Thank you for joining me again this evening for our nightly podcasts. I perform these podcasts in the hopes that you will be able to education yourself on the topics discussed so you can make better informed medical decisions regarding your health in the future. I am doctor Harrison Campbell of Restoration Health a premier sugar land chiropractors office. Previously we discussed the shoulder in great detail, covering the rotator cuff specifically. Tonight, we will be going over the other muscles in the shoulder joint and their specific functions.
To review let us break down the rotator cuff once before moving to the other muscle groups. The rotator cuff, as sugar land chiropractors know is composed of four muscles. These muscles are responsible for the internal and external rotations of the shoulder, hence the name rotator cuff. Additionally these muscles are the primary stability of the shoulder. Of the four muscles which form the rotator cuff the subscapularis muscle is the only muscle which internally rotates the shoulder.
This leaves the other three muscles to the external rotation of the shoulder. There is the infraspinatus and the teres minor. The infraspinatus sits below the spine of the scapula and the teres minor sits just below the infraspinatus. These two muscles are very rarely injured in shoulder injuries, but they do contained adhesions and painful nodules, which most people call knots. For sugar land chiropractors these pain nodules or trigger points can create pain in the shoulder and cause a build of of toxins due to decrease blood flow to that particular area of muscle fibers.
The final muscle of the rotator cuff is the supraspinatus. This muscle is located above the spine of the scapula and runs over the top portion of the shoulder. This muscle joins the infraspinatus and teres minor in being external rotators for the shoulder. Additionally sugar land chiropractors can tell you that this supraspinatus is also responsible for the initial abduction of the shoulder, approximately the first ten to twenty degrees of motion. Beyond that point the deltoid muscle takes over for abduction.
This brings us to the additional muscles of the shoulder. The deltoid will be where we start. As status this muscle is responsible for abduction of the arm, but the initial response is from the supraspinatus. This goes back to angles and levers. Due to the angle of contraction the deltoid can not efficiently elevate the arm from a resting position. This is where the supraspinatus does the initial work load and once the deltoid has a better angle of pull, it can take over and raise the arm. Now workout buffs are also going, but he deltoid can raise the arm to the front of the body and to the back of the body as well.
This is true, and sugar land chiropractors can tell you there are three heads to the deltoid the anterior, middle, an posterior deltoid. These three different heads become responsible for those motions mention above. That is why you often hear people talk of exercising the anterior delt or the posterior delt with certain exercises.
As for why this muscle is called the deltoid, it has to do with the Greek alphabet, or more specifically the shape of a letter in the alphabet. The delta in Greek is a triangle shaped letter and the deltoid muscle is a triangle shaped muscle. Thus, it was named deltoid due to the shape.
Moving on from the deltoid we will go to perhaps the most famous muscle of the arm, commonly shortened to the bicep. Sugar land chiropractors know the full name of this muscle is the biceps brachii. To break apart the naming for this muscle we know that bi means two and ceps means head. Therefore, the term biceps means two heads. Brachi means arm, thus the full name of the muscle is the two headed muscle of the arm. Pretty good description if you understand what this muscle looks like. There is a long and short head of the biceps. The short head runs from the arm and attaches to a boney protrusion from the scapula called the corocoid process. This is the process in the anterior shoulder near the armpit, and is usually very tender.
The long head of the biceps travels up the arm through the biceps tendon groove and attaches partially to the labrum and partially to the glenoid fossa rim. Now as you recall the labrum is a fibrous ring which runs around the glenoid fossa to turn a flat joint surface into a socketed surface for a ball and socket joint. Usually when someone tears the labrum the tear is the junction between the biceps tendon, the labrum, and the labrums attachment to the glenoid fossa. In some cases an injury hear can be referred to by sugar land chiropractors as a SLAP lesion.
SLAP stand for superior labrum tear anterior to posterior. This means the labrum has torn in the superior section, where the biceps tendon attaches, and the tear goes from the front of the shoulder, anterior, to the back of the shoulder, posterior.
Now we briefly mention the biceps tendon groove. This is a channel in the humerus for the tendon to travel. When the shoulder moves the rotator cuff keeps this biceps tendon in place. Should this not occur properly, there can occur a slipping of the biceps tendon. You can physically feel this thunk, due to the tension of the biceps muscle. Think of a guitar string being strung.
Thank you for joining me again this evening for another great podcast. I hope you enjoyed the discussion on the continuation of the shoulder musculature. As always should you or someone you know require a sugar land chiropractors services or simply have more questions on what was discussed please call Restoration Health today. We would love to schedule you an appointment and get you on the path to better health today. Thank you once again for joining us. Have a good night.