Teres Minor

Axillary Nerve, Posterior Cord, Posterior Division, Upper Trunk, 

Upper two-thirds of the axillary border of scapula, over the dorsal aspect. 

Over the greater tubercle of the humerus, on the inferior facet. Position 

Patient prone with arm abducted to ninety degrees and elbow flexed over edge of plinth. 

Insert one-third of the way between acromion (A) and inferior angle (lA) of scapula along lateral border. 

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LIGAMENTOUS ARTICULAR STRAIN TECHNIQUE FOR THE TERES MINOR... 

FIG. 19-1 Ligamentous articular strain technique for the teres minor. 

The capsule of the glenohumeral joint is loose and pleated. The ligaments, which are merely thickenings in the capsule, provide little support. The major support of the humerus into the fossa is provided by the rotator cuff muscles, which hold the head into the fossa. These muscles include the supraspinatus, infraspinatus, teres minor, and subscapularis. Abduction-adduction and axial and horizontal rotations are coupled in that angular motions are accompanied by translatory slides. The caudal slide of the humeral head with abduction confers increased freedom of motion on the supraspinatus tendon beneath the coracoacromial ligament. 

Total flexion of the shoulder joint can also be divided into three phases. In the first phase (0 to 60 degrees), the muscles used are the anterior fibers of the deltoid, the coracobrachialis, and the clavicular fibers of the pectoralis major. Motion is limited by the tension of the coracohu-meral ligament and by the resistance offered by the teres minor, teres major, and infraspinatus muscles. 

Biceps Tendon and Rotator Cuff 210 Long Head of the Biceps Tendon 210 Subscapularis Tendon 214 Supraspinatus Tendon 216 Infraspinatus and Teres Minor Tendons 223 Rotator Cuff Interval 226 Shoulder Beyond the Cuff 227 Glenohumeral Synovial Space 227 Subacromial Subdeltoid Bursa 229... 

From the anatomic point of view, the muscles of the shoulder may be subdivided into two main groups intrinsic musdes (subscapularis, supraspinatus, infraspinatus, teres minor, teres major and deltoid), which originate and insert on the skeleton of the upper limb, and extrinsic muscles, which join the upper limb with either the spine (trapezius, latis-simus dorsi, levator scapulae and rhomboid) or the thoracic wall (serratus anterior, pectoralis minor... 

Fig. 6.6). The posterior infraspinatus and teres minor muscles act as external rotators of the arm. 

Fig. 6.7. Rotator cuff anatomy. Schematic drawing of a perspective view through the humeral head illustrates the rotator cuff tendons and the biceps as they approach toward the greater (GT) and the lesser (IT) tuberosities. These tendons are relatively flat and form a hood covering most of the circumference of the humeral head. The supraspinatus (SupraS) and infraspinatus (InfraS) join to form a continuum of fibers inserting into the greater tuberosity. The teres minor tendon (Tm) is closely apposed to the inferior margin of the infraspinatus, whereas the subscapularis (SubS) courses separately from the other tendons of the cuff due to the interposition of the biceps tendon (Bt) between it and the supraspinatus...

Apart from the type of approach used, we perform a standard US examination of rotator cuff tendons starting with the long head of the biceps tendon as the initial key reference. The examination of the biceps is then followed by scanning the anterior (subscapula-ris), superior (supraspinatus) and posterior (infraspinatus and teres minor) aspects of the rotator cuff. To avoid confusion with the spatial planes of the body, we prefer to use the terms long-axis and short-axis rather than longitudinal and transverse to indicate the orientation of the scanning plane according to the axis of the examined structure. 

The examination of the infraspinatus and teres minor tendons requires transducer positioning on the posterior glenohumeral joint either with the... 

Fig. 6.40a,b. Normal infraspinatus and teres minor muscles, a Sagittal 12-5 MHz US image over the infraspinous fossa demonstrates the upper infraspinatus (InfraS) and the lower teres minor (Tm), each of which is characterized by an individual hyperechoic aponeurosis (arrows), b Same scanning plane in another patient. A single posterior muscle (arrowheads) formed by the union of the two bellies of the infraspinatus and teres minor is found. Observe the wide central aponeurosis of this muscle (arrows). Asterisk, spine of the scapula. The insert at the upper left side of the figure indicates transducer positioning... 

Although a caudal approach through the axilla has been described to evaluate the axillary pouch, posterior transverse scans are usually preferred for better accessibility. Once the teres minor tendon is localized, the transducer is shifted more caudally to investigate the space intervening between the humeral metaph-ysis and the inferior neck of the scapula, where the... 

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