little known muscle series – infraspinatus & teres minor

Time for another installment of … the little known muscle series. Today I’ll highlight 2 muscles that work in tandem. They are infraspinatus and teres minor.They are part of the shoulder’s rotator cuff.

Muscle mapquest: These muscles are found on the back of the shoulder blade. They lie at an angle more or less pointing up towards the top of the arm bone.

What do they do? As part of the rotator cuff, they work to stabilize the arm in the shoulder joint. Our shoulder joint is designed to allow for maximum range of motion. The trade-off is decreased stability. In addition to ligaments, there are 4 main muscles serving to stabilize the joint. Infraspinatus and teres minor partner with supraspinatus and subscapularis to accomplish this stability. Each of these muscles has its own action. Infraspinatus and teres minor laterally rotate the arm bone (humerus) in the shoulder joint. They also adduct, extend and horizontally abduct the arm. **Anatomy nerds see below for more detail on these fascinating actions.

The other main function of infraspinatus and teres minor is to act as brakes. Other muscles that move the arm are much bigger and stronger, like the pectoralis major, a big chest muscle. Pectoralis major is an antagonist to our subject muscles, as well as latissimus dorsi and teres major (in rotation). An antagonist in anatomy terms is a muscle that does the opposite action. To understand this important braking action, imagine a baseball pitcher throwing a 90-mile-an-hour fastball. It’s a wonder his arm doesn’t just fly out of the socket right behind the ball. Well, this demonstrates the action of the infraspinatus and teres minor. They stomp on the brakes so as to prevent dislocation, tears and sprains. At least they try to!

Why they are sore: Because these muscles are smaller in relation to their bigger antagonists and because they are typically weaker and less developed than the big guns, it’s not uncommon for them to be sore upon palpation (touching them) or massage. They can also be overwhelmed by sudden loads or overexertion. They are sore on most people I see for massage. And most people are surprised. “What’s that?” they ask. I don’t massage any MLB pitchers, so why are they sore on the average person? They are sore on most people because everything we do is in front of us: driving, working at the computer, doing the dishes, holding kids, etc. Our forward activities cause us to curl inward in our posture and this puts these small muscles in a constant stretch position. This makes them cranky. Weak, underdeveloped muscles tend to be sore because they are overpowered by their antagonists. Here’s what we can do to make them happier –

Loosen them: Massage is great for loosening up these muscles and for simply drawing our attention to them. If we don’t know a muscle is sore, we probably won’t pay any attention to it. Between professional massages, you can massage these muscles yourself at home. All you need is a tennis ball and a wall. Stand with your back against a wall. Place the tennis ball between you and the wall with the ball positioned where your shoulder blade is. Push your weight into the ball and roll it around until you find a spot that feels sore. This is a great way to massage your back in general. To find this infraspinatus and teres minor spot, I find it helpful to raise my arm to the side so it’s parallel with the floor. I scoot the ball over so that it’s at the edge of the shoulder blade along the border. When I find a “hurt so good” spot, I move my body so the ball massages the spot in a circular motion. Limit your tennis ball massage time to a short amount, like a minute or two. You can repeat it throughout the day, but keep it short each time otherwise you’ll make yourself really sore. Trust me – respect the tennis ball!

Strengthen them: A healthy shoulder has equally strong and developed rotator cuff muscles that stabilize the arm in the joint. If you participate in a sport or hobby that is shoulder- or arm-intensive, it would be smart to make sure you develop strength in all the rotator cuff muscles. A good trainer, physical therapist or even massage therapist can help you figure out what exercises you can do to strengthen what’s weak. You can also spend some time learning about medial and lateral rotation, abduction and adduction, flexion and extension, etc. and put together a regimen that addresses each action. Most men I know are interested in developing a super-burly looking chest by developing pectoralis major, and neglect these important stabilizer muscles. Don’t be like most men! Be smarter.

Comments? Questions? I hope this is helpful. Now go enjoy this amazing range of motion you’ve been given!

** Anatomy nerds: To understand rotation of the arm stand with arms hanging at your sides. When you laterally rotate your arms you rotate them so that your thumbs turn away from your body. The opposite would be medial rotation (rotate them so that the backs of your hands turn in toward your legs). Adduction is seen when you start with arms straight out to the sides at 90 degrees. Bring the arms down to the body. Extention is the action of moving the arms behind your body from a starting position of arms hanging at your sides. To see horizontal abduction, start with straight arms out to your sides at 90 degrees. Move the arms back behind the body in the same plane. Get the picture?


little known muscle series – subscapularis

This is the first is an occasional series about muscles most of us are unaware of…that is, until they get cranky. In each article, I hope to explain a bit about the muscle, it’s function and importance and how I address it during a massage session to my client’s benefit.

We’ll start with one of my favorites: subscapularis. Subscap for short. Now, for those of you who can’t remember high school anatomy class, I’ll start with the basics. Where in the world is it? Subscap is found on the front side of the shoulder blade, the side that is up against the back of your rib cage. This should immediately tip you off as to why this is a little known muscle! It attaches to the top of the arm bone, the humerus. It rotates the arm medially. That means that if your arm is hanging by your side, palm towards your leg, this muscle rotates the elbow backwards so that your hand is now facing the back of the body. Hopefully that’s clear.

Subscap is part of the rotator cuff. That may be a familiar term to some who have had shoulder injuries or strains. Subscap has 3 buddies that make up the rotator cuff (infraspinatus, teres minor, and supraspinatus). These muscles help stabilize the arm in the shoulder joint. One of the main reasons rotator cuff injuries are not uncommon is that these 4 muscles help stabilize a joint that has a great deal of range of motion. That range of motion comes at the cost of stability, especially when the muscles are weak, given a sudden jolt or load, or subjected to repetitive overuse. Fans of baseball are very familiar with pitchers experiencing rotator cuff injuries.

What I’ve found in my massage practice is that the rotator cuff muscles are worth checking into if a client is experiencing upper body strain or fatigue, if they clock long hours in front of a computer or steering wheel, and if they walk around with shoulders high and the head out in front of the body. I’ve found that when the subscap is tight, the shoulders ride high. When the subscap is able to release some of its tension, the whole shoulder can drop and relax.

So, how do you get to it if it’s up against the back of the shoulder blade you might fairly ask. I like to joke with my clients that the spa portion of the massage is about to end when we address subscap. If you were floating lazily on a cloud of relaxation, this is sure to bring you back to earth. One of my client’s likes to say this about working his subscaps: “You like to see grown men cry, don’t you?” Perhaps. Don’t worry, I never just spring subscap on clients. Anyway, here’s how we get to it. This next part is like anatomy mapquest:

with my client lying face up on the table,

I take the arm out from under the sheet,

bring it a little bit away from the body,

bend the elbow slightly and

put the hand on a towel on the table near the side of the body.

I put a dab o’ lotion in the armpit area and

slide my flat fingers in towards the subscap.

I am now gently “pinning” the muscle.

I instruct my client to push down with the hand.

This contracts the muscle (medial rotation) and stretches it.

Repeat, being sure to breathe and smile.

For some people this is very intense and has the feeling that we’re deep inside the body. For others it’s no big deal. We know it’s important work when it’s more intense. Sometimes I can feel the muscle twitching and then giving up its death grip on the shoulder. In combination with other upper body massage work, addressing this muscle can leave you feeling fantastic and much freer in the neck and shoulder region.

So, there you go! Let me know if you want to explore subscap during a massage session sometime (if you’re a local reader, of course – it’s very tricky to work on from a distance!). Do you have any rotator cuff stories to tell? Use the comments below to tell your tale.