The thyroid and parathyroid glands are located in the neck. The butterfly-shaped thyroid gland sits in front of the trachea and has superior, inferior, and recurrent laryngeal blood supplies. It drains into internal jugular veins. The parathyroid glands regulate calcium levels and are located behind the thyroid gland. Both glands receive nerve supply from cervical ganglia and drain lymphatically into deep cervical nodes.

1. THYROID AND
PARATHYROID
GLANDS
Le CATALYST

2. CONTENTS
THYROID GLAND
 Location
 Structure
 Relations
 Blood supply
 Lymphatic and nerve supply
 Development
PARATHYROID GLAND
• Location
• Blood supply
• Lymphatic and nerve supply
• Development

3. LOCATION
• Can be found in front of the
neck, just below the Adams
apple (thyroid notch).
• Lies in front of the trachea
• Covered by the pre tracheal
fascia.

4. STRUCTURE
It has a butterfly shaped structure.
The thyroid is made up of:
1 . the isthmus – overlying the 2nd and 3rd rings of the trachea;
2. the lateral lobes – each extending from the side of the thyroid cartilage down to
the level of the 6th tracheal ring;
3. an inconstant pyramidal lobe projecting upwards from the isthmus, usually on the
left side, which represents a remnant of the embryological descent of the thyroid.
• You cannot feel a normal size thyroid gland.

6. RELATIONS
• The gland is enclosed in the pre tracheal fascia, in turn covered by the
strap muscles and overlapped by the sternocleidomastoids.
• The anterior jugular veins course over the isthmus.
• On the deep aspect of the thyroid lie the larynx and trachea, with the
pharynx and esophagus behind and the carotid sheath on either side.
• Two nerves lie in close relationship to the gland; in the groove between
the trachea and esophagus lies the recurrent laryngeal nerve, and deep
the upper pole of the thyroid lies the external branch of the superior
laryngeal nerve passing to the cricothyroid muscle.

8. BLOOD SUPPLY
The endocrine glands, gram for gram, have the richest blood supply of
tissue in the body; the thyroid gland is no exception to this rule.
Three arteries supply and three veins drain the thyroid gland.
• The superior thyroid artery – arises from the external carotid and passes
to the upper pole;
• The inferior thyroid artery – arises from the thyrocervical trunk of the 1st
part of the subclavian artery and passes behind the carotid sheath to
back of the gland;
• The thyroidea ima artery – is inconstant; when present, it arises from
aortic arch or the brachiocephalic artery and runs upwards to the
aspect of the gland; supplies the isthmus and the pyramidal lobe.

9. VENOUS DRAINAGE
• the superior thyroid vein – drains the upper pole to the internal jugular
vein;
• the middle thyroid vein – drains from the lateral side of the gland to the
internal jugular;
• the inferior thyroid veins – often several; drain the lower pole to the
brachiocephalic veins.

11. NERVE SUPPLY
The gland receives
sympathetic nerve supply from
the superior, middle and inferior
cervical ganglion of the
sympathetic trunk.
The gland receives
parasympathetic nerve
supply from the superior
laryngeal nerve and the
recurrent laryngeal nerve.

12. LYMPHATIC DRAINAGE
Lymphatic drainage of the thyroid
gland involves the lower deep
cervical, pre-laryngeal, pre-tracheal,
and paratracheal nodes. The
paratracheal and lower deep
nodes, specifically, receive
drainage from the isthmus and the
inferior lateral lobes. The superior
portions of the thyroid gland drain
into the superior pre-tracheal and
cervical nodes

13. DEVELOPMENT
• The thyroid develops from a bud,
which pushes downwards from the
fetal tongue.
• This outgrowth, termed the
thyroglossal duct, then descends to its
definitive position in the neck.
• The lower end of the thyroglossal duct
proliferates to become the thyroid
gland, while the rest of the
duct disintegrates and disappears.
• The origin of the thyroid is, however,
commemorated by the foramen
caecum.
• The origin of the thyroid is, however,

14. PATHOLOGIES OF THE THYROID GLAND
• Goiter – deficiency of iodine or inflammation of the thyroid gland.
• Hyperthyroidism – excess production of thyroid hormone.
• Hypothyroidism – reduced production of thyroid hormone
• Thyroid cancer - rapid proliferation of thyroid cells
• Thyroid nodules – swelling of one part of one part of the gland
• Thyroiditis – inflammation of the thyroid gland
• Cretinism – failure of the thyroid gland to develop.
• Thyroglossal cyst – swelling in the midline of the neck, just above the thyroid
cartilage.
• Lingual thyroid – thyroid develops and fails to migrate.

16. LOCATION AND CHARACTERISTICS
• Parathyroid glands are four small glands of the endocrine system which regulate the
calcium in our bodies. Parathyroid glands are located in the neck behind the thyroid
where they continuously monitor and regulate blood calcium levels.
• are normally the size of a grain of rice, Occasionally they can be as large as a pea
still be normal.
• The four parathyroids are located behind the thyroid.
• The thyroid gland controls much of your body's metabolism, but the parathyroid
glands control body calcium.
• Parathyroid glands share a similar blood supply, venous drainage, and lymphatic
drainage to the thyroid glands.
• The superior parathyroid gland is fixed and the inferior parathyroid gland have
variable positions.

18. LYMPHATIC DRAINAGE
• Lymphatic vessels from the parathyroid glands drain
into deep cervical lymph nodes and paratracheal
lymph nodes.
• The nerve supply of the parathyroid derives from the
branches of the cervical ganglia of the thyroid gland.
The nerve supply to the parathyroid glands is
vasomotor.