UNIT 2 - Articulations Flashcards
Joint (articulation)
point of contact between two bones, between bone and cartilage, or between bone and teeth
-movement is not necessary
Functional Classification of joints
based on type of movement (degree) they allow
-further subdivided on basis of anatomical structure of the joint or range of motion permitted
synarthrosis
immovable joint; fibrous or cartilaginous depending on the nature of the connection, over time they might fuse
amphiarthrosis
slightly movable
fibrous or cartilagenous depending on the nature of the connection of the opposing bones
diarthrosis
freely movable joint
(cavity between bones surrounded by capsule, all of these joints are SYNOVIAL JOINTS, are subdivided into the amount or range of motion permitted)
Structural Classification
based on anatomical characteristics of two criteria
1. presences or absence of a space between the articulating bones
2. type of CT that binds the bones together
BONY FUSION, FIBROUS JOINTS, CARTILAGENOUS JOINGS, SYNOVIAL JOINTS
FB JOINT: SUTURE
unites bones of the skull
- irregular interlocking edges of sutures provide added strength and decreases the chance of fracture
FB JOINT: SYNDESMOSIS
- there is greater distance between the articulating bones and more fibrous CT
- Fibrous CT arranged either as a bundle (ligament) or as a sheet (interosseous membrane)
FB JOINT: GOMPHOSES
cone shaped peg fits into a socket
ex: roots of teeth with sockets of alveolar processes of maxillae and mandible
Fibrous Joints
- held together by fibrous CT rich in collagen fibers
- lack synovial cavity
- permit little or no movement
Cartilaginous Joints
- bones held together by cartilage
- lack synovial cavity
CG JOINT: Synchondroses
- rigid cartilaginous joints in which the connecting material is hyaline cartilage
(ex: epiphyseal plate, joint between first rib and manubrium of sternum)
CG JOINT: Symphysis
ends of articulating bones are covered with hyaline cartilage, but the bones are connected by a broad, flat disc of fibrocartilage
(all occur @ midline of the body)
Synovial Joints
- have synovial cavity
- united by dense irregular CT of an articular capsule and also by accessory ligaments
- shapes of articulating surfaces vary
- divided into 6 types:
1. Planar
2. Hinge
3. Pivot
4. Condyloid
5. Ball
6. Socket
meniscus
pad of fibrocartilage between opposing bones within a synovial joint
fat pads
localized masses of adipose tissue covered by a layer of synovial membrane
ligmanets
capsule that surrounds the entire joint is continuous with the periostea of the articulating bones
gliding motion
movement of relatively flat bone surfaces band and forth and from side to side over one another
angular
increase or decrease in angle between bones
flexion
decrease in angel between articulating bones (usually in sagittal plan/ anterior-posterior plane)
lateral flexion
movement of trunk in frontal plane
extension
increase in angel between articulating bones
*exept for ankle joint, extension returns you to anatomical position
hyperextension
extension beyond anatomical position
abduction
movement of a bone away from the midline
spreading fingers
adduction
movement of bone toward midline
cirumduction
flexion, abduction, extension, and adduction in succession, in which the distal end of a body part moves in a circle
rotation
movement of a bone around its longitudinal axis
- in limbs may be medial or lateral
- pivot and ball and socket joints permit rotation
elevation
superior movement of a body part
depression
inferior movement of a body part
protraction
anterior movement of a body part in transverse plane
retraction
posterior movement of a body in transverse plane
inversion
medial movement of the soles so that they face eachother
eversion
later movement of the soles so that they face away from each other
dorsiflexion
bending the food in the direction of the dorsum
plantar flexion
being the food in the direction of the sole (tiptoe)
supination
movement of the forearm that turns the palm anteriorly or superiorly
pronation
movement of the forearm that turns the palm posteriorly or inferiorly from anterior
opposition
movement of the thumb across the palm to touch fingertips on the same hand (allows us to grasp and hold objects between our thumb and palm)
gliding joint
articulating surfaces are flat or slightly curved
- permit side to side and back and forth movement
