

81 



SURFACE ANATOMY OF THE UPPER EXTREMITY 1325 



posterior part of the vaginal orifice. By inserting a finger into the vagina the fol- 

 lowing structures can be examined through its wall (Fig. 1230). Behind, from 

 below upward, are the anal canal, the rectum, and the rectouterine excavation. 

 Projecting into the roof of the vagina is the vaginal portion of the cervix uteri 

 with the external uterine orifice; in front of and behind the cervix the anterior 

 and posterior vaginal fornices respectively can be examined. With the finger in the 

 vagina and the other hand on the abdominal wall the whole of the cervix and 

 body of the uterus, the uterine tubes, and the ovaries can be palpated. If a speculum 

 be introduced into the vagina, the walls of the passage, the vaginal portion of the 

 cervix, and the external uterine orifice can all be exposed for visual examination. 

 The external urethral orifice lies in front of the vaginal opening; the angular 

 gap in which it is situated between the two converging labia minora is termed the 

 vestibule. The urethral canal in the female is very dilatable and can be explored 

 with the finger. About 2.5 cm. in front of the external orifice of the urethra are 

 the glans and prepuce of the clitoris, and still farther forward is the mons pubis. 



SURFACE ANATOMY OF THE UPPER EXTREMITY. 



ikin. The skin covering the shoulder and arm is smooth and very movable 

 on the underlying structures. In the axilla there are numerous hairs and many 

 sudoriferous and sebaceous glands. Over the medial side and front of the forearm 

 the skin is thin and smooth, and contains few hairs but many sudoriferous glands; 

 over the lateral side and back of the arm and forearm it is thicker, denser, and 

 contains more hairs but fewer sudoriferous glands. In the region of the olecranon 

 it is thick and rough, and is very loosely connected to the underlying tissue so 

 that it falls into transverse wrinkles when the forearm is extended. At the front 

 of the wrist there are three transverse furrows in the skin; they correspond respec- 

 tively from above downward to the positions of the styloid process of the ulna, 

 the wrist-joint, and the midcarpal joint. 



The skin of the palm of the hand differs considerably from that of the forearm. 

 At the wrist it suddenly becomes hard and dense and covered with a thick layer of 

 epidermis; on the thenar eminence these characteristics are less marked than else- 

 where. In spite of its hardness and density the skin of the palm is exceedingly 

 sensitive and very vascular, but it is destitute of hairs and sebaceous glands. It 

 is tied down by fibrous bands along the lines of flexion of the digits, exhibiting 

 certain furrows of a permanent character. One of these, starting in front of the 

 wrist at the tuberosity of the navicular bone, curves around the thenar eminence 

 and ends on the radial border of the hand a little above the metacarpophalangeal 

 joint of the index finger. A second line begins at the end of the first and extends 

 obliquely across the palm to reach the ulnar border about the middle of the fifth 

 metacarpal bone. A third line begins at the ulnar border about 2.5 cm. distal to 

 the end of the second and extends across the heads of the fifth, fourth, and third 

 metacarpal bones. The proximal segments of the fingers are joined to one another 

 on the volar aspect by folds of skin constituting the "web" of the fingers; these 

 folds extend across about the level of the centers of the proximal phalanges and their 

 free margins are continuous with the transverse furrows at the roots of the fingers. 

 Since the web is confined to the volar aspect the fingers appear shorter when viewed 

 from in front than from behind. 



Over the fingers and thumb the skin again becomes thinner, especially at the 

 flexures of the joints (where it is crossed by transverse furrows) and over the ter- 

 minal phalanges; it is disposed on numerous ridges in consequence of the arrange- 

 ment of the papillae in it. These ridges form, in different individuals, distinctive 

 and permanent patterns which can be used for purposes of identification. The 

 superficial fascia in the palm of the hand is made up of dense fibro-fatty tissue which 





