Lower Genitourinary Trauma.

Lower Genitourinary Trauma.

Tullington JE; Blecker N

StatPearls

2021

2021-01

Traumatic injuries can range from minor wounds to major, complex injuries causing shock and multi-system organ dysfunction. Trauma is the leading cause of death in patients between the ages of 15 and 24. It accounts for approximately 30% of all ICU admissions annually. The lower urogenital (GU) tract is composed of the bladder, urethra, vagina, uterus, ovaries, penis, scrotum, and testes. The lower GU tract is typically protected by the bony pelvis. The pelvis is a ring structure composed of the sacrum, the coccyx, and the innominate bones: the pubis, ischium, and ilium. The innominate bones join anteriorly at the pubic symphysis. Bladder Anatomy The urinary bladder functions as a reservoir. The size, shape, and spatial relation to surrounding organs differs depending on the volume within the bladder. An empty bladder lies within the protection of the bony pelvis. However, as the bladder fills, it extends superiorly into the abdominal cavity and is more prone to traumatic forces. The base of the bladder is closely related to the vagina in females and the rectum in males. The bladder neck is the most inferior portion and is generally the most fixed portion of the bladder. The pubovesical ligaments fix the bladder neck to the pubic bones in both males and females. It is essentially the internal urethral orifice. The anterior bladder is separated from the transverses fascia by adipose tissue, which is the retropubic space (space of Retzius). Bilateral ureters drain into the bladder at the ureteral orifices located on the trigone. The inferolateral surfaces are not covered by peritoneum. In males, the superior portion of the bladder is covered with peritoneum, which continues posteriorly and over the rectum to form the rectovesical pouch. In females, the superior surface is also mostly covered in peritoneum being reflected at the uterus, forming the vesicouterine pouch. The remainder of the superior bladder is separated from the cervix by areolar tissue. As the bladder fills and becomes distended, the anterior portion, which is not covered by peritoneum, is exposed over the pubic bones. The blood supply is mainly from the superior and inferior vesical arteries. These arise from the internal iliac artery. The veins that drain the bladder form a plexus on the inferolateral surface of the bladder and then drain into the internal iliac veins. Lymphatic drainage is generally to the external iliac nodal basin. There is both sympathetic (T10-L2) and parasympathetic (S2-S4) innervation to the bladder, which arises from the pelvic plexus. The bladder consists of 4 layers, the urothelium, lamina propria, muscularis propria, and serosa. The muscularis propria is the detrusor muscle and consists of 3 layers: inner and outer longitudinal and a circular layer. The detrusor is a smooth muscle. It relaxes to allow the bladder to fill and then contracts to empty the bladder. Bladder contraction is via parasympathetic actions. Urethra Anatomy The male urethra is about 18 to 20 cm in length. It is a conduit from the inferior bladder to the external urethral meatus. The posterior urethra is about 4 cm in length and is located above the corpus spongiosum. The prostatic urethra is a portion of the posterior urethra. The lowest portion of the prostatic urethra is fixed in place by the puboprostatic ligament rendering it immobile. The anterior urethra is surrounded by corpus spongiosum. The urethral artery branches from the internal pudendal artery just below the perineal membrane and travels within the spongiosum to the glans penis, giving off branches to the urethra. The dorsal penile artery helps provide blood to the urethra via the circumflex branches. The anterior urethra has venous drainage via the dorsal veins of the penis and the internal pudendal veins. These then drain into the prostatic plexus. The posterior urethra drains into the prostatic and vesicle plexus, which then drains into the internal iliac veins. The posterior urethra generally drains into the internal iliac nodes, whereas the anterior urethra drains into the deep inguinal lymph nodes. The prostatic plexus supplies the prostatic urethra. The internal urethra sphincter receives sympathetic innervation from the pelvic plexus to prevent retrograde ejaculation. Parasympathetic innervation is from S2 to S4. The female urethra is about 4 cm in total length. It is fixed anteriorly by the suspensory ligament of the clitoris and beneath the pubis by the posterior pubourethral ligaments. Female urethras are primarily supplied by the vaginal artery, with some flow coming from the inferior vesicle artery. The urethral veinous plexus drains into the vestal venous plexus around the bladder and into the internal pudendal veins. The lymphatics drain into both the internal and external iliac nodal basins. Parasympathetic innervation, similar to males, originates from the S2 to S4 nerves. Vagina, Uterus, and Ovaries Anatomy Female external genitalia consists of the mons pubis, labia minora and majora, clitoris, vestibule, and vestibular bulb. The mons pubis is the rounded area of adipose tissue anterior to the pubic symphysis. The labia majora are two folds that run longitudinally from the mons pubis to the perineum. Each is composed of adipose tissue, smooth muscles, and a deep membranous layer called Colles fascia, which is continuous with Scarpa’s fascia. The vestibule is the cavity between the labia minora; it contains the vaginal and external urethral orifices. Blood supply to the external genitalia arises from superficial and deep branches of the external pudendal branches of the femoral artery superior and the internal pudendal artery inferiorly. The vagina is a tube structure composed of fibromuscular tissue that goes from the vestibule to the uterus. The anterior vaginal wall supports the inferior bladder and the urethra. The upper portion of the posterior vagina is separated from the rectum by Denonvillier’s fascia and peritoneum (rectouterine pouch). The vagina receives its blood supply from the azygos arteries, which are branches of the uterine artery coming from the internal iliac artery. They run along the anterior and posterior vaginal walls. The venous drainage is via the vaginal veins, which empty into the internal iliac veins. The lymphatic vessels drain into the internal iliac, external iliac, and superficial inguinal basins. The pudendal nerve supplies the lower vagina; S2 to S4 nerves supply the upper vagina. The uterus is a muscular organ that is located between the bladder anteriorly and the rectum posteriorly. The uterus is a mobile organ, so its position can vary depending on the contents of the bladder and rectum. The uterus is very thick and muscular. It is composed of three layers: inner endometrium, middle myometrium, and the outer serosa. The anterior surface is covered in peritoneum that folds back to the bladder (uterovesical fold), whereas the posterior surface’s peritoneum continues onto the rectum (rectouterine pouch, or pouch of Douglas). The cervix communicates with the uterus at the internal os and the vaginal canal at the external os. The uterus receives its blood supply from the uterine artery. The uterine artery branches from the internal iliac and traverses the ureter anteriorly at the broad ligament. It is important to remember this relationship to avoid injury to the ureter while ligating the uterine artery. It then inserts into the uterus around the uterocervical junction. The uterine veins drain into the internal iliac veins. The lymphatic vessels drain into three nodal basins: the internal iliac, external iliac, and obturator. Innervation to the uterus is primarily from the inferior hypogastric plexus. Fallopian tubes run from the upper body of the uterus, with an opening into the uterus, to the abdominal os where the fimbria extends toward the ovary. The fallopian tube is broken into four sections: intramural, isthmus, ampulla, and infundibulum. The fimbriae are finger-like projections that extend from the infundibulum toward to ovary and aid in capturing oocytes as they are released from the ovary. Blood supply to the fallopian tubes is from branches of the ovarian and uterine arteries. The lateral two-thirds of the Fallopian tube drains into the pampiniform plexus to the ovarian veins. The medial portion drains into the uterine plexus. The lymphatic vessels drain into the para-aortic nodes and the internal iliac nodal basin. The ovaries lie on each side of the uterus, close to the abdominal wall. The ovaries are suspended in the mesovarium, a double fold of peritoneum. Ovaries consist of an inner medulla and an outer cortex. The ovary is surrounded by a capsule of connective tissue called the tunica albuginea. The suspensory ligament attaches to the superolateral surface of the ovary and contains the ovarian vessels and nerve. The ovarian ligament attaches the inferomedial portion of the ovary to the lateral uterus. The ovaries are supplied by the ovarian arteries, which branch directly from the aorta below the renal arteries. The veins draining the ovary form a plexus known as the pampiniform plexus. These form into the ovarian vein, which drains into the inferior vena cava on the right and the left renal vein on the left. Lymphatics drain into the para-aortic lymph nodes. Penis, Scrotum, and Testes Anatomy The penis is composed of four parts: base, shaft, glans, and foreskin (in uncircumcised males). The base is attached to the pubis by two suspensory ligaments, which are continuous with Buck’s fascia. The penis contains 2 columns of erectile tissue: 2 corpus cavernosa anteriorly and the corpus spongiosum posteriorly. The corpus spongiosum enlarges at the distal end and forms the glans of the penis. The glans is covered by foreskin in uncircumcised males. The skin overlying the shaft is mobile due to the lack of connections to the underlying fascia, whereas the skin of the glans is immobile due to its attachment to the underlying tunica albuginea. Under the penile skin lies the dartos fascia of the penis, then the deeper, tougher Buck’s fascia. Buck’s fascia covers both corpus cavernosum and splits to cover the corpus spongiosum. Blood supply to the corporal bodies rises from the penile artery, a branch of the internal pudendal artery. The penile artery has 3 main branches that supply the penis: cavernous artery, bulbourethral artery, and the dorsal penile artery. It is important to note these branches are highly variable. Three venous systems drain the penis: superficial, intermediate, and deep. The superficial system is within the dartos fascia; it forms a single superficial dorsal vein. The superficial dorsal vein is located just below the dartos fascia and ultimately drains into the great saphenous vein. The intermediate drainage occurs through the circumflex and deep dorsal veins. These are located within and deep to Buck’s fascia. They drain into the prostatic plexus. The deep system drains the proximal third of the penis via the deep and crural cavernous veins, ultimately draining into the internal dental vein. Lymphatic vessels drain into the superficial and deep inguinal nodal basins and the internal iliac nodes. The glans penis has the most sensation and is provided by the dorsal nerve. The dorsal nerve runs deep to Buck’s fascia on either side of the deep dorsal vein. Parasympathetic and sympathetic innervation to the corpus cavernosa is provided by the cavernous nerve, coming from the pelvic plexus. The scrotum is a dual-chambered sac composed of multiple tissue layers and contains the testicles, the vas deferens, and the epididymis. The scrotal layers include skin, dartos muscle, spermatic fascia, cremasteric fascia, and the internal spermatic fascia. Dartos is continuous with Colle’s fascia of the perineum and the dartos fascia of the penis. The gubernaculum fixes the testis in place within the scrotum. Arterial supply is from the external pudendal artery (from the femoral artery), scrotal branches of the internal pudendal artery, and cremasteric branches from the inferior epigastric artery. Venous drainage follows the arterial supply. Lymphatic drainage is to the ipsilateral superficial inguinal nodal basins. Innervation is provided by the ilioinguinal nerve (L1), genitofemoral nerve (L1, L2), posterior scrotal branches of the perineal nerve (S2-S4), and the perineal branch of the posterior femoral cutaneous nerve (S1-S3). The testes are suspended in the scrotum by the spermatic cord with the left testis lying lower than the right. Within the testis are the seminiferous tubules. Spermatogenesis occurs within the tubules. The testis is enclosed in a capsule that is composed of 3 layers: tunica vasculosa (innermost), tunica albuginea (middle), and the outer tunica vaginalis. The tunica vasculosa contains a plexus of blood vessels. The tunica albuginea is a dense layer composed mainly of collagen fibers. Posteriorly, it injects inward to form an incomplete fibrous septum within the testis. The tunica vaginalis is an extension of the peritoneal processus vaginalis; failure to obliterate the processus vaginalis results in direct communication between the peritoneal cavity and the scrotum. The testis receives its blood supply from multiple arteries. The testicular artery supplies about two-thirds of the testis. The remaining one-third comes from a combination of small arteries, including the vasal artery and the cremasteric arteries. The testicular artery arises from the aorta. The vasal artery arises from the superior vesicle artery, and the cremasteric artery is a branch of the inferior epigastric artery. The testis drains into the pampiniform plexus, which ultimately forms a single vein that drains into the inferior vena cava on the right and the left renal vein on the left. The lymphatic vessels drain predominantly into the inter-aortocaval and para-caval nodes. Sympathetic innervation is by the T10 nerve; sensory innervation is via T10 and the genitofemoral nerve (L1 and L2).

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NEOMED College of Medicine

Department of General Surgery

June 2021 List