1. bony, muscular landmarks Oblique muscle nodule: at the posterior margin of the scapular冈, located in the subcutaneous elevation. (Figure 2-36) Cui Xiaofang, Department of Neurology, Bayannur City Hospital Just superior fossa of the scapular Gonad: above the scapular Gonad, it is the attachment point of the supraspinatus muscle. Just inferior fossa of the scapular Gonad: below the scapular Gonad, it is the attachment point of the infraspinatus muscle. (Figure 2-37) Humerus Head: The humeral head can be felt rotating when the shoulder joint is flexed 90° and rotated internally and externally; when rotated internally, the greater and lesser tubercles of the humerus and the intermediate intertrochanteric sulcus can be palpated. (Figure 2-38) Acromion: at the lateral end of the clavicle. (Figure 2-39) The lateral end of the scapula and the acromion of the clavicle form the acromioclavicular joint. (Figure 2-40) The inferior and posterior margins of the acromion are the attachment points for the deltoid muscle. (Figure 2-41) Scapular facet: palpable on the lateral aspect of the acromioclavicular joint. (Figure 2-42) The rostral eminence: palpable on the medial aspect of the humeral head and just below the clavicle is the tip and medial margin of the rostral eminence, which is the attachment point for the tendon of the short head of the biceps brachii, rostro-humeral muscle, and pectoralis minor muscle. (Figure 2-43) Biceps groove: internal rotation of the upper arm, proximal to the midpoint of the humerus, the groove contains the long head of the biceps brachii and its tendons. （The anterior deltoid and the rostro-humeral muscles are the main flexors of the shoulder joint (Figure 2-44). The interosseous fibers of the pectoralis major, biceps brachii, serratus anterior, and trapezius are the secondary flexors. (Figure 2-45) Deltoid: Starts at the outer 1/3 of the clavicle, acromion, and scapular ridge. The end point is at the humeral deltoid ramus. Posterior Muscle Bundle (Spinal Division): abducts the shoulder joint at 90° flexion of the elbow joint and is palpable on the posterior aspect of the shoulder joint. (Figs. 2-46, 2-47) Middle fascicle (acromion): shoulder abduction is central between the anterior and posterior fascicles. (Figure 2-48) Anterior fasciculus of the deltoid (clavicular): the fasciculus can be palpated by performing a horizontal forward thrust of the shoulder. (Figure 2-49) Beak-humeral muscle: When the arm is flexed and adducted and the elbow is flexed, a taut, cord-like muscle can be felt on the medial surface of the arm, behind the biceps. (Figure 2-50) Origin: rostral process. End point: medial aspect of the middle of the humerus. (Figure 2-51) Biceps brachii longus belly: in front of the elbow area, in front of the arm and down to the deltoid, flexion and extension of the elbow joint can better visualize the belly of the muscle. (Figure 2-52) Biceps short head: proximal 1/3 of the front of the upper arm, near the pectoralis major. (Figure 2-53) Biceps Tendon: The biceps tendon is palpable at the elbow socket when the forearm is rotated back and the elbow is flexed against resistance. (Figure 2-54) Starting point of the biceps brachii muscle: the long head starts at the superior glenoid tubercle of the scapula, and the short head starts at the rostral eminence of the scapula. The end point is at the radial tuberosity. (Figure 2-55) Anterior Saw: Repeat a short inspiratory movement to see the finger-like projections attached to the ribs appear between the latissimus dorsi muscle posteriorly and the pectoralis major muscle anteriorly. (Figure 2-56) Starting point: ribs 1-8. End point: medial border of scapula and inferior angle. (Fig. 2-57) Obliques: upper fibers from the occipital protuberance outward and downward to the outer 1/3 of the clavicle. The lower fibers attach to the medial aspect of the scapular gonad and travel downward along the medial aspect of the spinous processes of the lower thoracic vertebrae. Depression of the scapula is evident. The middle fibers are palpable from the acromion to the spinous processes of the 7th cervical and upper thoracic vertebrae, and internalization of the scapula is evident. The trapezius muscle is flattened and due to rotation of the fibers will be palpable as a striated structure that is normal without tension and without tenderness. (Figure 2-58) The posterior fibers of the latissimus dorsi, teres major, and deltoid are the major extensor muscles of the shoulder joint. The teres minor and the long head of the triceps brachii are the qualifying extensor muscles. Painful shoulder extension suggests contractile tendonitis. (Figure 2-59) 3. Extensor digitorum longus: This muscle is palpable on the medial aspect of the upper arm and the posterior lateral portion of the thorax. (Figure 2-60) The origin is at the spinous processes of the lower six thoracic vertebrae and all lumbar vertebrae and the iliac crest. Stopping point: the crest of the lesser tuberosity of the humerus. (Figs. 2-62, 2-63) Greater trochanter: on the medial aspect of the upper arm, pushing upward on the posterior aspect of the thoracic contour, there is a distinct muscular protuberance that is this muscle. (Figure 2-61) Lesser Circle Muscle: With the shoulder abducted, the elbow flexed at 90°, and the forearm rotated forward, this muscle is found between the deltoid and the greater circle muscle on the lateral border of the scapula. (Figure 2-64) Proximal end of the long head of the triceps brachii tendon: Shoulder abduction, elbow flexion, 90° each, the distal end of the forearm abducts the elbow joint against resistance, and the tendon can be touched on the posterior shoulder between the posterior fascia of the deltoid muscle and the lateral aspect of the teres minor muscle. (Figure 2-65) Triceps: Starting point: long head from the subglenoid tuberosity of the scapula; medial head from the bony surface below the inner radial nerve groove; lateral head from the bony surface above the outer radial nerve groove. Stopping point: the ulnar humerus. (Figs. 2-66, 2-67) The middle fibers of the deltoid and the supraspinatus are shoulder abductors. The anterior and posterior fibers of the deltoid and the serratus anterior have an auxiliary role. Resistance to shoulder abduction pain suggests contractile tendonitis. (Figs. 2-68, 2-69) 4. Abduction The middle (acromion) fascicle of the deltoid: shoulder abduction is central between the anterior and posterior fascicles. Supraspinatus: the arm is abducted and the muscle is palpable in the supraspinatus fossa. (Figure 2-70) 5. Adduction Pectoralis Major: Starting point: medial half of clavicle, sternum, 1st-6th rib cartilage. End point: crest of the greater tuberosity of the humerus. (Figure 2-71, 2-72, 2-73, 2-74) 6. Internal rotation The subscapularis, latissimus dorsi, vastus lateralis, and pectoralis major are the main shoulder joint internal rotation muscles. (Fig. 2-75) Painful internal rotation of the shoulder joint is most often caused by tendinitis of the contractors. Subscapularis: Touching this muscle must isolate a gap between the scapula and the thorax. The lateral aspect of the finger is the latissimus dorsi muscle, the medial aspect anteriorly is the pectoralis major, and the subscapularis muscle is under the finger. (Figure 2-76) Starting point: subscapularis fossa. End point: humeral tuberosity. (Figure 2-77) 7. EXTERNAL ROTATION The infraspinatus and teres minor are the major muscles of external rotation of the shoulder. The posterior fibers of the deltoid assist in external rotation. (Figure 2-78) Infraspinatus: Starting point: infraspinatus fossa of the scapula. End point: middle portion of the greater tuberosity of the humerus, palpable in the infraspinatus fossa. (Figure 2-79) Lesser Circle Muscle: Starting point: dorsal surface of the lateral border of the scapula. Stopping point inferior portion of the greater tuberosity of the humerus, palpable between the deltoid and greater trochanter on the lateral border of the scapula. (Figures 2-80, 2-81)