639 MUSCLES, Oh my!

I confess! Growing up in the late 1950s I watched a LOT of television, mostly cartoons. There are too many cartoon theme songs embedded deep in my brain, and they emerge every once in awhile, tickled by an association. So it is with Popeye the Sailor Man. Here I am learning about the 639 muscles in our bodies, and what should come to mind but Popeye with his can of spinach and big arm muscles.

Sadly, that association now also conjures up athletes taking steroids. Sigh.

FUNCTIONS of our muscles

Our muscles serve many purposes. In order to sing along with Popeye you need to move your mouth. When you’ve had too much spinach, you wind up going to the bathroom. Our muscles move our skeleton, including the opening of our mouth and anus. Muscles also provide protection by closing openings, such as our mouth and eyes.

How do you stack up in height to Popeye? Stand up straight for a moment, and you are using your muscles to stabilize your joints and maintain your posture.

When you’ve been chilly, have you ever started jumping in place, or rubbed your hands together to get warm? Or perhaps you are an active person and engage in exercise fairly often. In both cases, our muscles produce heat. Are you smiling now, or quizzically cocking an eyebrow or making a face of disagreement? Eleven facial muscles communicate expressions.

NAMING of our muscles

With 639 muscles, it can be rather taxing to try and remember each and every name, let alone the muscle’s location. To make it a tad easier, muscle nomenclature makes use of descriptive terms. A muscle’s name may include:

  1. shape, such as the triangular Deltoid muscle in our shoulders, so named for its shape as an upside down Greek Deltoid (letter D)
  2. number of heads, with biceps=2 heads, triceps=3 heads and quadriceps=4 heads
  3. length, referring to a short muscle as brevis (think: brief or brevity) and a long muscle as longus
  4. location, for instance, the biceps brachi is in the arm and the biceps femoris is in the thigh (they say in real estate that location is everything 😉 )
  5. attachments, denoting what muscles are attached to one another, such as one of my favorite muscle names, the sternoclidomastoid, known as the “prayer muscle” located in the neck, it divides the neck into two triangles and connects the sternum, clavicle and mastoid process

INTERACTIONS of our muscles

Our muscles move in harmony (usually) with one another to carry out their functions. In any given action, the prime mover is the main muscle that carries out the function. In order for the prime mover to work, there is an antagonist muscle that relaxes. If you now flex your biceps, your triceps will relax. Our muscles are attached to our joints at an origin, which is the proximal (nearer, as in close proximity) portion of a limb, and at an insertion, which is the distal (further, as in the distant) portion of the limb.

ACTIONS of our muscles

There are fancy names, as well, for the various types of actions our muscles perform, and sometimes these action names wind up in the name of the muscle to provide further clues to the muscle’s location or function. Flexors decrease the angle of a joint (like sitting on your knees) and extensors increase the angle of a joint (when you straighten your bent knees). Adductors move toward your body’s midline (think: adding or coming closer to the center), while abductors move away from your body’s midline (think: something that has been abducted has been taken away). And lastly, supinators refer to the palm facing forward, and pronators refer to the palm facing backwards.

@brainbits: We have 3x more muscles (639) than bones (206). Muscle 639 was found in 1996 in the skull, thus “anatomy is not dead” as Marian Diamond says!


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