TERES MINOR MUSCLE: ORIGIN, INSERTION, INNERVATION, FUNCTIONS - ANATOMY AND PHYSIOLOGY - 2025

The teres minor is a thin muscle located in the shoulder. It is one of the four muscles that form a support and stability structure for this joint, which is called the rotator cuff.

The teres minor muscle is responsible for external or lateral rotation of the arm, from the shoulder. It is a very important muscle as it provides stability to the shoulder and prevents excessive internal rotation. This function reduces the probability of dislocation of the joint.

By Anatomography - en: Anatomography (setting page of this image), CC BY-SA 2.1 jp, The shoulder joint is made up of three bones, and reinforced by various ligaments and muscles. It has the greatest range of motion between the joints of the body. The shoulder achieves its movements by the action of the balanced and synergistic work of the different muscles that make it up.

Shoulder pain is one of the most common causes of trauma consultation and is usually caused by rotator cuff degeneration.

Other rotator cuff injuries require surgery, most of the time. However, in some cases, they can improve with non-invasive treatments (which will depend on the injury).

Inflammation of the tendons of the rotator cuff muscles, known as tendonitis, is one of the most common. It is a pathology that improves with physical therapy and rest. The tendon of the supraspinatus muscle is, in general, the most affected in this type of pathology.

It is important to treat in a timely manner any problem that affects the shoulder, since by decreasing the movements, the joint can become atrophied and require long processes of physical therapy for its full recovery.

Embryological origin

The extremities, both lower and upper, begin their formation at the end of the fourth week of gestation.

Stem cells, which have the ability to differentiate into any tissue, migrate to the area of ​​the upper extremities and the process of forming cartilage begins, which will eventually form bones.

By Aliasgharson - Own work, CC BY-SA 3.0, By the sixth week, shoulders and upper limbs can already be differentiated. Also the lower limbs are formed for that moment.

Around the eighth week of gestation, all the muscles that make up the rotator cuff, including the teres minor, are completely differentiated and in the position they will have after birth.

Structure, irrigation and innervation

The teres minor is a thin muscle that travels short. It originates on the posterior aspect of the scapula, specifically in an area called the infraspinatus fossa, and inserts on the upper part of the humerus, in the greater tubercle.

During its journey it is closely related to another muscle, the infraspinatus. In fact, they are sometimes found fused at their final insertion in the humerus.

Irrigation

The blood supply to the teres minor muscle comes from the posterior humeral circumflex and subscapular arteries. Both are direct branches of the axillary artery, which is the most important blood vessel in the upper limb.

From Henry Vandyke Carter - Henry Gray (1918) Anatomy of the Human Body (See "Book" section below) Bartleby.com: Gray's Anatomy, Plate 524translation of File: Gray524.png, Public Domain, https: //commons.wikimedia. org / w / index.php? curid = 22123354

The teres minor muscle, together with the teres major, the triceps, and the humerus, delimit an anatomical region known as the humerotricipital quadrilateral. The posterior humeral circumflux artery crosses this space accompanied by the vein of the same name and the axillary nerve.

The humerotricipital quadrilateral is an important region for orthopedists when performing surgical procedures involving the shoulder and upper arm, as it helps to identify these structures to avoid injury and allows placement within the surgical space.

Innervation

Sensory and motor innervation of the teres minor is provided by a posterior neurological branch of the axillary nerve.

The axillary nerve makes an identical route to that of the axillary artery, always being located on the scapula, giving branches to the muscles of the region.

From Henry Vandyke Carter - Henry Gray (1918) Anatomy of the Human Body (See "Book" section below) Bartleby.com: Gray's Anatomy, Plate 810, Public Domain, https://commons.wikimedia.org/w/index. php? curid = 541666

Once it reaches the lower border of this bone, it enters the humerotricipital quadrilateral together with the circumflex artery and vein, and divides into an anterior and a posterior branch. The posterior branch is the one that innervates the teres minor.

Features

The teres minor muscle is responsible for performing the external or lateral rotation movement of the arm, through the shoulder joint.

By User: Porco-esphino - Own work, Public Domain, The shoulder is a complex joint of the upper limb. It has the greatest range and variety of body movements.

The shoulder joint, or glenohumeral, is made up of the head of the humerus, which is round and fits into a cavity of the scapula called the glenoid cavity. Between these two structures there is a capsule that prevents friction and ensures safe movement of the joint.

The soft tissues of the shoulder are a group of muscles and ligaments that keep it stable and prevent injury. These stabilizing structures are divided into static and dynamic.

By OpenStax College - Anatomy & Physiology, Connexions Web site. http://cnx.org/content/col11496/1.6/, Jun 19, 2013., CC BY 3.0, Static stabilization is provided by the ligaments, while the dynamic stabilization is provided by the rotator cuff, which is an anatomical structure made up of the teres minor and three other muscles, the subscapularis, the supraspinatus and the infraspinatus.

By Henry Vandyke Carter - Henry Gray (1918) Anatomy of the Human Body (See «Book» section below) Bartleby.com: Gray's Anatomy, Plate 412, Public Domain, https://commons.wikimedia.org/w/index. php? curid = 527328

All originate from the scapula and attach to the humerus, stabilizing the shoulder in all directions except for its lower part.

In addition to performing the external rotation movement, the teres minor muscle has a secondary function, which is to prevent excessive internal rotation, which reduces the possibility of injuries due to dislocation, or dislocation, of the joint.

Clinical considerations

The way to examine the teres minor muscle is by observing its movement, both passive, assisted by the doctor, and active, carried out by the patient.

In the event of pain, the patient is asked to perform the movement but this time against resistance.

By US Navy photo by Mass Communication Specialist Seaman Apprentice Robert Winn - This Image was released by the United States Navy with the ID 091003-N-8960W-011 (next). This tag does not indicate the copyright status of the attached work. A normal copyright tag is still required. See Commons: Licensing. العربية - বাংলা - Deutsch - English - español - euskara - فارسی - français - italiano - 日本語 - 한국어 - македонски - മലയാളം - Plattdüütsch - Nederlands - polski - پښتو - português - svenska - Türkçe - сукаї - сука - svenska - Türkçe中文 （简体） - +/−, Public Domain, For this maneuver, the patient is placed on a flat surface and the shoulder is sought to be at a 90 ° angle. The physician places his hand with gentle but firm pressure on the patient's arm and is instructed to try to overcome the resistance by externally rotating the shoulder.

If the teres minor is injured, the patient cannot perform the movement and the sign is considered positive. This maneuver is known as a hornblower sign or a trumpet player sign.

Pain in the shoulder

Shoulder pain is one of the main reasons for consultation in trauma. Up to 65% of the cases of pain in this joint are the result of rotator cuff degeneration.

Diagnosis is made through physical examination and imaging tests such as magnetic resonance imaging (MRI).

The treatment of this pathology is medical and includes rest, hot and cold therapy and strengthening exercises.

By Bundesarchiv, Bild 183-1986-1126-015 / CC-BY-SA 3.0, CC BY-SA 3.0 de, In the case of more serious injuries, such as muscle tears, dislocations or muscle pulling, the treatment is surgical and must be carried out by an expert team in these types of procedures.

References

1. Juneja, P; Hubbard, JB (2019). Anatomy, Shoulder and Upper Limb, Arm Teres Minor Muscle. StatPearls. Treasure Island, FL. Taken from: ncbi.nlm.nih.gov
2. Mostafa E; Varacallo M. (2018). Anatomy, Shoulder and Upper Limb, Humerus. StatPearls. Taken from: ncbi.nlm.nih.gov
3. McCausland, C; Sawyer, E; Eovaldi, BJ (2019). Anatomy, Shoulder and Upper Limb, Shoulder Muscles. StatPearls. Treasure Island, FL. Taken from: ncbi.nlm.nih.gov
4. Maruvada, S; Varacallo, M. (2018). Anatomy, Rotator Cuff. StatPearls. Treasure Island, FL. Taken from: ncbi.nlm.nih.gov
5. Suárez Sanabria, N; Osorio Patiño, AM (2013). Biomechanics of the shoulder and physiological bases of the Codman exercises. Rev CES Med. Taken from: scielo.org.co