Cystic duct

Cystic duct
Cystic duct
	1:Right lobe of liver; 2:Left lobe of liver; 3:Quadrate lobe of liver; 4:Round ligament of liver; 5:Falciform ligament; 6:Caudate lobe of liver; 7:Inferior vena cava; 8:Common bile duct; 9:Hepatic artery; 10:Portal vein; 11:Cystic duct; 12:Hepatic duct; 13:Gallbladder
Details
Artery	cystic artery
Identifiers
Latin	ductus cysticus
MeSH	D003549
TA98	A05.8.02.011
TA2	3101
FMA	14539
	Anatomical terminology [edit on Wikidata]

Thecystic ductis theductthat (typically) joins thegallbladderand thecommon hepatic duct;the union of the cystic duct and common hepatic duct formsthe bile duct(formerly known as the common bile duct). Its length varies.

Anatomy

The cystic duct typically^[2]measures (sources differ) 2–4 cm^[3]^[4]/2–3 cm^[2]in length (though its length has been known to range from 0.5 cm to 9 cm^[3]), and 2–3 mm in diameter.^[2]^[4]It is often tortuous.^[3]^[4]

It is the distal continuation of the neck of the gallbladder, from where it is directed inferoposteriorly and to the left^[2]/medially^[4](this occurs in half of individuals^[3]). It typically^[2]terminates by uniting with thecommon hepatic ductto form thebile duct(usually anterior to the right hepatic artery).^[2]It usually joins the common bile duct from the right lateral side (forming an oblique angle between the two),^[4]and at such a distance that the bile duct is twice as long as the common hepatic duct.^[3]^[4]It often fuses with the common hepatic duct before actually opening into it after a variable distance^[4]^[3](this arrangement may have the purpose of directing bile flow distally instead of back towards the liver^[3]).

Structure

The inner surface of the cystic duct features spiral, crescentic mucosal folds - thespiral folds of cystic duct.^[4]^[3]

The inner surface of the proximal cystic duct exhibits a network of submicroscopic convoluted folds (rugae), whereas that of the distal cystic duct exhibits submicroscopic parallel longitudinal folds.^[3]

Histology

The epithelial lining of the inner surface of the duct is similar to that of the gallbladder and consists mostly ofcolumnar epithelial cellswith shortmicrovilliupon their apical surfaces.^[3]

The subepithelial layer consists ofelastic connective tissueand is highly vascular; vessels that are adjacent to the epithelialbasement membranearefenestrated,possibly to facilitate ion and fluid exchange with the bile as is the case in the gallbladder itself.^[3]

The outer fibromuscular layer containssmooth musclecontinuous with that of the gallbladder; some of the smooth muscle extends into the spiral valves.^[3]

Relations

It usually lies next to thecystic artery.^{[citation needed]}

Variation

The cystic duct may rarely be doubled.^[2]^[3]

An accessory hepatic duct may join the cystic duct.^[2]^[4]

A pathological diverticulum known as theHartmann’s pouchmay be present at the junction of the neck of bladder and the cystic duct.^[2]

Length

The duct may sometimes be extremely short (making cholecystectomy risky)^[2]or may rarely be altogether absent (so that the gallbladder is directly attached to the bile duct).^[2]^[4]^[3]

Shape

While most often tortuous, it may occasionally be curved, straight, or S-shaped.^[3]

Termination

The cystic duct may unite with the common hepatic duct so that the common hepatic duct is either very short or very long (and the bile duct in turn very long or very short, respectively),^[4]or it may instead unite with the a hepatic duct.^[3]

Occasionally, the cystic duct may first run alongside the common hepatic duct for some distance^[2]^[4]within thehepatoduodenal ligament^[4]before joining it.^[2]^[4]It sometimes join the common hepatic duct at its anterior, posterior, or medial side^[4]^[3](in the latter case by passing posteriorly around the common bile duct to join it from the other side).^[2]It may spiral around the common hepatic duct before joining it.^[4]

Very rarely, the cystic duct opens into theduodenum.^[3]

Function

Bile can flow in either direction between the gallbladder, and the common bile duct andhepatic duct.^[3]In this way, bile is stored in the gallbladder in between meal times. The hormonecholecystokinin,when stimulated by a fatty meal, promotes bile secretion by increased production of hepatic bile, contraction of the gall bladder, and relaxation of theSphincter of Oddi.

The bile duct was once thought to possess asphinctericfunction, however, it is now known that bile flow through the cystic duct proceeds unimpeded and is instead regulated by other mechanisms at other points of the biliary system.^[3]

Clinical significance

Gallstonescan enter and obstruct the cystic duct, preventing the flow of bile. The increased pressure in the gallbladder leads to swelling and pain. This pain, known asbiliary colic,is sometimes referred to as a gallbladder "attack" because of its sudden onset.

During acholecystectomy,the cystic duct is clipped two or three times and a cut is made between the clips, freeing the gallbladder to be taken out.

Additional images

Digestive system diagram showing the cystic duct
The gall-bladder and bile ducts laid open.
The portal vein and its tributaries.
Cystic duct.Visceral surface of liver.

References

^Standring S, Borley NR, eds. (2008).Gray's anatomy: the anatomical basis of clinical practice.Brown JL, Moore LA (40th ed.). London: Churchill Livingstone. pp. 1163, 1177,1185–6.ISBN 978-0-8089-2371-8.
^^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿSinnatamby, Chummy S. (2011).Last's Anatomy(12th ed.). Elsevier Australia. p. 265.ISBN 978-0-7295-3752-0.
^^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^tDasgupta, D.; Stringer, M. D. (March 2005)."Cystic duct and Heister's" valves "".Clinical Anatomy.18(2):81–87.doi:10.1002/ca.20118.ISSN 0897-3806.PMID 15696536.S2CID 24179512.
^^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^pStandring, Susan (2020).Gray's Anatomy: The Anatomical Basis of Clinical Practice(42th ed.). New York. pp.1217–1218.ISBN 978-0-7020-7707-4.OCLC 1201341621.{{cite book}}:CS1 maint: location missing publisher (link)

External links

Anatomy figure: 38:06-03at Human Anatomy Online, SUNY Downstate Medical Center - "The gallbladder and extrahepatic bile ducts."
Anatomy photo:38:14-0106at the SUNY Downstate Medical Center - "Stomach, Spleen and Liver: The Gallbladder and the Bile System"
liverat The Anatomy Lesson by Wesley Norman (Georgetown University) (liverinferior,biliarysystem)

[1] Standring S, Borley NR, eds. (2008).Gray's anatomy: the anatomical basis of clinical practice.Brown JL, Moore LA (40th ed.). London: Churchill Livingstone. pp. 1163, 1177,1185–6.ISBN 978-0-8089-2371-8.

[:022-2] ^^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿSinnatamby, Chummy S. (2011).Last's Anatomy(12th ed.). Elsevier Australia. p. 265.ISBN 978-0-7295-3752-0.

[:133-3] ^^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^tDasgupta, D.; Stringer, M. D. (March 2005)."Cystic duct and Heister's" valves "".Clinical Anatomy.18(2):81–87.doi:10.1002/ca.20118.ISSN 0897-3806.PMID 15696536.S2CID 24179512.

[:224-4] ^^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^pStandring, Susan (2020).Gray's Anatomy: The Anatomical Basis of Clinical Practice(42th ed.). New York. pp.1217–1218.ISBN 978-0-7020-7707-4.OCLC 1201341621.{{cite book}}:CS1 maint: location missing publisher (link)

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