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Зміст2. Duration of studies
4. Basic knowledges, abilities, skills, that necessary for the study themes (interdisciplinary integration)
5. Advices to the student.
The posterior wall of the inguinal canal
The Superficial Ring of the Inguinal Canal
Maldescent of a testis
5.2. Theoretical questions to studies
5.3. Materials for self-control
Ministry of Health of Ukraine
Bukovinian State Medical University
on methodical meeting of the Department of Anatomy, Topographical anatomy and Operative Surgery
“………”…………………….2008 р. (Protocol №……….)
The chief of department
for the 2nd-year foreign students of English-spoken groups of the Medical Faculty
(speciality “General medicine”)
for independent work during the preparation to practical studies
the Theme of studies
“Topographical anatomy of inguinal region. Topographical anatomy and operative surgery of the inguinal hernias”
Topographical Anatomy and Operative Surgery
of the Head, Neck, Thorax and Abdomen
Semantic module 3
“Topographical Anatomy and Operative Surgery of the Abdomen”
Chernivtsi – 2008
1. Actuality of theme:
The topographical anatomy and operative surgery of the abdomen are very importance, because without the knowledge about peculiarities and variants of structure, form, location and mutual location of abdominal anatomical structures, their age-specific it is impossible to diagnose in a proper time and correctly and to prescribe a necessary treatment to the patient. Surgeons usually pay much attention to the topographo-anatomic basis of surgical operations on the abdomen.
^ 2 working hours.
3. Objectives (concrete purposes):
To know the definition of regions of the abdomen.
To know classification of surgical operations on the abdomen.
To know the topographical anatomy and operative surgery of the organs of the abdomenal cavity.
5.1. Table of contents of the theme:
The Inguinal Region
The inguinal region is very important surgically because it is the site of inguinal hernias ("ruptures") in both sexes; however, they are much more common in males. The inguinal region is an area of weakness in the anterior abdominal wall, especially in males, owing to the prenatal penetration of the wall by the testis and spermatic cord.
The Inguinal Canal. This is an oblique passage, about 4 cm long in adults, through the inferior part of the anterior abdominal wall. It runs inferomedially, just superior and parallel to the medial half of the inguinal ligament. The inguinal canal has two walls (anterior and posterior), two openings (one at each end called the superficial and deep inguinal rings), a roof (superior wall), and a floor (inferior wall).
The anterior wall of the inguinal canal is formed mainly by the aponeurosis of the external oblique muscle. It is reinforced laterally by fibers of the internal oblique muscle; sometimes by those of the transversus abdominis muscle.
^ is formed throughout by the transversalis fascia, which is reinforced medially by the conjoint tendon, the common tendon of the internal oblique and transversus abdominis muscles.
The floor of the inguinal canal is formed by the superior surface of the inguinal ligament and the lacunar ligament.
The roof of the inguinal canal is formed by arching fibers of the internal oblique and transversus abdominis muscles. The inferior epigastric artery lies at the medial boundary of the deep inguinal ring; hence, its pulsations form a useful landmark during surgery for determining the location of this ring.
Owing to the obliquity of the inguinal canal, the deep and superficial inguinal rings do not coincide. Consequently, increases in intra-abdominal pressure act on the deep inguinal ring, forcing the posterior wall of the canal against the anterior wall.
This strengthens this weak part of the anterior abdominal wall. The inguinal canal has been likened to an arcade of three arches formed by the three flat abdominal muscles. Contraction of the external oblique muscle approximates the anterior wall of the canal (formed mainly by the aponeurosis of the external oblique) to the posterior wall (formed mainly by the transversalis fascia). Contraction of the internal oblique and transversus abdominis muscles makes them taut; as a result, the roof of the canal descends and the passage is constricted. During standing, these muscles continuously contract. During coughing and straining, the raised intra-abdominal pressure threatens to force some of the abdominal contents through the canal, producing a hernia. However, vigorous contraction of the arched fleshy fibers of the internal oblique and transverses abdominis muscles "clamp down." The action is like a halfsphincter that helps to prevent herniation. Immediately posterior to the superficial inguinal ring is the conjoint tendon; the rectus abdominis muscle is posterior to the conjoint tendon. When intra-abdominal pressure rises, the flat muscles of the abdomen contract, forcing the external oblique aponeurosis against the conjoint tendon, which then pushes against the rectus abdominis muscle. Hence, the conjoint tendon and rectus abdominis muscle reinforce the posterior surface of the superficial inguinal ring, tending to prevent herniation.
^ . Although it is called a ring, the superficial (external) inguinal ring is a more or less triangular aperture (deficiency) in the aponeurosis of the external oblique muscle.
The base of this triangle is formed by the pubic crest and its apex is directed superolaterally. The sides of the triangle are formed by the medial and lateral crura (L. legs) of the superficial inguinal ring. Emerging from the superficial inguinal ring is the spermatic cord in the male and the round ligament of the uterus in the female. In addition, the ilioinguinal nerve makes its exit through the ring to supply skin on the superomcdial aspect of the thigh. The central point of the superficial inguinal ring is superior to the pubic tubercle.
The lateral crus of the superficial inguinal ring is formed by the part of the external oblique aponeurosis that is attached to the pubic tubercle via the inguinal ligament. The spermatic cord rests on the inferior part of this crus. The medial crus of the superficial inguinal ring is formed by the part of this aponeurosis that diverges to attach to the pubic bone and pubic crest, medial to the pubic tubercle. Intercrural fibers from the inguinal ligament arch superomedially across the superficial inguinal ring. They prevent the crura from spreading apart.
The superficial inguinal ring is palpable just superior and lateral to the pubic tubercle. In men it can be examined by invaginating the skin of the scrotum with the tip of a digit (often the index finger), and probing gently superolaterally along the spermatic cord. If the ring is enlarged, it may admit the digit without causing pain. In women and children, the dimensions of the superficial inguinal ring are much less than in men and palpation of it is difficult. In male infants the superficial inguinal ring does not normally admit the tip of a digit.
The Deep Ring of the Inguinal Canal. This slitlike opening in the transversalis fascia is located just lateral to the inferior epigastric artery. This deep (internal) ring is immediately superior to the midpoint of the inguinal ligament and medial to the origin of the transverses abdominis muscle from the inguinal ligament. The deep inguinal ring is the opening of a fingerlike diverticulum of the transversalis fascia. It formed prenatally when the processus vaginalis evaginated ("pushed through") the transversalis fascia. The margins of the deep ring are not sharply defined, as are those of the superficial ring. When the external oblique is reflected and the epigastric vessels are displaced, it ceases to exist as a ring; however, from the internal aspect, a dimple in the peritoneum often marks the site of the deep inguinal ring.
Descent of the Testes. To understand the inguinal canal, some knowledge of the migration and descent of the testes is essential. The testes develop in the lumbar regions deep to the transversalis fascia, between it and the peritoneum. They normally pass through the inguinal canals into the scrotum just before birth. The site of the inguinal canal in the fetus is first indicated by the gubernaculum, a ligament that extends from the testis through the anterior abdominal wall and inserts into the internal surface of the scrotum. Later, a fingerlike outpouching or diverticulum of peritoneum, called the processus vaginalis, follows the gubernaculum and evaginates the anterior abdominal wall to form the inguinal canal. The processus vaginalis pushes extensions of the layers of the anterior abdominal wall before it. In males these prolongations of the layers of the anterior abdominal wall become the coverings of the spermatic cord. In both sexes the opening produced by the processus vaginalis in the external oblique aponeurosis forms the superficial inguinal ring. The testes usually enter the inguinal canals just before birth and pass inferomedially through them to enter the scrotum. Normally the stalk of the processus vaginalis obliterates shortly afterbirth, leaving only the part surrounding the testis, which becomes the tunica vaginalis. The scrotal ligament is the adult derivative of the gubernaculum.
^ (undescended testis or cryptorchidism) is a common abnormality. The testes are undescended in about 3% of full-term and 30% of premature infants. Undescended testes are usually located somewhere along the inguinal canal. Most undescended testes descend during the first few weeks after birth.
Descent of the Ovaries. The ovaries also descend from their sites of origin on the posterior abdominal wall to a point just inferior to the pelvic brim; however, they do not normally enter the inguinal canals. The processus vaginalis normally obliterates completely and the gubernaculums attaches to the uterus, where it is divided into the ligament of the ovary and the round ligament of the uterus. The round ligament of the uterus passes through the inguinal canal and attaches to the internal surface of the labium majus (homologous to half of the scrotum). Persistence of the processus vaginalis in a female, called a canal of Nuck clinically, may result in an indirect inguinal hernia. Cysts in the inguinal canal and labium majus may also develop from remnants of the processus vaginalis.
Summary of the Inguinal Canal. The inguinal canal is an oblique passage through the inferior part of the anterior abdominal wall. The chief protection of the inguinal canal is muscular. Its main constituent is the spermatic cord in males and the round ligament of the uterus in females. It contains the ilioinguinal nerve in both sexes. It has an opening at each end, the deep and superficial inguinal rings. The deep ring is a slitlike opening in the transversalis fascia and the superficial ring is a triangular opening in the aponeurosis of the external oblique. The inguinal canal has two walls (anterior and posterior), a roof, and a floor. The anterior wall is formed mainly by the aponeurosis of the external oblique muscle and is reinforced laterally by fibers of the internal oblique. The posterior wall is formed mainly by the transversalis fascia and is reinforced medially by the conjoint tendon. The floor is formed by the inguinal and lacunar ligaments. The roof is composed of the arching fibers of the internal oblique and transversus abdominis muscles.
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