I have to memorize this stuff somehow...and I'm starting to feel desperate. Oh, and these are not all of the muscles in the human body, just the ones the National Association of Sports Medicine deems as important to human movement.
Once upon a time, there was a lonely little shin muscle called the Anterior Tibialis. Located anterior to (in front of), the tibia in the lower leg, it was one of those muscles that was no fun to foam roll (ouch!!!) and placed a bone away from it's counterparts--the calves. It could get lonely in front of the tibia, and this wee muscle did have it's share of accidents--bumping into tables and the like--but it was always good at getting it's main job done. Every time Meg tapped her toes to the music, her Anterior Tibialis was hard at work.
The calves, meanwhile, had each other. On the posterior side of the leg, they partied together, taking Meg up on her toes as she walked and ran--in other words, plantarflexion. Her Gastrocnemius, Soleus, Posterior Tibialis (cousin and antagonist to the Anterior Tibialis) were all happy to work together, and to reap the benefits of a good foam-rolling after a long run. They were aided by the Peroneus Longus, slightly off to the side of the leg, which also had the fun job of eversion of the foot...not the most common movement, but a movement nonetheless.
The lower leg muscles pretty much worked alone, and while it was very important work, indeed, it was nothing on their superior neighbors. Not superior as in "better than," but superior in terms of where they are on the body--higher on the leg.
These muscles could be classified into two main groups: the Hamstring Complex, and the Quadriceps.
The Hamstrings were great in helping Meg kick herself in the butt--literally. These posterior muscles aided with knee flexion, which is bending the knee and raising the heel towards neighboring Gluteus Maximus. They consisted of the Biceps Femoris--Long Head, the Biceps Femoris--Short Head, the Semimembranosus, and the Semitendinosus. The Hamstrings were also particularly good at hip extension, and rotating that tibia bone of the lower leg (not that anyone really rotates the tibia on a regular basis). But in extending that hip, or flexing that knee, the Hamstrings were a mighty team.
Their anterior neighbors, the Quadriceps (who enjoyed going by the nickname Quads, and consisted of the Vastus Lateralis, the Vastus Medialis, the Vastus Intermedius, and the Rectus Femoris), were always antagonistic to the Hamstrings on the other side of the femur. When the Hamstrings said, "Flex that knee!" the Quads would roll their eyes and groan. "Oh, great!" they'd mutter. "Now we have to lengthen, just so the Hamstrings can flex the knee."
(Let it be noted that the Hamstrings had the same complaint whenever the Quads extended the knee. We call this Reciprocal Inhibition.)
Despite this antagonistic relationship, both muscle groups did their jobs well for Meg, so long as she kept them properly stretched and foam-rolled. It was sometimes possible for those Vastus muscles (like the Intermedius) to get a little too tight, causing low-back pain and chain-reaction sciatica in the intrepid runner. But her trainer showed her how to foam-roll that little sucker back into submission.
In a neighboring community to the Hamstrings and Quads were some seriously hip muscles...the hip musculature. Literally. These little hipsters liked to say things like, "We were doing flexion and extension before it was mainstream...and we abduct and adduct, too." These muscles were the bearded, soy-latte-drinking jerks of the muscle family.
Yet, they did their job. Which was moving hips and legs and just being hip(s) in general.
Specifically, the Adductors (Adductor Longus, Adductor Magnus, Adductor Brevis, Gracilis, Pectineus) were a great team in adduction. Adduction is bringing the thigh towards the middle of the body--for example, when the feet come together in a jumping jack, or in a single-leg balance where you bring one foot across in front of the opposite leg. And while the hip muscles always felt as though they were cooler than the other muscles in the neighboring upper thigh community, they weren't above helping the Hamstrings with hip extension. After all, it takes a village to balance on one foot.
The Adductors lived in the anterior section of this lumbo-pelvic-hip neighborhood. In the posterior section, lived the mighty Gluteus Maximus, and its posse, Gluteus Medius and Gluteus Minimus. Medius and Minimus liked to work opposite of the Adductors, sending the hips into abduction (which Meg learned to remember by thinking of the word "abdicate," like, "I'm abdicating the throne--I'm outta here!") Medius and Minimus were also good for aiding hip rotation.
Gluteus Maximus, meanwhile, was a big player in the hip extension game,
(Meg's glutes as a whole were particularly awesome, or so she was sometimes told.)
Just like human hipsters outnumber everyone else in Brooklyn, the hip(ster) muscles are many. Starting at the top of the pelvis and extending down the outside of the thighs, the Tensor Fascia Latae (and it's assistant, the Iliotibial Bands) were the leading authority on hip flexion. The TFL and IT Bands liked to brag about the times they helped Meg whenever she needed to do some high-stepping in her marching band days, while remaining ever alert to her needs as a runner. Meg tended to spend a lot of time stretching these muscles.
The lumbo-pelvic-hip neighborhood was completed by the Psoas (hip flexion, hip abduction, hip internal rotation), the Iliacus (hip flexion, hip external rotation), the Sartorius (hip flexion, external rotation, hip abduction), and the tiny-but-brutal Piriformis (hip external rotation, hip abduction, hip extension). The Psoas liked to help with spinal rotation, while the Piriformis liked to be a little back-pain-causing jerk to Meg...until her awesome trainer showed her how to subdue it, too.
If Meg was ever going to have a six-pack, it would be because of her Rectus Abdominus, and all of its work in aiding spinal flexion (sit-ups and crunches and misery, oh my!!), and, of course, a lot of cardiovascular exercise for fat-burning. The Rectus Abdominus was a proud member of the Abdominals, that family of muscles responsible for movements involving the spine, and other important jobs like supporting the torso. Surrounded by it's faithful allies the External and Internal Obliques, Meg was able to sit up from a prone position, bend her body from side to side, and rotate at the waist thanks to this family.
And thanks to her Diaphragm, that uppermost muscle of the Abdominals, Meg was able to take great breaths for singing.
Solidly located in the torso, another group of muscles liked to shout their motto: "We've got your back!" And they did. The Erector Spinae (consisting of the Iliocostalis, Longissimus, and Spinalis) and it's deputy, Multifudus, were the masters of spinal extension, particularly first thing in the morning, when Meg got out of bed and had a nice...big...strehhhhhhhtch...first thing. Both muscles extended from the cervical (neck) vertebrae to the lumbar (lower back) vertebrae, making them important to other movements as well, like rotation of the spine.
Meanwhile, the Quadratus Lumborum was a small muscle with one main movment: lateral flexion. It was almost completely overshadowed by the largest muscle in the back, the Latissiumus Dorsi ("Call me Lats," it liked to say to the pull-down machine at the gym). Lats had a bit of an identity crisis--while he was located on the back, he was attached--physically and emotionally--to the shoulders. Therefore, his main purpose in life was to aid in shoulder extension, adduction, and external rotation.
The shoulder musculature, it should be noted, consisted of the largest group of different muscles listed in "the Brick," as Meg fondly called her NASM book. Their relationships to the scapulae (shoulder blades) and to each other was as complicated as a large blended family, but basically, they were responsible for lifting whole arms, rowing boats, pushing annoying people off cliffs, and handy tricks like bench-pressing and pulling up one's pants. The Serratus Anterior, the Rhomboids (Major and Minor), and the Lower, Middle and Upper Trapezius muscles were all located on the posterior side of the body, while the Pectoralis Major made up the chest and it's Minor provided soreness in Meg's armpits. The slopes of her shoulders housed the Three Little Deltoids (Anterior, Medial and Posterior), and hiding out under the scapulae was the Teres Major.
The scapula itself had a small group of muscles called the Rotator Cuff (Teres Minor, Infraspinatus, Subscapularis, Supraspinatus)...and Meg never wanted to piss them off, because Rotator Cuff injuries are brutal.
All of these shoulder muscles looked down their noses at the muscles of the arms. "We do so much of the ground work for you," they would sneer. "And look at you, you get all the glory."
It was true. Meg could admire her emerging Biceps Brachii and Triceps Brachii as she gained strength, because just one little turn of her head had them right in view, all smooth and contoured and tanned from all of that summertime running. The Biceps and Triceps were friendly antagonists. "I'll lift the dumbell in a curl!!" the Biceps would shout. "Great!" the Triceps would reply. "When you get tired, I'll gently lower the dumbbell!" And so they would go about their merry way, flexing and extending and making Meg's guns look pretty darned good. The Biceps were aided by the Bracioradialis and Brachialis, while the Triceps mostly did their job alone.
Of course, all of these muscles were controlled by Meg's brain, housed at the most superior part of the body, the head. The head weighed a good ten pounds, so it was important it be supported by good, strong muscles in the neck. Fortunately, there was a great team on hand.
The Sternocleidomastoid, the Scalenes, Longus Coli and the Longus Capitus were responsible for cervical flexion, the act of bowing one's head. They also helped with lateral flexion, that side-to-side movement, and all forms of cervical rotation. The Levator Scapulae aided cervical extension, meaning Meg could look up at the clouds or the stars to her hearts'content...when she wasn't stuck at her laptop, memorizing muscle groups and tapping out ridiculous blog posts.
All of these muscles lived (mostly) in harmony, going about their daily jobs, bickering with the nervous system whenever a foam roller came near, and gaining strength every time Meg worked out. Her body grew stronger and her muscles stayed happy through endless movements and stretches and half marathons.