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Branchial cleft anomalies

Dr Yuranga Weerakkody et al.

Branchial cleft anomalies comprise of a spectrum of congenital defects that occur in the head and neck. The anomalies result from branchial apparati (6 arches) which are the embryologic precursors of the earand the muscles, blood vessels, bones, cartilage, and mucosallining of the face, neck, and pharynx ¹.

The 6 branchial arches give rise to 5 clefts.

The range of anomalies can include either a

cyst : no internal or external communication
fistula : communicate both internally and externally
sinus : incomplete tract

Cysts are considered to be commoner than the other two entities by a ratio of ~ 2 : 1 ⁶

Among fistulae and sinuses the order prevalence is thought to be: external draining sinus > complete fistula > internal draining sinus ⁶; although some anomalies can occur in combination.

The complete list therefore includes

first branchial cleft anomalies : 5 - 8 % ^1-8
second branchial cleft anomalies : commonest by far : 90 - 95 % ⁸
third branchial cleft anomalies : rare
fourth branchial cleft anomalies : rare
the fifth cleft does not give rise to the cervical sinus of His which is part of the reason that there are no fifth branchial cleft anomalies

The 3^rd and 4^th branchial arches tend to be very close and therefore the distinction between these two cleft anomalies can be difficult on imaging ^7-8.