Question
Ear pinna develops from ____________
| A. |
Ectoderm |
| B. | Endoderm |
| C. |
Mesoderm |
| D. |
All |
|
Correct Answer » A Explanation |
 |
Embryological Development of the Auricle
The auricle (pinna) develops from six auricular hillocks that appear around the first pharyngeal cleft during the 5th–6th week of development.
These hillocks arise from the first and second pharyngeal arches.
Distribution of hillocks:
First pharyngeal arch (Mandibular arch)
Forms:
-
Tragus
-
Crus of helix
-
Helix
Second pharyngeal arch (Hyoid arch)
Forms:
-
Antihelix
-
Antitragus
-
Lobule
These hillocks enlarge, fuse, and migrate to form the definitive auricle.
Embryologically, the external ear structures develop from ectoderm covering the pharyngeal arches.
Although mesenchyme (largely neural crest–derived) forms cartilage and connective tissue, the germ layer classification used in exams refers to the epithelial origin, which is surface ectoderm.
