Lecture: Chapter 08 Flashcards
JOINTS
a.k.a. “Articulations;” where two or more bones meet.
FUNCTIONS:
1) Give the skeleton mobility
2) Hold bones together, sometimes playing a protective role in the process
CLASSIFICATION OF JOINTS
classified by STRUCTURE & FUNCTION
STRUCTURAL CLASSIFICATIONS
1) Fibrous joints
2) Cartilaginous joints
3) Synovial joints
FUNCTIONAL CLASSIFICATIONS
1) Synarthroses - immovable joints (axial)
2) Amphiarthroses - slightly moveable joints (axial)
3) Diarthroses - freely moveable joints (mostly appendicular)
-FIBROUS JOINTS-
Joined by fibrous tissue; no joint cavity. Three types: sutures, syndesmoses, gomphoses.
SUTURES
fibrous joint
only in SKULL; Function: absorb mechanical stress; Major skull sutures: Coronal (frontal/parietal), Sagittal (both parietals), Squamous (temporal/parietal), Lambdoid (occipital/parietal)
SYNDESMOSES
fibrous joint
bones connected by a ligament; i.e. tibia and fibula
GOMPHOSES
fibrous joint
peg-in-socket; i.e. tooth in jaw
-CARTILAGINOUS JOINTS-
Bones joined by cartilage; TWO types: 1) Synchondroses, 2) Symphyses
SYNCHONDROSES
cartilaginous joint
hyaline cartilage joins the bones; e.g. coastal cartilage of the first ribs and sternum
SYMPHYSES
cartilaginous joint
fibrocartilage plate between bones; e.g. pubic symphysis & intervertebral joints
-SYNOVIAL JOINTS-
Bones are separated by fluid-filled cavity; diarthroses (freely moveable); Most joints, especially in limbs.
EXAMPLES OF SYNOVIAL JOINTS
1) Shoulder (clavicle, scapula): ball-in-socket, multiaxial plane
2) Hip (ilium, ischium, pubis): ball-in-socket, multiaxial
3) Elbow (humerus, radius, ulna) hinged
4) Thumb: saddle joint; biaxial.
BURSAE
little lubricating sacs that also act as shock absorbers; reduce friction between structures (bone & tendon, tendon & tendon etc.)
TENDON SHEATH
basically a long bursa that wraps around a tendon
MOVEMENTS OF SYNOVIAL JOINTS
All muscles are attached to bones in at least two places. The ORIGIN is more proximal; the INSERTION is more distal and across a joint. When a muscle contracts, it pulls the insertion toward the origin to move the bone.
GLIDING MOVEMENT
a.k.a. “Translation;” bone surfaces slide past one another; e.g. between rows of carpal (wrist) bones.
-ANGULAR MOVEMENTS-
changes the angle between two bones; (different types listed on following cards)
FLEXION
bending usually in sagittal plane (going forward - touching toes); * decreasing angle between bones; chin to chest
EXTENSION
opposite of flexion; straightening (rather than bending)
DORSIFLEXION
of foot
toes bend toward shin