anatomical compartments

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anatomical compartments and their connections as demonstrated by ectopic air. The same patient as in Fig. 13b. Fournier gangrene in a 67-year-old diabetic man, with extensive arteriosclerosis, already submitted to aortic bifemoral bypass years ago, still permeable (red circles – patent common femoral bypass grafts located anteriorly to native arteries, occluded on the left). Contrast-enhanced CT scan at level of acetabular dome shows endopelvic fascia and extraperitoneal pelvic spaces. Endopelvic fascia and its two layers are illustrated. The parietal layer covers the elevator muscle of anus and coccygeus (pelvic diaphragm) and the intrapelvic portions of the internal obturator and the piriformis muscles. The visceral layer covers inferior segments of the urinary bladder, lower third of the ureters, uterus, vagina and seminal vesicles; it forms a continuous line enveloping the perirectal fat, the mesorectal fascia. Pelvic spaces. Prevesical space is bordered by transversalis fascia anteriorly and umbilicovesical fascia posteriorly. Paravesical and presacral spaces are limited by parietal and visceral sleeves of the endopelvic fascia. Perivesical space is surrounded by umbilicovesical fascia and rectovesical septum. Perirectal space is involved by the rectal fascia and separated from the perivesical space by the rectovesical septum

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anatomical compartments and their connections as demonstrated by ectopic air. Duodenal perforation complicating ERCP in a 60-year-old man. Contrast-enhanced CT scan at the level of right renal hilum (a, b) and iliac crest (c) shows the retroperitoneal and interfascial planes. a Anterior pararenal space (APS) is limited by posterior parietal peritoneum and anterior renal fascia, with midline continuity; posterior pararenal space (PPS) between posterior renal fascia and transversalis layer of endoabdominal fascia; perirenal space (PS) between anterior and posterior renal fascias. Renal and lateroconal fasciae are laminated, defining potential spaces: the retromesenteric (RMP), the retrorenal (RRP) and lateroconal planes (LP) that all communicate at fascial trifurcation. b Axial image focused on fascial trifurcation. Ectopic gas is seen extending through the retromesenteric plane (RMP), retrorenal plane (RRP) and lateroconal plane (LP), and meeting at the fascial trifurcation (red star). Posterior pararenal space (PPS) anteriorly continues as a fat stripe in the properitoneal space (PP). c Inferior extension of the interfascial plane, delineated by ectopic gas/air. The retromesenteric and the retrorenal planes approximate one another as the fat cone of perirenal fat diminishes inferiorly, resulting in the combined interfascial plane (CIP); it continues in the pelvis along the anterolateral margins of the psoas muscle contiguous with the pelvic retroperitoneal perivesical and presacral spaces

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anatomical compartments and their connections as demonstrated by ectopic air. Cervical emphysema in a 63-year-old man with tracheal rupture after endotracheal intubation (respiratory failure in CPOD patient complicated by lung infection). Contrast-enhanced CT scan at supra–hyoid (a and b) and infra-hyoid (c and d) cervical levels, illustrate the cervical fascia and its layers. The superficial or investing layer (green line) is superiorly attached to the superior nuchal line of the occipital, the mastoid process of the temporal bone and the inferior border of the mandible, and inferiorly to the manubrium, clavicles and scapula; laterally it merges with subcutaneous tissues of the neck. The middle fascia (pink line) runs, anteriorly, from the hyoid downwards in front of the trachea and large vessels, ultimately blending with the fibrous pericardium; and posteriorly from the skull base, attaches to the prevertebral fascia, and merges with the investing fascia at the lateral borders of the infrahyoid muscles. The deep or prevertebral layer (blue line) encircles the paraspinous and perivertebral muscles; it runs from the skull base downwards to the coccyx; its more anterior layer contribute to the posterior and lateral wall of the retropharyngeal space and insert on the diaphragm; it gives off a thin lamina, the alar layer, attached to the prevertebral layer by loose connective tissue, creating a potential space between mediastinum and neck, the dangerous space (orange shaded area)—for free movement of air/gas between mediastinum and neck

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anatomical compartments and their connections as demonstrated by ectopic air. Imaging subcutaneous emphysema. Duodenal perforation complicating ERCP in a 75-year old woman. a Chest conventional PA radiography shows linear lucent areas in subcutaneous and chest wall tissues. b, c Contrast-enhanced CT scan at the level of the kidneys. The “lung window” (a) easily depicts the presence of air dissecting the retroperitoneum as well as extending to the abdominal wall; the “soft tissue window” (b) accurately localizes ectopic air/gas in the different planes of retroperitoneum, and in the abdominal muscular and subcutaneous tissue. Air is also seen in the contrast filled gallbladder (red star) with an air-fluid level (ERCP-related findings) and transverse colon (blue triangle)

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anatomical compartments and their connections as demonstrated by ectopic air. A 44-year-old man with silicosis and CPOD (chronic pulmonary obstructive disease), with an upper right lobe nodule, who developed secondary pneumothorax after biopsy; the lung did not expand with drainage, due to the development of broncho-pleural fistula; the drain was accidentally removed and the patient developed rapidly progressive emphysema. a Axial CT scan in lung windows depicts extensive subcutaneous emphysema and pneumomediastinum. b Axial CT scan 5 days later, shows that all ectopic air has been reabsorbed

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anatomical compartments and their connections as demonstrated by ectopic air. The same patient as in Fig. 3: tracheal rupture after endotracheal intubation. Sagittal (a) and coronal (b) reformatted CT scan illustrate cervico-thoracic continuum through retropharyngeal (orange) and visceral (in between pink lines) spaces

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anatomical compartments and their connections as demonstrated by ectopic air. Local sources of pneumomediastinum. a, b Spontaneous pneumomediastinum due to prolonged and forceful Valsalva manoeuvres in 21-year-old man. Axial CT scan with “lung window” demonstrates the Macklin effect: air is seen along the perivascular and peribronchial fascial sheaths (a), continuous to the mediastinum (red star) (b). c Oesophageal perforation by fishbone complicated by mediastinitis in a 61-year-old woman. Axial CT scan after oral iodinated contrast ingestion, distending the oesophagus (red square); extraluminal air bubbles (red arrows) are seen in mediastinum together with increased mediastinal fat attenuation, as well as multiple reactive lymph nodes. Normal permeable airways are seen (blue triangle) at level of carina

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anatomical compartments and their connections as demonstrated by ectopic air. Unilateral secondary spontaneous pneumothorax in a 69-year-old man with silicosis, and extensive emphysematous changes in lungs, with bullae. Axial CT scan depicts air spread in the mediastinum as a continuum space, and subcutaneous planes after percutaneous drainage of pneumothorax (chest tube not shown)

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anatomical compartments and their connections as demonstrated by ectopic air. The same patient as in Fig. 2. Axial CT in the “lung window” depicts the thoracoabdominal continuum. a The anterior blending of the endothoracic and endoabdominal fascias outlined by air: one in the midline, between the two slips of sternal origin of the diaphragm on the back of xiphoid process, and two parasagittal between the sternal and costal origins of the diaphragm—the sternocostal triangles or foramen of Morgagni. b The crura have separated, forming the oesophageal hiatus. The subpleural space of the thorax and subperitoneal space of the abdomen are in continuity through the subserous space within the oesophageal and aortic hiatus

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anatomical compartments and their connections as demonstrated by ectopic air. Emphysematous necrotising pancreatitis in a 64-year-old woman. Contrast-enhanced axial CT scan demonstrates a mottled collection of gas bubbles mainly involving the body and tail of the pancreas; inflammatory changes in the surrounding fat are seen. Gas spread is depicted along the retromesenteric plane and along properitoneal space (red star). RMP retromesenteric plane, APS anterior pararenal space, PP properitoneal space

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anatomical compartments and their connections as demonstrated by ectopic air. Sigmoid perforation during colonoscopy with polyp excision in a 77-year-old woman. Axial (a) and coronal (b) reformatted CT scan in “lung window” demonstrating the retroperitoneal anatomy delineated by air/gas. a Perirenal space limited by the anterior and posterior renal fascias, with bridging septa (red arrow) and adipose tissue. Posterior pararenal space anteriorly continues along the properitoneal flank stripe to the properitoneal space between the parietal peritoneum and the transversalis fascia. b On the left, the retromesenteric plane (RMP) and the perirenal space (PS) extend cranially to the dome of the diaphragm, where they blend with the left subdiaphramatic extraperitoneal space. Incidental anterior abdominal wall hernia. RRP retrorenal plane, PPR posterior pararenal space, PP properitoneal space, LP lateroconal space, CIP combined interfascial plane

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anatomical compartments and their connections as demonstrated by ectopic air. Duodenal perforation complicating ERCP in a 75-year-old woman. Sagittal reformatted (a) and axial (b) contrast-enhanced CT scan demonstrates the right superior extension of the interfascial plane. The multilaminated retroperitoneum is open towards the upper abdominal extraperitoneal space: the bare area of the liver, and communicates with liver hilum through the subperitoneal space of the hepatoduodenal ligament

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anatomical compartments and their connections as demonstrated by ectopic air. Anastomotic colorectal leak during a CT colonoscopy in a 81-year-old woman with a history of excision of recto-sigmoid adenocarcinoma 8 years previously. Coronal (a) and sagittal (b) reformatted CT scan. Continuity of the transversalis fascia with the parietal endopelvic fascia is depicted

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anatomical compartments and their connections as demonstrated by ectopic air. Local causes of extraperitoneal pelvic emphysema. (a) Sigmoid perforation (necrotising acute colitis probably due to fecaloma) in a 75-year-old female. Unenhanced-CT scans of pelvis shows gas pockets in the sigmoid mesocolon, extending superiorly to retroperitoneum through the combined interfascial plane. (b) Fournier gangrene in a 67-year-old diabetic man. Contrast-enhanced CT scan shows fluid and air pockets tracking in the corpora cavernosa, extending anteriorly to an enlarged scrotal sac containing gas and cranially to the ischiorectal fossa and subcutaneous tissue

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anatomical compartments and their connections as demonstrated by ectopic air. Air spread from pelvis to inferior limbs. a, b The same patient as in Fig. 2: a 44-year-old man with broncho-pleural fistula secondary to pneumothorax drainage and subsequent rapidly progressive emphysema from neck to groin. a Axial CT in “lung window” shows air spread through the thinned transversalis fascia and abdominal rectus below the level of arcuate line, involving inferior epigastric vessels. Air is seen anteriorly to iliac muscles (brown arrow). b Axial CT caudal to a demonstrates air spreading out the pelvis along with iliac vessels through the femoral canal. Air dissecting along muscular fibres and sheaths, as can be seen from the pelvis along iliac muscle until its insertion in the lesser femoral trochanter (brown line). The least resistance of subcutaneous tissues allow easy spread of subcutaneous emphysema. c, d A 60-year-old patient with colonic perforation at optical colonoscopy. Sagittal (c) and coronal (d) reformatted CT images illustrate air spread along the right inguinal (red star) canal and into the scrotal sac