Unit 8: Key terms
Joints (Articulations)
functional junctions between bones, bind parts of the skeletal system together, permit parts of the skeleton to change shape during childbirth, enable the body to move in response to skeletal muscle contractions
Structural classification of joints
1. fibrous 2. cartilaginous 3. synovial
Functional Classification of joints
1. synarthrotic 2. amphiarthortic 3. diarthortic
Synarthrotic
immovable
Amphiarthrotic
slightly movable
Diathrotic
freely movable
Fibrous Joints
are held together with dense connective tissue containing many collagen fibers found in bone in close contact
3 types of fibrous joints
1. Syndesmosis 2. Suture 3. Gomphosis
Syndesmosis
bones bound by a sheet of dense connective tissue or a bundle of dense connective tissue, amphiarthortic (flexible, may twist), lies between tibia and fibula
Suture
between flat bones of the skull, a thin layer of connective tissue (sutural ligament) connects bones, synarthrotic (immovable)
Gomphosis
cone-shaped bony process in a socket in the jawbone, tooth in the jawbone by the periodontal ligament, synarthrotic (immovable)
Cartilaginous joints
connected by hyaline cartilage or fibrocartilage
2 types of cartilaginous joints
1. Sychondrosis 2. Symphsis
Synchondrosis
bonds of hyaline cartilage unite bones, between the manubrium and the first rib ( costal cartilage, permanent, synarthortic)
Symphysis
pad of fibrocartilage between bones, articular surfaces covered by hyaline cartilage, amphiarthrotic (limited movement), pubic symphysis, the joint between bodies of adjacent vertebrae (intervertebral discs)
Synovial Joints
most joints are synovial joints, all are diarthrotic joints (freely movable)
Structure of a synovial joint
articular cartilage over articular ends of bones, the joint capsule consists of 2 layers: 1. outer fibrous layer 2. inner layer
The outer fibrous layer of a synovial joint
composed of ligaments
The inner layer of a synovial joint
synovial membrane which secretes synovial fluid
Function of synovial joints
allow more mobility but less stability than other joint types
Ligament
strand of dense, regular collagenous connective tissue, links one bone to another, provides additional strength and reinforcement to joint
Tendon
structural component of skeletal muscle, dense regular connective tissue, connect muscle to bone
Bursa
synovial fluid-filled fibrous structure minimizes function between moving parts of joints
Tendon Sheath
long bursa, surrounds tendons, protects tendons as they slide across joint
Types of synovial joints
6 types, classified by shape and movements they allow
Types of synovial joints: Ball-and-socket Joint
round head in the cup-shaped cavity, the widest range of motion, multiaxial, plus rotation, hip and shoulder
Types of synovial joints: Condylar Joint
oval condyle fits into the elliptical cavity, back-and-forth, side to side movement, biaxial movement, no rotation, joints between metacarpals, and phalanges
Types of synovial joints: Plane Joint
also called a gliding joint, almost flat or slightly curved, back and forth and twisting, nonaxial movement, wrist and ankle joints
Types of synovial joints: Hinge Joint
conex surface fits into concave surface of other bone, uniaxial movement (in 1 plane), elbow, joints between phalanges
Types of synovial joints: Pivot Joint
cylindrical surface rotates within a ring of other bones, uniaxial movement, rotation only, atlas (C1) and dens of axis (C2)
Types of synovial joints: Saddle Joint
both bones have concave and convex surfaces, biaxial movement (in 2 planes), carpal and metacarpal of thumbs
Types of Joint Movements: Abduction
bringing body parts away from your midline
Types of Joint Movements: Adduction
bringing body parts closer to your body (adding)
Types of Joint Movements: Flexion
bringing one bone closer to the body (flexing)
Types of Joint Movements: Extension
moving one bone away from your body (extending)
Types of Joint Movements: Hypertension
going even further with bending
Types of Joint Movements: Lateral Flexion
taking your whole body and moving it laterally to the left or right
Types of Joint Movements: Dorsiflexion
reducing the angle, bringing your foot closer to you leg
Types of Joint Movements: Plantar Flexion
making the angle greater, pushing your foot away
Types of Joint Movements: Circumduction
wide range of movement moving your arm in a small circle
Types of Joint Movements: Rotation
moving your arm in a big circle
Types of Joint Movements: Medial Rotation
moving your arm to your midline across your body, inward
Types of Joint Movements: Lateral rotation
moving your arm laterally away from your body
Types of Joint Movements: Supination
arms out, palms facing upward (holding a bowl of soup)
Types of Joint Movements: Pronation
palms facing down (anatomical position)
Types of Joint Movements: Inversion
move your foot or ankle inward
Types of Joint Movements: Eversion
move your foot or ankle outward
Types of Joint Movements: Protraction
pushing your neck out
Types of Joint Movements: Retraction
retracting your neck back
Types of Joint Movements: Elevation
moving your shoulder up
Types of Joint Movements: Depression
moving your shoulder down