Principles of articulation Flashcards
(29 cards)
What is structural classification dependent on?
- Presence or absence of a synovial cavity and the type of connective tissue
- Described as either fibrous, cartilaginous or synovial
What is functional classification dependent on?
- Based on the degree of movement permitted:
synarthrosis (immovable), amphiarthrosis (partially moveable), diarthrosis (freely moveable)
Describe fibrous joints
structural and functional features, types
- no synovial cavity
- held together by a fibrous connective tissue
- permits little/no movement
- 3 types: suture, syndesmosis, interosseous membrane
Describe suture joints
(type of joint, location, structure, function)
What is a synastosis?
- Fibrous joint
- Unite skull bones
- Thin layer of dense connective tissue
- Irregular, interlocking edges provide strength but permit no movement
- Ossification of a suture
Describe syndesmosis joints
(type of joint, location, structure, function)
Give 2 examples
- Fibrous joints
- More CT than in suture
- Connective tissue typically arranged into bundles (ligament)
- Permit slight movement (amphiarthrosis)
- e.g. anterior tibiofibular ligament, gomphosis (or dentoalveolar)
Describe interosseous membrane joints
(type of joint, structure, function)
e.g.
- Fibrous
- Sheet of dense connective tissue
- Binds adjacent long bones
- Amphiarthrosis
Between radius and ulna, tibia and fibula
Describe cartilaginous joints
- No synovial cavity
- Held together by a fibrocartilage or hyaline cartilage
- Permits little/no movement
- Types: synchrondosis, symphysis
Describe syndchrondosis joints
(type of joint, structure, function, example)
What happens at skeletal development?
- Cartilaginous
- CT= Hyaline cartilage
- Synarthrosis
- Epiphyseal plate (at skeletal maturity, epiphysis, metaphysis and epiphyseal plate fuse forming a synostosis)
Describe symphysis joints
type of joint, structure, function, example
- Cartilaginous
- CT= fibrocartilage
- Adjacent bones lined with hyaline cartilage but with a broad disc of fibrocartilage connecting them
- Amphiarthrosis
- All occur in midline of body
1. junction of manubrium and sternum
2. invertebral discs
3. Pubic symphysis
Describe synovial joints
- Synovial joint cavity between articulating bones
- Freely moveable- diarthrosis
- Layer of hyaline cartilage called articular cartilage
Describe the articular cartilage found at synovial joints
Location
Vascular supply
Composition
- Covers the bones at synovial joints
- Avascular
- Composed of collagen and proteoglycan
- Orientation of collagen structure imparts resistance to compression and an extremely low resistance surface
Describe the articular capsule found at synovial joints
Location
Compostition
- Encapsulates synovial joint
Composed of 2 layers
1: outer fibrous membrane which connects to periosteum
- flexibility permits movement
- fibres arranged into bundles- high tensile strength
2: Inner layer (synovial membrane)
- areolar connective tissue rich in elastic fibres
- occasionally contains structural articular fat pads
Describe the synovial fluid found at synovial joints
Where does it come from?
Composition
Function
- Secreted by synovial membrane
- Rich in hyaluronic acid, secreted by fibroblast-like cells and interstitial fluid from plasma
- Lubricates articular surface - reducing friction
- Shock absorption
- Supplies nutrition and removes waste from avascular articular cartilage. Phagocytes remove microbes and debris
Describe the accessory ligaments found at synovial joints
INTRACAPSULAR LIGAMENTS
- excluded from synovial fluid by folds in synovial membrane
e. g. anterior and posterior cruciate ligaments
EXTRACAPSULAR LIGAMENTS
- fibular and tibial collateral ligaments of knee
Describe the accessory articular discs found at synovial joints
What are they?
Function?
Pathology?
- Fibrocartilage pads lie between articular cartilage of some synovial joints e.g. meniscus of knee
- Help maintain joint stability and direct flow of synovial fluid
- Meniscal tears (common in athletes)
Describe the nerve and blood supply of synovial joints
- Nerve endings same as those that supply associated muscles
- Distributed to the articular capsule and associated ligaments
- pain and proprioception
**Many compartments are avascular. Otherwide rely on numerous branching of arteries and veins to supply tissue
What type of joint have associated bursae?
What are they?
What is their function?
- Synovial joints
- Fluid filled sacs lined with synovial like membrane
- Cushion movement between body parts which otherwise cause friction
What type of joint have associated tendon sheaths?
What are they?
Where are they found?
- Synovial joints
- Specialised membranes that wrap around tendons. Especially where many tendons come together and/or pass through a synovial joint capsule
What types of synovial joints are there?
Planar, hinge, pivot, condyloid, saddle, ball and socket
PLANAR (Synovial) joints
Structure
Movement
Eg
- Surfaces flat or slight curved
- permit back and forth, side-to-side movement
- Intercarpal and intertarsale
HINGE (Synovial) joints
Structure
Movement
Eg
- Concave surface of one bone fits the convex surface of another
- motion in a single axis (flexion/extension)
- knee, elbow
PIVOT (Synovial) joints
Structure
Movement
Eg
- Rounded or pointed surface of one bone pivots inside a ring formed by the other bone and a ligament
- rotation in a longitudinal axis (monoaxial)
- radioulnar joints, atlanto-axial joint
CONDYLOID (Synovial) joints
Structure
Movement
Eg
- Convex oval projection of one bone fit into oval depression of the other
- biaxial (flex/extend AND ab/adduct)
- MCP, wrist
SADDLE (Synovial) joints
Structure
Movement
Eg
- One bone fits into the saddle shaped bone it opposes
- Biaxial (flex/extend AND ab/adduct) + sometimes limited rotation
- e.g. carpometacarpal joint of d1
