Pelvis

·         In Extravasated urine by rupture of BULBOUS Part, The urine cannot spread laterally into the thigh because the inferior fascia of the urogenital diaphragm (the perineal membrane) and the superficial fascia of the perineum are firmly attached to the ischiopubic rami and are connected with the deep fascia of the thigh (fascia lata). It cannot spread posteriorly into the anal region because the perineal membrane and Colles' fascia are continuous with each other around the superficial transverse perineal muscles.

If the membranous part of the urethra is ruptured, urine escapes into the deep perineal space and can extravasate upward around the prostate and bladder or downward into the superficial perineal space.

·         Ischiorectal Fossa has the following boundaries:

1.       Anterior: the sphincter urethrae and deep transverse perineal muscle.

2.       Posterior: the gluteus maximus muscle and the sacrotuberous ligament

3.       Superomedial: the sphincter ani externus and levator ani muscles

4.       Lateral: the obturator fascia covering the obturator internus muscle

5.       Floor: the skin over the anal triangle

·         Deep fascia of the penis (Buck's fascia) is a continuation of the deep perineal fascia.Is continuous with the fascia covering the external oblique muscle and the rectus sheath.

·         Internal Pudendal Artery from IIA, But External is from FA.

·         Lymph vessels from the glans penis (or clitoris) and labium minus pass to the deep inguinal and external iliac nodes.

·         Urethral crest is located on the posterior wall of the prostatic urethra and has numerous openings for the prostatic ducts on either side.

Has an ovoid-shaped enlargement called the seminal colliculus (verumontanum), on which the two ejaculatory ducts and the prostatic utricle open. At the summit of the colliculus is the prostatic utricle, which is an invagination (a blind pouch) about 5 mm deep; it is analogous to the uterus and vagina in the female.

·         The internal anal sphincter (a thickening of the circular smooth muscle in the lower part of the rectum) is separated from the external anal sphincter (skeletal muscle that has three parts: subcutaneous, superficial, and deep) by the intermuscular (intersphincteric) groove called Hilton's white line.

·         Anal Canal has a point of demarcation between visceral and somatic portions called the pectinate (dentate) line, which is a serrated line following the anal valves and crossing the bases of the anal columns.

·         Pelvic splanchnic nerves (nervi erigentes)

Arise from the sacral segment of the spinal cord (S2-S4) and are the only splanchnic nerves that carry parasympathetic fibers. (All other splanchnic nerves are sympathetic.)Contribute to the formation of the pelvic (or inferior hypogastric) plexus, and supply the descending colon, sigmoid colon, and other viscera in the pelvis and perineum.

·         Contents of  Deep Perineal Pouch

1. Part of urethra and vagina.

2. Sphincter Urethrae.

3. Bulbourethral glands of Cowper.

4. Deep Transverse Perenei muscles.

5. Internal pudendal vessels and their branches.

6. Dorsal nerve of Penis or Clitoris

·         The anterior third of the scrotum is supplied mainly from the L1 (by way of the ilioinguinal and genitofemoral nerves), while the posterior two-thirds are innervated principally from the S3 (via the perineal and posterior femoral cutaneous nerves). The ventral axial line of the lower limb passes between these areas. A spinal anaesthetic, therefore, must be injected much higher to anaesthetize the anterior region.

·         In the midline behind the pubis, the preperitoneal space is known as the space of Retzius, while laterally it is referred to as the space of Bogros.

·         The pubococcygeus muscle is the most frequently torn muscle that results in female incontinence. The puborectalis, pubococcygeus, and iliococcygeus comprise the levator ani, the main muscular component of the pelvic floor. The pubococcygeus is the part of the levator ani most frequently damaged during parturition. Because the pubococcygeus surrounds and supports the neck of the bladder and the proximal urethra, urinary leakage is a common result, particularly during increased abdominopelvic pressure, as occurs, during coughing. Damage to the puborectalis results in fecal incontinence under similar situations.

·         The perineal body (central tendon of the perineum) is a fibromuscular node at the center of the perineum. It provides attachment for the bulbospongiosus, the superficial and deep transverse perineal muscles, and the sphincter ani externus muscles. Other muscles (ischiocavernosus, sphincter urethrae, and obturator internus) are not attached to the perineal body.

·         The deep dorsal vein of the penis lies medial to the dorsal artery of the penis on the dorsum of the penis and deep to Buck's fascia, drains into the prostatic plexus of veins, and is compressed against the underlying deep fascia of the penis during erection.

·         The lymphatic vessels from the ovary ascend with the ovarian vessels in the suspensory ligament and terminate in the lumbar (aortic) nodes. Lymphatic vessels from the perineum, external genitalia, and lower part of the anterior abdominal wall drain into the superficial inguinal nodes.

·         The iliohypogastric nerve innervates the skin above the pubis. The skin of the urogenital triangle is innervated by the pudendal nerve, perineal branches of the posterior femoral cutaneous nerve, anterior scrotal or labial branches of the ilioinguinal nerve, and the genital branch of the genitofemoral nerve.

·         The deep dorsal vein of the penis enters the pelvic cavity by passing under the symphysis pubis between the arcuate and transverse perineal ligaments.

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