Orthopedic Assessment Exam 1
What are the 2 types of motion? - ANSWER Translational (linear)
Angular (rotary)
What is an axis of motion? - ANSWER an imaginary line around which the body segment rotates
Why is the talocrural axis not a completely horizontal axis? - ANSWER the medical surface is smaller
which creates a cone shape making it an oblique axis
What is a moment arm? - ANSWER the perpendicular distance from the line of force action to the
axis of rotation
How do you calculate the moment arm? - ANSWER force x perpendicular distance
What is dynamic joint stability - ANSWER the generation of muscle tension required to counteract
external moments acting on joints
What is the difference between joint rotation and joint stabilization? - ANSWER - joint rotation:
direction of the pull must be more perpendicular to the bone
- joint stabilization: direction of pull must be more parallel to the bone
What are the three actions in joint kinematics? - ANSWER - spin: backward sliding offers forward
rolling
- roll: no sliding in opposite direction
- glide: linear movement across surface
Why must there be balance in joint kinematics? - ANSWER - balance between roll and glide will help
avoid dislocation
- balanced muscle contractions on both sides will stabilize the joint movement
What are synovial joints? - ANSWER articulating bones separated by a joint cavity that contains fluid
,What 4 things do freely movable diarthroses include? - ANSWER - synovial fluid: lubricates the joint
inside the capsule
- articular capsule: multiple layers that surrounds the synovial joint to any shape needed
- reinforcing ligaments: they hold the bones of the joint together while also setting limits on joint
movement
- articular cartilage: covers the articulating surface to minimize friction and absorb shock
What is a bursa? - ANSWER a fibrous, flattened sac filled with synovial fluid
What is the purpose of a bursa? - ANSWER to reduce friction in a joint
What is a tendon sheath? - ANSWER elongated bursa that wraps completely around a tendon
What 4 things determine stability in a synovial joint? - ANSWER - articular surfaces: determines
possible movements
- ligaments: restrains excessive/abnormal motion
- musculotendinous units spanning joints: creates muscle tension
- sub-atmospheric pressure: creates the vacuum
What are proteins? - ANSWER macromolecules composed of combinations of 20 types of amino acids
bound together with peptide bonds
What are the different types of protein structures? - ANSWER - strand
- helix (double or triple)
- sheet
What is an example of a triple-helix protein molecule? - ANSWER collagen
What is connective tissue made up of? - ANSWER - fibers: collagen and elastic
- flattened cells: fibroblasts
- Ground substance: matrix
, What is ground substance (matrix) made out of? - ANSWER - hyaluronate: makes tissue stronger and
lubricates
- proteoglycans: is the protein core
- water: mixes with hyaluronate to create mucus
What is the structure of collagen synthesis? - ANSWER - pro collagen: formed with fibroblast
- collagen molecule: triple helix of coiled polypeptide chains
What is made with hyaluronate and proteoglycans? - ANSWER Glycos-amino-glycANSWER (GAGs)
What are the branches in proteoglycans? - ANSWER sulfated muccopolysacchrides with negative
charges
What are the main parts of the knee meniscus? - ANSWER - hyaluronate
- proteoglycANSWER
- collagen
- elastin
- water
What is the composition percentages of the meniscus? - ANSWER - 26% weight solids
- 74% weight fluid
- less water will mean a smaller meniscus
What are the 3 functions of ligaments? - ANSWER - maintenance of joint stability
- guidance of joint motion
- mechanoreceptor afference (tells the CNS how much load is on the ligament)
What is the difference in structure between ligaments and tendons? - ANSWER - ligaments: nearly
parallel bundles
- tendons: completely parallel bundles
What are the 2 types of motion? - ANSWER Translational (linear)
Angular (rotary)
What is an axis of motion? - ANSWER an imaginary line around which the body segment rotates
Why is the talocrural axis not a completely horizontal axis? - ANSWER the medical surface is smaller
which creates a cone shape making it an oblique axis
What is a moment arm? - ANSWER the perpendicular distance from the line of force action to the
axis of rotation
How do you calculate the moment arm? - ANSWER force x perpendicular distance
What is dynamic joint stability - ANSWER the generation of muscle tension required to counteract
external moments acting on joints
What is the difference between joint rotation and joint stabilization? - ANSWER - joint rotation:
direction of the pull must be more perpendicular to the bone
- joint stabilization: direction of pull must be more parallel to the bone
What are the three actions in joint kinematics? - ANSWER - spin: backward sliding offers forward
rolling
- roll: no sliding in opposite direction
- glide: linear movement across surface
Why must there be balance in joint kinematics? - ANSWER - balance between roll and glide will help
avoid dislocation
- balanced muscle contractions on both sides will stabilize the joint movement
What are synovial joints? - ANSWER articulating bones separated by a joint cavity that contains fluid
,What 4 things do freely movable diarthroses include? - ANSWER - synovial fluid: lubricates the joint
inside the capsule
- articular capsule: multiple layers that surrounds the synovial joint to any shape needed
- reinforcing ligaments: they hold the bones of the joint together while also setting limits on joint
movement
- articular cartilage: covers the articulating surface to minimize friction and absorb shock
What is a bursa? - ANSWER a fibrous, flattened sac filled with synovial fluid
What is the purpose of a bursa? - ANSWER to reduce friction in a joint
What is a tendon sheath? - ANSWER elongated bursa that wraps completely around a tendon
What 4 things determine stability in a synovial joint? - ANSWER - articular surfaces: determines
possible movements
- ligaments: restrains excessive/abnormal motion
- musculotendinous units spanning joints: creates muscle tension
- sub-atmospheric pressure: creates the vacuum
What are proteins? - ANSWER macromolecules composed of combinations of 20 types of amino acids
bound together with peptide bonds
What are the different types of protein structures? - ANSWER - strand
- helix (double or triple)
- sheet
What is an example of a triple-helix protein molecule? - ANSWER collagen
What is connective tissue made up of? - ANSWER - fibers: collagen and elastic
- flattened cells: fibroblasts
- Ground substance: matrix
, What is ground substance (matrix) made out of? - ANSWER - hyaluronate: makes tissue stronger and
lubricates
- proteoglycans: is the protein core
- water: mixes with hyaluronate to create mucus
What is the structure of collagen synthesis? - ANSWER - pro collagen: formed with fibroblast
- collagen molecule: triple helix of coiled polypeptide chains
What is made with hyaluronate and proteoglycans? - ANSWER Glycos-amino-glycANSWER (GAGs)
What are the branches in proteoglycans? - ANSWER sulfated muccopolysacchrides with negative
charges
What are the main parts of the knee meniscus? - ANSWER - hyaluronate
- proteoglycANSWER
- collagen
- elastin
- water
What is the composition percentages of the meniscus? - ANSWER - 26% weight solids
- 74% weight fluid
- less water will mean a smaller meniscus
What are the 3 functions of ligaments? - ANSWER - maintenance of joint stability
- guidance of joint motion
- mechanoreceptor afference (tells the CNS how much load is on the ligament)
What is the difference in structure between ligaments and tendons? - ANSWER - ligaments: nearly
parallel bundles
- tendons: completely parallel bundles
