Trachea and oesophagus

This notes will cover brief anatomy of trachea and oesophagus

1. TRACHEA AND OESOPHAGUS
DR.YASHWANT LAXME PT

2. INIRODUCIION
•Trachea or windpipe is the patent tube for passage of
air to and from the lungs. In contrast, oesophagus
lying behind the trachea opens onlywhiledrinking or
eating. Thoracic duct brings the lymph from major
part of the body to the root of the neckpart of the body to the root of the neck

3. Trachea
•The trachea (Latin air aessel) is a wide tube lying
more or less in the midline, in the lower part of the
neck and in the superior mediastinum. Its uPPerend
is continuous with the lower end of the larynx. The
trachea in the neck is covered by the isthmus of the trachea in the neck is covered by the isthmus of the
thyroid gland and acts as a shield for trachea. At its
lower end the trachea ends by dividing into the right
and left principal bronchi

4. •The trachea is 10 to 15 cm in length. Its external
diameter measures about 2 cm in males and about
1.5 cm in females. The lumen is smaller in the
living than in the cadaver. It is about 3 mm at one
year of age. During childhood it corresponds to the year of age. During childhood it corresponds to the
age in years/ with a maximum of about 12 mm in
adults, i.e. it increases 1 mm per year tpto 12 years.

5. •
The upper end of the trachea lies at the lower border of the cricoid
cartilage, opposite the sixth cervical vertebra. In the cadaver its
bifurcated lower end lies at the lower border of the fourth thoracic
vertebra, corresponding in front to the stemalangle. However, in living
subjects, in the erect posture, the bifurcation lies at the lower border of
the sixth thoracic vertebra and descends still further during inspiration. the sixth thoracic vertebra and descends still further during inspiration.
•Over most of its length the trachea lies in the median plane, but near the
lower end it deviates slightly to the right. As it runs downwards, the
trachea Passes slightly backwards following the curvature of the spine.

6. •Relations of the Thoracic Part
Anteriorly
1 Manubriumsterni.
2 Sternothyroidmuscles.
3 Remains of the thymus.
4 Left brachiocephalicand inferior thyroid veins.
5 Aortic arch, brachiocephalicand left common carotid
arteries.
6 Deep cardiac plexus.
7 Some lymph nodes.

8. •Posteriorly
1 Oesophagus.
2 Vertebral column.
On the right side
1Right lung and pleura.
2 Right vagus. 2 Right vagus.
3 Azygosvein .
•On the left side
1Arch of aorta, left common carotid and left
subclavianarteries.
2 Left recurrent laryngeal nerve

9. Structure
•The trachea has a fibroelasticwall supported by a
cartilaginous skeleton formed by C-shaped rings. The
rings are about 76 to 20 in number and make the tube
convex anterolaterally. Posteriorlythere is a gap which is convex anterolaterally. Posteriorlythere is a gap which is
closed by a fibroelasticmembrane and contains
transversely arranged smooth muscle known as the
trachealis. The lumen is lined by ciliated columnar
epithelium and contains many mucous and serous glands.

10. •Arterial Supply
Inferior thyroid arteries.
•Venous Drainage
Into the left brachiocephalicvein
Lymphatic Drainage
To the pretrachealand paratrachealnodes.
Nerve supply
I Parasympathetic: Nerves through vagiand recurrent I Parasympathetic: Nerves through vagiand recurrent
laryngeal nerves. It is:
a.Sensory and secretomotorto the mucous membrane.
b.b. Motor to the trachealismuscle.
2 Sympathetic: Fibresfrom the middle cervical ganglion
reach it along the inferior thyroid arteries and are
vasomotor.

12. OESOPHAGUS
•FEATURE
The oesophagusis a narrow muscular tube,
forming the food passage between the pharynx
and stomach. It extends from the lower part of the
neck to the upper part of the abdomen. The neck to the upper part of the abdomen. The
oesophagusis about 25 cm long. The tube is
flattened anteroposteriorlyand the lumen is kept
collapsed; it dilates only during the passage of the
food bolus. The pharyngo-oesophagealjunction is
the narrowest part of the alimentary canal except
for the vermiform appendix

13. •The oesophagusbegins in the neck at the lower
border of the cricoidcartilage where it is
continuous with the lower end of the pharynx.
•It descends in front of the vertebral column
through the superior and posterior parts of the
mediastinum, and pierces the diaphragm at the
level of tenth thoracic vertebra. It ends by
opening into the stomach at its cardiac end at
the level of eleventh thoracic vertebra.

15. Curvature
•In general, the oesophagusis vertical, but
shows slight curvatures in the following
directions. There are two side to side
curvatures, both towards the Left . One is at curvatures, both towards the Left . One is at
the root of the neck and the other near the
lower end. It also has anteroposterior
curvatures that correspond to the curvatures of
the cervicothoracicspine

16. Constrictions
•Normally the oesophagusshows 4 constrictions at the
following levels.
•1 At its beginning, 15 crr./5 inch from the incisor teeth, where
it is crossed by cricopharyngeusmuscle.
•2 Where it is crossed by the aortic arch, 22.5 cm/9-inch from
the incisor teeth.
•2 Where it is crossed by the aortic arch, 22.5 cm/9-inch from
the incisor teeth.
•3 Where it is crossed by the left bronchus, 27 .5 cm / 17inch
from the incisor teeth.
•4 Where it pierces the diaphragm37 .5 cml15-inch from the
incisor teeth.
The distance from the incisor teeth are important in passing
instruments like endoscope into the oesophagus.

17. Relations of the ThorocicPart of the
Oesophogus
•Anteriorly
1 Trachea.
2 Right pulmonary artery.
3 Left bronchus.
4 Pericardium with left atrium.
5 The diaphragm.
Posteriorly•Posteriorly
1 Vertebral column.
2 Right posterior intercostalartefies.
3 Thoracic duct.
4 Azygosvein with the terminal parts of the hemiazygosveins.
5 Thoracic aorta.
6 Right pleural recess.
7 Diaphragm .

18. To the right
1 Right lung and pleura.
2 Azygosvein.
3 The right vagus
To the Left
1 Aortic arch.
2 Left subclavianartery.
3 Thoracic duct. 3 Thoracic duct.
4 Left lung and pleura.
5 Left recurrent laryrgealnerve, all in the superior
mediastinum.
In the posterior mediastinum, it is related to:
1The descending thoracic aorta.
2 The left lung and mediastinalpleura

19. Arterial Supply
•1 The cervical part including the segment up
to the arch of aorta is supplied by the inferior
thyroid arteries.
•2 The thoracic part is supplied by the •2 The thoracic part is supplied by the
oesophagealbranches of the aorta. 3 The
abdominal part is supplied by the oesophageal
branches of the Ieftgastric artery.

20. Venous drainage
•Blood from the upper part of the oesophagusdrains into the
brachiocephalicveins; from the middle part it goes to the
azygosveins; and fr.om the lower end it goes to the left gastric
vein and vena azygosvia hemiazygosvein. The lower end of
the oesophagusis one of the sites of portosystemic
anastomoses.
Lymphatic DrainageLymphatic Drainage
The cervical part drains to the deep cervical nodes; the
thoracic parttothe posterior mediastinalnodes; and
the abdominal part to the left gastric nodes.

21. Nerve supply
•1 Parasympathetic nerves: The upper half of the
oesophagusis supplied by the recurrent laryngeal
nerves, and the lower half by the oesophageal
plexus formed mainly by the two vagi.
Parasympathetic nerves are sensory, motor and
secretomotorto the oesophagus.
•2 Sympathetic nerves: For upper half of •2 Sympathetic nerves: For upper half of
oesophagus, the fibrescome from middle cervical
ganglion and run with inferior thyroid arteries.
For lower half, the fibrescome directly from
upper four thoracic ganglia, to form oesophageal
plexus before supplying the oesophagus.
Sympathetic nerves are vasomotor

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