naming muscles. muscles causing movement… skeletal muscle – an organ made of several different...
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Naming MusclesNaming Muscles
Muscles causing Muscles causing movement…movement…
Skeletal Muscle – an organ made of Skeletal Muscle – an organ made of several different types of tissue several different types of tissue including muscle tissue, vascular including muscle tissue, vascular tissue and nervous tissuetissue and nervous tissue
Tendon – attaches the skeletal Tendon – attaches the skeletal muscle to bone and pulls on bone muscle to bone and pulls on bone when the muscle contractswhen the muscle contracts
JointsJoints
Skeletal muscles usually cross one or Skeletal muscles usually cross one or more joints. When a muscle more joints. When a muscle contracts it pulls one bone closer to contracts it pulls one bone closer to anotheranother One bone stays in place while the other One bone stays in place while the other
movesmoves
Parts of a skeletal muscleParts of a skeletal muscle
Origin – the attachment of a muscle Origin – the attachment of a muscle on a stationary boneon a stationary bone
Insertion – the attachment of a Insertion – the attachment of a muscle on the movable bonemuscle on the movable bone
Belly – the fleshy portion of muscle Belly – the fleshy portion of muscle between the origin and insertionbetween the origin and insertion
Group ActionsGroup Actions
Most movements occur because Most movements occur because groups of muscles work together, groups of muscles work together, generally grouped in opposing pairsgenerally grouped in opposing pairs Ex – abductors and adductorsEx – abductors and adductors Ex – extensors and flexorsEx – extensors and flexors
Agonist – muscle that produces the Agonist – muscle that produces the desired movementdesired movement
Antagonist – muscle that relaxes when the Antagonist – muscle that relaxes when the agonist contractsagonist contracts
Synergists – another skeletal muscle that Synergists – another skeletal muscle that moves in the same general direction as moves in the same general direction as the agonist increasing the forcethe agonist increasing the force
Fixators – stabilize the origin and hold Fixators – stabilize the origin and hold other joints still so the agonist can work other joints still so the agonist can work more efficientlymore efficiently
Principle Skeletal MusclesPrinciple Skeletal Muscles
With over 700 skeletal muscles in the With over 700 skeletal muscles in the body, it will be easier to first learn body, it will be easier to first learn the naming system and then learn the naming system and then learn specific muscles region by regionspecific muscles region by region
Naming Skeletal MusclesNaming Skeletal Muscles
Muscles are named according to the Muscles are named according to the direction the fibers run, the size of direction the fibers run, the size of the muscle, the shape of the muscle, the muscle, the shape of the muscle, the action the muscle produces, the the action the muscle produces, the number of origins the muscle has number of origins the muscle has and/or the location of the muscleand/or the location of the muscle
DirectionsDirections
The following terms refer to the The following terms refer to the direction the muscle fibers run in direction the muscle fibers run in relation to the midline.relation to the midline.
RectusRectus
Parallel to the midlineParallel to the midline
TransverseTransverse
Perpendicular to the midlinePerpendicular to the midline
ObliqueOblique
Diagonal to the midlineDiagonal to the midline
SizeSize
Relative to other muscles in that Relative to other muscles in that groupgroup
MaximusMaximus
LargestLargest
MinimusMinimus
SmallestSmallest
Longus or LongissimusLongus or Longissimus
LongestLongest
LatissimusLatissimus
WidestWidest
MagnusMagnus
LargeLarge
MajorMajor
LargerLarger
MinorMinor
smallersmaller
VastusVastus
greatgreat
ShapeShape
General shape of the muscleGeneral shape of the muscle
DeltoidDeltoid
TriangleTriangle
TrapeziusTrapezius
TrapezoidTrapezoid
SerratusSerratus
Saw-toothedSaw-toothed
RhomboidRhomboid
Diamond ShapedDiamond Shaped
OrbicularisOrbicularis
CircularCircular
PectinatePectinate
Comb-likeComb-like
PiriformisPiriformis
Pear shapedPear shaped
PlatysPlatys
FlatFlat
QuadratusQuadratus
squaresquare
GracilisGracilis
slenderslender
ActionAction
Based on the action the muscle Based on the action the muscle performsperforms
Flexor/ExtensorFlexor/Extensor
Flexor – decreases the angle between Flexor – decreases the angle between bonesbones
Extensor – increases the angle between Extensor – increases the angle between bonesbones
Abductor/AdductorAbductor/Adductor
Abductor – moves a bone away from Abductor – moves a bone away from the midlinethe midline
Adductor – moves a bone toward the Adductor – moves a bone toward the midlinemidline
Levator/DepressorLevator/Depressor
Levator – elevates body partLevator – elevates body part Depressor – lowers body partDepressor – lowers body part
Supinator/PronatorSupinator/Pronator Supinator – turns palms upSupinator – turns palms up Pronator – turns palms downPronator – turns palms down
SphincterSphincter
Decreases the size of an openingDecreases the size of an opening
TensorTensor
Makes a body part rigidMakes a body part rigid
Number of OriginsNumber of Origins
Biceps – 2 headsBiceps – 2 heads
Triceps – 3 headsTriceps – 3 heads
Quadriceps – 4 headsQuadriceps – 4 heads
LocationLocation Muscles named for the Muscles named for the
structures that they structures that they are by. Examples are by. Examples include the include the sternocleidomastoid sternocleidomastoid muscle (runs from the muscle (runs from the sternum across the sternum across the clavicle to the mastoid clavicle to the mastoid process) and the process) and the temporalis (near the temporalis (near the temporal bone)temporal bone)