| These anomalies have included pneumatization, agenesis, and. |
| While plumage, molt patterns of wing feathers, feather wear, and breeding condition all can contribute to the determination of age in the fall, the degree of skull pneumatization is the most certain in passerines. |
| A consideration of the systemic factors that influence frontal sinus pneumatization. |
| In the summer and early fall, when most young birds are just beginning the pneumatization process, it is good to start at the rear and the side of the skull, working up towards the crown. |
| The etiology of maxillary hypoplasia is unknown, and the process by which abnormal pneumatization occurs is not well understood. |
| Many common anatomic variations in the nasal cavity have been observed, including paradoxical turbinates and pneumatization of the inferior, middle, and superior turbinates. |
