Exam 2 Flashcards
Biomechanics (Lec 3), Kinesiology + Spine (83 cards)
What does the henneman’s principle state? What is the benefit of it?
Motor units are recruited from smallest to largest (this helps preserve energy)
Differentiate between the two types of bone
Cortical Bone: Dense and forms the outer layer of a bone segment
Trabecular Bone: Low density and fills the inside of a bone segment
What are the 6 types of bone fractures?
- Compression Fracture (caused by compression)
- Tension Fracture (caused by pulling at both ends of the bone segment)
- Bending Fracture (caused by bending of the bone segment)
- Shear Fracture (caused by two forces going opposite directions… one force moves the upper part of the bone one way and one force moves the lower part of the bone the other way)
- Torsion Fracture (caused by twisting of the bone segment)
- Combined Loading Fracture [caused by compression and torsion (twisting) of a bone segment]
How do you strengthen a bone?
Weight bearing exercises
(Supported by Wolff’s Law: “If loading on a particular bone increases, the bone will remodel itself over time to become stronger to resist that sort of loading)
How is “stiffness” determined?
- The force that acts on an object (stress)
- The shape of the object (strain)
ex: An object is considered stiff if a large amount of force can only cause a small change of shape
What are the 3 types of joints?
Synarthrosis: Joints that can barely move (skull)
Amphiarthrosis: Joints that can slightly move
Diarthrosis: Joints that can move freely with a certain amount of “degrees of freedom”
Degrees of Freedom (DOF): The number of axis that the joint can move around
What are the 6 types of joints? describe and provide an an example for each
- Plane Joint: Allows for gliding motion only (ex: intercarpal joint)
- Hinge Joint: Allows for 1 degree of freedom and moves like a door hinge (ex: humeroulnar joint)
- Pivot Joint: Allows for 1 degree of freedom and described as a “ring like” bone rotating on another bone (ex: atlantoaxial joint)
- Saddle Joint: Allows for 2 degrees of freedom and has a convex and concave configuration (ex: CMC joint)
- Condyloid Joint: Allows for 2 degrees of freedom and described as an oval head sitting on an elliptical cavity (ex: radiocarpal joint)
- Ball and Socket Joint: Allows for 3 degrees of freedom (ex: hip and shoulder joints)
Differentiate between a close-packed and loose-packed joint position?
Closed-packed: Joint space is minimized
Loose-packed: Joint space is maximized
What are the 3 types of muscle fibers and their function?
Type I: Slow-twitch oxidative fibers
- High endurance, low power
Type IIa: Fast-twitch oxidative fibers
- Intermediate power and endurance
Type IIb: Fast-twitch gylcolytic fibers
- High power, low endurance
T or F? Posture muscles are more type I whereas power muscles are more type II
True
T or F? Atrophy is greater in type II muscle fibers than it is in type I
True
How do muscle neuromechanics work? provide an example
Alpha motor neurons send a signal to an axon, and the axon carries the signal to innervate muscle fibers
ex: flicking a light switch on, the current traveling through the wires, then eventually turning the lights on
T or F? Small size motor units control type I muscle fibers, medium size motor units control type IIa, large size motor units control type IIb muscle fibers
True
Fill in the blank…
_________ arranged muscles allow for greater ROM, while _________ arranged muscles allow for greater force
Parallel, Pennate
The point that marks the end of a stretch, and beginning of permanent muscle strain is called the…
Yield point
Differentiate between active and passive insufficiency
Active Insufficiency (muscle weakness): A position in which a muscle is weak due to extreme shortening or lengthening of a muscle
Passive Insufficiency (muscle tightness): A position in which joint mobility is restricted due to a muscle not being long enough (tight muscle) to allow full ROM
What is considered to be the ideal standing posture? where does the line of gravity go through?
Line of gravity goes through mastoid process, anterior to 2nd sacral segment, posterior to the hip joint, anterior to knee joint, anterior to ankle joint
What is the primary purpose of having a curvature in the spine?
Convert vertical compression into slight horizontal force (disperses the force better)
Which motions do they anterior longitudinal ligament (ALL), posterior longitudinal ligament (PLL), and ligamentum flavum limit?
Anterior Longitudinal Ligament (ALL): Limits lordosis and extension
Posterior Longitudinal Ligament (PLL): Limits kyphosis and flexion (located posterior to vertebral body, anterior to spinal cord)
Ligamentum Flavum: Limits kyphosis and flexion (Located posterior to spinal cord)
Which ligaments support the spine and it’s curve?
- Interspinous ligament
- Supraspinous ligament
- Apophyseal ligament
- Anterior longitudinal ligament
- Posterior longitudinal ligament
- Ligamentum Flavum
Describe the intervertebral discs
Contains the nucleus pulposus and annulus fibrosus
Nucleus Pulposus:
- Inner layer
- 70-90% water
Annulus Fibrosus:
- Outer layer
- Protects nucleus pulposus
- Fiber orientation goes several directions
What is a herniated disc?
When the nucleus pulposus protrudes out beyond the damaged annulus fibrosus
During Extension: Compresses the posterior disc, nucleus pulposus moves forward
During Flexion: Compresses the anterior disc, nucleus pulposus moves backward
What is the “end plate”?
A thin, porous plate that separates the disc and vertebrae that allows fluid inflow and outflow
- End plates are the “weak link” of the spinal column
Describe the curvature and movement norms of the atlanto-occipital joint. Which structures are concave/convex?
Occipital Condyle: Convex
Atlas: Concave
Flexion: 5 degrees
Extension: 10 degrees
Lateral Flexion: 5 degrees
Axial Rotation: Limited
