Anterior abdominal wall and inguinal region

Direct and indirect hernias

Direct=acquired. They are more common in men than women, though the number of women with direct inguinal hernias is increasing as the number of women practicing weight-lifting or doing heavy work increases. The neck of the hernia exits the abdomen medial to the inferior epigastric vessels.

Varicocele vs hydrocele

Fluid in the tunica vaginalis, usually a potential space, is termed a hydrocele. It may result from infection of the testis or epididymis, trauma, tumor or it may be idiopathic. Variococele is caused by the dilation of the tortuous veins of the pampiniform plexus. It is almost always on the left side, perhaps due to the venous drainage of the left testicular vein into the left renal vein as opposed to the right testicular vein, which drains directly into the inferior vena cava. The varicocele is evident when the patient is standing but often resolves when the patient lies down. Congested blood flow in the scrotum can raise the temperature around the testicle, which can decrease sperm production and fertility.

Direct vs Indirect inguinal hernia

Indirect---- associated with congenital patent processus vaginalis hernia follows path taken by testes as they descend: deep ring, inguinal canal, superficial ring, scrotal sac lies LATERAL to inferior epigastric vessels Direct---- lies medial to the inferior epigastric vessels. It is usually a result of increased intra-abdominal pressure pushing on the weak area, the inguinal triangle. The hernial sac protrudes into the abdominal wall, but not into the scrotum.

Umbilical folds

Median umbilical fold covering the median umbilical ligament (remnant of the urachus). The urachus is an remnant of the embryonic allantois. Medial umbilical folds covering the medial umbilical ligaments (or the obliterated umbilical arteries). Lateral umbilical folds covering the inferior epigastric vessel

Transversalis fascia

Origin of the abdominal muscles is on the posterior abdominal wall. Transversalis fascia (endoabdominal fascia) is the regional name for the deep investing fascia as it covers the TA muscle. In other areas it may be called psoas fascia, quadratus lumborum fascia. The transversalis fascia lies deep to the muscle layers. It is the deep fascial layer of the abdomen (endoabdominal fascia) and forms a continuous sheet of fascia lining the inner abdominal wall, analogous to the endothoracic fascia. A thin layer of adipose, the extra-peritoneal fat lies deep the transversalis fascia. Deeper still is the peritoneum, the serous membrane lining the abdominal cavity (akin to the parietal pleura).

External oblique

Origin: external surfaces of ribs 5-12, thoracolumbar fascia Insertion: linea alba, pubic tubercle, iliac crest

Transversus abdominis

Origin: internal surface of ribs 7-12, thoracolumbar fascia, iliac crest, lateral third of inguinal ligament Insertion: linea alba, pubic crest and pectineal line (conjoint tendon)

Internal oblique

Origin: thoracolumbar fascia, anterior 2/3 of iliac crest, lateral half of inguinal ligament Insertion: inferior borders of ribs 10-12, linea alba, pubic crest and pectineal line (via conjoint tendon)

Abdominal fascia

Outer, fatty layer (CAMPER'S)- continues into thigh and perineum. Fatty layer of labia majora. Fuses with deep layer before continuing into external genitalia Deep, fibrous layer (SCARPA'S membranous layer) - Confined to lower abdominal wall. Nearly devoid of fat. Attaches to the deep fascia of the thigh (fascia lata) just below the inguinal ligament. Fuses with the superficial layer in the scrotum to form the dartos layer (Dartos = Camper's + Scarpa's minus the fat plus muscle). Forms Colles' fascia in the perineum (also known as the superficial perineal fascia). potential space between Scarpa's fascia and the deep fascia of the abdominal muscle layer- susceptible to to fluid or pus accumulation especially following surgery

Rectus abdominis

Rectus sheath= aponeuroses of the three flat abdominal muscles. Rectus abdominis runs from the pubic crest to the xiphoid process and nearby ribs 5-7. Flexes the trunk and compresses abdominal viscera. tendinous intersections anchor the muscle to the anterior layer of the rectus sheath. Rectus Abdominis and the three flat muscles of the anterolateral abdominal wall are innervated by T7-T12 inter/sub-costal nerves and L1 (iliohypogastric and ilioinguinal divisions)

Nerves of the abdominal wall

T7-T11, subcostal, and L1

Descent of the testes

Testes develop from undifferentiated gonads on posterior abdominal wall Pathway is determined by gubernaculum "Descent" begins in 7th month "Descent" is normally complete at birth Differential growth + testosterone--> "descent"

Spermatic cord and testes

The genital branch of the genitofemoral nerve lies within the spermatic cord. The ilioinguinal nerve lies within the inguinal canal but lateral to the cord. Identify the tunica vaginalis, parietal and visceral layers.

Superficial inguinal ring

The medial and lateral crura surround the superficial inguinal ring. The intercrural fibers arch between the crura and support them.

Abdominal muscles above the arcuate line

above aponeurosis: EO and IO anteriorly . TA and transversalis fascia posteriorly transversalis fascia lines the entire abdominopelvic cavity, separated from the peritoneum by a layer of fat-filled extraperitoneal connective tissue

Abdominal muscles below the arcuate line

all three layers of aponeuroses pass anterior to the rectus muscle The transversalis fascia, extraperitoneal fat, and parietal peritoneum form the posterior layer of the rectus sheath below the arcuate line posterior wall of the sheath is relatively weak due to its lack of structure.

Spermatic cord contents

ductus deferens pampiniform plexus of testicular veins testicular artery genital branch of genitofemoral n. autonomics lymphatics

Cremaster muscle

exit the abdominal cavity lateral to the inferior epigastric vessels, under the arch of transversus abdominis. Muscle fibers from IO elongate as the cremaster muscle, and become one of the coverings of the spermatic cord, the cremasteric fascia.

Superior and inferior epigastric artery

inferior epigastric vessels enter the rectus sheath at the arcuate line. This anastomosis offers one alternate route to the lower extremity in the event of narrowing of the abdominal aorta

Inguinal canal

passageway traversed by the testicles and their associated ducts and vessels to "descend" into the scrotum- more like differential growth -roof: arches of IO and TA, conjoint tendon -floor: turned under inferior border of EO -anterior wall: EO aponeurosis reinforced laterally by IO -posterior wall: transversalis fascia laterally, conjoint tendon medial -deep inguinal ring, a normal 'defect' in the transversalis fascia -superficial ring, opening in EO, surrounded by medial and lateral crura and intercrural fibers

Female gonadal development

the ovaries remain in the pelvic cavity gubernaculum attaches to the uterus gubernaculum between the ovary and the uterus becomes the ovarian ligament or round ligament of the ovary. The part which lies between the uterus and the labia majora, which traverses the inguinal canal, and which is visible at the superficial ring, is the round ligament of the uterus.

Hernias

ventral hernias occurring through the spigelian fascia along the Spieghel's semilunar line and lie under the external oblique aponeurosis just outside the outer border of the rectus or "six-pack" muscles. occur at a level referred as 'spigelian hernia belt' -transverse band between the level of umbilicus (navel) and the line joining both anterior superior iliac spines. more common in women around 50 imaging studies to diagnose (US or CT)

Abdominal anastomoses

via branches of internal thoracic (from subclav) and inferior epigastric (from in iliac), superficial circumflex iliac + musculophrenic provide blood flow from heart to lower limb without having to go through the aorta venous anastomosis between the systemic and portal circulation via the paraumbilical veins. This is clinically significant in cases of portal hypertension transumbilical plane is also an important landmark in normal venous and lymphatic drainage of the superficial tissues: above the plane, drainage is in the cranial direction; below the plane, drainage is in the caudal direction

Inguinal triangle

weak area in the abdominal wall, bounded by the inguinal ligament inferiorly, the lateral border of rectus abdominis medially and the inferior epigastric vessels laterally. In this area only the transversalis fascia and peritoneum support the abdominal viscera

Testicular descent

2-3rd month---- The testes develop on the posterior abdominal wall. The ductus deferens and the neurovascular supply are attached to the superior pole. The gubernaculum, a cord of connective tissue, connects the inferior pole of the gonad with the labioscrotal folds (undifferentiated, at this time). A portion of the peritoneum called the processus vaginalis, evaginates over the pelvic brim, pushing the skin, superficial fascia and abdominal muscles ahead of it. 4th month IU----- Where the processus vaginalis crosses the pelvic brim, it passes through the transversalis fascia (forming the deep inguinal ring) and under the arch of transversus abdominis. The processus traverses the abdominal wall for a short distance medially, then pushes anteriorly through the superficial inguinal ring and, following the gubernaculum, enters the scrotum. The layers of the abdominal wall are carried along and extended into the scrotum

Undescended testicle

3 out of 100 full term male children are born with undescended testicle(s). As many as 30 out of 100 preterm male babies have undescended testicle(s). Men who have undescended testicles, whether treated or not, have increased risk of testicular cancer. Treatment: a variety of surgical procedures possible, open or laparoscopic, depending on where the testicle is located.