Chapter 9: Joints Flashcards
An articulation or arthosis
A joint; a point of contact between two bones; between bones and cartilage or between bone and teeth
This classification of joints is based on
1) the presence or absence of a space between the articulating joints called a synovial cavity and
2) the type of connective tissue that binds the bones together
Structural Classification of joints
Three structural classifications of joints:
- fibrous joints
- cartilaginous joints
- synovial joints
In this structural classification of joints, there is no synovial cavity, and the bones are held together by dense irregular connective tissue that is rich in collagen fibrers
Fibrous joints
This structural classification of joints there is no synovial cavity and the bones are held together by cartilage
Cartilaginous joints
In this structural classification of joints, the bones forming the joint have a synovial cavity and are united by the dense irregular connective tissue of an articular capsule and often by accessory ligaments
Synovial joint
Functional classifications of joints
- syntharthrosis
- Amphiarthrosis
- Diarthrosis
A syntharthosis joint
Immovable
An ampiarthrosis joint
a slightly movable joint
A diarthrosis joint
a freely moveable joint
What funcational classification of a joint is ALWAYS also a synovial joint?
a diarthrosis joint
What are the three types of fibrous joints?
Synarthosis
- Sutures
- Syndesmoses
- Interosseus joints
Sutures
Amphiarthrosis in infancy, synathrosis later on
Name for a suture that later becomes a bone in adulthood
Synostosis
A joint where there is more cartilage between the bones than a suture joint; usually cartilage is arranged as a bundle (ligament)
syndesmosis
Interosseous joint (fibrous joint)
between two bone s- tibia an dfibula and ulna and radius
Three types of cartilaginous joints
- synchondoses
- sympheses
- epiphyseal cartilages
This type of cartilaginous joint is one in which the connecting material is hyaline cartilage and is slightly movable to immovable (eg rib to manubrium)
Synchondrosish
This cartilaginous joint is a one in which the ends of articulating bones are covered with a hyaline cartilage, but a broad, flat disc of fibrocartilage connects the bones
Sympheses
_between manubrium and body; between symphisis pubis halves; interveertbral joints between bodies of vertebrae
The epiphyseal cartilages are hyaline cartilage growth centres and not movable joints. It eventually hardeds to form what kind of bony joint?
syntostosis
Synovial joints have what unique, distinguishing feature?
synovial cavity
What functional class are all synovial joints?
Diarthroses
What is the hyaline cartilage called that is covering the bones at a synovial joint?
Articular cartilage
What are the functions of articular cartilage in a synovial joint?
Reduce friction between bones and help absorb shock
What is the sleeve like capsule that surrounds a synovial joint?
Articular caspule or joint capsule
What are the two layers of the articular capsule called?
- Synovial membrane
- fibrous membrane
The outer layer of an articular capsule usually consists of dense irregular connective tissue (motstly collagen fibres) that attach tot he periosteum of the articulating bones and is called:
fibrous membrane
The inner layer of an articular capsule?
The synovial membrane
This membrane i s a thickened continuation of periosteom
Fibrous membrane
These fiber bundles are parallel bundles of dense regular connective tissue and are highly adapted to resist strains
Ligaments
What structure is a principle mechanical factor that holds bones together at the synovial joint?
ligaments
What is the synovial membrane composed of?
areolar connective tissue with elastic fibres
What are the accumulations of adipose tisue found in synovial membranes at joints?
articular fat pads
This is a viscous, clear or pale yellow fluid secreted by synovial membrane cells
synovial fluids
What does the synovial fluids consist of?
hyaluronic acid from synovial cells and interstitial fluid from blood plasma
Functions of synovial fluid?
= reduce friction
- absorb shock
- supply o2 and nutrients and remove CO2 and waste from chondrocytes in articular cartilage
What immune system does synovial fluid contain?
phagocytic cells
What are extracasular and intracapsular ligaments called?
accessory ligaments
Intracapsular ligaments
inside caspule by excluded from synovial cavity by folds in synovial membrane
eg. PCL and ACL
Extracapsular ligaments
outside the capsule
eg., tibia and fibula ligaments of the knee
What are articular discs or menisci?
Cresecent shaped pads of fibrocartilage that lie between the articular surfaces of the bone and are attached to the fibrous caspule
subdivide the synovial cavity into two spaces, allowing seperate movements in each space
eg. lateral and medial menisci
Functions of the menisci?
-shock absorption
-a better fit between articulating surfaces
-,adaptable surfaces for combined movements
-weight distributions
- distribution of synovial fluid actoss the articular surfaces of the joint
A fibrocartilaginous lip that extends from the edge of the joint socket; [prominent in the ball and socket joints of shoulder and hip
Helps deepernt he socket and increase area of contact between ball and socket
labrum
What do the nerves that supply the joint also suply?
The muscles that move that joint
Where are nerve endings distribute din the joint?
in the articular capsule and associated ligaments
What do the joint nerves send info about?
- pain
- degree of movement and stretch at a joint
Tube like bursae that wrap around certain tendons that experience considerable friction as they pass thorugh tunnels formed by connective tissue and bone
tendon or synovial sheaths
Inner layer of the tendon or synnovial sheath?
Visceral layer, attached to surface of the tendon
Outer layer of the tendon or synovial sheath?
Pariental layer; attached to bone
What is found between the visceral and parietal layers of the tendon sheeth>
A cavity containing a film of synovial fluid
What does a tendon sheath do?
Protects all sides of a tendon with back and forth movement
What is a saclike structure that is strategically situatied to allieviate friction in some kjoints?
bursae
Bursae walls consist of?
An oiuter fibrous membrane of thin, dense connective tissue lined by a synovial membrane. Filled with a small amount fluid
WHat are bursae located between?
skin and bone, tendons and bones, muscles and bones or ligaments and bones
Four main categories of movements at synovial joints
- gliding
- angular movements
- Rotation
- Speciial
The movement of relatively flat bone surfaces back and forth and side to side over one another; little change in angle between bones
Gliding movement
An increase or decrease in angle between bones
Angular movement
Types of angular movements:
flexion
lateral flexion
extension
hyperextension
abduction
adduction
circumduction
Movement of bone around longitudinal axis; in limbs may be meidal (toward midline) or lateral (away from midline)
Rotation
Movements that occur at specific joints
Special movements
This is the superior movement of a body part
elevation
This is the inferior movement of a body part
depression
this is the anterior movement of a body part in transverse plane
protraction
this is the posterior movemennt of a body part in transverse plane
retraction
The medial movement of sole
inversion
the lateral movement of sole
eversion
bending foot in the direction of dorsum (superior surface) (ankle joint)
dorsiflection
Bending the foot in the direction of the plantar surface (sole)
planter flexion
Movement of forearm that turns palm anteriorly
supination
movement of forearm that turns palms posteriorly
pronation
Movement of thumb across palm to touch fingertips on same hand
opposition
Angular
decrease in angle between articulating bones, usually in sagittal plane
flexion
increase in angle between articulating bones, usually in sagittal plane
extension
movement of trunk in frontal plane
lateral flexion
extension beyond anatomical position
hyperextension
movement of bone away from midline, usually in frontal plane
abduction
movement of bone towards midlines, usually in frontal plane
adduction
flexion, abduction, extension, adduction and rotation in succession; distal end of body part moves in circles
circumduction
6 categories of synovial joints
- plane joints
- hinge joints
- pivot joints
- condyloid joints
- saddle joints
- ball and socket joints
This type of synovial joint is flat or slightly curved, permits back and forth movement between surfaces of flat bone, may also rotate against each other
Biaxial if back and forrth movement
triaxial if rotational movement also permitted
Plane joint
This joint is uniaxial and one bone is typically fixed while the other bone moces around it
hinge joint
Uniaxial joint that allows rotation only and involves the rounded or pointed surface of one bone articulated iwth a ring formed partly by another bone
Pivot joints
eg. atlanto-axial joint
This biaxial joint sees the convex oval-shaped projection of one bone fit into the oval-shaped depression of another bone; it allows biaxial movement (flex/extens & abd/adduct & limited circumduction)
Condyloid joints
eg. wrist and metacar
This joint sees the articular surface of one bone being saddle shaper and the articular surface of the other bone fits into the saddle
Biaxial
Saddle joint
This triaxial joint consists of a ball like surface of one bone fitting into the cuplike depression of the other bone
ball and socket joint
