anat trachea 2 (1).pptx dipali pdf new ..

Presentation on anatomy of trachea

1. TRACHEA Position, length, Anatomical Relations, Structure, Functions, Disorders

2. FRONT VIEW

3. SIDE VIEW

4. BACK VIEW

5. INTRODUCTION The trachea is a hollow, tube-like structure . The trachea, also known as the windpipe, is a U-shaped tube that connects the voice box (larynx) to the lungs. It’s a key part of the respiratory system, allowing air to pass from the nose or mouth to the lungs.
The average length of the trachea is about 11.8 centimeters , and a male’s trachea is typically longer than a female’s.
A mucous membrane, similar to those in the nasal cavity, lines the interior of the trachea. Cells in this membrane, called goblet cells, release mucus to help prevent microorganisms and debris from entering the lungs.

6. The trachea is also lined with tiny hair-like structures called cilia. These help push mucus that contains debris or pathogens out of the trachea. A person then either swallows or spits out the mucus.
Soft tissue makes up most of the trachea, and cartilage provides extra support.
The trachea runs parallel to the esophagus and lies just in front of it. The back of the trachea is softer to allow the esophagus to expand when a person is eating.
Due to their proximity, a small piece of cartilage in the larynx automatically covers the opening of the trachea to prevent food or drink from getting into it when the person is eating.

7. If food or drink do get into the trachea, this typically causes the person to cough. If a piece of food is particularly large, it could become trapped in the trachea and obstruct breathing.

8. LOCATION AND POSITION The trachea is located in the lower neck and upper chest, between the collarbones and behind the notch at the base of the throat. It’s a midline structure that runs in front of the esophagus and between the top lobes of the lungs.
The trachea starts at the bottom of the larynx, at the level of the sixth cervical vertebra. It ends at the carina, where it splits into the left and right main bronchi, at the level of the fourth thoracic vertebra. The trachea extends from the inferior margin of the cricoid cartilage (C6) and branches into the right and left main bronchi at the carina, located at the T4 vertebral body level, in the plane of Ludwig. It is usually situated in a midline position and can be displaced slightly to the right at the arch of the aorta.

9. STRUCTURE OF TRACHEA C artilage rings The trachea is made up of 16–20 C-shaped cartilage rings that support the trachea and allow it to move and flex when you breathe.  The rings are separated by a thin membrane, and the free ends of the rings are connected by muscle bands. Mucosa A moist tissue that lines each ring of cartilage. The mucosa contains goblet cells, which produce mucus that traps dust and other debris.

10. Cilia Small, hair-like structures in the inner layer of the trachea that move in rhythm to push mucus out of the trachea. Trachealis muscle A muscle located between each ring of cartilage.  When you cough, the trachealis muscle contracts to help expel air more forcefully. Blood and lymphatic vessels A complex network of tissue in the base of the mucous membrane that includes blood vessels and lymphatic vessels. The blood vessels control cellular maintenance and heat exchange, while the lymphatic vessels remove foreign particles. 

11. The trachea consists of four histological layers. The mucosa represents the innermost layer and it is lined with pseudo stratified ciliated columnar epithelium. The second histological layer is the submucosa. It consists of connective tissue that contains mucus glands, smooth muscle, vessels, nerves and lymphatics. The third layer is the musculocartilaginous layer which is represented by the cartilaginous rings and intervening smooth muscle. Lastly, the most external layer is provided by the fibroelastic adventitia. Trachea or windpipe is lined by pseudo stratified ciliated epithelium. Outside is C shaped cartilaginous rings . These rings prevent collapse of trachea during expiration. Trachea bifurcate at 5 th thoracic vertebrae T5

12. ANATOMICAL RELATIONS OF TRACHEA Anterior
The sternum, strap muscles, thyroid isthmus, ascending aorta, brachiocephalic artery, right common carotid artery, superior vena cava, and inferior thyroid veins
Posterior
The esophagus
Lateral
The lateral walls of the thyroid gland, left common carotid artery, arch of the azygos vein, right and left recurrent laryngeal nerves, and right and left vagus nerves
Right side
The pleura, right vagus , brachiocephalic trunk, right lung, right brachiocephalic vein, superior vena cava, and azygos vein
Left side
The left recurrent nerve, aortic arch, left common carotid and subclavian arteries, and left subclavian artery

13. The right and left lobes of the thyroid gland sit anterolateral to the proximal cervical trachea and the isthmus connecting the two lobes tends to cross the anterior trachea at the 2 nd or 3 rd tracheal ring . In addition to the proximal trachea, the inferior thyroid artery provides blood to the inferior thyroid gland. The esophagus has an intimate relationship with the trachea along its course). The esophagus begins at the level of the cricoid cartilage and runs toward the gastroesophageal junction along the left posterior border of the trachea. Fibroelastic membranes and rare muscle fibers lie between the longitudinal muscle of the outer esophagus and the trachealis muscle. The right posterior border of the trachea runs along the anterior aspect of the vertebral bodies. Occasionally, the esophagus may be found more laterally on the left side making it prone to injury during mediastinoscopy .

14. There are a number of large blood vessels lying in close proximity to the trachea that must be respected during tracheal operations. The brachiocephalic, or innominate, artery is the first branch of the aortic arch. It originates at the right anterior aspect of the trachea and runs superiorly from left-to-right over the right anterolateral portion of the distal and mid trachea. The left common carotid artery is the next branch of the aorta. It takes off just to the left of the trachea’s midline and runs superiorly from right-to-left over the left anterolateral trachea. The superior vena cava courses toward the right atrium along the right anterior aspect of the trachea. The azygous vein, coursing superiorly along the right side of the thoracic vertebral column before bending anteriorly, joins the superior vena cava lateral and just superior to the right tracheobronchial angle. Care must be taken during mediastinoscopy to anticipate this landmark so as to avoid mistaking the azygos vein for a lymph node during biopsy.

15. The main pulmonary artery, or pulmonary trunk, lies anterior and to the left of the carina . Its branches, the right and left pulmonary artery, run laterally and anterior to their corresponding main stem bronchi before branching into the lobar arteries of the right and left lungs. 

16. BLOOD SUPPLY The trachea’s blood supply comes from multiple sources, including:
Inferior thyroid arteries: The upper trachea receives blood from the tracheoesophageal branches of the inferior thyroid arteries. These branches originate from the right and left thyrocervical trunks, which branch off the subclavian arteries.
Bronchial arteries: The lower trachea, carina, and bronchi receive blood from the bronchial arteries, which usually come from the proximal descending aorta.
Subclavian, internal mammary, and innominate arteries: Small branches from these arteries also supply the trachea.
The trachea’s blood vessels branch out from the sides and enter the trachea over its lateral wall. As the branches approach the trachea’s wall, they split into superior and inferior branches. These branches join with the branches of the arteries above and below, and then split into branches that supply the anterior and posterior parts of the trachea.

17. Venous drainage The trachea's venous drainage is via the brachiocephalic, azygos , and accessory hemiazygos veins. The inferior thyroid venous plexus receives drainage from the trachea, and then empties into the brachiocephalic veins.  Arterial supply The trachea receives arterial blood from the tracheal branches of the inferior thyroid artery. 

18. DEVELOPMENT OF TRACHEA In the fourth week of development of the human embryo as the respiratory bud grows, the trachea separates from the foregut through the formation of ridges which eventually separate the trachea from the esophagus, the tracheoesophageal septum. This separates the future trachea from the esophagus and divides the foregut tube into the laryngotracheal tube. By the start of the fifth week, the left and right main bronchi have begun to form, initially as buds at the terminal end of the trachea.

The trachea is no more than 4 mm in diameter during the first year of life, expanding to its adult diameter of approximately 2 cm by late childhood. The trachea is more circular and more vertical in children compared to adults, varies more in size, and also varies more in its position in relation to its surrounding structures.

19. The trachea is surrounded by 16 to 20 rings of hyaline cartilage; these ‘rings’ are incomplete and C-shaped. Two or more of the cartilages often unite, partially or completely, and they are sometimes bifurcated at their extremities. The rings are generally highly elastic but they may calcify with age.

20. FUNCTIONS OF TRACHEA The function of the trachea is to be the main passageway for air to pass from the upper respiratory tract to the lungs. As air flows into the trachea during inhalation, it is warmed and moisturized before entering the lungs. Most particles that enter the airway are trapped in the thin layer of mucus on the trachea walls. They are then moved up toward the mouth by cilia, where they can be coughed up or swallowed.
The U-shaped sections of cartilage that line the trachea are flexible and can close and open a little as the trachealis muscle at the back of the rings contracts and relaxes. These small contractions of the trachea occur involuntarily as part of normal breathing (respiration).

21. In addition to delivering air, the trachea aids in disease defense. Mucus in the trachea aids in the capture of germs such as viruses and pathogenic bacteria before they enter the lungs.
The trachea also serves to control the temperature of the air that enters and exits the lungs.
On chilly days, the trachea warms and humidifies the air before it reaches the lungs.
On hot days, the trachea aids in the cooling of the air through evaporation. The trachealis muscle that joins the two ends of the tracheal ring can contract thereby constricting the tracheal tube. This is useful for increasing the pressure during coughing to evacuate any irritants more effectively.

22. DISORDERS OF TRACHEA Many people with tracheal conditions do not have any symptoms. That said, some of the common signs and symptoms that can point to a problem with the trachea include:
Trouble breathing
Coughing (which may include coughing up blood)
Hoarse voice
Wheezing, shortness of breath
Frequent upper respiratory infections and/or asthma that does not seem to get better with treatment
Difficult swallowing
High-pitched noises when breathing (stridor)

23. Congenital Disorders These are present at birth and may be due to developmental abnormalities:. 1. Tracheomalacia Description: Weakness of the tracheal cartilage leads to collapse during breathing. Symptoms: Stridor, difficulty breathing, recurrent respiratory infections. Causes: Genetic syndromes, prematurity. Treatment: Often resolves with age, but severe cases may require surgery or stenting. 2. Tracheoesophageal Fistula ( TEF ) Description: Abnormal connection between the trachea and esophagus. Symptoms: Difficulty feeding, choking, recurrent pneumonia. Diagnosis: Imaging and bronchoscopy. Treatment: Surgical repair.

24. 3. Tracheal Stenosis Description: Narrowing of the trachea due to incomplete cartilage rings. Symptoms: Stridor, cyanosis, respiratory distress. Treatment: Surgery (tracheoplasty). Acquired Disorders Tracheomalacia (Acquired) Causes: Chronic inflammation (e.g., COPD), prolonged intubation, external compression.

Symptoms: Persistent cough, wheezing, dyspnea.

Treatment: Airway stents, CPAP, or surgical intervention.

25. Tracheal Neoplasms Types:
Benign: Papillomas, hemangiomas.

Malignant: Squamous cell carcinoma, adenoid cystic carcinoma.

Symptoms: Persistent cough, hemoptysis, airway obstruction.

Diagnosis: Bronchoscopy and biopsy.

Treatment: Surgery, radiation, chemotherapy (depending on type and stage).

26. Infections Common Causes:
Acute tracheitis (e.g., bacterial tracheitis caused by Staphylococcus aureus).
Chronic infections (e.g., tuberculosis, fungal infections).
Symptoms: Fever, productive cough, difficulty breathing.
Treatment: Antibiotics, antivirals, or antifungals based on the pathogen Trauma Causes: Blunt or penetrating neck trauma, intubation injury.
Symptoms: Subcutaneous emphysema, difficulty breathing, voice changes.

Treatment: Airway stabilization and surgical repair.

27. Inflammatory and Autoimmune Disorder a. Tracheobronchial Inflammation Causes: Infections, irritants (e.g., smoke, pollutants), allergies.

Symptoms: Cough, wheezing, chest discomfort.

Treatment: Anti-inflammatory agents, bronchodilators, supportive care. B. Granulomatosis with Polyangiitis Description: Autoimmune vasculitis affecting the trachea.

Symptoms: Subglottic stenosis, hemoptysis, stridor.

Treatment: Immunosuppressive therapy (e.g., corticosteroids, cyclophosphamide).

28. Functional Disorders Tracheal Diverticulum Description: Outpouching of the tracheal wall. Symptoms: Often asymptomatic, but may cause cough or infections. Treatment: Monitoring, surgical excision if symptomatic. Foreign Body Aspiration Causes: Accidental inhalation (common in children). Symptoms: Acute onset cough, wheezing, choking. Treatment: Emergency bronchoscopy.