Transcript Naming Muscle

Naming Muscles
I.
Skeletal muscles are named according to certain criteria
A. Location- may indicate bone or body region that muscle is
associated with
Ex. Zygomaticus- associated with the zygomatic arch in the skull
B. Shape- Muscles often have a definitive shape, after which they are
name
Ex. Deltoid means triangle (and the deltoid muscle is triangular)
C. Relative Size
1. Maximus= largest
2. Minimus= smallest
3. Longus= long
4. Brevis= short
Ex. Gluteus maximus (larger)
and minimus (smaller)
Naming Muscles
D. Direction of Muscle Fibers
- may
reflect the direction of the fibers in
relation to midline or other axis
1. Rectus= straight (runs parallel)
2. Transversus/oblique ( right angles)/
obliquely
Ex. Rectus femoris- muscle that runs
parallel with the femur
E. Number of Origins
1. Biceps= two origins
2. Triceps= three origins
3. Quadriceps= four origins
Ex. Biceps Brachii
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F. Location of origin and
insertions
1. may be named
according to the
attachment points
2. Origin is always
named first
Ex.
Sternocleidomastoid
(dual origin on sternum
and clavicle; insertion
on mastoid process
Naming Muscle
G. Action
1. Uses words such as flexor, extensor, or adductor
Ex. Adductor longus on thigh adducts the thigh
H. Sometimes several criteria are combined in a name.
Ex. Extensor carpi radialis longus
1. muscle’s action (extensor)
2. joint it acts on (carpi= wrist)
3. Where it is (radialis = radius of forearm)
4. size (long relative to other wrist muscles
Naming Muscle
II. Muscle Interactions- four functional groups
A. Prime mover- provide the major force for
producing a specific movement. Also
called the agonist
Ex. Biceps Brachii for forearm flexion
B. Antagonist- oppose or reverses a
particular movement
Ex. Triceps brachii for forearm
extension (oppose biceps)
C. synergist- aid agonist (prime movers) by
promoting the same movement or reducing
undesireable or unnecessary movements
that might occur as the prime mover
contracts.
Ex. Semimembranosis helps the
biceps femoris with thigh extension
and knee flexion
Naming Muscle
D. Fixators- a synergist that immobilizes or stabilizes a bone or a
muscle’s origin
Ex. Rotator cuff muscles (terest minor, infraspinatus, supraspinatus,
subscapularis)
E. Example of movement of all four involved in a movement
a. prime mover= pectoralis major (shoulder flexion)
b. antagonist= lattisimus dorsi
c. synergist= biceps brachii
d. fixator= rotator cuff
Naming Muscle
III. Muscle MovementsMuscles move toward their origin from the insertion of
the muscle. Origin is the bone point that does not move
and the insertion is the bone attachment that does move.
Ex. Origin- sternum and clavicle
Insertion- mastoid
Muscle when it contracts pulls the mastoid (skull) down
toward the sternum and clavicle (bringing your head
toward your chest)
A. Flexion- bending movement that brings two
articulating bones closer together.
B. Extension- reverse of flexion, moves the bones
further apart.
Joint animations
Naming Muscle
C. Abduction- movement of limb away
from the mid-line
D. adduction- movement of limb toward
the mid-line.
E. Circumduction- moving a limb so it
describes a cone in space
F. Rotation- turning of a bone on its long
axis, this also includes lateral and medial
rotation of hip and shoulder
G. Supination- palm up
H. Pronation palm down
* Inversion: sole of foot is turned medially
* Eversion- sole of foot is turned laterally
*plantar flexion- point toes
* dorsiflexion- pull toes towards shin
Naming Muscle
Question of the Week:
• What does the uvula
do?
• Prevents food from
entering nasal cavity
• Thought to help in
swallowing
• Can initiate gag reflex
• Aids in some of the
voice sounds we make
• Can increase sound of
snoring
Bifurcated uvula