Lecture Notes: General Surgery

Harold Ellis, Sir Roy Calne, Christopher Watson

Self-assessment Questions

37 The thyroid

  • 1. From what does the thyroid gland develop?

    Correct answer:

    The thyroid gland forms as a diverticulum originating in the floor of the pharynx, and descends through the tongue, past the hyoid, to its position in the neck.

  • 2. What is the foramen caecum?

    Correct answer:

    This is the remnant of the diverticulum of the thyroid gland, which leaves a pit at the base of the tongue. It lies at the junction of the anterior two-thirds and the posterior one-third of the tongue.

  • 3. What can result from incomplete descent of the thyroid gland?

    Correct answer:

    Ectopic thyroid tissue.

  • 4. What can result if there is incomplete destruction of the thyroid track?

    Correct answer:

    This may result in fistula or sinus formation.

  • 5. What should you suspect in all cases of midline nodules in the neck?

    Correct answer:

    Ectopic thyroid tissue.

  • 6. What should always be done before a thyroid lump in the midline of the neck is removed?

    Correct answer:

    A radioiodine scan should be performed to ensure that there is normal thyroid tissue present in the correct place before the lump is removed.

  • 7. What is a lingual thyroid? What are the clinical features?

    Correct answer:

    Rarely, the thyroid fails to descend into the neck. Such a patient presents with a lump at the foramen caecum of the tongue. This is termed a lingual thyroid, and may represent the sum total of thyroid tissue, or may be a remnant that failed to descend.

  • 8. What is a thyroglossal cyst? How is it diagnosed?

    Correct answer:

    A thyroglossal cyst forms in the embryological remnants of the thyroid and presents as a fluctuant swelling in or near the midline of the neck. It is diagnosed by its characteristic physical signs. (1) It moves upwards when the patient protrudes the tongue, because of its attachment to the tract of the thyroid descent. (2) It moves on swallowing, because of its attachment to the larynx by the pretracheal fascia.

  • 9. How would you treat a thyroglossal cyst?

    Correct answer:

    Such cysts should be removed surgically, together with remnants of the thyroglossal tract and the body of the hyoid bone, to which it is closely related.

  • 10. What is a thyroglossal fistula? What are the clinical features?

    Correct answer:

    This presents as an opening onto the skin in the line of the thyroid descent, in the midline of the neck. It may discharge thin, glairy fluid and attacks of infection can occur.

  • 11. How would you treat a thyroglossal cyst?

    Correct answer:

    The treatment is to excise the fistula, and this excision must be complete. The track runs in close relationship to the body of the hyoid; therefore, this should be removed in addition to the fistula. Dissection is continued up to the region of the foramen caecum at the tongue.

  • 12. What type of substances does the thyroid gland produce?

    Correct answer:

    The thyroid gland is concerned with the synthesis of the iodine-containing hormones thyroxine (T4) and tri-iodothyronine (T3).

  • 13. Which three hormones are produced by the thyroid gland?

    Correct answer:

    Thyroxine (T4) and tri-iodothyronine (T3). Calcitonin is also produced by the parafollicular C cells.

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