Oesophagus, Trachea and Great vessels of...

Oesophagus, Trachea and Great vessels of Thorax

Dr. Ifeanacho

ABIREH MBBS, MSc, PGDE, MWACS

7/8/2019 www.abireh.com 1

Introduction -Mediastinum


OESOPHAGUS A muscular tube 25 cm in length Begins at the lower border of the cricoid

cartilage (C6) Passes through the diaphragm at T10 Ends in the abdomen at the cardiac orifice of

the stomach at T11 Has cervical, thoracic and abdominal parts 7/8/2019 www.abireh.com 3

Oesophagus -parts Cervical portion Begins in the midline in front of the

prevertebral fascia Inclines to the left Enters the thoracic inlet


Oesophagus -parts


Oesophagus -parts

Thoracic portion Passes downwards through the superior

mediastinum Returns to midline at T5 Deviates to the left again at T7 Curves forward to pass in front of the

descending thoracic aorta


Oesophagus -parts

Pierce the diaphragm 2.5 cm to the left of the midline at 7th left costal cartilage

Here fibres from the right crus of the diaphragm sweep around the oesophageal opening in a sling-like loop


Oesophagus -parts

Abdominal portion 1-2cm Length depends on muscle tone and degree

of distension of the stomach


Oesophagus -Relations Superior mediastinum It is crossed by the arch of the aorta on its left,

and vena azygos on its right Trachea lies anteriorly


Oesophagus -Relations

Posterior mediastinum Anterior Left main bronchus and the right pulmonary

artery Pericardium and the posterior sloping fibres

of the diaphragm Posterior Thoracic duct 7/8/2019 www.abireh.com 10


Thoracic duct lies at first, to its right, then behind and to its left in the superior mediastinum

Hemiazygos, accessory hemiazygos and right posterior (aortic) intercostal arteries

Mediastinal pleura touches the oesophagus on both sides


Oesophagus -Constrictions Cricopharyngeal sphincter Narrowest part of the oesophagus Commencement of the oesophagus 15 cm from the incisor teeth Aortic arch 22 cm from incisor


Oesophagus -Constrictions


Oesophagus -Constrictions

Left principal bronchus 27 cm from incisor Opening in the diaphragm 38 cm from the incisor teeth Left atrium Causes indentation when enlarged


Oesophagus –Arterial supply Upper part -Inferior thyroid arteries Middle part Oesophageal branches from aorta Bronchial arteries Lower part -Oesophageal branches of left

gastric artery


Oesophagus –Venous drainage Upper part -Brachiocephalic veins Middle part -Azygos system of veins Lower part-Oesophageal tributaries of left

gastric vein (empties into portal vein There is an anastomosis between portal and

systemic venous systems in this lower part It lies at T8 (level with the central tendon) (T8

vertebra)


Oesophagus -Lymphatics Cervical part -Deep cervical nodes Thoracic part -Tracheobronchial and

posterior mediastinal nodes Abdominal part -left gastric and coeliac nodes There exist lymphatic channels within the

wall of the oesophagus So drainage from any given area does not

strictly follow the above pattern


Oesophagus -Nerve supply Upper part -Recurrent laryngeal nerves Sympathetic fibres from cell bodies in the

middle cervical ganglia Middle and lower parts -fibres from thoracic

sympathetic trunks and greater splanchnic nerves

Parasympathetic from the vagus nerves


Oesophagus -Nerve supply

Motor supply Vagus From cell bodies in the nucleus

ambiguous for the upper striated muscle part From the dorsal motor nucleus with

relay in plexuses in the wall for the lower visceral muscle part


Oesophagus -Nerve supply

Secretomotor fibres from the vagus

Pain fibres run with the vagal and sympathetic supply


TRACHEA It is the continuation of the larynx It is 10 cm long and 2 cm wide 3mm wide in first year of life Equal in mm to age in years Starts below the cricoid cartilage at C6 5 cm above jugular notch


Trachea It enters thoracic inlet in the midline Passes downwards and backwards behind the

manubrium Bifurcate into two principal (main) bronchi at

T5 May stretch up o 15cm in full inspiration Then bifurcation descends to the level of T6


Trachea -Parts Cervical part This is 5 cm long From cricoid cartilage to the jugular notch This part lies in the midline in contact with

front of the oesophagus Recurrent laryngeal nerve runs in the groove

between trachea and oesophagus


Trachea -Parts


Trachea -Parts

Carotid sheath and lobes of thyroid gland lie to the side

Isthmus of the thyroid gland is adherent to 2nd , 3rd and 4th tracheal rings

Inferior thyroid veins and anterior jugular venous arch lie in front

Thyroidea ima artery and the upper end thymus also lie anterior


Trachea -Parts Thoracic part This runs through the superior mediastinum in

front of the oesophagus Anterior relations Manubrium with sternohyoid and sternothyroid

muscles attached Thymus (remnants) Inferior thyroid and left brachiocephalic veins Brachiocephalic and left common carotid

arteries


Trachea -Relations


Trachea -Relations

Lateral relations -right Right vagus Right lung and pleura Arch of the azygos vein Right brachiocephalic vein Superior vena cava


Trachea -Relations


Trachea -Relations

Lateral relations – left Left common carotid and subclavian arteries Pleura Left vagus nerve Arch of the aorta (curves backwards over the

left bronchus) Left recurrent laryngeal nerve


Trachea -Relations


Trachea –Blood supply Branches of inferior thyroid and

bronchial arteries Veins drain to inferior thyroid vein


Trachea -Lymphatics Pre- and paratracheal nodes Inferior deep cervical nodes


Trachea –Nerve supply Mucous membrane Afferent fibres -Vagi and recurrent laryngeal

nerves Smooth muscles and blood vessels Sympathetic fibres from upper ganglia of the

sympathetic trunks


Trachea –Nerve supply


Trachea -Function The rings keep the airway open Mucus traps particles Cilia clears debris (by beating upwards) Glandular secretion helps to humidify

air


Trachea -Function

During swallowing the trachea is stretched as the larynx moves upwards

ut the bifurcation does not move Elasticity restores the normal position The trachealis muscle controls the diameter of

the tube


Trachea -Function

During coughing there is a 30% increase in transverse diameter

Produced by compressed air in the trachea while the vocal cords are shut

The trachea narrows to 10% less than the resting diameter at the instant the cords open

This increases the explosive force of the blast of compressed air


GREAT VESSELS -THORAX These vessels carry blood to and from the

heart They include: Aorta Pulmonary trunk Superior vena cava Inferior vena cava


Aorta The thoracic portion can be divided into: Ascending aorta Arch of aorta Descending (Thoracic aorta) Only the arch of the aorta is in the superior

mediastinum


Aorta


Ascending aorta The ascending aorta emerges from the

pericardium Then approaches the manubrium And becomes arch of aorta at the level of

manubriosternal joint T4/5


Arch of aorta The arch of aorta passes backwards over the

left bronchus to reach the body of T4 to the left of the midline

The arch is initially anterior and finally lateral to the trachea

Three branches arise from the superior border of the arch of the aorta


Arch of aorta


Arch of aorta -Relations Phrenic and vagus nerves crosses on its left

side Phrenic nerve passes in front of root of the

lung Vagus nerve passes behind the root of the

lung Sympathetic and vagus branches to the

superficial part of the cardiac plexus lie between the phrenic and vagus nerve


Arch of aorta -Relations

Left superior intercostal vein passes across the arch deep to the phrenic nerve

Left recurrent laryngeal nerve hooks around the ligamentum arteriosum to pass upwards on the right side

The pulmonary trunk bifurcates into right and left pulmonary arteries in the concavity of the arch

The trachea and oesophagus lie on the right


Arch of aorta -Relations

The adventitial layer of the arch contains baroreceptors innervated by vagal nerve fibres, which are concerned with the reflex control of the heart rate

Aortic bodies lie under the arch (around the ligamentum arteriosum)

Supplied by vagal fibres Chemoreceptors concerned with respiratory

reflexes


Arch of aorta -Branches Brachiocephalic trunk Left common carotid Left subclavian arteries At their origins, all three are crossed

anteriorly by the left brachiocephalic vein


Arch of aorta -Branches

Brachiocephalic trunk (First branch) Largest of the three branches At origin it lies behind the manubrium It is slightly anterior to the other two

branches It ascends slightly posteriorly and to the right



The brachiocephalic trunk divides at right sternoclavicular joint into:

Right common carotid artery Right subclavian artery The arteries mainly supply the right side of

the head and neck and the right upper limb, respectively



Thyroidea ima artery is a branch of brachiocephalic trunk seen occasionaly

Supply the thyroid gland



Left common carotid artery (2nd branch) It arises from the arch just to the left and

posterior to the brachiocephalic trunk Ascends through the superior mediastinum

along the left side of the trachea Supplies the left side of the head and neck



Left subclavian artery (3rd branch) It arises from the arch of aorta just to the left

posterior to the left common carotid artery Ascends through the superior mediastinum

along the left side of the trachea Supplies the left upper limb


Thoracic aorta Begins at the lower edge of vertebra T4 As continuation of the arch of aorta It ends at lower edge of T12 It passes through the aortic hiatus posterior to

the diaphragm at T12 It lies directly anterior to the lower thoracic

vertebral bodies


Thoracic aorta -Branches


Superior vena cava Formed by confluence of the two

brachiocephalic veins At lower border of 1st right costal cartilage It passes vertically downwards behind the

right border of the sternum Pierces the pericardium at 2nd costal cartilage Enters the upper border of the right atrium at

3rd right costal cartilage


Superior vena cava


Superior vena cava

Azygos vein at level of sternal angle There are no valves in the superior vena cava,

brachiocephalic veins or the azygos system of veins


Superior vena cava


Pulmonary trunk Contained within the pericardial sac It is covered by the visceral layer of serous

pericardium Lies in a common sheath with the ascending

aorta


Pulmonary trunk

It arises from the conus arteriosus of the right ventricle

Slightly anterior to aortic orifice Ascends, moving posteriorly and to the left,

lying initially anterior and then to the left of the ascending aorta

Divides at T5/6, posterior to 3rd left costal cartilage


Pulmonary trunk

Right pulmonary artery Passes to the right, posterior to the ascending

aorta and the superior vena cava, to enter the right lung

left pulmonary artery Passes inferiorly to the arch of the aorta and

anteriorly to the descending aorta to enter the left lung


Pulmonary trunk


Inferior vena cava Passes through the diaphragm at T8 It enters the fibrous pericardium A short portion lies within the pericardial sac

before entering the right atrium While within the pericardial sac, it is covered

by serous pericardium except for a small portion of its posterior surface


Inferior vena cava


Pulmonary vein A very short segment of each pulmonary vein

lie within the pericardial sac Usually two from each lung Pass through the fibrous pericardium and

enter the superior region of the left atrium on its posterior surface


Pulmonary vein


Pulmonary vein

In the pericardial sac, all but a portion of the posterior surface of these veins is covered by serous pericardium

The oblique pericardial sinus is between the right and left pulmonary veins, within the pericardial sac


Ligamentum arteriosum Ligamentum arteriosum is the obliterated

ductus arteriosus Ductus arteriosus connects the pulmonary

trunk with the arch of aorta and allows blood to bypass the lungs during development

Ductus arteriosus closes soon after birth and forms the ligamentous connection observed in the adult


Ligamentum arteriosum


Azygos system of veins


Diaphragmatic openings


Thank you for listening


Oesophagus, Trachea and Great vessels of...

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