Clinical Anatomy 11e
In May , the science building at Holyoke Community College was named in her honor. To help learners prepare for future careers in health care, Career Connection Videos and Homeostatic Imbalance discussions have been updated, and end-of-chapter Clinical Case Studies have been extensively reworked to include new NCLEX-Style questions.
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Your email address will not be published. Save my name, email, and website in this browser for the next time I comment. Find Book. Send to a friend. About The Author Elaine N. Add to Wishlist. Add to Compare. Qty Add to Cart. The book continues to offer just the right balance of anatomy, physiology, and clinical coverage to make the content complete, but not overwhelming.
New clinical photos in the Homeostatic Imbalance feature help students visualize diseases and disorders, and new integrated Concept Links help students make connections across topics and body systems. Written specifically for the one-semester course, this text presents a superior teaching and learning experience for you and your students. Instructors can easily assign a wide range of question and activity types for automatic grading. However, the two septa overlap and this patency of the foramen ovale is of no functional significance.
If the septum secundum is too short to cover the foramen secundum in the septum primum, an atrial septal defect persists after the septum primum and septum secundum are pressed together at birth. This results in an ostium secundum defect, which allows shunting of blood from the left to the right atrium. This defect lies high up in the atrial wall and is relatively easy to close surgically.
A more serious atrial septal defect results if the septum primum fails to fuse with the endocardial cushions. This ostium primum defect lies immediately above the atrioventricular boundary and may be associated with a defect of the pars membranacea septi of the ventricular septum. In such a case, the child is born with both an atrial and ventricular septal defect.
Occasionally the ventricular septal defect is so huge that the ventricles form a single cavity, giving a trilocular heart. Congenital pulmonary stenosis may affect the trunk of the pulmonary artery, its valve or the infundibulum of the right ventricle. If stenosis occurs in conjunction with a septal defect, the compensatory hypertrophy of the right ventricle developed to force blood through the pulmonary obstruction develops a sufficiently high pressure to shunt blood through the defect into the left heart; this mixing of the deoxygenated right heart blood with the oxygenated left-sided blood results in the child being cyanosed at birth.
This results from unequal division of the truncus arteriosus by the spinal septum, resulting in a stenosed pulmonary trunk and a wide aorta which overrides the orifices of both the ventricles. The displaced septum is unable to close the interventricular septum, which results in a ventricular septal defect.
Cyanosis results from the shunting of large amounts of unsaturated blood from the right ventricle through the ventricular septal defect into the left ventricle and also directly into the aorta. A persistent ductus arteriosus Fig. If left uncorrected, it causes progressive work hypertrophy of the left heart and pulmonary hypertension.
Aortic coarctation Fig. More commonly there is a short segment involved in the region of the ligamentum arteriosum or still patent ductus. In these cases, circulation to the lower limb is maintained via collateral arteries around the scapula anastomosing with the intercostal arteries, and via the link-up between the internal thoracic and inferior epigastric arteries. Clinically, this circulation may be manifest by enlarged vessels being palpable around the scapular margins; radiologically, dilatation of the engorged intercostal arteries results in notching of the inferior borders of the ribs.
Abnormal development of the primitive aortic arches may result in the aortic arch being on the right or actually being double. An abnormal right subclavian artery may arise from the dorsal aorta and pass behind the oesophagus—a rare cause of difficulty in swallowing dysphagia lusoria. Rarely, the division of the truncus into aorta and pulmonary artery is incomplete, leaving an aorta—pulmonary window, the most unusual congenital fistula between the two sides of the heart.
The superior mediastinum This is bounded in front by the manubrium sterni and behind the first four thoracic vertebrae Fig. Above, it is in direct continuity with the root of the neck and below it is continuous with the three compartments of the inferior mediastinum. Its principal contents are: the great vessels, trachea, oesophagus, thymus— mainly replaced by fatty tissue in the adult, thoracic duct, vagi, left recurrent laryngeal nerve and the phrenic nerves Fig.
The arch of the aorta is directed anteroposteriorly, its three great branches, the brachiocephalic, left carotid and left subclavian arteries, ascend to the thoracic inlet, the first two forming a V around the trachea. The brachiocephalic veins lie in front of the arteries, the left running almost horizontally across the superior mediastinum and the right vertically downwards; the two unite to form the superior vena cava.
Posteriorly lies the trachea with the oesophagus immediately behind it lying against the vertebral column. The oesophagus The oesophagus, which is 10 in 25 cm long, extends from the level of the lower border of the cricoid cartilage at the level of the 6th cervical vertebra to the cardiac orifice of the stomach Fig. Course and relations Cervical In the neck it commences in the median plane and deviates slightly to the left as it approaches the thoracic inlet. On the left side it is also related to the subclavian artery and the terminal part of the thoracic duct Fig.
Thoracic The thoracic part traverses first the superior and then the posterior mediastinum. From being somewhat over to the left, it returns to the midline at T5 then passes downwards, forwards and to the left to reach the oesophageal opening in the diaphragm T For convenience, the relations of this part are given in sequence from above downwards.
Posteriorly lie the thoracic vertebrae, the thoracic duct, the azygos vein and its tributaries and, near the diaphragm, the descending aorta. On the left side it is related to the left subclavian artery, the terminal part of the aortic arch, the left recurrent laryngeal nerve, the thoracic duct and the left pleura.
In the posterior mediastinum it relates to the descending thoracic aorta before this passes posteriorly to the oesophagus above the diaphragm. On the right side there is the pleura and the azygos vein. Below the root of the lung the vagi form a plexus on the oesophagus, the left vagus lying anteriorly, the right posteriorly. In the abdomen, passing forwards through the opening in the right crus of the diaphragm, the oesophagus comes to lie in the oesophageal groove on the posterior surface of the left lobe of the liver, covered by peritoneum on its anterior and left aspects.
Behind it is the left crus of the diaphragm.
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Blood supply is from the inferior thyroid artery, branches of the descending thoracic aorta and the left gastric artery. The veins from the cervical part drain into the inferior thyroid veins, from the thoracic portion into the azygos vein and from the abdominal portion partly into the azygos and partly into the left gastric veins. The lymphatic drainage is from a peri-oesophageal lymph plexus into the posterior mediastinal nodes, which drain both into the supraclavicular nodes and into nodes around the left gastric vessels.
It is not uncommon to be able to palpate hard, fixed supraclavicular nodes in patients with advanced oesophageal cancer. Radiographically, the oesophagus is studied by X-rays taken after a barium swallow, in which it is seen lying in the retrocardiac space just in front of the vertebral column. Anteriorly, the normal oesophagus is indented from above downwards by the three most important structures that cross it, the arch of the aorta, the left bronchus and the left atrium.
In portal hypertension these veins distend into large collateral channels, oesophageal varices, which may then rupture with severe haemorrhage probably as a result of peptic ulceration of the overlying mucosa. This is therefore the side of election to approach the oesophagus surgically. Development of the oesophagus The oesophagus develops from the distal part of the primitive fore-gut.
From the floor of the fore-gut also differentiate the larynx and trachea, first as a groove the laryngotracheal groove which then converts into a tube, a bud on each side of which develops and ramifies into the lung. This close relationship between the origins of the oesophagus and trachea accounts for the relatively common malformation in which the upper part of the oesophagus ends blindly while the lower part opens into the lower trachea at the level of T4 oesophageal atresia with tracheooesophageal fistula.
Less commonly, the upper part of the oesophagus opens into the trachea, or oesophageal atresia occurs without concomitant fistula into the trachea. Rarely, there is a tracheo-oesophageal fistula without atresia Fig. The thoracic duct Figs 37, The cisterna chyli lies between the abdominal aorta and right crus of the diaphragm.
It drains lymphatics from the abdomen and the lower limbs, then passes upwards through the aortic opening to become the thoracic duct. This ascends behind the oesophagus, inclines to the left of the oesophagus at the level of T5, then runs upwards behind the carotid sheath, descends over the subclavian artery and drains into the commencement of the left brachiocephalic vein see Fig.
The left jugular, subclavian and mediastinal lymph trunks, draining the left side of the head and neck, upper limb and thorax respectively, usually join the thoracic duct, although they may open directly into the adjacent large veins at the root of the neck. The upper oesophagus ends blindly; the lower oesophagus communicates with the trachea at the level of the 4th thoracic vertebra.
On the right side, the right subclavian, jugular and mediastinal trunks may open independently into the great veins. Usually the subclavian and jugular trunks first join into a right lymphatic duct and this may be joined by the mediastinal trunk so that all three then have a common opening into the origin of the right brachiocephalic vein. This usually results in lymphoedema of the legs and scrotum but occasional involvement of the main channels of the trunk and thorax is followed by chylous ascites, chyluria and chylous pleural effusion.
If noticed at operation, the injured duct should be ligated; lymph then finds its way into the venous system by anastomosing channels. If the accident is missed, there follows an unpleasant chylous fistula in the neck. Such injuries are followed by a chylothorax.
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The thoracic sympathetic trunk Fig. It then passes behind the medial arcuate ligament of the diaphragm to continue as the lumbar sympathetic trunk. The thoracic chain bears a ganglion for each spinal nerve; the first frequently joins the inferior cervical ganglion to form the stellate ganglion. Each ganglion receives a white ramus communicans containing preganglionic fibres from its corresponding spinal nerve and donates back a grey ramus, bearing postganglionic fibres.
Pulmonary A. They lie medial to the sympathetic trunk on the bodies of the thoracic vertebra and are quite easily visible through the parietal pleura For their distribution see pages and Clinical features A high spinal anaesthetic will produce temporary hypotension by paralysing the sympathetic vasoconstrictor preganglionic outflow from spinal segment T5 downwards, passing to the abdominal viscera.
On the examination of a chest radiograph The following features should be examined in every radiograph of the chest. Centering and density of film The sternal ends of the two clavicles should be equidistant from the shadow of the vertebral spines. General shape Any abnormalities in the general form of the thorax scoliosis, kyphosis and the barrel chest of emphysema, for example should always be noted before other abnormalities are described. Bony cage The thoracic vertebrae should be examined first, then each of the ribs in turn counting conveniently from their posterior ends and comparing each one with its fellow of the opposite side , and finally clavicles and scapulae.
Unless this procedure is carried out systematically, important diagnostic clues e. The mediastinum The outline of the mediastinum should be traced systematically. Special note should be made of the size of the heart, of mediastinal shift and of the vessels and nodes at the hilum of the lung. Lung fields Again, systematic examination of the lung fields visible in each intercostal space is necessary if slight differences between the two sides are not to be overlooked. Abnormalities When this scheme has been carefully followed, any abnormalities in the bony cage, the mediastinum or lung fields should now be apparent.
They should then be defined anatomically as accurately as possible and checked, where necessary, by reference to a film taken from a different angle. Radiographic appearance of the heart For the appearance of the heart as seen at fluoroscopy, reference should be made to a standard work in radiology or cardiology. In the present account, only the more important features of the heart and great vessels which can be seen in standard posteroanterior and oblique lateral radiographs of the chest will be described.
The heart and great vessels in anteroposterior radiographs Fig. These should be examined as follows. Size and shape of the heart Normally the transverse diameter should not exceed half the total width of the chest, but since it varies widely with bodily build and the position of the heart, these factors must also be assessed. The shape of the cardiac shadow also varies a good deal with the position of the heart, being long and narrow in a vertically disposed heart and broad and rounded in the socalled horizontal heart.
The right border of the mediastinal shadow is formed from above downwards by the right brachiocephalic vein, the superior vena cava and the right atrium. Beneath this there are, successively, the shadows due to the pulmonary trunk or the infundibulum of the right ventricle , the auricle of the left atrium, and the left ventricle.
The shadow of the inferior border of the heart blends centrally with that of the diaphragm, but on either side the two shadows are separated by the well-defined cardiophrenic angles. The heart and great vessels in anterior oblique radiographs The left oblique view Fig. The right oblique view Fig. This border can be defined more accurately by giving the patient barium paste to swallow; the outlined oesophagus is indented by an enlarged left atrium. The xiphoid.
The costal margin extends from the 7th costal cartilage at the xiphoid to the tip of the 12th rib although the latter is often difficult to feel ; this margin bears a distinct step, which is the tip of the 9th costal cartilage. Identify this tubercle by direct palpation and also by running the fingers along the adductor longus tendon tensed by flexing, abducting and externally rotating the thigh to its origin at the tubercle.
Feel the firm vas deferens between the finger and thumb as it lies within the spermatic cord at the scrotal neck. Trace the vas upwards and note that it passes medially to the pubic tubercle and thence through the external inguinal ring, which can be felt by invaginating the scrotal skin with the fingertip. Vertebral levels Fig.
It also corresponds to the level of termination of the spinal cord. This corresponds to the level of the bifurcation of the aorta. It is also a useful landmark in performing a lumbar puncture, since it is well below the level of the termination of the spinal cord, which is approximately at L1 see page In the healthy adult it lies at the junction of L3 and L4 vertebrae. It is lower in the infant and, naturally, when the abdomen is pendulous.
It is higher in late pregnancy. Surface markings Fig. The upper border follows a line passing through the 5th intercostal space on each side. Spleen This underlies the 9th, 10th and 11th ribs posteriorly on the left side commencing 2 in 5 cm from the midline. Pancreas The transpyloric plane defines the level of the neck of the pancreas which overlies the vertebral column. From this landmark, the head can be imagined passing downward and to the right, the body and tail passing upwards and to the left.
Aorta This terminates just to the left of the midline at the level of the iliac crest at L4; a pulsatile swelling below this level may thus be an iliac, but cannot be an aortic, aneurysm. Kidneys The lower pole of the normal right kidney may sometimes be felt in the thin subject on deep inspiration.
Anteriorly, the hilum of the kidney lies on the transpyloric plane four finger breadths from the midline. Posteriorly, the upper pole of the kidney lies deep to the 12th rib. The right kidney normally extends about 1 in 2. Using these landmarks, the kidney outlines can be projected on to either the anterior or posterior aspects of the abdomen.
In some perfectly normal thin people, especially women, it is possible to palpate the lower pole of the right kidney and the sigmoid colon if loaded with faeces; in most of us, only the aorta is palpable. If there were, we would presumably be unable to take a deep breath or enjoy a large meal!
This, in the lower abdomen, forms a superficial fatty layer of Camper and a deeper fibrous layer of Scarpa. In the perineum it is attached behind to the perineal body and posterior margin of the perineal membrane and, laterally, to the rami of the pubis and ischium. It is because of these attachments that a rupture of the urethral bulb may be followed by extravasation of blood and urine into the scrotum, perineum and penis and then into the lower abdomen deep to the fibrous fascial plane, but not by extravasation downwards into the lower limb, from which the fluid is excluded by the attachment of the fascia to the deep fascia of the upper thigh.
Nerve supply The segmental nerve supply of the abdominal muscles and the overlying skin is derived from T7 to L1. This distribution can be mapped out approximately if it is remembered that the umbilicus is supplied by T10 and the groin and scrotum by L1 via the ilio-inguinal and iliohypogastric nerves— see Fig. The muscles of the anterior abdominal wall These are of considerable practical importance because their anatomy forms the basis of abdominal incisions.
The rectus abdominis Fig. At the tip of the xiphoid, at the umbilicus and half-way between, are three constant transverse tendinous intersections; below the umbilicus there is sometimes a fourth. These intersections are seen only on the anterior aspect of the muscle and here they adhere to the anterior rectus sheath. Posteriorly they are not in evidence and, in consequence, the rectus muscle is completely free behind. At each intersection, vessels from the superior epigastric artery and vein pierce the rectus. The sheath in which the rectus lies is formed, to a large extent, by the aponeurotic expansions of the lateral abdominal muscles Fig.
The anterior rectus sheath on the left side has been reflected laterally. Posteriorly lie the posterior part of this split internal oblique aponeurosis and the aponeurosis of transversus abdominis. The posterior wall at this level is made up of the only other structures available — the transversalis fascia, the thickened extraperitoneal fascia of the lower abdominal wall , and peritoneum. The posterior junction between b and c is marked by the arcuate line of Douglas, which is the lower border of the posterior aponeurotic part of the rectus sheath.
At this point the inferior epigastric artery and vein from the external iliac vessels enter the sheath, pass upwards and anastomose with the superior epigastric vessels which are terminal branches of the internal thoracic artery and vein. The rectus sheaths fuse in the midline to form the linea alba stretching from the xiphoid to the pubic symphysis.
The lateral muscles of the abdominal wall comprise the external and internal oblique and the transverse muscles. These correspond to the three layers of muscle of the chest wall — external, internal and innermost intercostals, and, like them, have their neurovascular bundles running between the second and third layer. They are clinically important in making up the rectus sheath and the inguinal canal, and also because they must be divided in making lateral abdominal incisions.
Their attachments can be remembered when one bears in mind that they fill the space between the costal margin above, the iliac crest below, and the lumbar muscles covered by lumbar fascia behind. Medially, as already noted, they constitute the rectus sheath and thence blend into the linea alba from xiphoid to pubic crest.
The obliquus externus abdominis external oblique arises from the outer surfaces of the lower eight ribs and fans out into the xiphoid, linea alba, the pubic crest, pubic tubercle and the anterior half of the iliac crest. From the pubic tubercle to the anterior superior iliac spine its lower border forms the aponeurotic inguinal ligament of Poupart. The obliquus internus abdominis internal oblique arises from the lumbar fascia, the anterior two-thirds of the iliac crest and the lateral two-thirds of the inguinal ligament.
It is inserted into the lowest six costal cartilages, linea alba and the pubic crest.
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The transversus abdominis arises from the lowest six costal cartilages interdigitating with the diaphragm , the lumbar fascia, the anterior twothirds of the iliac crest and the lateral one-third of the inguinal ligament; it is inserted into the linea alba and the pubic crest. Note that the external oblique passes downwards and forwards, the internal oblique upwards and forwards and the transversus transversely. The anatomy of abdominal incisions Incisions to expose the intraperitoneal structures represent a compromise on the part of the operator.
On the one hand he requires maximum access; on the other hand he wishes to leave a scar which lies, if possible, in an unobtrusive crease, and which will have done minimal damage to the muscles of the abdominal wall and to their nerve supply. The nerve supply to the lateral abdominal muscles forms a richly communicating network so that cuts across the lines of fibres of these muscles, with division of one or two nerves, produce no clinical ill-effects.
The segmental nerve supply to the rectus, however, has little cross-communication and damage to these nerves must, if possible, be avoided. The copious anastomoses between the blood vessels supplying the abdominal muscles make damage to these by operative incisions of no practical importance. Midline incision The midline incision is made through the linea alba.
Superiorly, this is a relatively wide fibrous structure, but below the umbilicus it becomes almost hair-line and the surgeon may experience difficulty in finding the exact point of cleavage between the recti at this level. Being made of fibrous tissue only, it provides an almost bloodless line along which the abdomen can be opened rapidly and, if necessary, from Dan in the North to Beersheba in the South! Paramedian incision The paramedian incision is placed 1 in 2. This incision has the advantage that, on suturing the peritoneum, the rectus slips back into place to cover and protect the peritoneal scar.
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The adherence of the anterior sheath to the rectus muscle at its tendinous intersections means that the sheath must be dissected off the muscle at each of these sites, and at each of these a segmental vessel requires division. Having done this, the rectus is easily slid laterally from the posterior sheath from which it is quite free. The posterior sheath and the peritoneum form a tough membrane down to half-way between pubis and umbilicus, but it is much thinner and more fatty below this where, as we have seen, it loses its aponeurotic component and is made up of only transversalis fascia and peritoneum.
The inferior epigastric vessels are seen passing under the arcuate line of Douglas in the posterior sheath and usually require division in a low paramedian incision. The rectus receives its nerve supply laterally and the muscle medial to the incision must, in consequence, be deprived of its innervation and undergo atrophy; it is an incision therefore best avoided.
Subcostal incision The subcostal Kocher incision is used on the right side in biliary surgery and, on the left, in exposure of the spleen. The skin incision commences at the midline and extends parallel to, and 1 in 2. The anterior rectus sheath is opened, the rectus cut and the posterior sheath with underlying adherent peritoneum incised. The small 8th intercostal nerve branch to the rectus is sacrificed but the larger and more important 9th nerve, in the lateral part of the wound, is preserved.
The divided rectus muscle is held by the intersections above and below and retracts very little. It subsequently heals by fibrous tissue. This incision is valuable in the patient with the wide subcostal angle. Where this angle is narrow, the paramedian incision is usually preferred. The aponeurosis of the external oblique is incised in the line of its fibres obliquely downwards and medially ; the internal oblique and transversus muscles are then split in the line of their fibres, and retracted without their having to be divided.
On closing the incision, these muscles snap together again, leaving a virtually undamaged abdominal wall. Transverse and oblique incisions Incisions cutting through the lateral abdominal muscles do not damage their richly anastomosing nerve supply and heal without weakness. They are useful, for example, in exposing the sigmoid colon or the caecum or, by displacing the peritoneum medially, extraperitoneal structures such as the ureter, sympathetic chain and the external iliac vessels.
Thoraco-abdominal incisions An upper paramedian or upper oblique abdominal incision can be extended through the 8th or 9th intercostal space, the diaphragm incised and an extensive exposure achieved of both upper abdomen and thorax. Paracentesis abdominis Intraperitoneal fluid collections can be evacuated via a cannula inserted through the abdominal wall.
The coils of gut are not in danger in this procedure because they are mobile and are pushed away by the tip of the trocar. These two landmarks are also used for insertion of cannulae for laparoscopic surgery. The inguinal canal Fig. Questions on the anatomy of this region are probably asked more often than any other in examinations because of its importance in diagnosis and treatment of hernias.
The canal is 1. It passes downwards and medially from the internal to the external inguinal rings and lies parallel to and immediately above, the inguinal ligament. The conjoint tendon represents the fused common insertion of the internal oblique and transversus into the pubic crest and pectineal line. The internal or deep ring represents the point at which the spermatic cord pushes through the transversalis fascia, dragging from it a covering which forms the internal spermatic fascia. This ring is demarcated medially by the inferior epigastric vessels passing upwards from the external iliac artery and vein.
The external or superficial ring is a V-shaped defect in the external oblique aponeurosis and lies immediately above and medial to the pubic tubercle. The inguinal canal transmits the spermatic cord and the ilio-inguinal nerve in the male and the round ligament and ilio-inguinal nerve in the female. The spermatic cord comprises Fig.
Clinical features An indirect inguinal hernia passes through the internal ring, along the canal and then, if large enough, emerges through the external ring and descends into the scrotum.
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If reducible, such a hernia can be completely controlled by pressure with the fingertip over the internal ring, which lies 0. This pulse can be felt at the mid-inguinal point, half-way between the anterior superior iliac spine and the symphysis pubis see Fig. If the hernia protrudes through the external ring, it can be felt to lie above and medial to the pubic tubercle, and is thus differentiated from a femoral hernia emerging from the femoral canal, which lies below and lateral to this landmark see Fig.
A direct inguinal hernia pushes its way directly forwards through the posterior wall of the inguinal canal. Since it lies medial to the internal ring, it is not controlled by digital pressure applied immediately above the femoral pulse. Occasionally, a direct hernia becomes large enough to push its way through the external ring and then into the neck of the scrotum. This is so unusual that one can usually assume that a scrotal hernia is an indirect hernia. The only certain way of determining the issue is at operation; the inferior epigastric vessels demarcate the medial edge of the internal ring, therefore an indirect hernia sac will pass lateral and a direct hernia medial to these vessels.
Quite often both a direct and an indirect hernia coexist; they bulge through on each side of the inferior epigastric vessels like the legs of a pair of pantaloons. Peritoneal cavity The endothelial lining of the primitive coelomic cavity of the embryo becomes the thoracic pleura and the abdominal peritoneum.
Each is invaginated by ingrowing viscera which thus come to be covered by a serous membrane and to be packed snugly into a serous-lined cavity, the visceral and parietal layer respectively. In the male, the peritoneal cavity is completely closed, but in the female it is perforated by the openings of the uterine tubes which constitute a possible pathway of infection from the exterior.
To revise the complicated attachments of the peritoneum, it is best to start at one point and trace this membrane in an imaginary round-trip of the abdominal cavity, aided by Figs 47 and At this level the membrane is smooth apart from the shallow ridges formed by the median umbilical fold the obliterated fetal urachus passing from the bladder to the umbilicus , the medial umbilical folds the obliterated umbilical arteries passing to the umbilicus from the internal iliac arteries and the lateral umbilical folds the peritoneum covering the inferior epigastric vessels.
A cicatrix can usually be felt and seen at the posterior aspect of the umbilicus, and from this the falciform ligament sweeps upwards and slightly to the right of the midline to the liver. In the free border of this ligament lies the ligamentum teres the obliterated fetal left umbilical vein which passes into the groove between the quadrate lobe and left lobe of the liver.
Elsewhere, the peritoneum sweeps over the inferior aspect of the diaphragm, to be reflected on to the liver leaving a bare area demarcated by the upper and lower coronary ligaments of the liver and on to the right margin of the abdominal oesophagus. After enclosing the liver for further details, see page 95 , the peritoneum descends from the porta hepatis as a double sheet, the lesser omentum, to the lesser curve of the stomach.
Here it again splits to enclose this organ, reforms at its greater curve, then loops downwards, then up again to attach to the length of the transverse colon, forming the apron-like greater omentum. The transverse colon, in turn, is enclosed within this peritoneum which then passes upwards and backwards as the transverse mesocolon to the posterior abdominal wall, where it is attached along the anterior aspect of the pancreas.
At the base of the transverse mesocolon, this double peritoneal sheet divides once again; the upper leaf passes upwards over the posterior abdominal wall to reflect on to the liver at the bare area , the lower leaf passes over the lower part of the posterior abdominal wall to cover the pelvic viscera and to link up once again with the peritoneum of the anterior wall.
This posterior layer is, however, interrupted by its being reflected along an oblique line running from the duodenojejunal flexure, above and to the left, to the ileocaecal junction, below and to the right, to form the mesentery of the small intestine. The mesentery of the small intestine, the lesser and greater omenta and mesocolon all carry the vascular supply and lymph drainage of their contained viscera. The lesser sac Fig. The right extremity of the sac opens into the main peritoneal cavity via the epiploic foramen or foramen of Winslow Fig. Notice that none of these important boundaries can be incised to release the strangulation; the bowel must be decompressed by a needle to allow its reduction.
If the cystic artery is torn during cholecystectomy, haemorrhage can be controlled by this manoeuvre named after James Pringle , which then enables the damaged vessel to be identified and secured. Intraperitoneal fossae A number of fossae occur within the peritoneal cavity into which loops of bowel may become caught and strangulated. The subphrenic spaces Fig. One or more of these spaces may become filled with pus a subphrenic abscess walled off inferiorly by adhesions. There are five subdivisions of clinical importance.
The right and left subphrenic spaces lie between the diaphragm and the liver, separated from each other by the falciform ligament. The right and left subhepatic spaces lie below the liver. The right is the pouch of Morison and is bounded by the posterior abdominal wall behind and by the liver above. It communicates anteriorly with the right subphrenic space around the anterior margin of the right lobe of the liver and below both open into the general peritoneal cavity from which infection may track, for example, from a perforated appendix or a perforated peptic ulcer.
The left subhepatic space is the lesser sac which communicates with the right through the foramen of Winslow. It may fill with fluid as a result of a perforation in the posterior wall of the stomach or from an inflamed or injured pancreas to form a pseudocyst of the pancreas. The right extraperitoneal space lies between the bare area of the liver and the diaphragm.
It may become involved in retroperitoneal infections or directly from a liver abscess. A finger is then passed upwards and forwards between liver and diaphragm to open into the abscess cavity. An anteriorly placed collection of pus below the diaphragm can alternatively be drained via an incision placed below and parallel to the costal margin.