International Journal of Science and Healthcare Research Vol.5; Issue: 2; April-June 2020 Website: ijshr.com Case Report ISSN: 2455-7587 Abnormal Passage of Oesophagus through the Diaphragm - A Case Report Dasari Chandi Priya1, Mrudula Chandrupatla2, N. Archana1 1Assistant Professor, 2Professor and HOD, Department of Anatomy, Apollo Institute of Medical Sciences and Research, Hyderabad, Telangana, India, 500090. Corresponding Author: Dasari Chandi Priya ABSTRACT convex superior surface faces thoracic cavity and concave inferior surface faces Diaphragm is a musculo-aponeurotic sheet abdominal cavity. The muscular component separating thoracic and abdominal cavities. It of diaphragm arises from the circumference has few apertures in it providing passage for of thoracic outlet and it has 3 components structures traversing between both the cavities. i.e. sternal, costal and lumbar. Sternal fibres Out of those, oesophageal hiatus (OH) has got more surgical importance as it goes through arise from the posterior aspect of xiphoid muscular portion of diaphragm and is prone to process and costal fibres from the inner changes in hiatal diameter due to excursions of surface of lower six costal cartilage and ribs, diaphragm. This should lead to stomach interdigitating with transversus abdominis. herniation into thoracic cavity and acid reflux The lumbar part arises from medial and with inspiration but it is prevented by the lateral arcuate ligaments, which extend arrangement of crural diaphragm around the OH across psoas major and quadrates lumborum and angle at the entry of oesophagus into muscles, and also from the right and left stomach as studied by Collis et al. However, due crura. The right crus arises the anterolateral to age or congenital defects, above mentioned surfaces of the bodies and intervertebral pathologies do occur. This has led to discs of the upper three lumbar vertebrae. pronounced research into normal anatomy of OH and most of the studies have found that right The left crus arises from the corresponding crus provides significant contribution to OH parts of the upper two lumbar vertebrae. The margins. During cadaveric dissection at our medial tendinous margins of the crura meet college in the department of Anatomy, we have in the midline to form an often poorly a found OH, in a cadaver, bounded by the crura defined arch, the median arcuate ligament. on both sides and median arcuate ligament All these fibres insert into central tendon. anteriorly. Aorta and other routinely found Many structures pass between the structures are seen passing through the same abdominal and thoracic cavities through the hiatus posterior to the oesophagus. Precise openings in the diaphragm. However there knowledge about oesophageal hiatus is essential are mainly three openings for the passage of for better understanding of physiological and inferior vena cava, esophagus and aorta. clinical phenomena. Caval opening, quadrilateral in shape, lies at the level of intervertebral disc between 8th Key words: Diaphragm openings, Oesophageal th hiatus, Crura, Median arcuate ligament. and 9 thoracic vertebrae and passes through the central tendon of diaphragm. It INTRODUCTION conveys IVC, which adheres to the margins Diaphragm is a dome shaped, of opening, and right phrenic nerve. Aortic th musculofibrous sheet separating the thoracic opening is seen at the level of 12 thoracic cavity from the abdominal cavity. Its vertebra, conveying aorta, thoracic duct, International Journal of Science and Healthcare Research (www.ijshr.com) 73 Vol.5; Issue: 2; April-June 2020 Dasari Chandi Priya et.al. Abnormal passage of oesophagus through the diaphragm – a case report lymphatic trunks, azygous and hemiazygous ligament was well developed. Aorta was veins. It is bounded by crura on both sides, found to enter into the abdominal cavity vertebral column posteriorly and median through the same opening along with other arcuate ligament anteriorly. structures like azygous vein and thoracic Anterosuperiorly and to the left of this, duct, posterior to the oesophagus. Vena oesophageal opening (elliptical in shape) is Caval opening was in its usual location i.e. present. It lies at the level of 10th thoracic within the central tendon. No other vertebra and transmits the oesophagus, abnormalities were found in the abdomen vagal trunks and gastric nerves, oesophageal and other regions of the body. branches of the left gastric vessels and some lymphatic vessels. It is bounded by muscle DISCUSSION fibres that originate from the medial part of Diaphragm is chiefly an inspiratory the right crus and cross the midline, forming muscle along with non-ventilatory a loop approximately 2.5 cm long, around functions. As it separates the abdominal and the terminal part of the oesophagus. Inner thoracic cavities; there are several structures fibres of this loop are circumferentially which will either pass through it, or between arranged. The condensed peri-esophageal it and the body wall including blood vessels, tissue forms “phernico-esophageal nerves and the oesophagus. There are ligament” which is attached to esophagus various apertures to do the same but three and prevents upward displacement of the large openings are constantly found. They same. Repeated stress and loss of elastic are aortic opening (osseo-aponeurotic), fibres in the phernico-esophageal ligament oesophageal and vena caval openings, causes widening of oesophageal hiatus (OH) approximately, at the level of T12, T10 and and leads to the formation of sliding hernia. T8 vertebra respectively. Out of these [1] Oesophageal hiatus is most vulnerable to apertures, oesophageal hiatus (OH) has visceral herniation because it faces directly attracted considerable attention as it is prone into the abdominal cavity and, hence, is to more changes during diaphragmatic directly subjected to the pressure stresses excursions. It may be because the opening is between the two cavities. [2] Though it is not completely filled by the contents to widely accepted that muscle fibres from the allow for expansion of oesophagus [2] and diaphragmatic crura form the boundaries for there is possibility of weakening of oesophageal hiatus, there are many phernico-esophageal ligament with aging. disagreements between various authors Since middle of 20th century, there has been regarding contribution of crura to the considerable research into functional and boundaries of this hiatus. Thus it becomes anatomical factors causing acid reflux. necessary to thoroughly understand/report Subsequently it was found that high the variations in formation of oesophageal pressure in the physiological lower hiatus for a successful hernial repair. oesophageal sphincter, angle of entry of esophagus into stomach and the formation CASE REPORT of oesophageal hiatus by the crura of During routine dissection session of diaphragm were found to have key role in Anatomy, as a part of undergraduate preventing acid reflux, hiatal hernia etc. [3,4] curriculum, we found a variation in the In this setting, various studies were passage of oesophagus through the conducted to demonstrate the formation of diaphragm of a 65 year old, male cadaver. OH anatomically and the pillars or crura The sternal, costal and lumbar origins of were found to have an important role in the diaphragmatic fibres were normal. same. But there were many disagreements. Oesophageal opening in the diaphragm was Collis et al [3] found 15 different types of bounded by crura on both sides and median arrangement of crura in formation of OH. arcuate ligament anteriorly. Median arcuate Listerud & Harkins [5] described 11 different International Journal of Science and Healthcare Research (www.ijshr.com) 74 Vol.5; Issue: 2; April-June 2020 Dasari Chandi Priya et.al. Abnormal passage of oesophagus through the diaphragm – a case report types of formation. A study by Loukas M et reflex), and also to prevent excessive al [6] showed 6 different types of OH widening of OH, during inspiration. [3] formation. In spite of these differences, all But the cadaver in our case showed the studies agreed that significant the oesophagus passing through an opening contribution was made by fibres of right which was bounded by the crura on both crus. [3, 6-8] In majority of the subjects, the sides and median arcuate ligament right crus divides into a dorsal bundle and a anteriorly (Fig 1). Thus OH was not ventral bundle. Dorsal bundle forms the left surrounded by muscles from either crura. limb and the ventral bundle forms the right Aorta was seen to be passing beneath the limb of OH. As they approach the OH, these esophagus through the same opening. This limbs cross each other in a scissor-like finding goes in contrary to the findings of manner and bound the hiatus. The lateral previous literature, which stresses the role fibers of each limb insert into the central of crura in closing the lumen of esophagus tendon while the medial fibers form the and preventing upward displacement of hiatal margins and decussate at the midline gastroesophageal junction during in front of the esophagus. [9] Such an inspiration. Since it is a cadaveric finding, arrangement is required to close the lumen we could not elicit the person’s medical of oesophagus, maintain the angle between history. To the best of our knowledge, none oesophagus and stomach (to avoid acid of the previous literature has showed such an arrangement of OH. IVC Median arcuate ligament Right dome Oesophagus Left dome Aorta Fig 1: Passage of oesophagus in between the two crura. (IVC = Inferior Vena Cava). Embryological basis: 4. The mesentery of the esophagus, in The diaphragm develops from the following which the crura of the diaphragm sources. [10] develop. 1. The septum transversum, which forms According to textbooks, musculature of the central tendon of the diaphragm diaphragm is derived from lateral body wall 2. The two pleuroperitoneal membranes and oesophageal mesenchyme in its dorsal 3. Muscular components from somites at mesentery in addition to somites of cervical cervical segments three to five region. But studies by Babiuk RP [11] et al International Journal of Science and Healthcare Research (www.ijshr.com) 75 Vol.5; Issue: 2; April-June 2020 Dasari Chandi Priya et.al.