Normal Size of Thyroid Glands: Average Dimension of Thyroid Gland

The thyroid gland is one of the largest glands in the body. Its shape resembles that of a butterfly. It is located in the anterior side of the neck, just under the Adam’s apple near the larynx and trachea.

  • This uniquely shaped gland has two cone-shaped lobes or wings which are connected by the isthmus.
  • The two wings are namely:

o    Lobus dexter

o    Lobus sinister

  • The thyroid gland has several functions, including:

o    Production of hormones T3 (triiodothyronine) and T4 (thyroxine), these are responsible in the regulation of:

o    Body temperature

o    Blood pressure

o    Heart rates

o    It also helps in the physical and mental growth development of a child.

o    Regulating Metabolism

o    Production of calcitonin

o    Thus helps in calcium homeostasis.

Dimension & Weight Of Thyroid Gland

  • The normal size of the thyroid gland in adults is 4 to 4.8 cm x 1.0 to 1.8 cm x 0.8 to1.6 cm.
  • Its normal weight ranges between 15-25 grams.
  • The weight of this gland grows heavier in women.
  • It escalates up to 50% during the early part of the menstrual cycle. This increase in size or volume of the gland from is considered normal.
  • Women experience a temporary increase in thyroid size not only during early menstrual cycle but also during pregnancy.
  • Smokers have larger thyroids than non-smokers.
  • People who grew up and living in United States, Japan, Britain and Ice land have smaller thyroids due to the prevalence of iodine in their diet.

Changes in the size of the thyroid gland can also signify something pathologic. There are two major disorders of the thyroid gland, including:

  • Hyperthyroidism
    • Overproduction of thyroid hormones that results in the formation of toxic goiter.
    • This causes an increase in metabolism.
    • Signs include:
      • Hypertension
      • Intolerance to heat
      • Increase heart rate
      • Jitteriness
      • Thirst
      • Inability to focus on one thing
      • Feeling flushed all the time
      • Unexplained, unintended weight loss
    • This can be treated with drugs, and depending on the situation, surgery may be necessary.
  • Hypothyroidism
    • The underproduction of thyroid hormones; due to iodine insufficiency.
    • This will lead to a general slowing down of the metabolism rate.
    • Signs include:
      • Intolerance to cold
      • Slow heart rate
      • Sluggishness
      • Constant fatigue
      • Unexplained weight gain
    • Supplements can be given to patients with decreased levels of thyroid hormones.

The hyperactivity or hypo-activity of the thyroid gland may cause serious problems that require treatment. It is important to seek medical attention when any abnormality is suspected.

Average Size Of Thyroid Gland In Infants And Children

  • In infants, the size of the thyroid gland increases gradually.
  • It approximately weighs 1 gram at birth and increases every year until it reaches its normal adult size of about 15-25 grams at age 15.
  • To evaluate the thyroid size in children, the use of the “rule of thumb” is preferred.
  • This is because each lobe of the thyroid is compared to the size of the terminal phalanx of a child’s thumb.

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