Congenital branchial apparatus
malformation in a Haflinger colt.
The first branchial apparatus
normally gives rise to the eustachian tube, tympanic cavity, mastoid antrum, a portion of the tympanic membrane, external auditory canal, the mandible, maxilla, and the malleus and incus.
In in vitro teratogenicity studies with rat embryos, changes at the branchial apparatus
were seen at 25 [micro]M for both triadimefon and triadimenol (Menegola et al.
The branchial apparatus
of all vertebrates is composed of 6 pharyngeal arches, but only 4 are well developed in mammals and birds.
The majority of cystic neck masses in children are congenital malformations and include thyroglossal duct cysts, branchial apparatus
cysts, dermoid cysts, and lymphatic malformations.
2,4,5) Hence, the embryologic origin of this anomaly, although related to the branchial apparatus
, differs completely from that of the typical branchial cleft fistulas, as well as from that of the ectopic salivary fistulas found at the base of the neck.