Muscle Names
Name _________KEY___________________
The muscles of the body can often be difficult to remember, as their names are usually long, confusing, and
in Latin. The key to learning the muscles is to understand the basic naming conventions. Once you see
recognize the patterns, they will be much easier to remember.
Muscles are names according to the following conventions:
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Muscle Shape – (Deltoid – triangle shape, or Orbicularis – orbit or circular shape)
Muscle Size – (Major/Minor - large/small, Maximus – Largest, Minimus - smallest; Vastus –
Large)
Muscle Length – (Longis – Long; brevis (brief) – short)
Muscle Location – [Dorsi or Dorsal – backside; Infra / Supra - lower and upper; Medialis /
Lateralis - medial (toward the inside), lateral (toward the outside)]
Muscle Action – (flexor and extensor - flexes or extends a bone; Adductor – accomplishes
adduction)
Number of Muscle Origins or Insertions – (triceps – three heads)
Direction of Muscle Fibers – (oblique – fibers arranged diagonally; transversus – fibers arranged
horizontally; rectus – fibers arranged vertically)
Named for the Region or the Bone they are attached to – (temporalis – by the temporal bone;
biceps femoris - two headed muscle attached to the femur; extensor carpi radialis longus - long
muscle that runs the length of the radius (bone) to the carpals (wrist bones) that extends the fingers)
Named for Origin and Insertion Points the muscle connects to – (sterno = sternum; cleido =
clavicle; mastoid = mastoid process on the temporal bone)
A. Muscles act in antagonistic pairs. Most movements are a result of the coordinated action of several
muscles or groups of muscles. While one group contracts to cause a particular motion, the opposing
muscle group relaxes. In the table below, describe the terms and provide an example for a particular
movement.
Term
Prime Mover
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Definition
muscle with the major responsibility for
a certain movement
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Example
Action = flexion of elbow
Muscle = biceps brachii
Antagonist
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muscle that opposes or reverses a prime
mover
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Action = flexion of elbow
Muscle = triceps brachii
Synergist
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muscle that aids a prime mover in a
movement and helps prevent
rotation/undesirable movement
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Fixator
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stabilizes the origin of a prime mover
(specialized synergists)
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Action = flexion of fingers
Synergist muscles that
stabilize wrist so that the
prime mover can cause
flexion
Postural muscles that
stabilize vertebral column
Muscles that anchor scapula
to thorax
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What two muscles work as antagonists to flex and extend the forearm at the elbow joint?
1. Flexion – Biceps brachii
2. Extension – Triceps brachii
What muscle acts as the abducting prime mover (abductor) of the humerus? ______Deltoid__________
What muscle acts as the adducting prime mover (adductor) of the humerus? Pectoralis major/Latissimus
dorsi
Named for the Region or the Bone they are attached to: The temporalis muscle is named for its close
proximity to the temporal bone. Where would the following muscles be located? Be Specific.
1. Tibialis anterior: ____Front or anterior side of tibia__________________________________
2. Rectus Femoris: ____Vertical fibers around the thigh (femur) region________________________
3. Levator Scapulae: ____Elevates the scapula________________________________
4. Transversus Abdominus: __Horizontal fibers in the abdominal area________________________
Muscle Size and Length: The term Maximus means “largest,” whereas the term minimus means
“smallest.” The term longus refers to “long” and the term brevis means “short.” Please provide a few
examples of muscles that include these terms and explain where and what they might look like.
1. _Gluteus maximus (the largest of the gluteal muscles in the buttock region) ________
2. _Fibularis longus (a long muscle that is close to the fibula in your calf region) _____
3. _Vastus lateralis (large muscle on the lateral side of your thigh; part of the quadriceps group)
Number of Muscle Origins/Insertions: Some muscles are named for the number of origins they possess/
Use of the prefixes “bi,” “tri,” and “quad” indicates two, three, and four heads of origin respectively.
Provide one example of each. Be specific and write the muscle’s full name.
1. Bi - ___Biceps brachii________________________________________________________
2. Tri - ___Triceps brachii____________________________________________________________
3. Quad - __Quadriceps femoris____________________________________________________
Origin and Insertion: Some muscles are named after their origin (s) and insertion (s). Some examples are
provided in the table below. Please provide the origin and insertion for these muscles. Be Specific.
Muscle Name
Origin (s)
Insertion (s)
Flexor carpi ulnaris
distal humerus & posterior
ulna
Carpal of wrist & 5th
metacarpal
Sternocleidomastoid
Sternum & clavicle
Temporal bone (mastoid
process)
Muscle Shape: Some common shapes include triangular (delta), rectangular (rectus), trapezoid, and
circular. Provide an example of each of the following shapes below. Include the whole muscle name.
1. Trapezoid: __Trapezius__________________________________________________________
2. Triangular: __Deltoid_________________________________________________________
3. Rectangular: __Rectus femoris or Rectus abdominus___________________________________
Muscle Action: The principle action of a muscle is sometimes used in naming a muscle. Evaluate the
names of muscles listed below and describe the specific movement.
1. Adductor Muscles: ________Adduction of thigh (movement toward the body midline)________
2. Extensor carpi radialis: ______Extension (extends wrist and abducts hand)_________________
3. Flexor carpi ulnaris: ________Flexion (flexes wrist and adducts hand)______________________
Direction of Muscle Fibers: Some muscle names are based on the direction in which the fibers run. It
would include rectus (vertical), transversus – (horizontal), and oblique (at angle; diagonal). Give an
example of each type. Hint: there is one area of the body that has all three – read about the abdominal
girdle.
1. _Rectus abdominus—(vertical fibers)________________________________________________
2. _Transversus abdominus—(horizontal fibers)_________________________________________
3. _Internal and External Obliques—(diagonal fibers)____________________________________
Muscle Location: Some muscles are named according to directional terminology. Example: Dorsi/Dorsal –
backside; Supra/Infra – upper/lower. Where would the following muscles be located? Be Specific.
1. Latissimus dorsi: __dorsal trunk of torso______________________________________________
2. Vastus medialis: __medial thigh located anterior to femur (part of quadriceps group)_______
3. Vastus lateralis: ___lateral thigh located anterior to femur (part of quadriceps group)_______
List the criterion or criteria that were used in naming the following muscles. An example is given in
the table below.
Muscle Name
Criterion/Criteria
Quadriceps femoris
Number of origins (quad = 4); location (femoris = femur)
Adductor brevis
Action (adduction); Muscle Size/length (short)
Rectus abdominus
Orientation/Direction of fibers (vertical); Muscle Location (abdomen)
Biceps brachii
Number of origins (two); Muscle Location (upper arm)
External intercostals
Muscle Location (superficial); Named for the location of the bones they
are attached to (inter = between, costal = ribs)
Orbicularis oculi
Muscle Shape (circular); Muscle Location (eye)
Pectoralis major
Muscle Size (large); Muscle location (chest)
Frontalis Muscle
Muscle named for the bone which they are attached to (frontal bone)