1. Muscular Nomenclature
There are 8 Criteria for Naming Muscles

2. 1. Size
Muscles are:
Large (MAXIMUS or MAGNUS) or Small (MINIMUS) ex: Gluteus Maximus
Short (BREVIS) or Long (LONGUS) Ex: Adductor Longus

3. 2. Shape There are only 3 that we will concern ourselves with:
TRAPEZIUS (Large diamond-shaped muscle along our back)
DELTOID (Refers to triangular shaped muscle on shoulders)
SERRATUS Anterior (Saw-toothed shaped muscle due to attachment on ribs)

4. 3. Direction of Muscle Fibers
Muscles will be parallel, perpendicular, or diagonal in relation to the midline of the body.
RECTUS identifies muscles which run parallel. Ex: Rectus Abdominis
OBLIQUE runs at an angle. Ex: External Oblique
TRANSVERSE means the muscle runs perpendicular to the body. Ex:

5. 4. Action of the Muscle This is what the muscle DOES.
FLEXORS – decrease an angle at a joint
EXTENSORS – increase an angle at a joint
PRONATORS – turn limbs to face downwards
SUPINATORS – turns limbs to face upwards
LEVATORS – lift things up
DEPRESSORS – push or pull things down
ROTATORS – produce movement around an axis
ABDUCTORS – move bones away from midline of body
ADDUCTORS – bring parts back towards the midline. Ex: Adductor longus
SPHINCTERS – close openings. Ex: Pyloric Sphincter in stomach

6. 5. Number of Points of Origin
Some are named based on how many points of attachment they have at their origin
For example:
BICEPS brachii has 2 points of origin
TRICEPS brachii has 3 points of origin
The QUADRICEPS in your leg has 4 points of origin
FYI: ceps means “head”, brachii means “branches”

7. 6. Origin and Insertion
A few muscles are named based on WHAT they are connected to
Ex: STERNOCLEIDOMASTOID – originates from the sternum and clavicle and inserts into the mastoid process of the skull.

8. 7. Function of Muscle
A small number of muscles are based on their major function
Ex: MASSETER – comes from the Greek word for “chew”, and that’s what the masseter helps you to do
Ex: RISORIUS – comes from the Latin word for “laugh”, and this muscle is crucial for the expressions of smilling and laughing

9. 8. LOCATION Some are named based on where they are found
Ex: TEMPORALIS muscle is located over the temporal bone
Ex: ZYGOMATICUS is located over your zygomatic cheek bone