SURFACE ANATOMY Ai 



JRFACE MARKINGS 



of the scapula and extend to the third and fifth ribs respectively, just lateral to the 

 corresponding costal cartilages. On the front of the elbow-joint a triangular space 

 the anticubital fossa is mapped out for convenience of reference. The base of 

 the triangle is a line joining the medial and lateral epicondyles, while the sides are 

 formed respectively by the salient margins of the Brachioradialis and Pronator 

 teres. 





Fio. 1235. Front of right upper extremity, showing surface markings for bones, arteries, and nerves. 



Mucous Sheaths. On the volar surfaces of the wrist and hand the mucous 

 sheaths of the Flexor tendons (Fig. 1233) can be indicated as follows. The sheath 

 for Flexor pollicis longus extends from about 3 cm. above the upper edge of the 

 transverse carpal ligament to the terminal phalanx of the thumb. The common 

 sheath for the Flexores digitorum reaches about 3.5 to 4 cm. above the upper edge 

 of the transverse carpal ligament and extends on the palm of the hand to about 

 the level of the centers of the metacarpal bones. The sheath for the tendons to the 

 little finger is continued from the common sheath to the base of the terminal phalanx 

 of this finger; the sheaths for the tendons of the other fingers are separated from 

 the common sheath by an interval; they begin opposite the necks of the meta- 

 carpal bones and extend to the terminal phalanges. The mucous sheaths of the 

 Extensor tendons are shown in Fig. 1234 (see also page 459). 



FIG. 1236. Back of right upper extremity, showing surface markings for bones and nerves. 



Arteries (Fig. 1235). The course of the axillary artery can be marked out by 

 abducting the arm to a right angle and drawing a line from the middle of the 

 clavicle to the point where the tendon of the Pectoralis major crosses the promi- 

 nence of the Coracobrachialis. Of the branches of the axillary artery, the origin 

 of the thoracoacromial corresponds to the point where the artery crosses the 

 upper border of Pectoralis minor; the lateral thoracic takes practically the line of 

 the lower border of Pectoralis minor; the subscapular is sufficiently indicated by 



