muscular system Flashcards
types of muscle based on Muscle fiber arrangement
Parallel: Usually > ROM potential
Oblique: Shorter, greater strength potential, less ROM
types of parallel muscles
Strap – long & thin, fibers run entire length ( sternocleidomastoid)
Fusiform – spindle shaped, attach to tendons – not all fibers run length of muscle (biceps)
Rhomboidal- four sided and flat
Triangular – flat and fan shaped, narrow attachment at one end, broad at the other
(Pectoralis Major)
oblique muscles
Unipennate – look like one side of feather,
Have central tendon, muscle fibers go to one side (Flexor Pollicis)
Bipennate – looks like whole feather
Have central tendon, muscle fibers on both sides (interosseous)
Multipennate – many fibers with oblique tendons in between (deltoid)
Resting position
Resting position: Length of muscle at rest (un-stimulated or no forces)
Irritability
Irritability: Muscles ability to respond to stimulus. (Not an emotional state!)
Contractibility
Contractibility: Ability of muscle to contract/shorten.
Extensibility
Extensibility: Ability to stretch or lengthen in response to force
Elasticity
Elasticity: ability to rebound to the resting length after removal of force.
When a person “stretches” before exercise, he/she is demonstrating which muscle tissue characteristic?
Extensibility
Tension
Tension is the force “built up” in muscle
Passive Tension
Passive Tension: tension from the “non-contractile” units of the muscle. Like stretching a rubber band
Active tension
Active tension: Tension from contractile units of muscle like releasing one side of that rubberband
tone
Tone: slight tension present when muscle is at rest
Normal muscle tone
Normal muscle tone reflects the muscles’ state of readiness
Abnormal muscle tone
Abnormal muscle tone refers to “low” or “high” (spasticity). Abnormal tone is associated with CNS disorders.
high tone ex) cerabal palsy- muscles are spastic- muscles keep firing
low tone ex) someone with a stroke (can have high or low) when a limb just hangs= low tone
ex) someone who is paralysed= low tone
Excursion
Muscles’ total length between maximally shortened length to maximally stretched length.
If max contracted muscle is 3 cm in length, and max stretched state is 9 cm, then excursion is?
6 cm
why is excursion important
There is an optimum range in which every muscle contracts most effectively.
This is why there are specific guidelines for MMT.
Without adequate excursion, full joint ROM can not be achieved.
Length-Tension Relationship
Multi-joint muscles have length-tension relationship
The inability of a muscle that spans two or more joints to be stretched sufficiently to produce a foil range of motion in all the joints simultaneously
Active insufficiency
Active insufficiency: The inability of a muscle to shorten enough to cause full range of motion simultaneously at both joints it passes
Passive insufficiency
Passive insufficiency : the inability to further lengthen to provide full range of motion at both joints.
occurs when the muscle cannot be stretched enough to permit full range of motion at both joints at the same time. Examples: - biceps femoris during knee extension and hip flexion
Active Insufficiency Examples:
Active Insufficiency Examples:
can’t fully extend hip AND flex knee at same time
Passive Insufficiency Examples:
Passive Insufficiency Examples:
make a fist when wrist is fully flexed
full hip flexion and full knee extension
Passive insufficiency of the multijoint muscles of the extensors of the wrist and fingers should limit finger and wrist flexion when they are performed together. Greater range of motion of wrist flexion should be possible with the fingers extended.
A muscle that can not be lengthened simultaneously over all the joints it crosses is said to be?
Passively insufficient
A muscle that can not contract any further to move both of the joints it crosses is said to be?
Actively insufficient
Muscle contraction is strongest when…
Muscle contraction is strongest when it has been stretched first (IMMEDIATELY FIRST) (Kicking a ball = hip extension to flexion)
Multi-joint muscles have advantage because…
Multi-joint muscles have advantage in that they contract over one joint while elongating over another (climbing stairs)
Flexion of hip (elongates) and knee (shortening), extension of hip (shortening) and knee (elongates)
Tenodesis
Extrinsic extensors stretched over radius when wrist is in flexion
Extrinsic finger flexors stretched over radius when wrist is in extension
Tenodesis functionally important
To people with quadriplegia who have no hand function, but have active wrist extension
If your fingers do not work then you can use tenodesis- you can bend your wrist and your fingers will naturally bend
NEVER do wrist extension and finger extension at the same time it will fuck up your hands!
you have Better contractile ability or better tension when ….
Better contractile ability or better tension when muscle is elongated or stretched before a contraction
Length-tension relationship is optimized in
Length-tension relationship is optimized in two-joint or multi-joint muscles i.e. hamstring action in climbing stairs, biceps action in rowing with an oar, intrinsics when typing.
Types of muscle contractions
Isometric = no joint movement Isotonic = joint movement
Isotonic
two types
Isotonic = joint movement
Concentric = shortening contraction
Muscle attachments move closer together
Movement occurs against gravity (most cases)
Acceleration activity
Eccentric = lengthening contraction
Muscle attachments move farther away
Movement occurs with gravity (most cases)
Deceleration activity
Agonist
Agonist – Prime Mover, causes motion
Antagonist
Antagonist – muscle that performs opposite motion of the agonist
Synergist
Synergist – a muscle that works with other muscles to enhance a motion
Co-contractor
Co-contractor – when agonist and antagonist contract at the same time
Stabilizer
Stabilizer – group of muscles that provide support so that the agonist is more effective (example: the trunk during push-ups)
Neutralizer
Neutralizer – prevents unwanted motion
Example: Elbow flexion without supination
Open Chain
Open Chain = distal end is free to move in space
Ex) holding a bottle of water- distal end can still move/free
Ex) walking- open when foot up/ moving, but closed when foot steps nd hits the ground
Closed chain
Closed chain = distal chain is fixed
Ex) doing push ups- distal end can not move/not free
Ex) sitting-standing- legs are closed
“length of kinematic chain
“length of kinematic chain” = number of joints involved in completing a particular motion
ex-sit- stand = Hip, knee, ankle- 3
