Joints + Ligaments Flashcards
Classification of joints (3)
Fibrous, cartilaginous, synovial
Types of fibrous joints? (2)
Sutures
Syndesmoses
What are sutures? Where are they found?
Immovable fibrous joints (in adults) only found in the skull
Found where margins of skull bones meet (edge-edge or overlapping)
Sutural ligament?
zone of connective tissue connecting articulating bones
= remnants of mesenchyme sheet from skull ossification
Where are oesteogneic cells found? What do they do?
On sutural surfaces
Capable of laying down bone
What are fontanelles?
Gaps between bones at birth (before bone has grown together)
what is synostosis?
When sutural ligament → bone (by osteogenic cells when growth at the suture is complete)
Suture is obliterated (at 30yrs+)
what are syndesmoses?
Closely opposed bony surfaces bound together by fibrous tissue
Allows small about of movement
Types of cartilaginous joints (2)
Primary cartilaginous joints = synchondroses
Secondary cartilaginous joints = symphyses
What are synchondroses?
TEMPORARY joints (allow GROWTH in bones, NOT MOVEMENT) Obliterated by ossification of cartilage
What are symphyses?
Joint where bones are covered by hyaline cartilage + held together by a plate of fibrocartilage
What is a fibrous capsule? Function?
Fibrous bag around a synovial joint
Stops bones slipping apart and dislocating
Mechanisms to reduce friction in synovial joints? (4)
Articular cartilage
Synovial fluid
Synovial membrane
Intra-articular structures
Simple synovial joint?
Between 2 bones (2 articulating surfaces)
Compound synovial joint?
Between more than one articulating surface
More than one mating pair is formed - each sticking to their own partners
Complex synovial joint?
When an intra-articular disc is present in the joint cavity (intervening between the articulating surfaces)
Axes for joint movement (3)
Anteroposterior axis = from front to back through articular end of bone
Transverse axis = from side to side through articular end of bone
Vertical axis = passing vertically down from the articular end
UNIAXIAL JOINTS?
= can rotate around one axis (posses one degree of freedom)
BIAXIAL JOINTS?
= can rotate around two axes (posses two degrees of freedom)
MULTIAXIAL JOINTS
= can rotate in all three axes (+ permit rotation around axes in intermediate positions between the 3 major planes) (three degrees of freedom)
Plane Joints
Between relatively flat articular surfaces
Movement due to one bone sliding over its partner
Hinge Joints
Uniaxial joints resembling hinges of a door
Joint capsule = thickened on each side (provides a collateral ligament)
Pivot Joints
Bony pivot surrounded by an osteoligamentous ring (made of bone and fibrous tissue)
Uniaxial (restricted to rotation around a longitudinal axis passing down centre of pivot)
Condylar Joints
Limit movement largely to 1 axis (but allow small degree of movement to an axis at the other right angle)
Two distinct convex male surfaces articulating with 2 concave female surfaces
Ellipsoid Joints
Have an oval convex male surface received by an elliptical concave female surface
Biaxial (movement in two planes at right angles to each other)
Saddle(Sellar) Joints
Biaxial
Articulating surfaces are concavo-convex
Surfaces maximally convex in one plane + maximally convex in the plane at right angles to it)
Ball + Socket Joints
Formed when globular male head is received into a cup-like female concavity of another bone
Close packing postion?
Where two synovial articular surfaces perfectly fit together = close-packed position
Loose packed position?
Where synovial articular surfaces are NOT perfectly fitted together
Blood supply for joints?
periarticular arterial plexuses
Synovial joint innervation?
Innervated by the nerves which supply the muscles acting on the joint
