Prelab Images - Pectoral Region & Breast

Prelab Images - Pectoral Region & Breast

Prelab should consist of reading the lab manual and dissector answers and viewing the dissection video. To begin your study, you may find it useful to look over the Netter's or LWW Atlas images listed below.
Step 1. Review the bony landmarks. (Play movie)
Crest of greater tubercle of humerus is labeled on plate N420 or TG2-03. The clavicle can be seen on plates N419 and N420 or TG2-03. The suprasternal (jugular) notch, manubrium, sternal angle, body, and xiphoid process of the sternum can be seen in plate N185 or TG4-04. The coracoid process can be seen anteriorly in plate N420 or TG2-03A and posteriorly in plate N421 or TG2-03B.
Step 2. Remove the skin from the chest wall as in Figure 2. (Play movie)
Perform this step the same way you skinned the back. Make a midline incision from the suprasternal notch to a couple inches below the xiphoid process and then make skin flaps like you have done before. Reflect the skin flaps laterally. Plates N180 or TG1-17, N257, and N192 or TG4-02 should give you an idea of where to look for the lateral and anterior cutaneous branches of the intercostal nerves. Plate N188 or TG2-12 is similar to what you will see in lab except you will have a lot of subcutaneous tissue on top of the muscle. The best view of the serratus anterior is plate N188. The long thoracic nerve comes from the brachial plexus (plate N430 and N429 or TG2-13) to innervate the serratus anterior (plate N188). The lateral thoracic artery branches off the axillary artery in plates N427 or TG2-15B and N429 or TG2-15A and supplies blood to the serratus anterior in plate N188. Plate N183 or TG4-07 is another view of the neurovascular supply of the serratus anterior. The insertion of the serratus anterior into the scapula is shown in plate N420 or TG2-06.

Plate N182 or TG2-10A and TG2-10B identifies the features of the breast. In lab you want to remove a section of the breast so you can have a view similar to this plate. Plate N183 or TG4-02 and TG2-11 shows the blood supply to the breast. Plate N184 or TG2-11 is an extremely important plate that shows the lymph drainage of the breast. Plates N188 or TG4-02 and N189 or TG4-11 show the course of the lateral cutaneous nerves that innervate the skin of the breast.
Step 3. Identify and reflect the pectoralis major muscle and identify its blood and nerve supply. (Play movie)
Pectoralis major is seen in plate N188 or TG2-12. The anterior axillary nodes are seen in plate N184 or TG2-11B. The cephalic vein in the deltopectoral groove is seen in plate N424 or TG2-12. You need to cut through the pectoralis major's attachment to the sternum and clavicle and reflect it laterally without damaging the underlying neurovasculature. The lateral pectoral nerve (supplies pectoralis major) and medial pectoral nerve (supplies pectoralis major and minor) both come from the brachial plexus (plate N430 or TG2-13). After reflecting pectoralis major your view will look something like plate N188 or TG2-12. The pectoral branch of the thoracoacromial artery is shown at its origin in plate N427 or TG2-15, perforating the clavipectoral fascia with the lateral pectoral nerve in plates N188 or TG2-12 and N428, and supplying pectoralis major and minor in plate N429 or TG2-15. The insertion of pectoralis major is seen in plate N420 or TG2-06.
Step 4. Identify and reflect the pectoralis minor muscle, identify its blood and nerve supply and clavipectoral fascia. (Play movie)
Pectoralis minor is seen covered in fascia in plates N428 and N188 or TG2-12 and cleaned in plate N189 or TG4-07. Clavipectoral fascia is labeled in plate N188 or TG2-12. Plates N430, N429 or TG2-15, N188 or TG4-07 may once again be helpful in tracing the neurovascular supply to pectoralis major and minor. Plates N428 or TG2-12, N429 and N189 or TG4-07 show the cephalic vein terminating into the axillary vein. Next, pectoralis minor must be reflected laterally by removing it from its origin on the ribs. The insertion of pectoralis minor on the coracoid process can be seen in plate N420 or TG2-06.