Henry Gray (18251861). Anatomy of the Human Body. 1918.
posterior part of the vaginal orifice. By inserting a finger into the vagina the following 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.
11. Surface Anatomy of the Upper Extremity
Skin.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 respectively 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 elsewhere. 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 terminal phalanges; it is disposed on numerous ridges in consequence of the arrangement of the papillæ 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