Diverticulum

Diverticula are described as being true or false depending upon the layers involved:

• False diverticula (also known as "pseudodiverticula") do not involve muscular layers or adventitia. False diverticula, in the gastrointestinal tract for instance, involve only the submucosa and mucosa, such as Zenker's diverticulum. False diverticula are typically synonymous with pulsion diverticula, which describes the mechanism of formation as increased intraluminal pressure.
• True diverticula involve all layers of the structure, including muscularis propria and adventitia, such as Meckel's diverticulum.{{Cite book | last1=Townsend | first1=Courtney M. Jr. |title=Sabiston Textbook of Surgery: The Biological Basis of Modern Surgical Practice |last2=Daniel Beauchamp |first2=R. |last3=Mark Evers |first3=B. |last4=Mattox |first4=Kenneth L. |year=2017 |isbn=9780323299879 |edition=20th |location=Philadelphia, PA |oclc=921338900}} True diverticula are typically synonymous with traction diverticula, which describes the mechanism of formation as pulling forces external to the structure.

• The kidneys are originally diverticula in the development of the urinary and reproductive organs.
• The lungs are originally diverticula forming off of the ventral foregut.
• The thymus appears in the form of two flask-shape diverticula, which arise from the third branchial pouch (pharyngeal pouch) of the endoderm.{{Cite book |last=Standring |first=Susan |title=Gray's Anatomy: The Anatomical Basis of Clinical Practice |year=2016 |isbn=9780702052309 |edition=41st |location=[Philadelphia] |oclc=920806541}}
• The thyroid gland develops as a diverticulum arising from a point on the tongue, demarcated as the foramen cecum.

File:Oesophageal diverticula.svg

• Esophageal diverticula may occur in one of three areas of the esophagus:

:#Pharyngeal (Zenker's) diverticula usually occur in the elderly, through Killian's triangle between the thyropharyngeus and cricopharyngeus muscle of the inferior pharyngeal constrictors.

:#Midesophageal diverticula

:#Epiphrenic diverticula are due to dysfunction of the lower esophageal sphincter, as in achalasia.{{Citation |last1=Yam |first1=Julie |title=Esophageal Diverticula |date=2019 |url=http://www.ncbi.nlm.nih.gov/books/NBK532858/ |work=StatPearls |publisher=StatPearls Publishing |pmid=30422453 |access-date=17 July 2019 |last2=Ahmad |first2=Sarah A.}}

• A duodenal diverticulum can be found incidentally in 23% of normal people undergoing imaging. It can be either congenital or acquired, but the acquired form is more common and is due to the weakness of the duodenal wall, which causes protrusions. It is usually found at the second or third part of duodenum, around the ampulla of Vater. Food debris may enter the diverticular outpouchings, causing inflammation or diverticulitis. On CT or MRI imaging, it appears as a sac-like outpouching. If the diverticulum is filled with contrast agents, the wall would be thin and may contain air, fluid, contrast material, or food debris. If the food debris is broken down by bacteria, the outpouching may show "faeces sign". Inflammation of the duodenal wall shows thickening of the wall. Rarely, on barium studies in congenital duodenal diverticula, the contrast material fills up the true lumen, causing "windsock" deformity.{{Cite journal |last1=Barat |first1=M. |last2=Dohan |first2=A. |last3=Dautry |first3=R. |last4=Barral |first4=M. |last5=Boudiaf |first5=M. |last6=Hoeffel |first6=C. |last7=Soyer |first7=P. |date=October 2017 |title=Mass-forming lesions of the duodenum: A pictorial review |journal=Diagnostic and Interventional Imaging |language=en |volume=98 |issue=10 |pages=663–675 |doi=10.1016/j.diii.2017.01.004 |pmid=28185840 |doi-access=free}}
• A jejunal diverticulum is a congenital lesion and may be a source of bacterial overgrowth. It may also perforate or result in abscesses.
• A Killian-Jamieson diverticulum is very similar to a pharyngeal esophageal diverticulum, differing in the fact that the pouching is between the oblique and transverse fibers of the cricopharyngeus muscle.{{Cite journal |last1=O'Rourke |first1=Ashli K. |last2=Weinberger |first2=Paul M. |last3=Postma |first3=Gregory N. |date=May 2012 |title=Killian-Jamieson diverticulum |journal=Ear, Nose, & Throat Journal |volume=91 |issue=5 |pages=196 |doi=10.1177/014556131209100507 |issn=1942-7522 |pmid=22614553 |doi-access=free}}
• A Laimer diverticulum is an outpouching that occurs in the Laimer triangle between the cricopharyngeus and superior esophageal circular muscle.
• Colonic diverticula, although found incidentally during colonoscopy, may become infected (see diverticulitis) and can perforate, requiring surgery.{{Cite journal |last1=Feuerstein |first1=Joseph D. |last2=Falchuk |first2=Kenneth R. |date=August 2016 |title=Diverticulosis and Diverticulitis |journal=Mayo Clinic Proceedings |volume=91 |issue=8 |pages=1094–1104 |doi=10.1016/j.mayocp.2016.03.012 |issn=1942-5546 |pmid=27156370 |doi-access=free}}
• Gastric diverticula are very infrequent.{{Cite journal |last1=Shah |first1=Jamil |last2=Patel |first2=Kalpesh |last3=Sunkara |first3=Tagore |last4=Papafragkakis |first4=Charilaos |last5=Shahidullah |first5=Abul |date=April 2019 |title=Gastric Diverticulum: A Comprehensive Review |journal=Inflammatory Intestinal Diseases |volume=3 |issue=4 |pages=161–166 |doi=10.1159/000495463 |issn=2296-9365 |pmc=6501548 |pmid=31111031}}
• Meckel's diverticulum, a persistent portion of the omphalomesenteric duct, is present in 2% of the population,{{Cite journal |last1=Elsayes |first1=Khaled M. |last2=Menias |first2=Christine O. |last3=Harvin |first3=Howard J. |last4=Francis |first4=Isaac R. |date=July 2007 |title=Imaging manifestations of Meckel's diverticulum |journal=AJR. American Journal of Roentgenology |volume=189 |issue=1 |pages=81–88 |doi=10.2214/AJR.06.1257 |issn=1546-3141 |pmid=17579156|s2cid=45677981 }} making it the most common congenital gastrointestinal malformation.{{Cite journal |last1=Sagar |first1=Jayesh |last2=Kumar |first2=Vikas |last3=Shah |first3=D. K. |date=October 2006 |title=Meckel's diverticulum: a systematic review |journal=Journal of the Royal Society of Medicine |volume=99 |issue=10 |pages=501–505 |doi=10.1177/014107680609901011 |issn=0141-0768 |pmc=1592061 |pmid=17021300}}

File:Histopathology of a false diverticulum of the gallbladder.jpg

• Rokitansky-Aschoff sinuses are diverticula in the gallbladder due to chronic cholecystitis{{Cite journal |last1=Stunell |first1=H |last2=Buckley |first2=O |last3=Geoghegan |first3=T |last4=O’Brien |first4=J |last5=Ward |first5=E |last6=Torreggiani |first6=W |year=2008 |title=Imaging of adenomyomatosis of the gall bladder |journal=Journal of Medical Imaging and Radiation Oncology |volume=52 |issue=2 |pages=109–117 |doi=10.1111/j.1440-1673.2008.01926.x |issn=1754-9477 |pmid=18373800 |s2cid=42685012}}

Most of these pathological types of diverticula are capable of harboring an enterolith. If the enterolith stays in place, it may cause no problems, but a large enterolith expelled from a diverticulum into the lumen can cause obstruction.{{Cite journal |vauthors=Chaudhery B, Newman PA |year=2014 |title=Small bowel obstruction and perforation secondary to primary enterolithiasis in a patient with jejunal diverticulosis |journal=BMJ Case Reports |volume=2014 |pages=bcr2014203833 |doi=10.1136/bcr-2014-203833 |pmc=3962938 |pmid=24626387}}

• Bladder diverticula are balloon-like growths on the bladder commonly associated with chronic outflow obstruction, such as benign prostatic hyperplasia in older males. Usually found in pairs on opposite sides of the bladder, bladder diverticula are often surgically removed to prevent infection, rupture, or even cancer.
• Calyceal diverticula are usually asymptomatic, but if a stone becomes lodged in the outpouching, they may present with pain.{{Cite book |title=Oxford American Handbook of Urology |date=2011 |publisher=Oxford University Press |others=Albala, David M. |isbn=9780199707720 |location=Oxford |oclc=655896560}}
• Urethral diverticula are usually found in women aged 30 to 70 years old, in between 1 and 6% of adult women. Since most cases are without any symptoms, the true incidence is unknown. Symptoms may vary from frequent urinary tract infections, painful sexual intercourse (dyspareunia), or symptoms due to cancer. A urethral diverticulum is located on the anterior vaginal wall, 1 to 3 cm inside the vaginal introitus. MRI is preferred as the imaging method of choice due to its excellent soft-tissue resolution. On T2-weighted imaging, it shows a high signal in the diverticulum due to the presence of fluid inside it. Vaginal ultrasonography is highly sensitive in diagnosing the diverticulum, but it is strongly dependent on the skills of the operator.{{Cite journal |last1=Greiman |first1=Alyssa K. |last2=Rolef |first2=Jennifer |last3=Rovner |first3=Eric S. |date=2 January 2019 |title=Urethral diverticulum: A systematic review |journal=Arab Journal of Urology |language=en |volume=17 |issue=1 |pages=49–57 |doi=10.1080/2090598X.2019.1589748 |issn=2090-598X |pmc=6583718 |pmid=31258943}}

• A diverticulum of Kommerell is an outpouching (aneurysm) of the aorta where an aberrant right subclavian artery is located.{{Cite journal |last1=Raymond |first1=Steven L. |last2=Gray |first2=Sarah E. |last3=Peters |first3=Keith R. |last4=Fatima |first4=Javairiah |date=25 June 2019 |title=Right-sided aortic arch with aberrant left subclavian artery and Kommerell diverticulum |journal=Journal of Vascular Surgery Cases and Innovative Techniques |volume=5 |issue=3 |pages=259–260 |doi=10.1016/j.jvscit.2019.02.009 |issn=2468-4287 |pmc=6600077 |pmid=31304436}} It is unusual nomenclature, in that focal dilatations of a blood vessel are properly referred to as aneurysms.
• Cardiac diverticulum is a very rare congenital malformation of the heart that is usually benign.{{Cite web |last=Vazquez-Jimenez |first=Dr. Jaime |year=2003 |title=Cardiac diverticulum |url=http://www.orpha.net/data/patho/Pro/en/CardiacDiverticulum-FRenPro3437.pdf |access-date=14 January 2008 |publisher=Orphanet Encyclopedia}}

File:Diverticule de Meckel.jpg|Meckel's diverticulum

File:Diverticula, sigmoid colon.jpg|Large bowel (sigmoid colon) showing multiple diverticula: the diverticula appear on either side of the longitudinal muscle bundle (taenium).

File:Diverticulum of the colon.jpg|Colonic diverticulum

File:Harnblasendivertikel-transversal.jpg|Diverticulum of the urinary bladder of a 59-year-old man, transverse plane

File:BladderdiverticuliwithstoneMark.png|Bladder diverticula containing stones: the bladder wall is thickened due to possible transitional cell carcinoma.

File:UOTW 56 - Ultrasound of the Week 2.webm|Bladder diverticula as seen on ultrasound with doppler{{Cite web |date=21 August 2015 |title=UOTW #56 - Ultrasound of the Week |url=https://www.ultrasoundoftheweek.com/uotw-56/ |website=Ultrasound of the Week}}

File:UOTW 56 - Ultrasound of the Week 1.webm|Bladder diverticula as seen on ultrasound

• Christine Menias
• Skeletal pneumaticity

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Category:Medical terminology