From the Research
The third, fourth, and fifth branchial clefts in human embryological development ultimately disappear through a process of obliteration, with the most recent and highest quality study supporting this process 1.
Embryological Development of Branchial Clefts
The third branchial cleft contributes to the formation of the lower portion of the cervical sinus, which normally obliterates completely. The fourth branchial cleft similarly undergoes obliteration after contributing briefly to lower cervical development. The fifth branchial cleft is rudimentary in humans and typically regresses entirely, leaving no persistent structures.
Clinical Implications
When these clefts fail to obliterate properly, they can result in branchial anomalies such as cysts, sinuses, or fistulas, most commonly arising from the second branchial apparatus rather than these more caudal clefts. This normal obliteration process contrasts with the first and second branchial clefts, which contribute to the formation of the external auditory meatus and the development of the tympanic membrane, respectively.
Key Points
- The third, fourth, and fifth branchial clefts disappear through a process of obliteration.
- The third branchial cleft contributes to the formation of the lower portion of the cervical sinus.
- The fourth branchial cleft undergoes obliteration after contributing briefly to lower cervical development.
- The fifth branchial cleft is rudimentary in humans and typically regresses entirely.
- Failure of obliteration can result in branchial anomalies, with the second branchial apparatus being the most common source 2, 3, 4, 1.