52 LABORATORY MANUAL OF HUMAN ANATOMY 



Compare the distance between the acromion and the ster- 

 nal extremity of the clavicle on the two sides. Why would 

 such a comparison be of importance in surgical diagnosis? 



(b) Outline of sternum. 



(ba) Manubrium sterni. 



Jugular notch (incisura jugularis) (0. T. suprasternal 

 notch). 



(bb) Corpus sterni (0. T. gladiolus). 



Angle of sternum (angulus sterni) (0. T. angulus Ludovici, 

 angle of Louis), an important landmark in counting ribs 

 and intercostal spaces. 

 (be) Processus xiphoideus (0. T. ensiform process). 



(c) Costal arches I -XII. 



(ca) Ribs (costae I.-XIL). 



(cb) Costal cartilages (cartilagines costales). 



Is a " rickety rosary" present ? 



(d) Coracoid process of scapula (processus coracoideus scapulae). Note 



its relation to the infraclavicular fossa (fossa infraclavicularis or 

 Mohrenheim's fossa) and the relation of the clavicular origins of 

 the M. pectoralis major and the M. deltoideus to the latter. 



(e) Breast (mamma). 



(ea) Papilla mammae, or nipple of the breast. 



Note its exact level and its distance from the anterior 

 median line. 



(eb) Body of breast (corpus mammae). 



Note its dimensions. 



(ec) Areola mammae. 



(1) Sebaceous glands (Gl. sebaceae). 



(2) Areolar glands (Gl. areolares [Montgomerii]). 



(ed) Accessory breasts (mammae accessoriae) . 



Are any present? What is the direction of the so-called 

 " milk-line" ? Note that of the two rows of milk-glands 

 running from the forelimb to the inguinal fold, the head- 

 ward portions are preserved in primates, the tailward por- 

 tions in ruminants. What are meant by the terms poly- 

 mastism, polythelism , and atavism? 



(f) Boundaries of axillary fossa (upper extremity abducted). 



(fa) Anterior axillary fold (plica axillaris anterior). 



To what is it due? 



(fb) Posterior axillary fold (plica axillaris posterior). 



To what is it due? Which fold extends to the lower 

 level ? 



(g) Upper extremity of humerus. 



Palpate, in the axillary fossa, the medial surface of the surgical 

 neck (collum chirurgicum) and feel the head of the humerus (caput 

 humeri) rotate when the arm is rotated. 



Skin and Superficial Fascia, with Vessels and Nerves. 



Make the following incisions in the skin (cf. Fig. 7) : 



(a) In the linea mediana anterior from the fossa jugularis to the tip of 

 the processus xiphoideus. 



