Anatomy of the ureter. Which one is TRUE?
The ureter is up to 30 cm long. From its origin behind the renal artery, each ureter descends over the anterior border of the psoas to the pelvis. In doing so, it passes behind the gonadal vessels but over the bifurcation of the common iliac vessels. In men, the ureter continues along the lateral wall of the pelvis and then turns forward at the ischial spine to enter the bladder just after it is crossed by the vas deferens. In women, the ureter turns forwards and medially at the ischial spine and runs in the base of the broad ligament where it is crossed by the uterine artery. It continues forward passing the lateral fornix of the vagina to enter the bladder. The four layers in the wall of the ureter include the inner transitional cell epithelium, lamina propria, smooth muscle and outer adventitia. The blood supply is from several sources; in the abdomen the ureter receives branches from the renal, gonadal, common iliac arteries and the abdominal aorta. In the pelvis, it is supplied by the internal iliac artery and its branches including the vesicle, uterine, vaginal and middle rectal arteries. There are three main points of narrowing along its course: at the pelvi-ureteric and vesico-ureteric junctions and over the common iliac vessels.
Anatomy of the renal vasculature. Which one is TRUE?
Roughly a quarter of the cardiac output is supplied to the kidneys via the paired renal arteries. They branch from the aorta at the level of L2 just below the origins of the superior mesenteric (SMA) and adrenal arteries. The right artery passes behind the inferior vena cava (IVC) first, in contrast to the left, which passes almost directly to the kidney. Before entering the hilum, each artery initially gives off a single posterior segmental branch that passes behind the renal pelvis to supply the posterior aspect of the kidney. It can cause obstruction of the pelvi-ureteric junction if it passes in front of the ureter. After entering the hilum, the artery commonly divides into four anterior segmental branches (apical, upper, middle and lower). The divisions and blood supply of the anterior and posterior segmental arteries give rise to a longitudinal avascular plane, known as Brodel’s line, 1–2 cm posterior to convex border of the kidney. Segmental arteries give rise to lobar arteries within the renal sinus, which become interlobar arteries that lie in between the Columns of Bertin in the parenchyma. These give off arcuate branches, which become the interlobular arteries that eventually form the afferent arteries of the glomeruli. The renal vein lies in front of the artery in the renal hilum. The right vein is 2–4 cm in length in comparison to the left, which may be up to 10 cm. The left renal vein reaches the IVC by passing behind the SMA and in most cases in front of the aorta.
Which one of the following is TRUE regarding the adrenal glands?
The pair of adrenal glands are located just above each kidney in the retroperitoneum enclosed by Gerota’s fascia. In the newborn, the glands weigh much more but the cortex undergoes a degree of atrophy over the following 12 months to reach the adult weight of 5 g. The right gland is more triangular in shape and lies higher than the left. Each is made up of an outer cortex and an inner medulla, which contains catecholamine producing chromaffin cells. The cortex makes up the majority of the gland weight and consists of three distinct zones producing different hormones:
The blood supplying the glands stems from the aorta, inferior phrenic and ipsilateral renal arteries. Preganglionic sympathetic fibres directly innervate the medulla to stimulate catecholamine release.
Anatomy of the penis. Which one of the following is TRUE?
The two corpora cavernosa originate as the crus penis from the inferior ischiopubic rami and perineal membrane in the superficial pouch. Their outer surfaces are covered by the ischicavernosus muscles. They come together below the pubic symphysis, separated by a midline septum and surrounded by the tunica albuginea. The corpus spongiosum lies underneath in a groove and contains the urethra. The proximal end is dilated to form the bulb of the penis, which originates from the centre of the perineal membrane, and is covered by the bulbospongiosus muscle. Distally, the spongiosum expands and caps the two corpora to form the glans penis, containing the external urethral meatus at its tip. The three bodies are further surrounded by a deeper Buck’s fascia, which merges proximally with the tunica albuginea, and a superficial dartos fascia, which merges with Colles’ fascia in the perineum. The suspensory ligament helps to maintain the erect penis in an upright position for coitus and has three components including, the superficial fundiform, suspensory ligament proper and the arcuate subpubic ligaments. The penis and urethra is supplied by the internal pudendal artery, which divides into three branches:
The skin and dorsal structures are supplied by the external pudendal artery, which runs in the dartos fascia and originates from the femoral artery.
The nerves supplying the penis include:
Anatomy of the anterior abdominal wall and fascial layers. Which one of the following is TRUE?
The anterior abdominal wall is made up of several layers including skin, superficial (Camper’s) and deep (Scarpa’s) fascia, muscle, extraperitoneal fascia and parietal peritoneum. Camper’s fascia is just beneath the skin and continuous with the superficial fat over the rest of the body. Scarpa’s fascia blends with the superficial layer superiorly and laterally but inferiorly it continues as the deep fascia of the thigh 1 cm below the inguinal ligament, and medially, it becomes Buck’s fascia. Colles’ fascia lines the scrotum (or labia majora) and perineum and inserts posteriorly to the edges of the urogenital diaphragm and inferior ischiopubic rami. The wall musculature consists of the outer external oblique, internal oblique and inner transversus abdominus. They play a role in respiration, movement and increase abdominal pressure during micturition, defaecation and childbirth. The external oblique originates from the anterior surface of the lower 8th rib and inserts inferiorly to the lateral half of the iliac crest and medially to the rectus sheath. Its fibres run lateral to medial. The internal oblique originates from the lumbodorsal fascia and iliac crest. Its fibres run at right angles to the external oblique, from medial to lateral, and the muscle inserts onto the anterior surface of the lower four ribs and the rectus sheath medially. Transversus abdominis originates from the lumbodorsal fascia and iliac crest and inserts medially into the rectus sheath. Its fibres run horizontally. The aponeuroses of the three muscles form the rectus sheath that surrounds the rectus abdominis muscle and they meet in the midline to form the avascular linea alba. The composition of the rectus sheath varies depending on the arbitrary arcuate line, which is a third of the way from the umbilicus to the pubic symphysis. Below the line, the aponeuroses of all three muscles pass in front of the rectus abdominis, leaving its posterior surface covered by transversalis fascia. Above the line, the rectus is covered anteriorly by the aponeuroses of the external and internal oblique, and posteriorly by the aponeuroses of internal oblique and transversus abdominis. The sheath is attached to the rectus abdominis anteriorly at segmental tendinous intersections.
Pyramidalis, when present, lies in front of the lower end of rectus abdominis that originates from the pubic symphysis and inserts into the linea alba. The inguinal canal lies parallel to and just above the inguinal ligament at the lower end of the anterior abdominal wall that transmits the ilioinguinal nerve and the spermatic cord (round ligament in women). It is 4 cm in length and extends medially and inferiorly from the deep (internal) to the superficial (external) inguinal rings. The boundaries of the canal include the inguinal ligament in the floor, the external oblique as the anterior wall (reinforced laterally by the internal oblique), mainly tranversalis fascia as the back wall and the roof by the conjoint tendon, which is formed from fusion of the lower fibres of internal oblique and transversus abdominis. The deep ring is an opening in the transversalis fascia that lies 1 cm above the inguinal ligament midway between the anterior superior iliac spine and pubic symphysis. The inferior epigastric artery lies medial to the ring. The superficial ring lies medial to and above the pubic tubercle and is an opening within the external oblique aponeurosis. The upper abdominal wall is supplied by the superior epigastric artery (branch of the internal thoracic artery) and the lower half by the deep circumflex iliac and inferior epigastric arteries (branches of the external iliac artery).
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