Transcript Naming the Muscles

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Origin: the immovable end of the
muscle; attached to a relatively
immovable bone
Insertion: the end of the muscle
attached to a movable bone
**When a muscle contracts, its insertion
is pulled toward its origin.
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Prime mover (agonist): the muscle
that provides most of the
movement in an action
Synergists (antagonists): the
muscles around the prime mover
that assist it in an action
Prime Mover
Synergist
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Latin and Greek roots
Characteristics Used to Name Muscles
1) direction of their fibers
2) size
3) location
4) which bones they attach to
5) function
**The names of muscles often contain
combinations of each of the above.
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Determined in relation to the midline of
the body
Rectus: (Latin for “straight”)
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Parallel to the midline
Ex: rectus femoris and rectus abdominis
Oblique: at an angle to the midline
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Ex: internal and external obliques of
the thorax
Longus: long
 Brevis: short
 Maximus: largest or greatest
 Major: larger
 Vastus: huge
 Minimus: least or smallest
 Minor: smaller
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Oris: mouth
Digitorum: finger or toe
Oculi: eye
Pollicis: thumb
Palmaris: palm of the hand Costals: rib
Abdominus: abdomen
Brachii: arm
Hallicus: great toe
Femoris: thigh
Carpi: wrist
Tibialis: shin bone
Spinalis: spine
Peroneus: fibula Scapularis: shoulder blade
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Spinalis thoracis
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Biceps brachii
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Rectus femoris
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Adductor pollicis longus
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Orbicularis oculi
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External intercostals
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Tibialis anterior
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Peroneus longus
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Many muscles are named as a result of their
association with a particular bone.
The temporalis muscle is found covering the
temporal bone.
The frontalis muscle is found covering the
frontal bone of the skull.
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Some muscles are named for their
origin and insertion.
The first part of the muscle name
indicates the origin, while the second
part of the name indicates the insertion.
Ex: sternocleidomastoid = sterno
(breastbone) and cleido (clavicle)
insertion; mastoid (breast shaped)
process on the skull
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Some muscles have multiple origins.
This number will often be used in the
name.
Ex: biceps brachii and triceps brachii
Bi is Latin for two
Tri is Latin for three
Ceps refers to the head
So the biceps brachii has two heads that
attach to two different origins.
In addition to having the name of the bone in
the muscle name, the position in relation to
the bone or body part may be in the muscle
name.
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Supra: above or over
Infra: below or beneath
Sub: below or under
Lateralis: the side
Medialis: the middle
Inter: between or among
External: outer
Internal: inner
Superior: above or over
 Inferior: underneath
 Dorsi: the back
 Anterior: in front of
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Ex: supraspinatus, infraspinatus,
subscapularis, vastus lateralis, vastus
medialis, intercostals, external internal
obliques, superior and inferior rectus of the
eye
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Early anatomists often named muscles after
the shapes they resembled.
Deltoid: delta = triangle; oid = like
Trapezius: trapez = table
Serratus: saw
Teres: round
Orbicularis: orbi = circle, cul = little
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Latissimus: lat = broad/wide, simus = like
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Deltoid=
=
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Serratus =
=
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Orbicularis: orbi = circle, cul = little
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=
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What would the following muscles look like
and where would they be found?
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Latissimus dorsi
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Orbicularis oculi
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Orbicularis oris
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flexion : flex = bend (decreases the angle at a
joint)
extension: ex = out; ten = stretch (increases the
angle at a joint)
adduction: ad = toward; duct = lead (pulls the
limb toward the midline)
abduction : ab = away from; duct = lead (pulls the
limb away from the midline)
pronation: pron = bent forward (turning the palm
downward)
supination: supin = lying on the back (turning
the palm upward)
EX) Flexor carpi radialis is
a muscle of the
human forearm that acts to
flex and
(radial) abduct the hand.
EX) Extensor digitorum is a muscle
that extends the medial four digits of
the hand.