Trachea | Structure, Function & Location

by DR. HAMID HUSSAIN
Trachea | Structure, Function & Location

Introduction

  • The trachea is a mobile cartilaginous and membranous tube. Formed by ‘C shaped rings.
  • The rings are about 16-20 in number and make the tube convex anterolaterally.
  • The trachea is a wide tube lying in the midline.
  • The upper end of the trachea lies at the lower border of the cricoid cartilage (opposite 6h cervical vertebrae) of the larynx. And extends downwards in the midline of the neck.
  • In the thorax, it ends by dividing into two main bronchi at the level of lower border of 4 thoracic vertebrae.
* Vertebral level- C-T,- In cadaver
*Vertebral level- C-T- In living erect posture.

Measurement

  • Length- 4-6 inches (10-15 cm.)
  • External diameter- 2 cm. in males, 1.5 cm. in females.
  • Lumen is smaller in the living than in the cadaver.
    3 mm.- At I year.
    12 mm.- In adult.

Relations

Cervical partThoracic part
1. Anteriorly- Skin, fascia, isthmus of the thyroid gland.
Sternohyoid and sternothyroid muscles.
Left brachiocephalic vein and inferior thyroid vein.
1. Anteriorly- Manubrium sterni, sternothyroid muscle, left brachiocephalic vein and inferior thyroid vein, left common carotid artery-
2. Posteriorly- Esophagus, vertebral column.2. Posteriorly– Esophagus, vertebral column.
3. Laterally (Side to side)- Lobe of thyroid gland.3. Right side- Right lung and pleura, azygos vein, right vagus nerve.
Left side- Arch of aorta, left common carotid artery, left subclavian artery.

Arterial Supply

  • Inferior thyroid artery.

Venous Drainage

  • Inferior thyroid vein.
  • Left brachiocephalic vein.

Lymphatic Drainage-

  • Pretracheal nodes.

Nerve Supply

  • Sympathetic- Fibres from the middle cervical ganglion.
  • Parasympathetic- Vagus- through recurrent laryngeal nerve.

Applied Aspect

  1. Clinically the trachea is palpated in the suprasternal notch.
  2. Tracheal tug.
  3. The trachea may get compressed by pathological enlargements of the thyroid, thymus, lymph nodes and the aortic arch. This causes dyspnoea, irritable cough and often a husky voice.
  4. Tracheostomy- Surgical creation of an opening into the trachea.
  5. Tracheotomy- An incision of the trachea.

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