About Skeletal Muscles
Terms
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- Rectus
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fibers run parallel to the midline
ex: rectus abdominus - Transverse
-
fibers run perpendicular to midline
ex: transverse abdominus - oblique
-
fibers run perpendicular to midline
ex: external oblique - frontalis
- a muscle near the frontal bone
- tibialis anterior
- a muscle near the tibia
- maximus
-
largest
ex: gluteus maximus - minimus
-
smallest
ex: gluteus minimus - longus
-
longest
ex: palmaris longus - brevis
-
shortest
ex: peroneus brevis - biceps
-
indicates two origins
ex: biceps brachii
biceps femoris - triceps
-
indicates three origins
ex: triceps brachii - quadriceps
-
indicates four origins
ex: quadriceps femoris - deltoid
-
having a triangular shape
ex: deltoid - trapezius
-
having a trapezoid shape
ex: trapezius - serratus
-
having a sawtooth shape
ex: serratus anterior - rhomboideus
-
having a diamond shape
ex: rhomboideus major - sternocleidomastoid
- originates on sternum and clavicle and inserts on mastoid process of temporal bone
- flexor
-
decreases the angle at the joint
ex: flexor carpi radialis - extensor
-
increases the angle at the joint
ex: extensor carpi ulnaris - abductor
-
moves a bone away from the midline
ex: abductor pollicis longus - adductor
-
moves a bone closer to the midline
ex: adductor magnus - levator
-
produces an upward movement
ex: levator scapulae - depressor
-
produces a downward movement
ex: depressor labii inferioris - supinator
-
turns the palm upward or anteriorly
ex: supinator - pronator
-
turns the palm downward or posteriorly
ex: supinator - sphincter
-
decreases the size of an opening
ex: external anal sphincter - tensor
-
makes a body part more rigid
ex: tensor fascia latae - rotator
-
moves a bone around its longitudinal axis
ex: rotatores - first class levers
-
think of a see-saw. there are not many examples of these in the body
ex: head resting on the vertebral column
fulcrum= joints between the atlas and occipital bone
resistance= bones of the face
effort= contraction of the muscles of the upper back - second class levers
-
FRE think of a wheelbarrow
ex: raising the body on the toes
fulcrum= ball of the foot
resistance= the body
effort= contraction of the calf muscles to pull the heel upward - third class levers
-
FER allow for greater speed and range of motion
most common type found in the body
ex: flexing the forearm at the elbow
fulcrum= elbow joint
effort= contraction of the biceps brachii
resistance= weight of the forearm