Pectoralis major

Clipping through the hardened fibers of the pectoralis major and exposing thereby the pectoralis minor, its fibers were seen to be almost, if not quite, as dried out as were those of the outer muscle. ... 

Fig. 4.2 Detailed anatomy of the anterolateral chest, demonstrating the axillary vein with the pectoralis major and minor muscles removed. (From Belott PH, Reynolds DW. Permanent pacemaker and cardioverter defibrillation implantation. In Ellenbogen KA, Kay N, Wilkoff BL, eds. Clinical cardiac pacing and defibriUation, 2nd ed. Philadelphia WB Saunders, 2000, with permission.)...

Fig. 4.3 Anatomic relationship of the axillary vein to the pectoralis minor muscle. The pectoralis major has been removed. Note the cephalic vein draining directly into the axillary vein at approximately the first intercostal space. (From Belott PH. Unusual access sites for permanent cardiac pacing. In Barold SS, Mugica J, eds. Recent advances in cardiac pacing Goals for the 21st century. Armonk, NY Futura Publishing, 1997, with permission.)...

Fig. 4.20 A Incision carried down to the surface of the pectoralis major muscle and its orientation with respect to the deltopectoral groove noted. B Insert demonstrating the deltopectoral groove and orientation of the lateral border of the clavicular head of the pectoralis major. (From Belott PH. Blind axiUar venous access. Pacing Clin Electrophysiol 1999 22(7) 1085-1089, with permission.)...

Blind puncture through pectoralis major muscle using deep landmarks... 

Edge sternal head of pectoralis major muscle... 

Reflecting the lateral clavicular head of the pectoralis major muscle creates the lateral submuscular approach. In this case, an initial vertical incision is made along the deltopectoral groove. The dissection is carried down to the snrface of the pectoralis fascia. The lateral border of the pectoralis major clavicnlar head is retracted medially and a subpectoralis major muscle plane of dissection established. 

The lateral anterior axillary submuscular pectoral approach calls for creation of a dissection plane in the anterior axillary fold (104). A dissection plane is easily established as the pectoralis major is separated at the planes created between the pectoralis major and minor muscles. A skin incision is created inferiorly along the anterolateral axillary fold. It is carried down to the surface of the pectoralis major muscle. Both the pectoralis major and minor muscles are identified and separated and a plane of dissection is created between them. This approach usually requires a separate incision for venous access and tunneling to the axillary fold ineision. The inferolateral margin of the pectoralis major muscle is easily separated from the adjacent subcutaneous tissue for establishing a large plane of dissection. The ICD should be placed as medial as possible with the leads lateral to avoid the risk of CAN abrasion. With the ICD or pacemaker in the pocket, a careful multilayered closure is used. 

In the second phase (90 to 150 degrees), upward rotation of the scapula causes the glenoid fossa to tilt and face upwards as the humerus locks on the glenoid fossa. The trapezius and serratus anterior primarily contribute. The movement is restricted to some extent by the pectoralis major and latissimus dorsi but is facilitated by concomitant rotations of the sternoclavicular and acromioclavicular joints. 

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. 

It is typical to find somatic dysfunction in the upper thoracic region, both of the vertebrae and their ribs. Upper cervical somatic dysfunction is often present. A fairly common finding is that of a trigger point in the left pectoralis major muscle. 

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