Articulations Flashcards
Definition of Articulation
-Place of contact between bones, bone & cartilage or bones & teeth
Classifications of Articulations
- Structurally;
a) Fibrous: bones held together by dense regular CT
b) Cartilagenous: bones joint by cartilage
c) Synovial: fluid - filled cavity that separates cartilage-covered articulating surfaces of bones - Functionally;
a) Synarthrosis: immobile joint
b) Amphiarthrosis: Slightly mobile joint
c) Diarthrosis: freely mobile joint
Tradeoff between Mobility & Joint stability
-5 articulations from most mobile to lease mobile
*mobility and stability are inversely related
Glenohumeral joint -> Hip joint -> Elbow joint -> Intevertebral joints -> Suture (skull)
Name the 3 types of fibrous joints
- Gomphoses
- Sutures
- Syndesmoses
Gomphoses, Sutures & syndesmoses
-General shape, where found and level of mobility
Gomphoses: resembles peg in socket
-only one= articulation of roots of teeth w/ mandible & maxillae (held in place by periodontal membrane)
Sutures: immobile fibrous joints (synarthrosis)
-only b/w certain bones of skull
-have distinct, interlocking usu. irregular edges that increase strength & decrease no. of fractures
Syndesmoses: Articulating bones joined by long strands of dense regular CT only
-amphiarthorsis (e.g. ulna & radius; tibia & fibia)
Name the 2 types of cartilaginous Joints
- Synchondroses
2. Symphyses
Synchondroses & Symphyses;
-Mobility, function and examples
- Synchondroses: joined by hyaline cartilage
- all synarthroses
- e.g. attachment of first rib to sternum by coastal cartilage, constochondrial joints (boints b/w bony ribs and coastal cartilage), spheno - occipital synchondrosis found b/w body of sphenoid & basilar part of occipital bone
- Symphyses: pad of fibrocartilage b/w articulating bones
- resists compression & stresses
- acts as shock absorber
- amphiarthrosis
- e.g. pubic symphsis
Synovial Joints
- Are freely movable articulations that are separated by a space called the joint cavity (only type of articulation w/ it)
- Includes most commonly known joints (e.g. knee, elbow, glenohumeral)
- ARE ALL DIARTHROSIS
Classification of Synovial joints (based on surfaces & types of movement they allow)
- Uniaxial: Bone moves in just one plane or axis
- Biaxial: Bone moves in 2 planes/axes
- Multiaxial: Bone moves in multiple planes/axes
Name the 6 types of Synovial joints (least to most mobile)
- Plane joint
- Hinge joint
- Pivot joint
- Condyle joint
- Saddle joint
- Ball & socket joint
Plane Joint
AKA planar or gliding joint
- simplest type
- only allows side to side movement
- articulates surfaces of bones that are flat or planar
e.g. Intercarpal and intertarsal joints
Hinge Joint
- uniaxial
- convex surfaces of one bone fits into concave depression of other
- single axis
e.g. elbow joint (trochlea notch of ulna fits into troclea of humerous), knee & finger [interphalageal joint]
Pivot Joint
- uniaxial
- 1 articulating bone w/ rounded surface fits into ring formed by ligament and another bone
e.g. proximal radionuclear joint, atlantoaxial joint
Condyle Joint
AKA condyloid or ellipsoid
-biaxial w/ oval, convex surface on one bone concave on 2nd bone
e.g. metacarpphalngeal joints of fingers 2 to 5 (aka knucles
Saddle joint
-convex & concav regions on articulate surfaces of bones (e.g. carpometacarple joint of thumb)
Ball & socket Joint
- multiaxial joint
- spherical head of 1 fits into rounded, cuplike socket of other
e.g. hip joint and glenohumeral bone
Name the 4 types of movements at Synovial Joints
- Gliding motion
- Angular Motion
- Rotational Motion
- Special movements
Gliding motion
- 2 opposing surfaces slide slightly back and forth or side-to-side
- angle between bones doesn’t change
- typically occur along plane joints
Anglular Motion (7 associated terms)
- either increases or decreases angles between 2 joints
- flexion: decrease angle (anterior-posterior plane)
- extension: increase angle (AP plane)
- hyperextension: extension of joint >180 degrees
- lateral flexion: trunk of body moves in coronal plane laterally
- abduction: Move away - body part moves away from trunk of body
- adduction: move towards - body part moves toward body midline
- circumduction: proximal end remains stationary while distal end makes circular motion
Rotational motion
- pivoting motion in which bone turns on its own longitudinal axix
e. g. atlantoaxial joint - pronation: medial rotation of forearm so palm of hand is directed posteriorly or inferiorly
- superination: forearm rotates laterally so palm faces anteriorly and radius parallel w/ ulna
Special movements
- Things that don’t fit into other categories
- e.g. elevation/depression, dorsiflexion & planatar flexion, protraction & retraction & opposition
