Arthrology Flashcards
What is archeology?
study of joints structure and function
What are articulations?
joints
Where do arrticulations occur?
where two or more bones meet
where bone meets cartilage
when bone meets tooth
How are joints classified?
structurally
functionally
How are joints structurally classified?
Presence of a cavity - some joints have articulating structures in contact with one another, others have a space between the articulating structures (synovial cavity)
Connective tissue - may be composed of collagenous fibrous tissue, cartilage, ligament or dense irregular tissue
What are the categories used when classifying structurally ?
Synovial joints – identified by a cavity
Fibrous joints – identified by connective tissue type
Cartilaginous joints - identified by connective tissue type
How are joints functionally classified?
degree of movement (not movement type)
What are the three categories used to functionally classify?
a) Synarthroses Immovable
b) Amphiarthroses Slightly moveable
c) Diarthroses
Freely moveable (Only synovial joints)
What are fibrous joints?
Held together by fibrous / collagenous connective tissue
• No synovial cavity
• Three subdivisions :-
-Sutures (seams)
-Syndesmoses (band)
-Gomphoses (bolt)
• Subdivisions due to different structures being involved in forming an articulation / differing degrees of movement possible
What are sutures?
- present in the skull
- thin layers of fibrous tissue connecting plates of bone
- immovable
- Irregular in shape
- become ossified in adult animals leading to fusion of the associated bones
What are syndesmoses?
-thicker bands of fibrous tissue
-Articulating bones greater distance apart
-allow a slight degree of movement
E.g. interosseous membrane between the large metacarpal and small metacarpal bones of the horses’ distal thoracic limb
What is gomphoses?
- dentoalveloar joints
- roots of teeth and the alveolar processes of the maxilla and mandible
- immovable
What are cartilaginous joints?
• Lacking a synovial cavity
• Held together by cartilage
• Two subdivisions of cartilaginous joints:-
Synchondroses
Symphyses
Difference between the two subdivisions:
• Type of cartilage that unites the articulation – (hyaline or fibrocartilage)
• Degree of movement that is possible between the articulating structures (none or slight)
What are synchondroses?
Articulations united by hyaline cartilage
• Immovable
• Epiphyseal plates are main example - plates of hyaline cartilage connecting the diaphysis (long middle section) and epiphysis (short end sections) of long bones
• Ossify when growth ceases
• Joint is then referred to as a synostosis (joint united by
bone).
What are symphyses?
Articulations involving hyaline and fibrocartilage
Slightly moveable
Ends of the bones are covered in hyaline cartilage
Flat disc of fibrocartilage unites the articulating structures
Located along the midline of the body
Examples include intervertebral joints and the pubic symphysis
What are synovial joints?
Articulations where there is a synovial cavity
Held together by an articular capsule composed of dense irregular connective tissue and ligaments
All similar in structure
Classified as diarthroses
How are synovial joints classified?
type
movement they allow
What are the six subdivisions of synovial joints?
arthrodial trochoid ellipsoid sellaris spheroid ginglymus
What are the key structures found within synovial joints?
synovial cavity
synovial fluid
articular capsule
articular cartilage
What is the synovial cavity?
space located between the articulating bones of a synovial joint
purpose is to enable the joint to be freely moveable
What is synovial fluid?
Normal synovial fluid is viscous and clear/pale yellow in colour
Composed of hyaluronic acid secreted by the synovial membrane
Plus interstitial fluid filtered from blood plasma
What is synovial fluid?
Fills the synovial cavity and has three main purposes;
- Lubricates the joint and reduces friction
- Maintains the ‘health’ of the chondrocytes (cells of cartilage) within the articular cartilage by supplying nutrients / removing waste products
- Contains phagocytes which to maintain joint health by removing foreign bodies
Viscosity varies with exercise (sticky to watery)
Volume present within joint varies with joint size and activity (up to 40 cm3)