The thyroid gland is endocrine producing thyroid hormone, located in mid line of anterior neck, lies in the visceral space completely enveloped by pre-tracheal fascia, extends from level C5 to T1 and lies anterior to the thyroid-cricoid cartilages and the first 5–6 tracheal rings.

• H shaped organ, upper pole round and low pole tapered.
• Well defined smooth, regular surface.
• Homogenous texture with mildly hyperechogenic in compare to the strap muscle.
• 4–6 cm in length and <2 cm in diameter.