por He teres major muscle It is located in the upper limbs and forms the shoulder, together with other neighboring muscle-tendon structures, it deals with adduction and internal rotation of the arm.
The teres major is a short muscle and is one of the six muscles that make up the scapulohumeral group, that is, they join the scapula bone with the humerus, which is the upper arm bone. It is part of the so-called intrinsic muscles of the shoulder.
Isolated injury to this muscle is rare, but it can occur in high performance athletes. Its clinical importance is based on the fact that it can be used as a graft when there is a tearing injury to other shoulder muscles.
It is also of great importance as an anatomical reference for the surgeon in any surgical procedure that involves the armpit, since it establishes, together with other muscles, the limit between the axillary space and the arm.
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Anatomy
The teres major is one of the muscles that makes up the shoulder. It is short and cylindrical in shape. It extends from the scapula to the humerus, if it were projected towards the skin its route would be from the lower part of the armpit to the middle part of the arm.
It is closely related to the muscles: teres minor and latissimus dorsi, also known as latissimus dorsi. Its fibers run parallel to those of the latter muscle.
It receives its blood supply from a branch of the circumflex scapular artery, which is a major axillary blood vessel. The inferior subscapular nerve is responsible for innervation.
The muscle is of particular importance in surgical anatomy, as it forms the region known as the humerotricipital quadrilateral located in the axilla. This region defines the limit between the armpit and the arm when surgeries are performed in that region.
Together with the teres minor muscle and the triceps muscle, the teres major makes up this axillary anatomical region through which important vascular and neurological elements, such as the axillary nerve and the posterior circumflex artery, make their way.
Function
Thanks to its attachment to both the scapula and the upper part of the humerus, the teres major muscle is responsible for performing three movements of the arm.
Its activation achieves internal rotation of the arm, adduction and also retroversion, which is to bring the arm behind the back. Thus, when we try to touch the opposite shoulder in front or behind the body, it is thanks to the activation of the teres major.
Its close relationship with the latissimus dorsi muscle leads it to fulfill accessory functions in some of the movements that the latter performs when activated. Its fibers and those of the dorsal run parallel, joining at some point in certain movements, especially shoulder extension.
clinical considerations
injuries
Injury to the teres major muscle is a rare event but it can occur and should always be on the mind of the physician or trainer as a possible area of injury. Due to its location, it is difficult to establish that the teres major is the injured muscle.
Those exercises that lead to muscle overload can cause injury. Movements such as pull-ups and sports such as tennis, skiing, rowing, and swimming are activities to consider in the medical history of a patient with signs of teres major trauma.
Typically, symptoms of injury include pain that can be felt down the back of the arm, toward the deltoid or triceps muscle, which make up the outside of the shoulder, and even toward the elbow.
Although the muscle inserts on the scapula, pain is rarely in this location.
The doctor must try to highlight the muscle lesion through some clinical maneuvers. You should first try passive mobilization, that is, helping the patient to carry out the movement, and then begin palpation of the tender points or pain trigger points.
Due to the location of the muscle, it is difficult to palpate it. A simple way used by clinicians to achieve palpation of teres major pain trigger points is by following the fibers of the latissimus dorsi muscle.
The fibers of this muscle run parallel to the teres major. In this way, when palpating the latissimus dorsi, we locate the teres major by palpating in the same direction, but on the inside.
Treatment
Most teres major injuries improve with clinical therapy. This means that, with rest and oral analgesics, it is enough to observe the healing of the trauma.
Muscle massages performed by a professional physiotherapist or chiropractor are also of great help for complete improvement.
In some cases, especially when there is a tear or detachment, surgical therapy is necessary. However, it is important to clarify that these injuries are not common.
Strengthening
To avoid muscle injuries, health professionals recommend exercises that strengthen it.
Very few people place emphasis on training this muscle, either because they are ignorant of its existence or because they consider it of little importance. This exclusion in the exercise routine can lead to muscle injury.
Teres major strengthening exercises are similar to those for the latissimus dorsi muscle. The important thing is not to overload the muscle, but to train it progressively until the increase in its resistance is achieved.
Activities that can be done both in the gym and outdoors include rowing and weight-bearing pull-ups. Once mastery of these activities has been achieved, you can begin to add weight-bearing exercises to your training activities.
One of the most effective exercises to achieve the strengthening of the teres major consists of the so-called rowing with dumbbells.
This activity is accomplished using a dumbbell of a weight that can be controlled. The knee and hand of the opposite arm to the one to be exercised should be supported on an exercise bench.
With a straight back, the elbow is brought back, raising the dumbbell, as if imitating the movement of the oar. With this exercise, you work on the teres major muscle and the dorsal muscle, strengthening it and avoiding injuries.
References
Miniate MA; Varacallo M. (2019). Anatomy, Shoulder and Upper Limb, Shoulder. StatPearls. Taken from: ncbi.nlm.nih.gov
Mostafa E; Varacallo M. (2018). Anatomy, Shoulder and Upper Limb, Humerus. StatPearls. Taken from: ncbi.nlm.nih.gov
Dancker, M.; Lambert, S; Brenner, E. (2017). Teres major muscle – insertion footprint. Journal of anatomy; 230, 631–638
Cousin, J; Crenn, V.; Fouasson-Chailloux, A; Dauty, M; Fradin, P; Gouin, F; Venet, G. (2018). Isolated Rupture of the Teres Major Muscle When Water Skiing: A Case Report and Literature Review. Case reports in orthopedics. Taken from: nlm.nih.gov
Donohue, B.F.; Lubitz, MG; Kremcheck, T.E. (2017) Sports Injuries to the Latissimus Dorsi and Teres Major. The American Journal of Sports Medicine. Taken from: nlm.nih.gov