Vagina-Supports of the Vagina-Blood Supply-Vulva-Nerve Supply-Vulval Infection-The Vulva and Pregnancy-Urethral Infection-Urethral Injuries-Catheterization

Vagina

The vagina not only is the female genital canal but also serves as the excretory duct for the menstrual flow from the uterus and forms part of the birth canal. This muscular tube extends upward and backward between the vulva and the uterus (see Fig. 8.4). It measures about 3 in. (8 cm) long. The cervix of the uterus pierces its anterior wall. The vaginal orifice in a virgin possesses a thin mucosal fold, called the hymen, which is perforated at its center. The upper half of the vagina lies above the pelvic floor within the pelvis between the bladder anteriorly and the rectum posteriorly; the lower half lies within the perineum between the urethra anteriorly and the anal canal posteriorly
.

Supports of the Vagina

■■ Upper third: Levatores ani muscles and transverse cervical, pubocervical, and sacrocervical ligaments

■■ Middle third: Urogenital diaphragm

■■ Lower third: Perineal body

Blood Supply

Arteries

The vaginal artery, a branch of the internal iliac artery, and the vaginal branch of the uterine artery supply the vagina.

Vulva

The term vulva is the collective name for the female external genitalia and includes the mons pubis, labia majora and minora, the clitoris, the vestibule of the vagina, the vestibular bulb, and the greater vestibular glands.

Blood Supply

Branches of the external and internal pudendal arteries on each side.

The skin of the vulva is drained into the medial group of superficial inguinal nodes.

Lymph Drainage

Medial group of superficial inguinal nodes
.

Nerve Supply

The anterior parts of the vulva are supplied by the ilioinguinal nerves and the genital branch of the genitofemoral nerves. The posterior parts of the vulva are supplied by the branches of the perineal nerves and the posterior cutaneous nerves of the thigh.

Vulval Infection

In the region of the vulva, the presence of numerous glands and ducts opening onto the surface makes this area prone to infection. The sebaceous glands of the labia majora, the ducts of the greater vestibular glands, the vagina (with its indirect communication with the peritoneal cavity), the urethra, and the paraurethral glands can all become infected. The vagina itself has no glands and is lined with stratified squamous epithelium. Provided that the pH of its interior is kept low, it is capable of resisting infection to a remarkable degree.

The Vulva and Pregnancy

An important sign in the diagnosis of pregnancy is the appearance of a bluish discoloration of the vulva and vagina as a result of venous congestion. It appears at the 8th to 12th week and increases as the pregnancy progresses.

Urethral Infection

The short length of the female urethra predisposes to ascending infection; consequently, cystitis is more common in females than in males.

Urethral Injuries

Because of the short length of the urethra, injuries are rare. In fractures of the pelvis, the urethra may be damaged by shearing forces as it emerges from the fixed urogenital diaphragm.

Catheterization

Because the female urethra is shorter, wider, and more dilatable, catheterization is much easier than in males. Moreover, the urethra is straight, and only minor resistance is felt as the catheter passes through the urethral sphincter.

Vagina-Relations-Function-Supports of the Vagina-Vaginal Examination-Prolapse of the Vagina-Vaginal Trauma

Vagina

The vagina is a muscular tube that extends upward and backward from the vulva to the uterus. It measures about 3 in. (8 cm) long and has anterior and posterior walls, which are normally in apposition. At its upper end, the anterior wall is pierced by the cervix, which projects downward and backward into the vagina. It is important to remember that the upper half of the vagina lies above the pelvic floor and the lower half lies within the perineum. The area of the vaginal lumen, which surrounds the cervix, is divided into four regions, or fornices: anterior, posterior, right lateral, and left lateral. The vaginal orifice in a virgin possesses a thin mucosal fold called the hymen, which is perforated at its center. After childbirth, the hymen usually consists only of tags

Relations

■■ Anteriorly: The vagina is closely related to the bladder above and to the urethra below.

■■ Posteriorly: The upper third of the vagina is related to the rectouterine pouch (pouch of Douglas) and its middle third to the ampulla of the rectum. The lower third is related to the perineal body, which separates it from the anal canal.

■■ Laterally: In its upper part, the vagina is related to the ureter; its middle part is related to the anterior fibers of the levator ani, as they run backward to reach the perineal body and hook around the anorectal junction. Contraction of the fibers of levator ani compresses the walls of the vagina together. In its lower part, the vagina is related to the urogenital diaphragm and the bulb of the vestibule.

 

Function

The vagina not only is the female genital canal, but it also serves as the excretory duct for the menstrual flow and

Supports of the Vagina

The upper part of the vagina is supported by the levatores ani muscles and the transverse cervical, pubocervical, and sacrocervical ligaments. These structures are attached to the vaginal wall by pelvic fascia. The middle part of the vagina is supported by the urogenital diaphragm. The lower part of the vagina, especially the posterior wall, is supported by the perineal body.

Vaginal Examination

The anatomic relations of the vagina are of great clinical importance. Many pathologic conditions occurring in the female pelvis may be diagnosed using a simple vaginal examination.

The following structures can be palpated through the vaginal walls from above downward:

■■ Anteriorly: The bladder and the urethra

■■ Posteriorly: Loops of ileum and the sigmoid colon in the rectouterine peritoneal pouch (pouch of Douglas), the rectal ampulla, and the perineal body

■■ Laterally: The ureters, the pelvic fascia and the anterior fibers of the levatores ani muscles, and the urogenital diaphragm

Prolapse of the Vagina

The vaginal vault is supported by the same structures that support the uterine cervix. Prolapse of the uterus is necessarily associated with some degree of sagging of the vaginal walls. However, if the supports of the bladder, urethra, or anterior rectal wall are damaged in childbirth, prolapse of the vaginal walls occurs, with the uterus remaining in its correct position.

Sagging of the bladder results in the bulging of the anterior wall of the vagina, a condition known as a cystocele. When the ampulla of the rectum sags against the posterior vaginal wall, the bulge is called a rectocele.

Vaginal Trauma

Coital injury, picket fence–type of impalement injury, and vaginal perforation caused by water under pressure, as occurs in water skiing, are common injuries. Lacerations of the vaginal wall involving the posterior fornix may violate the pouch of Douglas of the peritoneal cavity and cause prolapse of the small intestine into the vagina

forms part of the birth canal.