Thyroid thyroid anatomy

Thyroid or thyroid gland (lat. glandular thyroid ) lies below m. sternothyroideusa and m. sternohyoideusa, anteriorly in the neck at the level of the C5-T1 vertebrae. It consists primarily of the left and right lobes, anterolaterally of the larynx and trachea. The relatively thin isthmus connects the lobes through the trachea, usually anterior to the second and third tracheal rings. The thyroid gland is surrounded by a thin connective capsule, which sends connective tissue pieces deep into the gland. Dense connective tissue attaches the capsule to the upper tracheal rings. Outside the capsule is a loose sheath formed by the visceral layer of the prehistoric leaf of the deep cervical fascia.

Arteries of the thyroid gland

arteries of the thyroid gland
Thyroid relationships. (A) M. sternothyroideus was excised to show lobes of normal thyroid. The isthmus lies anterior to the second and third tracheal rings. (B) The parathyroid glands are usually wrapped in a fibrous capsule on the posterior surface of the thyroid gland. (C) Functional layer of cervical organs, transverse section. In this person, the thyroid gland is asymmetrically enlarged.

They supply a heavily circulating thyroid gland And. Superior thyroid and And. Inferior thyroid. These blood vessels lie between the fibrous capsule and the loose fascial sheath. Usually the first branch And. carotis externae, And. Superior thyroid descends to the upper peaks of the gland, penetrates the prehistoric layer of the deep cervical fascia, and divides into an anterior and posterior branch which mainly perfuses the anterosuperior surface of the gland. A. inferior thyriodea , the largest branch truncusa thyrocervicalisa (a branch of the first part And. subclaviae), flows superomedially posterior to vaginae caroticae fasciae cervicalis (envelopes And. carotis internae) to reach the posterior surface of the thyroid gland.

It divides into several branches that penetrate the prehistoric layer of the neck’s deep envelope and supplies the posteroinferior part of the gland, including the lower tips. The right and left superior and inferior thyroid arteries anastomose a lot inside the gland, providing it with abundant blood supply and at the same time allowing collateral circulation between And. subclaviae and And. carotis externae.

Artery thyroidea has

artery in throat
Artery thyroidea has

In approximately 10% of people, small, odd And. thyroidea has started from truncusa brachiocephalicusa; however, it can also be separated from the aortic arch or the right And. carotis communis. subclaviae or And. thoracicae internae. This small artery climbs to the trachea’s anterior surface, which circulates, and continues to the isthmus of the thyroid gland, where it branches and circulates. This artery’s possible presence must be considered when performing interventions in the midline of the neck inferior to the isthmus as it is a potential source of bleeding.

Thyroid veins

thyroid gland veins
Dissection of the left side of the root of the neck

Lymphatic drainage of the thyroid gland

Lymphatic drainage of the thyroid gland
Lymphatic drainage of the thyroid, larynx and trachea

Lymphatic vessels of the thyroid gland flow in the interlobular connective tissue, usually near the arteries, communicate with the lymphatic vessels’ network in the capsule. From there, the vessels pass to the prelaryngeal, prehraheal, and paratracheal lymph nodes, which drain into the superior (from the prelaryngeal nodes) and inferior (from the pretracheal and paratracheal nodes) deep cervical lymph nodes. Laterally, lymph vessels located along the superior thyroid veins flow directly into the deep cervical lymph nodes. Some lymph vessels may flow into the brachiocephalic lymph nodes or the ductus thoracicus.

Nerves of the thyroid gland

Thyroid nerves come from the superior, middle, and inferior cervical sympathetic ganglia. They reach the gland through the cardiac and superior and inferior thyroid periarterial plexuses accompanying the thyroid arteries. These fibers are vasomotor, not secretomotor. They cause the narrowing of blood vessels. The pituitary gland hormonally regulates endocrine secretion from the thyroid gland.

Cysts of the ductus thyroglossus

Thyroid development begins at the base of the embryonic pharynx, at the site marked by a small opening – foramen cecum, in the postnatal language dorsum. Thus, the developing gland descends from the tongue into the neck, passing anteriorly from the hyoid bone and thyroid cartilage to reach the final position anterolaterally from the trachea’s superior portion. During the descent, the thyroid gland is attached to the foramen cecum ductus thyroglossus. This ductus normally disappears, but remnants of epithelium can form cysts along with any point of thyroid descent. The cyst is usually near or inside the body of the lingual bone and forms a swelling on the anterior part of the neck.

Ectopic thyroid gland

It is rare for the thyroid gland not to descend from its origin in the tongue, resulting in the lingual thyroid gland. Incomplete lowering results in the gland being placed high in the neck, on or below the hyoid bone. As a rule, the ectopic thyroid gland in the neck’s medial plane is the only thyroid tissue present. Occasionally, thyroid glandular tissue is associated with cysts of the ductus thyroglossus. Therefore, it is important to distinguish the ectopic thyroid gland from the cyst when they are removed. Otherwise, a complete thyroidectomy can occur, leaving the person permanently dependent on thyroid medications.

Accessory thyroid glandular tissue

Parts ductus thyroglossal can remain and create thyroid tissue. Accessory thyroid glandular tissue can occur anywhere along the embryonic course ductus thyroglossal (for example, in the thymus inferior to the thyroid or in the thorax). Accessory thyroid tissue may develop in the neck laterally to thyroid cartilage; it usually lies on m. thyrohyoideus. Although accessory tissue may be functional, it is usually not large enough to maintain the normal function of the thyroid is removed.

Pyramidal lobe of the thyroid gland

Approximately 50% of the thyroid gland has a pyramidal lobe. This lobe, which varies in size, extends superiorly from the isthmus of the thyroid gland, usually to the left of the medial plane; the isthmus may be incomplete. The connective tissue bundle, often containing accessory thyroid tissue, may be continuous from the pyramidal lobe’s apex to the hyoid bone. The pyramidal lobe and bundle develop from remnants of epithelium and connective tissue ductus thyroglossal.

Enlargement of the thyroid gland

Nonplastic and non-inflammatory enlargement of the thyroid gland, in addition to the variable enlargement that can occur during menstruation and pregnancy, is called a goiter. Goiter is the result of iodine deficiency. It is common in certain parts of the world where salt and water lack iodine. An enlarged gland is the cause of swelling of the neck that can press on the trachea, esophagus, and n—recurrent larynx. When the gland enlarges, it can enlarge anteriorly, posteriorly, inferiorly, or laterally. It cannot increase in the superior direction due to m. sternothyroideusa and m. sternohyoideusa. The gland can also expand below the sternum when it is a goiter.

Thyroidectomy

Removal of a malignant tumor of the thyroid gland or other surgical procedures sometimes requires removing the gland (thyroidectomy). In the surgical treatment of hyperthyroidism, the posterior part of each lobe of the enlarged thyroid is usually preserved. This is a procedure called ‘almost complete thyroidectomy,’ which is done to protect n. recurrent larynx and n. superior larynx and the parathyroid glands were spared. Postoperative bleeding after thyroid surgery can press on the trachea, making it difficult to breathe. Blood accumulates inside the fibrous capsule of the gland.

Injury of the recurrent laryngeal nerve

Injury n. recurrent larynx is always present during neck surgery. Near the lower tip of the thyroid gland, gums n. the recurrent larynx, is closely related. Inferior thyroid and its branches. This nerve can pass anteriorly or posteriorly from the arteries’ branches, and it can also pass between them. Because of this relationship, And. The inferior thyroid is pinched laterally from the thyroid gland, not close to the nerve. Although the risk of injury to the left n. recurrent larynx smaller during surgery due to its vertical ascent from the upper mediastinum, the artery and nerve are also closely connected near the thyroid gland’s lower tip. Hoarseness is a common sign of unilateral injury n. recurrent larynx, however, temporary aphonia or phonation obstruction and laryngeal spasm may occur. These signs are usually the result of pinching n—superior larynx during surgery due to blood clotting pressure and serous exudate after surgery.
Sources:
Sources:

 

  • Marušić A., Human Anatomy, Medicinska naklada, 2002.
  • Moore K., Clinically Oriented Anatomy, Lippincott Williams & Wilkins, 2005.
 

Epidural hematoma

An epidural hematoma, sometimes called an extradural hematoma, accumulates blood that forms between the skull’s inner surface and the outer layer of the hard meninges  (dura mater). Often, epidural hematomas are associated with a history of trauma and an associated skull fracture and are typically seen in younger individuals who have suffered head trauma. About 15-20% of epidural hematomas are fatal.

Unlike subdural hematoma, it is difficult to establish head trauma. Clearly, extradural hemorrhages are usually perceived by purely defined head trauma.

 

Clinical picture

hernia_types

A typical presentation is that of a younger patient with a blow to the head (often during sports activity or as a result of motorcycle accidents) who suffered (not necessarily) transient loss of consciousness. In one-third of patients, the clinical picture is characterized by the sudden loss of consciousness at the time of trauma. After the injury, return to normal consciousness ( lucid interval ), which usually lasts about half an hour, but usually have a constant and often severe headache. Over the next few hours, the disturbance of consciousness gradually develops again due to hematomas’ growth. By displacement of the cerebral hemispheres causes compression of the brainstem by uncle herniation. The characteristic symptom is ipsilateral anisocoria and areflexia (Hutchinson’s pupil), with a deepening coma that ends in death if emergency neurosurgical intervention is not undertaken.

If bleeding in the posterior cranial fossa is characterized by developing consciousness disorders, neck stiffness, and cerebellar symptoms. Shift brain tissue in the caudo-cranial direction causes damage to the brainstem or herniation through the foramen magnum, which causes rapid death. The hernia here is tonsillar and causes the Cushing’s Triassic: hypertension, bradycardia, and irregular breathing.

 

Pathophysiology

The bleeding source is typically a ruptured meningeal artery, usually the middle meningeal artery (a.meningea media). In 75% of cases, skull fractures are also present. Pain in the form of a severe headache is caused by detachment of the dura from the bone during the hematoma spread. The posterior cranial fossa is a rare site of injury in general, including subdural hematoma. Occasionally an epidural hematoma may result from venous bleeding, typically due to venous sinus injury due to a related fracture.

The fact that younger patients are more likely to be affected by this injury results from the demographics of patients with head injuries and the changes that occur in the dura mater in older patients – them. The dura is much more attached to the skull.

Epidural hematomas are unilateral in more than 95% of cases. 95% of them are also located supratentorial. Temporoparietally, 60% of them (pterion, which lies above the middle meningeal artery, are relatively weak and prone to injury), frontally 20%, parietal-occipital 20%. Less than 5% of epidural hematomas are located infratentorial in the posterior cranial fossa (which is more common due to bleeding from a sinus injury).

Because epidural hematomas are located between the skull and the parietal layer of the dura mater, which is actually the periosteum of the bone, the spread of the epidural hematoma is usually limited by cranial sutures, as the periosteum passes through a suture connected to the outer periosteal layer. This helps distinguish an epidural from a subdural hematoma – a subdural hematoma is not limited to sutures.

However, epidural hematomas can pass through the venous sinuses and elevate them if no sutures are present – the venous sinuses are located between the dura’s parietal and visceral layers. 

There are exceptions, of course. For example, if the skull fracture itself passes over the sutures or if the sutures are abnormally dilated (e.g., physiological in a newborn).

Diagnosis

ct hematoma

Treatment

As with other types of intracranial hematomas, blood can be removed surgically to reduce pressure on the brain. The hematoma is removed by trepanation or craniotomy.

Prognosis

The prognosis is good even with a relatively large hematoma if the hematoma is removed quickly. Small hematoma without mass effect or «  swirl.»The sign can be treated conservatively, which sometimes results in the dura’s calcification. Delayed complications, usually associated with meningeal blood vessel injuries, such as pseudoaneurysm and AV fistula, are sometimes encountered. The prognosis is generally better if there was a lucid interval. 

Abdominal aorta

Most of the arteries that supply the posterior abdominal wall come from the abdominal aorta. The subcostal arteries separate from the thoracic part of the aorta and are distributed below the twelfth rib. The abdominal aorta is approximately 13 cm long. It begins at the diaphragm’s aortic hiatus at the level of the T12 vertebra and ends at the level of the L4 vertebra dividing into right and left. iliacau communis. The aortic bifurcation level is 2-3 cm inferior and to the left of the navel in level cristae iliacae . Aa. iliacae communes diverge and flow inferolateral, following the medial edge m. psoasa major to the pelvic hoop. Here is each And. iliaca communis shared in And. internal iliac and And. external iliac. A. iliaca interna enters the pelvis, an And. iliaca externa coming up m. iliopsoas. Before leaving the abdomen, from And. iliacae externae separates And. epigastric inferior and And. circumflexa ilium profunda which supply the anterolateral abdominal wall.

Abdominal aortic relations

Abdominal aorta

From superior to inferior, important anterior relations of the abdominal aorta are with:

  • celiac plexus and ganglion
  • the body of the pancreas and the splenic vein
  • left renal vein
  • the horizontal part of the duodenum
  • small bowel bandages.

The abdominal aorta descends anteriorly from the body of the T12-L4 vertebrae. The left lumbar veins pass posteriorly from the aorta to v. cavae inferior. On the right side, the aorta touches v. azygos, tank chyle, ductus thoracicus, right crus diaphragm, and right celiac ganglion. The aorta touches the left crus of the diaphragm and the left celiac ganglion on the left.

Aortic pulsation and aortic abdominal aneurysm

Because the aorta lies posterior to the pancreas and stomach, these organs’ tumors can transmit aortic pulsations that can be mistaken for an abdominal aortic aneurysm, a localized enlargement of the aorta. Deep palpation can detect an aneurysm, usually the result of congenital or acquired weakness of the arterial wall. The large aneurysm’ pulsations can be felt to the left of the midline; you can easily move the pulsating mass from one side to the other. Different imaging methods can confirm the diagnosis if in doubt.

Acute rupture of the abdominal aortic aneurysm is associated with severe pain in the abdomen or back. If not recognized, such an aneurysm has a mortality rate close to 90% due to large blood loss. Surgeons can repair an aneurysm by opening it, inserting a prosthesis, and suturing the aneurysmal aorta wall over the prosthesis to protect it. Many vascular problems today are treated with endovascular catheterization procedures.

When the anterior abdominal wall is relaxed, especially in children and lean adults, the inferior part of the abdominal aorta can be pressed against the body of the L4 vertebra by firm pressure on the anterior abdominal wall over the navel. You can apply this pressure to control bleeding in the pelvis or lower limbs.

Abdominal aortic branches

Branches of the descending (thoracic and abdominal) aorta can be described using the three planes in which they originate and flow, the ‘vascular planes’ and can be classified as visceral or parietal, and paired or odd. The paired parietal branches of the aorta supply blood to the diaphragm and the posterior abdominal wall.

For And. The sacral median, an odd parietal branch, can be said to occupy the fourth (posterior) plane because it starts from the posterior surface of the aorta, just before its bifurcation.

Superficial anatomy of the abdominal aorta

The abdominal aorta may be shown on the anterior abdominal wall by a band (approximately 2 cm wide) extending along the midline. Approximately 2.5 cm is superior from the transpyloric plane to the point slightly inferior and the navel’s left. This point depicts the site of aortic bifurcation into common iliac arteries. As the site of aortic bifurcation, it is also taken to the left of the center of the line joining the crista iliac’s highest points. This imaginary line helps examine obese people for whom the navel is not a reliable landmark.

Hemorrhoids

They are a common problem, but some people, despite this, are still too embarrassed to seek help for the painful burning, itching, and bleeding that hemorrhoids provoke. Pharmacies sell many products that help – creams, pads, ointments, and suppositories. As a widely accepted criterion, doctors suggest that you should avoid products that are on sale and contain ingredients whose name ends with “kain.” They contain an anesthetic that provides instant relief, but they cause increased irritation if used regularly. In addition to these drugs, there are, of course, quite several home remedies which you can try.

Pleasure of warmth

Fill the tub with warm water, then lower yourself into it. You should sit with your knees raised, allowing maximum exposure of the anal area to warm water. You will find that it relieves pain. You may sometimes feel that warm water promotes increased blood flow to the area, which helps narrow the swollen veins.

Try adding a full bag of bitter salt before immersing yourself in the tub to help shrink hemorrhoids. Stir the water well to dissolve it well.

Instead of filling the whole bathtub every time you need to alleviate the discomfort, you can buy a “sitting bathtub.” These bathtubs are designed only for sitting in them; they can be found in medical equipment stores. Or if you have a bidet – and you’re not too big – you can dip your butt into it. Filling the basin is much faster than filling the whole tub, and since it is more practical, you will probably do it more often.

For external hemorrhoids, apply a warm, damp tea bag. You can do this while sitting on the toilet bowl. The heat has a beneficial effect, and you can have the added benefit of one of the main components of tea, tannic acid. It helps reduce pain and swelling and promotes blood clotting, which helps stop bleeding.

Sit on the ice

Hemorrhoids

Fill durable plastic bag ice, wrap it in a thin cloth – an old pillow is an ideal choice – and sit on it. You can also use a bag of frozen peas (also wrapped in fabric), which will be more conveniently shaped according to your contours. The cold narrows the dilated blood vessels, providing tremendous relief. Sit for up to 20 minutes on an ice seat. There is no limit to how often you can do this, but take a break of at least ten minutes between two treatments. Alternating hot and cold – using a sedentary bath between ice treatments also helps.

Tap, don’t comb

Soak a piece of cotton wool with undistilled hamamelis and apply it on hemorrhoids. It is rich in tannins, which cause blood vessels to constrict.

Drowning Vaseline, which is also found in many treatments hemorrhoids that are on sale, can help provide relief to the affected area.

Both liquid vitamin E and wheat germ oil are effective against hemorrhoids. Soak a piece of cotton wool in them and apply them several times a day.

If you can find it in health food stores, try a balm that contains comfrey or calendula, as both of these ingredients provide relief and speed healing.

Although it sounds strange, the coating prepared from grated potatoes has an astringent and soothing effect.

Get out

Find a comfortable sofa several times a day, stretch out and lift your feet. What pleases irritated nerves also helps with the code hemorrhoids. In this outstretched position, you remove the load from your overloaded anal area, and at the same time, improve blood flow to the area that needs it. It is best to take 30 minutes for this “task.” If you sit or stand for a long time, try to change your position often.

Try seeds

Include more fiber in your diet. Research shows that a high-fiber diet can significantly reduce the intensity of symptoms of hemorrhoids, including pain and bleeding. Fiber-rich foods include whole-grain bread and whole grains, fresh fruits and vegetables, brown rice, and nuts.

When you eat more fiber, you need to maintain your body’s water supply to avoid constipation. Make sure you drink enough fluids so that your urine is pale and not dark or yellow.

Limit sitting or lifting heavy loads

Everyone who sits a lot should be in a standing position for a while. If you spend most of your time at a desk, walk for 5 minutes, at about every hour. Each time you get up, you reduce the pressure on the rectal area, which leads to the appearance of hemorrhoids.

Lifting a heavy load creates pressure on the anal area. If you need to lift a sofa or closet, say you have back problems and look for volunteers.

If you have a habit of lifting weights while working out in the gym, make sure you skip squat exercises. Each time you lower and then raise again, you create direct pressure on the rectum. Avoid, too, exercises that involve sitting for a long time, such as exercising on a bicycle in the gym.

The politics of the throne room

The key to avoiding hemorrhoids is not to strain, so apologize and head to the toilet whenever you need to. The delay problem leads to imprisonment. And that means you have to work harder when you go to the bathroom. It’s a call to appear hemorrhoids.

After emptying the hose, wipe slightly moistened under tap water, plain, white paper with no added odor. Perfumed, colored toilet paper may have aesthetically pleasing details, but additional chemical compounds can be irritating.

Use a paper towel-lined on the outside and with some non-perfumed moisturizer.