LITMIR.BIZ

Скачать книгу

Deep dorsal vein to vesicle plexus, deep external pudendal veins to femoral vein and internal pudendal veins to internal iliac vein Dorsal nerve of the clitoris, a branch of the pudendal nerve To deep inguinal and internal iliac nodes Vestibule Branches of the internal pudendal artery Tributaries to the external pudendal vein Perineal branch of the pudendal nerve To superficial inguinal nodes External urethral meatus and urethra Vesical and vaginal arteries which are branches of the anterior internal iliac artery Via plexus around the urethra to vesicle plexus around the bladder neck and into the pudendal veins Pudendal nerve Urethral lymphatics drain into the internal and external iliac nodes Vagina The vaginal artery may arise from the internal iliac artery or one of its branches, most commonly the internal pudendal artery. The uterine artery supplies a descending branch to the upper vagina, and there is frequently a vaginal branch from the middle rectal artery. The lower vagina is supplied by branches of the internal pudendal artery. These vessels anastomose with each other in or on the vaginal walls. Vessels from the right and left sides anastomose to form unpaired, midline, anterior, and posterior azygos arteries The veins of the vagina drain to the uterovaginal plexus, which itself communicates with the uterine, vesical, and rectal venous plexuses, all of which drain mainly to the internal iliac veins Nerve fibres accompany the vessels as they penetrate the walls of the body of the uterus, cervix, and vagina. There is general agreement that almost all of the motor fibres to uterine muscle are sympathetic, while afferent innervation of the body is sympathetic and that of the cervix is parasympathetic The upper two‐thirds is with the cervix to the internal and external iliac nodes. The lower vessel third drains with the rest of the perineum to the superficial inguinal nodes Perineum Perineal artery Internal pudendal vein Pudendal nerve Superficial inguinal nodes Pelvic floor Lumbosacral plexus (S2–S4)

Blood supply of the vulva

Branches of the internal iliac and femoral arteries and veins supply and drain the perineum, and the details are shown in Table 2.2.

Internal pudendal artery

The internal pudendal artery, a branch of the internal iliac artery, leaves the pelvis through the greater sciatic notch below the piriformis muscle. Lying on the tip of the ischial spine, it turns forwards through the lesser sciatic foramen to enter the anal triangle posteriorly. Within this triangle it runs forwards on the side wall of the ischiorectal fossa enclosed by the fascia of the pudendal canal. During its course through the ischiorectal fossa, it gives off the inferior rectal artery, which arches over the fascial roof of the fossa to reach and supply the anococcygeal raphe, anal canal, and perineal body. After entering the urogenital triangle, the internal pudendal artery gives off the perineal branch to the perineal body and the posterior structures in the superficial perineal pouch. It enters the deep perineal pouch and supplies the erectile tissue lying in the vestibule, by perforating branches into the superficial perineal pouch, and the clitoris, by way of its deep and superficial terminal branches through the apex of the urogenital diaphragm.

Femoral artery

      The femoral artery gives off the superficial and deep external pudendal arteries in the femoral triangle. The superficial external pudendal artery pierces the deep fascia of the thigh anteriorly, to overlie the round ligament of the uterus. It runs medially to supply the mons pubis and labia. The deep external pudendal artery pierces the deep fascia of the thigh medially to enter the labia of the vulva. The terminal branches of the internal and external pudendal arteries anastomose with one another in the superficial perineal pouch.

Venous drainage

      The venous drainage follows the same pathways and eventually reaches the femoral and internal iliac veins. The internal iliac veins drain a rich venous plexus in the pelvic floor, which contributes to draining all the pelvic viscera. The venous drainage of the terminal gastrointestinal tract is therefore partially to the pelvic plexus but principally to the portal system via the superior rectal and thence the inferior mesenteric vein. The pelvic venous plexus therefore provides a portal systemic anastomosis, and portal hypertension can predispose to distension and even thrombosis of the pelvic, rectal, vaginal, and vulval veins.

Microscopic anatomy

      The dermal microvasculature consists of a deep arterial plexus, the fascial network. The vessels from this region extend upwards to the border of the subcutaneous fat and then form a cutaneous network. This gives off branches to the appendages and ascending arterioles to a subpapillary plexus, which in turn forms capillary loops in the papillary layer between the dermoepidermal ridges. Blood is drained from these capillaries by venules which drain down to intermediate plexuses.

Lymphatic drainage of the vulva

The lymphatic system transports fluids such as leaked protein from the extravascular compartment of the dermis. Small capillaries arise in the extracellular tissue spaces and form larger channels, which drain to the regional lymph nodes, and then via intermediate nodes before eventually returning to the thoracic duct. Any midline structure has bilateral lymphatic drainage. Therefore, the lymphatic drainage of either labium majus or minus is to both the ipsilateral and contralateral superficial lymph nodes [27].

      The superficial regional lymph nodes of the perineum are found in two groups at the base of the femoral triangle. They communicate freely with one another and drain the whole of the perineum, including the lower thirds of the urethra, vagina, and anal canal.

      These subsequently drain to deep nodes in the pelvis and ultimately to para‐aortic nodes on the posterior abdominal wall.

      A variable number of lymph nodes lie transversely in the superficial fascia of the thigh, immediately below the medial two‐thirds of the inguinal ligament. The superficial femoral or subinguinal lymph nodes lie on both the medial and lateral aspects of the long saphenous vein. There are between 3 and 20 of these, and the lateral nodes send efferent lymphatics to the external iliac deep lymph nodes.

The external iliac lymph nodes

      The external iliac lymph nodes are described in relationship to the external iliac vessels. They communicate freely with one another and with the obturator node, a large constant node, near the obturator nerve. It lies below the external iliac vessels on the side wall of the pelvis.

Medial group

      The medial group of three to six nodes lies on the medial side of the origin of the external iliac vein. Up to three of these nodes may be found in the femoral triangle medial to the femoral vein, where they are referred to as the deep femoral nodes. If all three are present, the lower one is situated just below the junction of the great

Скачать книгу