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Flashcards in Joints Deck (23):
1

joints

sites of union b/n bones or bodies of cartilage

consist of tissues which unite bones & cartilages at these sites

2

articular surfaces of a joint

surface areas of the apposing structures (generally)

3

fibrous joints

united by fibrous (connective) tissue

ex. distal tibiofibular joint of leg, joints b/n flat bones of skull (suture joints)

4

cartilagenous joints

bones are united by cartilage

2 classes: primary & secondary

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primary cartilagenous joints (synchondroses)

apposing bones are joined by hyaline cartilage

ex. growth plates of growing long bones, union of first rib w/ manubrium of sternum

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secondary cartilagenous joints

articular surfaces of bones covered by thin layers of hyaline cartilage, & hyaline cartilage plates are united by a layer of fibrocartilage

ex. manubriosternal joint, pubic symphysis, intervertebral discs

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fibrocartilage

contains a very high concentration of collagen protein fibers in its matrix

dif type of collagen than that found in matrix of hyaline cartilage

8

synovial joints

artiuclation in which articular surfaces of bones are separated by a membrane-bound, fluid filled cavity

provide greatest degree of movement b/n bones at expense of stability of joint

degree of movement is inversely proportional to its stability

9

articular cartilage

thin layer of hyaline cartilage that covers articular surfaces of bones in a synovial joint

10

synovial membrane

lines fluid-filled cavity between synovial joints, except where the cavity is bored by articular cartilage

11

synovial fluid

fluid secreted by the highly vascular synovial membrane of a synovial joint

rich in hyaluronic acid

has consistency of thick machine oil

functions as an excellent lubricant b/n bones

12

fibrous capsule

dense, fibrous connective tissue that encloses an entire synovial joint

13

articular disc (structure)

piece of fibrocartilage interposed like a shelf or pad b/n articulating surfaces of a synovial joint

around its circumference, anchored to the fibrous capsule of the joint

14

menisci

articular disc of a synovial joint that's incomplete & crescent shaped

ex. knee joint

15

functions of articular discs & menisci

shock absorption

assistance in providing more even distribution of weight & synovial fluid

improvement of the fit of articular surfaces

16

plane joints

type of synovial joint

apposed articular surfaces are flat or almost flat & the boens slide on one another

ex. sternoclavicular & acromioclavicular joints

17

hinge joints

type of synovial joint

resemble the hinge on a door

articular surfaces are molded to each othe rin such a way to allow movement in one plane (uniaxial)

allow flexion & extension

ex. elbow, knee, ankle, & interphalangeal joints

18

pivot joints

type of synovial joint

movement occurs around one axis (uniaxial)

a central bony pivot is surrounded by a ligamentous ring & rotation is the only movement possible

movement occurs as the pivot turns within the ring, or as the ring turns around the pivot, around the longitudinal axis

ex. atlantoaxial & proximal & distal radioulnar joints

19

condylar (ellipsoid) joints

type of synovial joint

biaxial joints that allow movement around 2 principla axies which are at right angles to each other

an elliptical convex articular surface fits into an elliptical concave aritcular surface

the movements of flexion-extension, abduction-adduction take place

a combination of these movements allows circumduction around a third axis, but rotation around the third axis is not possible b/c of the ellipsoid shape of the bones

ex. radiocarpal (wrist) & metacarpophalangeal (knuckle) joints

20

saddle joint

type of synovial joint

biaxial b/c two principal axes of movement

articular surfaces are saddle-shaped

movements include flexion-extension, abduction-adduction, & circumduction (same as condylar)

modest amount of axial rotation is seen as well

ex. carpometacarpal joint of thumb

21

ball & socket joints

type of synovial joints

ball-shaped head of one bone fits into the socket-like concavity of another

arrangement permits maximum degree of all movement (flexion-extension, abduction-adduction, circumduction, & rotation

greater depth of socket = more stable joint = more limited movement

ex. shoulder & hip joints

22

3 main factors that determine stability of a joint

shape of articular surfaces (ex. hip)

ligaments (ex. knee)

tone of muscles around the joint (ex. shoulder)

23

innervation of synovial joints

Hilton's law: the nerve supplying a joint also supplies the muscles that act across the joint & the skin covering the articular insertions of these muscles

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