitin sulfate ground substance.
symphysis
bones are joined by fibrocartilage
- fibrocartilage: made of thick bundles of collagen fibers embedded in chondroitin sulfate ground substance.
The hyaline cartilage of the epiphyseal plate (growth plate) forms:
a synchondrosis that unites the shaft (diaphysis) and end (epiphysis) of a long bone and allows the bone to grow in length.
The pubic portions of the right and left hip bones of the pelvis are joined together by:
fibrocartilage, forming the pubic symphysis.
what is a synchondrosis?
cartilaginous joint where bones are joined by hyaline cartilage.
- temporary or permanent
example of temporary synchondrosis
- epiphyseal plate (growth plate) of a growing long bone
- unites the diaphysis (shaft) and epiphysis (end of the bone)
how does epiphyseal plate contribute to bone growth
epiphyseal plate contains growing hyaline cartilage which gradually turns to bone, causing bone to lengthen
when does epiphyseal plate stop growing?
- stops growing in late teens to early 20s
- when cartilage stops growing, plate is replaced by bone, fusing diaphysis and epiphysis
why is epiphyseal plate considered a temporary synchondrosis
- eventually replaced by bone, lengthening stops once epiphyseal plate fuses
what is another example of temporary synchondrosis
unite the ilium, ischium, pubic portions of hip bone during growth are temporary. these fuse into a single adult hip bone once growth stops
permanent synchondrosis example
first sternocostal joint, where first rib is attached to the maubrium of the sternum by costal cartilage, and joints between ribs and their costal cartialge
what is symphysis
cartilaginous joint where bones are joined by fibrocartilage which is stronger than hyaline cartilage and allows for limited movemetn
why is fibrocartilage stronger than hyaline cartilage
contains thick collagen fibres, making is stronger and better able to resist pulling and bending forces
what is an example of a symphysis within a narrow gap
pubic symphysis, where pubic portions of the right and left hip bone and joined by fibrocartilage across a narrow gap
example of symphysis with a wider gap?
intervertebral symphysis, located between vertebrae in the spine, where a thick intervertebral disc unites the bones
what role does the intervertebral disc play?
cushions the vertebrae, allowing small movements and absorbing shock- important during high impact activities
how is symphysis classified functinonally
amphiarthrosis- limited movement
what is a synovial joint
- most common
- presence of a joint cavity
- allows for smooth and flexible movement
what key features distinguish synovial joints from fibrous and cartilaginous joints
- joint cavity
- fluid filled space where articulating surfaces of bones contact eacother
what is articular capsule
- is a fibrous connective tissue structure that forms the walls of the joint cavity and attaches to each bone just outside the articulating surface
function of articular cartilage is synovial joints
thin layer of hyaline cartilage, covers surfaces of bones, reduces friction and prevents bone damage during movement
what is synovial membrane
- lines inner surface of the articular capsule and secrets synovial fluid to lubricate the joint and nourish the articular capsule
role of synovial fluid
- lubricates joint
- reduces friction
- provides nourishment to articular cartilage, which lacks blood vessels
synovial joints functional classification
diarthrosis
how are bones connected at synovial joints?
connected by ligaments, strong bands of fibrous connective tissue that anchor the bones together and prevent separation
how do muscles and tendons contribute to joint support?
muscles and tendons act across joints to provide additional support.
- tendons attach muscles to bones and as forces on a joint increase, muscle contractions strengthen to help resist forces and stabilize joints
function of muscles acting as “dynamic ligaments”
- muscles can act as dynamic ligaments by increasing their contraction strength in response to higher forces on the joints
- offer additional support in joints like the shoulder where ligaments are weak
what is articular disk
- fibrocartilage structure between articulating bones
- unite bones
- shock absorption and cushion
- like ink needs meniscus
function of meniscus in knee joint
- provides shock absorption and cushioning between bones
- helps reduce wear and tear during movement
what is a bursa
A bursa is a thin connective tissue sac filled with lubricating fluid. It is located near joints, where skin, ligaments, muscles, or tendons can rub together, and reduces friction between these structures.
