THE THORACIC WALL. 91 



the third and sixth ribs ; and inframammary, below the sixth rib. Laterally the sixth rib divides 

 the area into two regions, axillary above and infraaxillary below. Posteriorly the space above 

 the spine of the scapula is known as the suprascapular ; that below as the infrascapular ; that 

 between the vertebral borders of the scapula as the interscapular. ED.] 



Supernumerary ribs occasionally occur. The supernumerary rib proceeding from the last 

 cervical vertebra (Fig. 39) is of practical importance only when it extends to the first rib or to 

 the sternum. In these cases the subclavian artery is placed unusually high up, since it runs over 

 this supernumerary rib (as it ordinarily does over the normal first rib) in a shallow groove. The 

 pulsation of the artery may consequently be easily seen or felt above the clavicle. In from five 

 to ten per cent, of such cases this anomaly produces symptoms (violent neuralgias and pares- 

 thesias, or thrombosis and aneurysm) which demand operative interference. 



FIG 30 Cervical ribs. The seventh cervical vertebra (indicated by the figure 7) articulates with a small cervical 

 rib upon the left, and with a complete cervical rib upon the right which reaches to the sternum. The figures i and 

 indicate the first two thoracic vertebrae. 



Inspection and Palpation of the Thorax. In a male subject in whom the origins of the 

 pectoralis major muscles are weU developed, a broad shallow furrow may be seen over the sternum. 

 At the upper end of the sternum this anterior median furrow passes into the suprasternal notch; 

 at the lower end of the sternum it is continuous with the so-called scrobiculus cordis or pit of the 

 stomach * In the latter fossa, which may be quite deep, the xiphoid process may project 

 anteriorly or may have an inward curve endangering the liver. The sternal angle, or the angle 

 of Ludwig, as already stated, may be more or less prominent at the junction of the manubrn 

 and the gladiolus; it corresponds to the attachment of the second rib and furnishes the starting 

 point for counting the intercostal spaces. In the female the anterior median furrow (the bos< 

 is produced by the presence of the mammary glands. The nipple is situated at 1 



* Both of these designations are bad, since neither the heart nor the stomach, but the liver, is situated beneath 

 the abdominal wall in this location. 



