System: Endocrine

Posterior Pituitary

Posterior Pituitary The structure highlighted in purple is the posterior pituitary. The pituitary gland is a pea-sized endocrine gland located within the hypophyseal fossa of the sphenoid bone in the middle cranial fossa. The pituitary gland extends from the hypothalamus (highlighted in blue) and can be divided into: 1)      Anterior pituitary (highlighted in green) 2)      Posterior pituitary (highlighted in purple) The two parts of the pituitary have different embryological origins. The anterior pituitary develops from ectoderm from an area of the pharynx known as Rathke’s pouch, whereas the posterior pituitary arises from neuroectoderm, as an extension of the hypothalamus. The anterior pituitary …

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Posterior Pituitary

Isthmus of Thyroid Gland

Isthmus of Thyroid Gland The structure indicated is the isthmus of the thyroid gland. The thyroid gland sits anteriorly in the neck, just inferior to the thyroid cartilage. It is located deep to the overlying strap muscles (sternohyoid, sternothyroid and omohyoid). It has two lateral lobes connected in the centre by the isthmus. The isthmus lies over the 2nd and 3rd rings of the trachea The lateral lobes extend from the lateral aspects of the thyroid cartilage down as far the 6th ring of the trachea. Occasionally a pyramidal lobe is present, which is an upward extension of the isthmus, …

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Isthmus of Thyroid Gland