Terminology
Kinematics vs Kinetics
Kinematics: describes how an object moves
Kinetics: study of forces that cause or influence movement of the body (why on object moves)
Explain the difference between a synergist and neutralizer muscle and give one example of each
Synergist: work together to perform a particular muscle action
Neutralizer: prevent unwanted movement that can do 2 or more action
ball and socket
What is the long shaft located in the middle of the long bone called?
Diaphysis
Which lever has an axis of rotation (fulcrum) between the internal and external moment arm
first class lever
Osteokinematics vs. Arthrokinematics
Osteokinematics: movement of bones around a joint (flexion, extension, abduction, adduction, internal/external rotation, etc.)
Arthrokinematics: movement between the joint surfaces (roll, slide, spin)
What is a force couple?
Force couple action is when two or more muscles produce forces in different linear directions but produces torque in the same rotary direction
What type of synovial joint is the radiocarpal joint?
What is the highly vascular component of bone that tendons attach to?
Periosteum
Which lever has a longer external moment arm than internal moment arm?
3rd class lever
Describe what a moment arm is?
Shortest perpendicular distance between line of action of force and axis of rotation
What is the correct order in terms of size?
Sarcomere, myofilament, myofibril, muscle fiber, muscle, muscle fascicle
Muscle (largest)
fascicle: bundle of muscle fibers
Muscle fiber: single muscle cell (multiple nuclei) containing myofibrils
Myofibrils: contains repeat sarcomeres
Sarcomere: contractile unit of muscle fiber
Myofilament: protein fibers inside muscle cells that generate force (actin: thin; myosin: thick)
What are the 3 joint classifications and describe them
Synarthrosis: junction between bones allowing little to no movement (sutures of the skull)
Amphiarthrosis: formed primarily by fibrocartilage and hyaline cartilage, allowing limited amounts of motion and provide shock absorption (intervertebral joint, pubic symphysis)
Diarthrosis (synovial joint): articulation contains a fluid filled joint cavity between two or more bones. (tibiofemoral, glenohumeral, most joints...)
What is the medullary cavity and its function?
Hollow space inside the diaphysis of a long bone. Contains bone marrow and is a passageway for nutrient carry arteries.
Plantar flexion is an example of what kind of lever
2nd class lever
What is translation in kinematics, and what are its two type?
translation: linear motion in which all points of a body move the same distance in the same direction
Rectilinear translation: movement in a straight line
curvilinear translation: movement along a curved path
What is the length-tension relationship (in explanation, explain at which point is active tension the highest or lowest)
Length-tension relationship is the connection between the length of the muscle and the amount of force (tension) it can produce.
The lowest amount of active tension is at very short or very long muscle lengths (very short: due to too much overlap, resulting in fewer effective cross-bridging; very long: no or very few cross-bridging is occurring.)
Highest amount: at optimal muscle length, where actin and myosin have the ideal overlap to form the greatest number or cross-bridges
Name at least 5 common elements of a synovial joint
1. synovial fluid
2. articular cartilage
3. articular capsule
4. synovial membrane
5. capsular ligament
6. blood vessels
7. sensory nerves
Name the 5 types of bones and give one example of each
Long bones: femur, humerus, ulna, etc.
Short bones: carpal bones, tarsal bones, etc
flat bones: scapula, sternum, etc.
Irregular bones: vertebrae, skull, face bones
Sesamoid bones: patella, sesamoid bones of the thumb and big toe
When holding a weight in your hand, which elbow flexion angle has greater external torque, 45 or 90 degrees?
What is a vector?
Represents the magnitude and direction of a force
What are the 4 muscle shapes and name one key feature of each
Fusiform: fibers run parallel to one another; provide large ranges of motion; biceps brachii
Triangular: Expansive proximal attachment converging to a small distal attachment; provide a stabilized base for generating force; gluteus Medius
Rhomboidal: Expansive proximal and distal attachments; suited to stabilize a joint or provide large forces (depending on cross sectional area); gluteus maximus
Pennate: resemble shape of a feather; large force potential, limited excursion
Name all 7 synovial joints and their degree of freedom
Hinge: 1 (humeroulnar & interphalangeal joint)
pivot: 1 (proximal radioulnar & atlantoaxial joint)
ellipsoid: 2 (radiocarpal joint)
saddle joint: 2 (carpometacarpal joint of the thumb & sternoclavicular joint)
Condyloid: 2 (tibiofemoral & metacarpophalangeal joint)
*Tibiofemoral joint could be classified as a modified hinge joint.
Plane joint: variable (intercarpal & intertarsal joint; scapulothoracic joint*)
Ball and socket: 3 (shoulder & hip joint)
According to the convex-concave rule, how does the ulna move during elbow flexion/extension
concave surfaces of the ulna roll and glide in the same direction over the convex surfaces of the humerus
What are the benefits of a 3rd class lever compared to a 2nd class lever and vice versa?
3rd class lever has poor leverage (mechanical advantage), requiring greater effort force, but provides greater speed and range of motion
2nd class lever has good leverage, requires less effort force to move a load (good for power)