Muscles of the body Flashcards
Most skeletal muscles run from one _____ to another.
bone
What is the origin of a muscle?
- Less movable attachment of a muscle
- start
What is the insertion of a muscle?
The more movable attachment of a muscle
- end
The ________ of the muscle moves towards the _______.
insertion towards origin
Skeletal muscles are arranged into ________.
fascicles
What are fascicles?
Bundle of fibres running parallel to one another.
How does fascicle arrangement allow one to determine?
Tells you about the action of the muscle.
What is the power of the muscle determined by?
1 - The number of muscle fibres in the muscle (more fibres means more power)
2 - Length of the fibres
What are the different, basic muscle types?
Parallel - fusiform - straplike Circular Triangular/convergent Pennate - unipennate - bipennate - multipennate
What are parallel muscles?
Fibres run parallel to the long axis of the muscle.
What are the two types of parallel muscles (i.e. where the fibres run parallel to the long axis of the muscle)?
Provide an example for each.
Fusiform - biceps brachii
Straplike - sartorius
Describe a fusiform muscle.
Parallel muscle
- central belly with two tapered ends
Describe a straplike muscle.
Parallel
- long, thin, strappy type muscle
Between both biceps brachii and sartorius, which would be more powerful?
Biceps brachii:
- bigger, thicker
- shorter muscle that can contract quicker
What does circular muscle do? Where would you find it?
Give an example.
Circular muscles help close any type of orifice.
ex: orbicularis oris - helps close the mouth
What does pennate mean?
Feather; fibres attach obliquely
What does unipennate mean?
Give an example muscle.
All the fascicles are one the same side of the tendon
ex: extensor digitum longus
What does bipennate mean?
Give an example muscle.
Fascicles on both sides of the central tendon
ex: rectus femoris
What does multipennate mean?
Multiple insertions in featherlike arrangement
ex: deltoid
“A muscles cannot reverse the movement it produces.” Explain this.
When a muscle contracts and performs its movement, another muscles must undo the action.
These muscle with opposite actions will lie on opposite sides of a joint.
Whenever a muscle crosses a joint it….(finish the statement).
Performs an action on that joint.
What is a prime mover/Agonist?
Has a major responsibility for a certain movement.
What is an antagonist?
Opposes or reverses the movement of a prime mover.
What is a synergist?
Helps the prime mover.
How can a synergist help the prime mover?
1 - By adding extra force
2 - By reducing undesirable movements
3 - Stabilizing the prime mover
What is a fixator?
Type of synergist.
- Holds a bone/joint firmly in place
- Stabilizes the prime mover so it can act more efficiently
What are the different kinds of muscular contractions?
Concentric contraction
Eccentric contraction
Isometric contraction
What is concentric contraction?
Muscle shortens and does work
What is eccentric contraction?
Muscle generates force as it lengthens.
- resisting gravity - acts as a brake
- negative work
What is an example of an eccentric contraction?
Squats
What is DOMS, what is it caused by?
Delayed Onset Muscular Soreness.
Caused mostly by eccentric contraction since most of the muscle tears occur during eccentric contraction.
What are isometric contraction?
Contraction to stabilize, not shortening or lengthening.
How are muscles divided into compartments.
Dense regular CT divides limb muscles into compartments.
What are muscle compartments?
Group of skeletal muscles that arose from a common embryonic origin
The CT that divides muscles into compartments wraps after what layer?
The epimysium
Muscles in opposing compartments are what?
What do they share?
Agonist and antagonist pairs
Share a common blood and nerve supply
What are the different muscles compartments of the arm?
Give an example for both.
Anterior and posterior
A - biceps brachii
P - triceps brachii
What are the different muscle compartments of the thigh?
Anterior
Posterior
Lateral
Medial
What does the anterior compartment muscles of the arm do?
The posterior?
Anterior - flex the shoulder or elbow
Posterior - extend the shoulder or elbow
What does the anterior compartment of the thigh do?
Posterior?
Posterior (think hamstring curl)
- extends hip, flexes knee
- backswing phase of walking
Anterior (Think leg extension)
- flex the hip, extend the knee
What do the medial compartment muscles of the thigh do?
Lateral?
Medial
- adduct thigh
Lateral
- abduct thigh
There are 4 general rules for muscle actions as they cross a joint. What are they?
A muscle that crosses on the \_\_\_\_\_\_\_ side of joint produces \_\_\_\_\_\_. 1 - Anterior - flexion 2 - Posterior - extension 3 - Lateral - abduction 4 - medial - adduction
What are the different ways in which skeletal muscle can be named?
Location Shape Relative size Direction of fascicles and muscle fibres. Number of origins Action
Give an example muscle who’s name provides the location.
Brachialis - located on the arm
Give an example muscle who’s name provides the shape.
Deltoid - triangular
Give an example muscle who’s name provides the relative size
Gluteus maximus - large
Give an example muscle who’s name provides the location of attachments.
Brachioradialis
first name is origin, second is insertion.
Origin - arm
insertion - radius
Give an example muscle who’s name provides the number of origins.
Biceps - two
Give an example muscle who’s name provides the action?
Extensor digitum longus
- extends fingers
Where is the origin and insertion of the external intercostal muscles?
External intercostals pull the ribcage up and out, insertion moves towards origin so,
Insertion on the bottom rib, origin on the upper rib
Where is the origin and insertion of the internal intercostal muscles?
Internal intercostals pull the ribcage down and in so,
insertion - top rib
origin - bottom rib
Where is the origin and insertion of the diaphgram?
When contracted, flattens, dome when relaxed so,
middle is insertion, origin is around edge.
How many muscles cross the shoulder joint and insert on the humerus?
Nine
What muscle can be injured when doing that cat back on the DL?
erector spinae
What are the chief forearm flexors?
Biceps and brachialis
brachialis is a synergist
biceps is the PM
What are the chief forearm extendors?
Triceps (PM) and anconeus (synergist)
Brevis means?
Short
Magnus means?
Large
The quadriceps femoris has 4 different _______. These are not _______.
heads
not origins
How does the tensor fasciae latae stabilize the trunk on the thigh?
Making IT band taut
Hamstrings cross the ___ and _____ joints on the ______ side.
This means they do what?
Hip and knee
Posterior
Flexes thigh and extends hip
