|
|
Origin |
|
Pharyngeal cleft |
Ectoderm (Mnemonic: c = c) |
|
Pharyngeal arch |
Mesoderm |
|
Pharyngeal pouch |
Endoderm (Mnemonic: u = n) |
1st Pharyngeal pouch- form tubotympanic recess
1. Proximal part of tubotympanic recess: Auditory / Eustachian tube
2. Distal part of tubotympanic recess: Tympanic / Middle ear cavity
3. Inner layer (Endoderm) of tympanic membrane
2nd Pharyngeal pouch-
1. Palatine tonsil
2. Tonsilar fossa
3rd Pharyngeal pouch-
1. Ventral region: Thymus
2. Dorsal region: Inferior parathyroid gland
4th Pharyngeal pouch-
1. Ventral region: Ultimobranchial body
2. Dorsal region: Superior parathyroid gland
NOTE: The parathyroid glands (superior and inferior) are located on the posterior/dorsal side of the thyroid, so the parathyroid glands (superior and inferior) are derived from the dorsal region of the 4th and 3rd pharyngeal pouches.