Joints I Flashcards
Joint/Articulation
site of contact between bones or between cartilage and bone (bones/joints develop from the same embryonic tissue)
Surfaces of the bone covering the joint is …
articular surfaces, the covering articular cartilage
Role of Joints
to allow movement amongst rigid bones, however not all joints allow movement - e.g. sutures in the skull and temporary joints
Temporary Joint - 4 points
designed to allow growth of bone, found in immature bones with bony epiphysis and a bony diaphysis - epiphyseal plate/growth plate, not designed for movement, eventually obliterated by ossification of growth plate
2 categories for classifying joints
Function and Structure
Function category - 3 types based on the degree of movement
synarthroses, amphiarthroses and diarthroses
synarthroses
immoveable
amphiarthroses
slightly moveable
diarthroses
freely moveable
Structure category - 3 types based on presence/absence of a joint cavity & type of connective tissue
Fibrous, cartilaginous and synovial
Define a fibrous joint
bones connected by fibrous tissue with no joint cavity
Define a cartilaginous joint
bones connected by cartilage with no joint cavity
Define a synovial joint
bones not connected, form joints and have a joint cavity
3 types of fibrous joint
Sutures, Syndesmoses and Gomphoses
Describe sutures - 6 points
connected by fibrous tissue, found only in the skull, bones of the skull vault bound tightly with fibrous tissue = sutural ligaments - this immobility is important to give protection to brain/special sense organs, found where the margins of the bone meet, sutural surfaces = designed to interlock
serrated
saw-like (sutures)
denticulate
tooth-like (sutures)
Describe sutures in a foetus/young child - 3 points
bones of cranial vault have not yet met so there are gaps covered only by fibrous tissue = fontanelles - allow for further growth in size of the brain, when growth is complete the sutural ligament is replaced with bone (late 20s) = synostosis
Describe Syndesmoses - 3 points
held together by fibrous connective tissue but not as firmly as sutures, only 1 true syndesmoses - between the distal ends of the tibia & fibula = inferior tibiofibular joint, permits some movement but no true movement, superior tibiofibular joint and the radius & ulna joints are joined by sheet of fibrous tissue (interosseous membrane) which have much larger fibres and so aren’t true syndesmoses
Describe Gomphosis - 2 points
specialised fibrous joints between teeth and supporting bones of the jaw, tooth root anchored to bony walls of socket by thin fibrous membrane = periodontal membrane
3 types of cartilaginous joints
Primary cartilaginous joints, secondary cartilaginous joints and synovial
Describe primary cartilaginous joints (synchondroses) - 2 points
held together by a plate of hyaline cartilage, mostly temporary joints - allows for growth (e.g. between epiphyses and diaphyses of long bone) and for growth of skull base until about 25 yrs
Example of a primary cartilaginous joint
Between ribs and costal cartilages - cost-chondral joints
Describe secondary cartilaginous joints (symphyses) - 5 points
have articular surfaces and bones are covered by hyaline cartilage, bones held together by plate of fibro-cartilage, allows slight movement, not all are permanent joints, the 2 halves of the mandible are joined by symphyseal joint in midline - united after 1st year of life