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The pharyngeal clefts, also known as branchial clefts or grooves, are essential structures in early embryonic development. Derived from ectoderm, these clefts form indentations between the pharyngeal arches and play a crucial role in head and neck formation. The derivatives of the pharyngeal clefts are especially important for students preparing for the USMLE Step 1 exam due to their clinical implications.
Pharyngeal Cleft | Derivative |
---|---|
1st Cleft | Develops into the external auditory meatus |
2nd-4th Clefts | Form temporary cervical sinuses which are later obliterated by the growth of the 2nd pharyngeal arch mesenchyme |
A pharyngeal cleft cyst is a congenital anomaly that results from incomplete obliteration of the cervical sinus.
Feature | Pharyngeal Cleft Cyst | Thyroglossal Duct Cyst |
---|---|---|
Location | Lateral neck, anterior to sternocleidomastoid | Midline of neck |
Movement with Swallowing | Does not move | Moves with swallowing |
Origin | Persistent cervical sinus | Remnant of thyroglossal duct |