Introduction: Ultrasound is the most reliable imaging modality for thyroid evaluation due to the limitations in the clinical examination of this gland. Thyroid gland developmental anomalies are rare. Most of its variations are due to the persistence of the thyroglossal duct and the absence of the isthmus. The aim of this study was to determine the incidence of pyramidal lobe and agenesis of the thyroid isthmus in Nnewi population using ultrasound. Materials and method: A total of 321 subjects resident in Nnewi, including 167 males and 154 females, were randomized. A written consent was obtained from all patients. The subjects were aged between 18 and 35 years. This was a prospective cross-sectional study. Thyroid glands were scanned using a 2-dimensional ultrasound machine with a 7.5 MHz transducer; model Siemens Sonoline Prima which was made in Japan for Siemens Medical System Incorporated, ultrasound Group, Issaquah, WA, 98029-7002, USA. Results: The study revealed no incidence of pyramidal lobe and agenesis of the thyroid isthmus in the study population. Conclusion: This study has clearly demonstrated no incidence of pyramidal lobe and agenesis of the thyroid isthmus in subjects resident in Nnewi, Nigeria.
