Biomechanics Flashcards
Tendons attach the muscle to:
Bone, skin, or another muscle
What is usual structure of a tendon?
Thick, cordlike
Tendons sometimes form a thin, flattened sheet, termed ______
aponeurosis
Origin
Less movable attachment of a muscle
Insertion
More movable attachment of the muscle
Insertion is pulled ______ (toward/away from) the origin.
Toward
Origin typically lies _______ (proximal/distal) to the insertion
Proximal
Name the Four Organizational Patterns in Fascicles (of muscle fibers)
Circular
Convergent
Parallel
Pennate
Circular
Muscle is also called a sphincter b/c contraction of the muscle closes off the opening
Convergent
Muscle has widespread muscle fibers that converge on a common attachment site and are often triangular is shape
Parallel
Fascicles run parallel to its long axis
- have a central body, called the belly, or gaster
Pennate
Have one or more tendons extending through their body, and the fascicles are arranged at an oblique angle to the tendon (strongest muscles)
Example of Circular
Orbicularis oris
Example of Parallel: Strap-like
Stemocleidomastoid
Example of Parallel: Fusiform
Biceps Brachii
Example of Convergent
Pectoralis major
Example of Unipennate
Flexor pollicis longus
Example of Bipennate
Rectus femoris
Example of Multipennate
Deltoid
Effort (load or moment arm) = ?
Work required (the muscles do the work(
Load (load or resistance arm) = ?
What is being resisted or being moved (the body part)
Fulcrum = ?
Point of movement (the joint)
Resistance Arm
Distance between axis and point of resistance application
Force Arm
Distance between axis and point of force
Lever Formula
F x FA = R x RA
In the body, a long bone acts as a ______, a joint serves as the ______, and the _____ is generated by a muscle attached to the bone.
lever
fulcrum
effort
Three Classes of Levers in the Body
First-class Second-class Third-class
First-class Lever System
Has a fulcrum in the middle, between the force and the resistance
Second-class Lever System
Resistance is between the fulcrum and the applied force
Third-class Lever System
Force is applied between the resistance and the fulcrum
Most common levers in the body
Muscle Agonists
aka Prime Mover
contracts to produce a particular movement
Muscle Antagonists
Actions oppose those of the agonists
Synergists
Assist the prime mover in performing its action
The contraction contributes to tension exerted close to the insertion of the muscle or stabilizes the point of origin; may also stabilize the origin of the agonist
Called fixators
