Meet Your Muscles: How muscles are named?

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How muscles are named?

You don’t have to be a kinesiology expert to understand the importance of anatomy. To build your muscles, you need to know your muscles. Just ask yourself: Would you drive a car without knowing the gear box, the gas pedal or the ignition?  Probably not! Therefore, there are some very important lessons about muscle anatomy every successful bodybuilder needs to know. Naming your skeletal muscles is definitely one of the most important among them. By the end of this article you will be able to explain how understanding the muscle names helps describe shapes, location, and actions of various skeletal muscles.

Naming of skeletal muscles

At first glance, it may appear that muscles have some pretty outrageous names, but by understanding some key characteristics, naming skeletal muscles will seem a bit more practical and straightforward.

The first thing you will notice as you start studying the muscles of the body is that many of the names seem difficult and foreign. The terms are less difficult if you keep in mind that many have Latin roots. However, when you understand the names of muscles it will help you remember where the muscles are located and what they do. In order words, everything will be more logical and easier to learn, understand, and remember.

Criteria for naming skeletal muscles

We name muscles by considering the qualities listed below. Understanding these terms will make the task of learning muscles easier.

In short, we name muscles in respect to their location, size, shape, direction (orientation of the fibers), number of origins, location of origin and inser­tion, and action.

However, not all muscles are named in this manner. Some muscles are named for what seem to be strange reasons. An example of this is the group of muscles called “hamstrings” because these are the muscles by which a butcher would hang a slaughtered pig.

I. Muscles named for their shape

Shape is a descriptive feature we often use for naming many muscles. Examples:

  • Deltoid muscle covering the shoulder (for the Greek letter delta, meaning triangle)
  • Rhomboid muscle (rhombus shaped)
  • Trapezius muscle covering the upper back and part of the neck and shoulders (named for its trapezoidal shape – diamond-shaped muscle)

All these muscles are shaped like a familiar object.

Trapezius muscle - named for its trapezoidal shape

Trapezius muscle – named for its trapezoidal shape

Rhomboideus major - rhombus shaped

Rhomboideus major – rhombus shaped

II. Muscles named for their size

The relative size of a muscle can be used to name a muscle, especially if it is compared to the size of nearby muscles. For example, maximus (biggest), minimus (smallest), longus (longest), and brevis (shortest).

  • The gluteus maximus is the largest muscle of the gluteal (buttock) region.
  • Nearby, there is a small gluteal muscle, the gluteus minimus, and a midsize gluteal muscle, the gluteus medius.
gluteus maximus

The biggest muscle in the human body is the gluteus maximus

III. Muscles named for its location

We name many muscles as a result of their location. The brachialis (arm muscle) and gluteus (buttock) muscles are examples.

Furthermore,

  • For example, the pectoralis major is an important muscle of the chest. The term pectoral means relating to the chest.
  • Other muscles, such as vastus lateralis and vastus medialis, indicate their location by including lateralis (toward the side) and medialis (toward the mid­line) in their names.
muscles named for its location

pectoralis major – the term pectoral means relating to the chest

IV. Muscles named for fiber direction

Muscles may be named according to the orientation of their fibers. The term rectus means straight. Therefore the fibers of the rectus abdominis muscle run straight up and down and are parallel to each other.

Other examples:

  • Oblique means slanted or at an angle. For example, the external abdominal oblique is an abdominal muscle that slants outward, at an oblique angle, away from the midline.
  • Transverse means in a crosswise direction. For example, the transverse abdominis is an abdominal muscle with a crosswise alignment.
Muscles named for fiber direction

Muscles may be named according to the orientation of their fibers

V. Muscles named for number of divisions

Muscles may be named according to the number of divisions (number of heads or number of origins) forming them.

For example:

  • The biceps brachli, also known as the biceps muscle, is formed from two divisions (bi – means two and -ceps means head). This is the muscle of the anterior upper arm that flexes the elbow.
  • The triceps brachii, also known as the triceps muscle, is formed from three divisions (tri – means three and -ceps means head). This is the muscle of the posterior upper arm that extends the elbow.
  • The quadriceps femoris is formed from four muscle divisions (quadri -means four and -ceps means head). This large muscle, located on the anterior thigh, assists in extending the femur (bone of the upper leg).
naming skeletal muscles

Quadriceps muscle – The name derives from Latin four-headed muscle of the femur

VI. Muscles named for their actions (functions)

The function of a muscle is frequently a part of its name. The adductor muscles of the thigh adduct, or move, the leg toward the midline of the body. The abductor muscles of the thigh abduct, or move, the leg  away from the midline of the body. Furthermore, terms such as flexor (flex the arm), extensor (extend the arm), etc., are added as prefixes to muscle names to indicate the kind of movement generated by the muscle.

naming muscles by their actions

The adductor muscles of the thigh adduct, or move, the leg toward the midline of the body

muscle action: flexion vs. extension

muscle action: flexion vs. extension

Closing thoughts

Muscle names are not just a bunch of random Latin words, but rather, are named according to a set of informal rules; and once you understand those rules, you can pretty much tell where any muscle is located and what it does. Most of the almost 700 skeletal muscles of the body are named on the basis of one or more distinctive characteristics. If you understand these characteristics, you will find it much easier to learn and and remember the names of the many individual muscles. Knowing your muscles is a must for all of us engaged in weight training.

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2 Comments

  1. OMG thank you! I’m trying to become a personal trainer and this just helped me tremendously. Thinking about it like this just totally makes sense to me. If you have any more examples like this I would love to see it. Thanks again!

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