Penis. Structure of the penis

The penis, penis, consists of the paired cavernous body of the penis, corpus cavernosum penis, and the unpaired spongy body of the penis, corpus spongiosum penis. The penis has a closed back of the scrotum, fixed to the anterior surface of the pubic bones, the root of the penis , radix penis. Distinguish the body of the penis, corpus penis, and the glans penis, glans penis.

In the body of the penis, the upper or anterior surface is distinguished - the dorsum of the penis, the dorsum penis, and the lower, or posterior, - the urethral surface, facies urethralis.

The head represents the free end of the penis . It is conical, slightly flattened from above and below. Its lower surface is somewhat flattened. The posterior, rising edge of the head is thickened, forms the crown of the head, corona glandis, it is separated from the body by a shallow groove - neck of the head, collum glandis.

At the top of the head opens the external opening of the urethra , ostium urethrae externum.

The skin of the penis is thin, stretchable; It is separated from the loose fascia by the loose fiber and is therefore easily mobile. The skin of the glans penis is also thin, but it is tightly fused with the underlying cavernous body of the cavernous body and is therefore immobile. In the neck region of the head, the skin is collected in the form of a fold that covers the head and protrudes in front of it by a longer, then shorter, edge - this is the foreskin of the penis, the preputium penis. Thus, between the head and the foreskin, an open, bag-shaped cavity is formed. Consequently, the foreskin has two skin surfaces: the inner one, the more tender, facing the head, and the outer one, the denser one. The inner layer of the skin of the prepuce contains a significant number of glands of the foreskin, glandulae preputiales, which produce a sebaceous secret. In their structure they are complex alveolar glands. On the lower surface of the head skin - the foreskin, forms a longitudinal fold - the frenulum of the foreskin, frenulum preputii, by means of which the skin is connected to the opposite surface of the preputial sac. As if its continuation, along the lower surface of the penis in the middle passes the dermal seam of the penis, raphe penis.

The cavernous bodies of the penis , corpora cavernosa penis, represent almost cylindrical formations with pointed anterior and posterior ends. The posterior end is the penis, crus penis, each cavernous body begins from the periosteum of the medial edge of the lower branch of the pubic and the branch of the ischium in the region of the sublobe angle. In front, both cavernous bodies of the penis are connected by their medial surfaces. On the bottom of their surface is a groove, in which lies the spongy body of the penis. The latter is attached to it by dense connective tissue. Along the upper surface of the cavernous bodies of the penis is a deep furrow, in which the dorsal vessels and nerves are located. The anterior ends of the cavernous bodies of the penis are dressed, like a hat, with a head.

The cavernous body is surrounded by a dense white envelope of the cavernous body, tunica albuginea corporis cavernosi. Its thickness is up to 2 mm. It gives the inside of the cavernous body the processes - the trabeculae of the cavernous body, the trabeculae corporis cavernosi, formed by a connective tissue containing smooth muscle tissue, the contraction of which retards blood in the cells of the cavernous bodies during erection. Trabeculae isolate inside the cavernous body filled with blood cavities - cells of the cavernous body, cavernae corporis cavernosi. They are lacunar spaces - caves (cells), caverna, formed by altered capillaries and lined with endothelium.

Blood supply to the cells of the cavernous and spongy body is accomplished by the curved arteries, aa. Helicinae, opening directly into the caves, and venous outflow occurs through the deep dorsal vein, v. Dorsalis profunda penis, and deep veins of the penis, vv. Profundae penis.

Where the right and left cavernous bodies are connected, the septum of the penis, the septum penis, separates them from the other. In the septum there are openings through which the vessels of the cavernous bodies are joined together.

The spongy body of the penis , corpus spongiosum penis, is considerably smaller in volume than the cavernous bodies, it is flattened in anteroposterior direction; The posterior end of it is thickened and forms a bulb of the penis, bulbus penis. The bulb is adjacent to the urogenital diaphragm. Its two halves are well visible, since they are covered with bulbous-spongy muscles, mm. Bulbospongiosi.

The front part of the spongy body of the penis passes into the glans penis, glans penis. On the posterior surface of the latter there is a recess, which includes the anterior ends of the cavernous bodies of the penis; The head is tightly joined to them. The urethra penetrates the bulb from above and follows the entire length of the spongy body to the top of the head, where it opens with the outer opening of the urethra, ostium urethrae externum. The spongy body of the penis is dressed with a thin white shell of the spongy body, tunica albuginea corporis spongiosi. Trabeculae of the spongy body, trabeculae corporis spongiosi, more delicate than the trabeculae of the cavernous bodies, depart from it into the interior of the body. The spongy body of the penis contains cells of the spongy body, cavernae corporis spongiosi. From the belly of the head along the middle line to the wall of the urethra there is a septum of the head, septum glandi.

Outside the aboral shell of the cavernous bodies is the deep fascia of the penis , fascia penis profunda, which covers both the cavernous bodies and the spongy body of the penis. This is followed by a more powerful superficial fascia of the penis, fascia penis superficialis, in which surface vessels and nerves pass. It is a continuation of the superficial fascia of the perineum, the superficial fascia of the anterior abdominal wall and the fleshy membrane of the scrotum and is connected to the skin of the penis through a loose connective tissue. There is no subcutaneous connective tissue layer on the glans penis. From the front of the pubic symphysis to the back of the penis is a short ligament, suspending the penis, lig. Suspensorium penis, formed by elastic fibers that depart from the superficial fascia of the abdomen, and interlacing in the belly shell. The other is a sling-like ligament of the penis, lig. Fundiforme penis, is directed from the white line of the abdomen downwards and covers the penis from the sides; The fibers of this ligament penetrate into the scrotum, weaving into the fleshy shell.

Innervation: n. Dorsalis penis (afferent). Nn. Cavernosi penis of plexus hypogastricus inferior (efferent sympathetic), nn. Erigentes (parasympathetic).

Blood supply: cavernous and spongy bodies - a. Dorsalis penis and a. Profunda penis from a. Pudenda interna, skin and shells - rr. Scrotales anterior, bulb - a. Bulbi penis, spongy body and urethra - a. Urethralis. Venous blood flows out by v. Dorsalis penis profunda and v. Bulbi penis in plexus venosus vesicalis, and then in v. Iliaca interna, no v. Dorsalis penis superficialis in v. Femoralis. Lymphatic vessels divert lymph to nodi lymphatici iliaci interni and inguinales superficiales.

You will be interested to read this:

• Prostate.
• Bulbourethral glands .
• Male urethra.
• Peritoneum cavity of small pelvis is male.
• Scrotum .