Lecture 6 - Joints Flashcards
functions of joint
- > give skeleton mobility
- > holds skeleton together
classification of articulations
- > functional (what does it do?)
- > structural (what is it made of)
functional classification of joints
- > synarthroses (immovable)
- > amphiarthroses (slightly movable)
- > diarthroses (freely movable, to an extent)
structural classification of joints
- > fibrous joints
- > cartilaginous joints
- > synovial joints
types of fibrous joints
- > sutures
- > syndemoses
- > gomphoses
characteristics of sutures
- > rigid, immovable, interlocking joints
- > in middle age, sutures ossify and fuse (synostoses)
characteristics of syndemoses
- > a joint held together by a ligament
- > fibre length varies therefore so does movement
characteristics of gomphoses
- > fibrous connection (periodontal ligament) which holds the tooth in the socket
types of cartilaginous joints
- > synchondroses
- > symphyses
characteristics of cartilaginous joints
- > bones united by joints
- > no joint cavity
- > partially movable
what is a synchondroses joint
an immovable joint which unites bones with hyaline cartilage
ie. growth plate
what is a symphyses joint
a slightly movable joint made of fibrocartilage which connects bone to bone
ie. intervertebral disks
characteristics of synovial joints
- > freely movable
- > connection between two bones separated by a fluid-filed joint cavity
- > include all limb joints; most joints in the body
What are the 6 feature of synovial joints
- articular cartilage: hyaline cartilage (prevents friction)
- joint cavity (filled with synovial fluid)
- Articular capsule (2 layers)
- Synovial fluid
- different types of reinforcing ligaments (3)
- nerve and blood vessels
what are the two layers of the articular capsule?
- > External fibrous layer (dense connective tissue)
- > Internal synovial membrane (loose connective tissue which makes synovial fluid)
What is synovial fluid
- > made of plasma and hyaluronic acid
- > it lubricates and nourishes articular cartilage
- > contains phagocytic cells to remove debris
- > in the joint cavity
what are the different reinforcing ligaments of a synovial joint
capsular - > thickened layer of fibrous layer
extracapsular - > outside the capsule
intracapsular- > deep to capsule; covered by synovial menbrane
what does it mean to be double jointed
when your ligaments and joint capsules are loose and/or stretchy
Which structures do only some synovial joint have
- > fatty pads
- > articular discs
What is the function of fatty pads?
They’re for cushioning between fibrous layer and synovial membrane or bone ie. hip/knee
What are articular discs
also known as menisci
they’re fibrocartilage which separates articular surfaces to improve “fit” of bone, stabilize joint and reduce wear and tear
What structures are associated with synovial joints but aren’t apart of the joint itself
- > bursae
- > tendon sheaths
What are bursae
they’re sacs lined with a synovial membrane and filled with synovial fluid which help reduce friction at the joint
what are tendon sheaths
a layer of synovial membrane (elongated bursa) which wrap around tendon to reduce friction
what are the three stabilizing factors of synovial joints
- > shapes of articular surfaces (minor role)
- > ligaments number and location (limited role)
- > muscle tendons that cross joints (most important)
origin vs insertion
origin - > portion of the muscle attached to immovable . bone (superior end of bicep)
insertion - > portion of muscle attached to movable bone (inferior end of bicep)
What are gliding movements
when one flat bone surface glides and slips over another
ie. carpal bones
List all the types of angular motions of joints and how they move
- > flexion (muscle shortens)
- > extension (lengthens)
- > hyperextension (too far)
- > Abduction (limb away from body)
- > adduction (limb towards body)
- > circumduction (circle)
What is hyperextension
excessive extension beyond normal range of motion
List all the types of rotations of joints and how they move
- > internal rotation (towards body)
- > external rotation (away body)
ie rotation of humerus and femur (must be bent)
List all the types of special motions of joints and how they move
- > pronation (palm back) and supination (palm forward)
- > dorsiflexion (foot-shin) and plantar flexion (point)
- > inversion (roll ankle) and eversion (break ankle)
- > protraction (sick out) and retraction (retract)
- > elevation (up) and depression (down)
- > opposition (ballgaze)
What are the different shapes of synovial joints?
- > plane joints
- > hinge joints
- > saddle joints
- > ball-and-socket joint
- > condylar joint (ball and socket but more oval; restricted)
- > pivot joint
