Joint and Muscle Structure Flashcards
Wolff law
-Bones will adapt based on stress or demands placed on them
-Tissue properties and joint shapes will change as a result of the demands on them
Structure types of joints
-Fibrous
-Cartilaginous
-Synovial
Joint movement types
- synarthrosis
-amphiarthrosis - Diarthrosis
Fibrous joint
-join together by fibrous interosseous connective tissue with little to no movement (synarthrosis)
Suture joint: bone edges interlock, one another. Example: frontal and parietal bones.
Gomphosis: Peg in hole joint, tooth in mandible
Syndesmosis: joined by interosseous ligament; radius and ulna
Cartilaginous joints
- Connected by fibrocartilage, or Highline cartilage; allows for some movement (amphiarthrosis)
Symphysis: directly joined by fibrocartilage and covered with hyaline ; intervertebral joints and pubic symphysis
Synchondrosis: connected by Highline cartilage; growth, plates, and ribs
Synovial joints
- no connective tissue; free to move (diarthrosis)
-Stabilization provided by capsule, ligaments, muscles
-Inner layer: provides lubrication and nutrition
-outer layer, dense a regular connective tissue, good innovation, proprioception
Type one joint receptor
Ruffini: senses stretch
-Located in fibrous layer of joint capsules
Type two joint receptors
Pacini: compression or changes in hydrostatic pressure of a joint
-Located throughout joint capsule and in deep layer of fat pads
Type Three joint receptors
Golgi pressure and forceful joint motion into extremes
-Inner layer of joint capsules, ligaments and tendons
Type four unmyelinated, free nerve endings
-Mechanical stress or biomechanical stress
-located around blood vessels, fat pads, collateral ligaments
Synovial fluid
-made up of hyaluronate (viscosity to fluid essential for lubrication within the synovial folds.)
-lubricin (cartilage on cartilage lubrication)
-Clear or pale yellow fluid
Uniaxial axial joints
Hinge joint: humeroulnar
Pivot joint: proximal radioulnar joint
Biaxial joints
Condyloid: radiocarpal joint
Saddle joint: 1st carpometacarpal joint
Triaxial joints
Plane joint: intercarpal joint
Ball-and-socket: hip joint
Osteokinematics
Movement of bones for physiological joint motion
-Described by plain of movement , axis of motion, and direction
Arthrokinematics
Movement of the joint surfaces
Roll: role of one joint surface on another (often occurs with slide)
Slide : linear translation on one or another (often occurs with role)
Spin: rotation
Concave moving on convex rule
Roll and glide occur in the same direction
Ex: Tibia moves on femur by rolling, anteriorly and sliding interiorly
Convex moving on concave rule
Roll and glide occur in opposite directions
-femur moving on tibia rolls posteriorly while sliding anteriorly
Close – packed joint play
- full congruence on surfaces
-Usually extreme range of motion
– Joint is compressed, while capsule and ligaments are taught
No distraction, no further movement available
– Tightest position
Loose – packed joint play
– Incongruent surface
– Usually mid position
– Ligaments and capsule laxity: distraction available
– Rest position
Soft end feel
Limited by soft tissues
Elbow flexion
Firm end feel
Limited by capsule/ligament structures
Knee extension
Hard end feel
Limited by bone
Elbow extension
Type one collagen
– Most tension
– Majority of collagen in body
Type two collagen
Compression
Hyaline cartilage
- type two cartilage
– Resist compressive forces from joint surfaces
– Avascular
Fibrocartilage
– Mostly type one
– Resist, compressive and tensile forces (meniscus and intervertebral discs
-Limited vascularity
Isotropic materials
Display same mechanical behaviors, no matter the direction of the force applied
-Glass cup
Anisotropic material
Behave differently, depending on the size and direction of the force
Example: iPad
Mechanical behaviors: toe region
Laxity in tissue begins to straighten
Mechanical behaviors: elastic region
Can return to original shape and size after being deformed
Mechanical behaviors: yield point
Following elastic region, the yield point signals, the point of no return for the tissue
Mechanical behaviors: plastic region
Residual deformations of the tissues will be permanent
Mechanical behaviors: failure point
Tear or break of tissues
Strain
Deformation in response to an externally applied load
(Final length – original length)/original length
Brittle
Little deformation required before failure
Ductile
Great deformation required before failure
Titin
Structural protein within the cycle that maintains position of myosin during muscle contraction
Pennation
Orientation of muscle fibers to tendon
Length tension relationship
Optimal circle length is 1.2x resting length
Active insufficiency: decreased force capability due to shorten state of agonist, and Lincoln state of antagonist
Reverse action
Proximal segment of body moves while the distal segment remains stationary
– Closed chain
Pathokinesiology of muscle: Immobilization in short position
– Decrease number of sarcomeres
– Increase sarcomere length, atrophy, and connective tissue
Pathokinesiology of muscle: immobilization in long position
– Long cast in knee extension
– increased number of sarcomeres
– Decreased sarcomere length
– Hypertrophy
