Joint structure and function Flashcards
what are the solid joints
- fibrous joint
- cartilaginous joints
what are caveatted joints
- synovial joints
what are the two divisions of joints
- solid joints
- cavitated joints
what joints do not move very much
- solid joints do not move very much therefore this means fibrous and cartilaginous joints do not move very much
what skeleton are solid joints mainly in
axial
what skeleton are caveatted joints main in
appendicular
describe the structure of fibrous joints
- No synovial cavity
- Articulating bones held together by fibrous connective tissue
- Little or no movement
name some fibrous joints
- sutures
- synostosis
- syndesmosis
- gomphosis
what are sutures
- these are fibrous joints that are between the bones of the skull
what is a synostosis
- this is an ossified suture in the skull
- for example we actually have two frontal bones together and they fuse together to form a single frontal bone
- immovable
what is a syndemosis
- sheet of fibrous tissue between bones,
- it is the interosseous membrane
- it keeps the radius and the ulnar tethered and stops them separating as you move
what is a gomphosis joint
cone-shaped peg fits into a socket
- e.g. teeth this is held by the periodontal ligament
what happens in the skull of children
- sutures do not form straight away
- there is a fibrous tissue that connects the frontal bone
- anterior frontanal
what is the anterior frontanatal
- present in children
- opening in the skull
- stays open for about 18-24 months,
- then it becomes no longer papltable
- can be used to check intracranial pressure as it causes the anterior frontanatal to bulge
describe the structure of the cartilaginous joints
- No synovial cavity
- little or no movement, little more movement then the fibrous joints
- Articulating bones connected by cartilage either fibrous or hyaline cartilage
what is the symphysis connected by
fibrocartilage
what is the synchrondosis connected by
hyaline cartilage
name some cartilaginous joints
- symphysis
- synchrondosis
describe what the symphysis is between
- IV discs and pubic symphysis, this means that the pelvis is a bit more flexible at the front
describe what synchrondosis is between
- Epiphyseal growth plate and costochondral joints, it is also in the sternal, connects the ribs to the sternum which is hyaline cartilage
what can adapt and change
- the fibrocartilage joints is subjected to change
describe an example of the fibrocartilage joints adapting and changing
for example women who are about to give birth is that the pubic symphysis softens and becomes more flexible, this helps give a widened pelvic outlook during childbirth and prevents the pelvis from breaking
what are the layers of cartilage that surround the IV disc
fibrocartilage
describe the structure of synovial joints
- freely movable
- two bones capped with hyaline cartilage
- comes from endochondral ossification and this remains as the hyaline articulating cartilage
- fibrous capsule that acts as a water tight seal
- synovial membrane
what does the synovial membrane do
– produces the synovial fluid
- makes sure that the synovial fluid is the correct composition
what do the bursa do
- the bursa often interconnect with the joint capsule
- cushions and protections of the joint
how are the bursa used in the knee
- The knee has lots of bursa as it has lots of tendons that run from it and over it that need to be protected
- The joint capsule extends into the popliteal fossa
- Bursa is kept behind the quadriceps helps suspend and keeps bursa from dropping into the knee joint with gravity
what type of cartilage is articular cartilage in synovial joints
hyaline cartilage
describe the structure of articular cartilage
- Smooth, slippery and very low coefficient of friction
- Elastic, resilient structure that acts as a shock absorber to protect underlying bone
- Deeper layer merges via a calcified layer with the subchondral bone
describe the ECM of articular cartilage
- 80% water - this means that it can act as a shock absorber, when you squeeze the cartilage the water will come out and when you take the pressure off the water is attracted back into the cartilage due to the proteoglycans in the ECM
- Collagen type II – this gives it structure
- Proteoglycans – this act as the water attracting part of the ECM, and hold it into the cartilage giving gel like ECM
what do many synovial joints also contain
- they also contain accessory ligaments and articular discs
what do ligaments do
– Ligaments connect bone to bone
• Help to stabilise and hold joint together
what do articular discs do
– Articular discs modify shape of joint surfaces
• Help maintain stability of joint, and direct flow of synovial fluid to areas of greatest friction
what re the two layers of the articular capsule
- outer fibrous capsule
- inner synovial membrane
describe the structure fo the articular cartilage
- avascular therefore it relies on synovial fluid for its nutrition
what is the disease that causes the loss of articular cartilage
- Oesoarthritis – degeneration of articular cartilage
what are the types of synovial joints
plane pivot ball and socket condyloid hinge saddle
describe the movement and examples of planar joints
- side to side and back and forth gliding movements
- Example, intercarpals, intertarsals, facet joints of vertebral column
describe the movement and examples of hinge joints
convex surface of one bone fits into concave surface of another bone.
• Flexion and extension in a single plane
– Examples, elbow, knee
describe the movement and examples of pivot joints
• - round or pointed surface of one bone fits into a ring formed by another bone and a ligament
• Rotational movements
– Example, atlas rotating about the axis, radius in annular ligament of the ulna
describe the movement and examples of condylar joints
• oval shaped condyle of one bone fits into elliptical cavity of another bone
• Flexion-extension, abduction-adduction and circumduction
– Example, joint between carpals and radius
describe the movement and examples of saddle joints
one bone is saddle-shaped, the other is the rider
• Flexion-extension, abduction-adduction, and circumduction
– Example, carpometacarpal joint of thumb
describe the movement and examples of ball and socket joints
• - ball-shaped surface of one bone fits into cup-like depression of other
• Flexion-extension, abduction-adduction, rotation and circumduction
– Example, shoulder and hip joints
