• Brachiocephalic veins

Large veins of the thorax

Right brachiocephalic vein: formed at the root of the neck by

the union of the right subclavian & the right internal jugular veins.

Left brachiocephalic vein: has a similar origin. It passes

obliquely downward and to the right behind the manubrium sterni

and in front of the large branches of aortic arch. It then joins the

right brachiocephalic vein to form the superior vena cava.

•Superior vena cava (SVC) (Left + right) brachiocephalic veins.

Contains all the venous blood from head and neck and both

upper limbs.

The azygos vein joins the posterior aspect of the SVC just

before it enters the right atrium of the heart.

Large veins of the thorax

• Azygos veins Main azygos V +inferior hemiazygos V +superior hemiazygos V

They drain blood from:-

The posterior parts of the intercostal spaces

Posterior abdominal wall

The pericardium

The diaphragm

The bronchi

The esophagus

Consist of:

Main Azygous vein : Origin variable, but usually formed by union of the Rt. ascending lumbar vein and the Rt. subcostal vein. At level T5 – it arches forward to empty into post aspect of SVC.

The azygos vein has numerous tributaries, including 8 lower right intercostal veins, the right superior intercostal vein, the superior & inferior hemiazygos veins, and numerous mediastinal veins.

Inferior hemiazygos vein: Formed by LT. ascending lumbar vein + Lt. subcostal vein It ascends through the left crus of diaphragm and, at about the level of the 8th thoracic vertebra, it turns to the right and joins the azygos vein.

Superior hemiazygos vein: formed by union of the 4th to 8th intercostal veins At level T7, it joins the azygos vein

.

Large veins of the thorax

• Inferior vena cava Pierce the central tendon of diaphragm at level T8 Enters the lowest part of the Rt atrium

Azygos vein and caval obstruction

In case of obstruction

of superior or inferior

venae cavae, the azygos

veins provide an

alternative pathway to

return venous blood to

the right atrium of the

heart.

This is possible

because azygos veins

and their tributaries

connect the superior and

inferior venae cavae.

Large veins of the thorax

• Pulmonary veins Leave each lung carrying oxygenated blood to LA

Large arteries of the thorax

• Aorta is the main arterial trunk that delivers oxygenated blood from

the left ventricle of the heart to the tissues of the body.

Aorta

Ascending aorta

Arch of the aorta

Descending aorta

Abdominal Thoracic

Large arteries of the thorax • Ascending aorta It is contained in the pericardial sac and covered by a visceral

layer of serous pericardium, which also surrounds the pulmonary

trunk in a common sheath

Begins at the base of the left ventricle

Runs upward and forward to Rt half of sternum (sternal angle), At

this point, it enters the superior mediastinum and is then referred

to as the aortic arch. Superior to this point, it posses three bulges

(sinuses) at the root which are posterior, right, and left aortic

sinuses.

•The right and left coronary arteries originate from the anterior and posterior aortic sinuses, respectively.

Large arteries of the thorax • Arch of the aorta Lies behind the manubrium sterni

arches upward, backward, and to the left

At level of sternal angle, it becomes continuous with descending

aorta. Branches of Aorta

Brachiocephalic artery

Left common carotid artery

Left subclavian artery

Large arteries of the thorax • Descending thoracic aorta

Lies in the posterior mediastinum, it begins as a continuation of

the arch of the aorta on the left side of the lower border of the

body of the 4th thoracic vertebra

Reach anterior surface of vertebral column

At level T12, it passes behind the diaphragm and becomes

continuous with the abdominal aorta.

Branches:

Posterior intercostal arteries

Subcostal arteries

Pericardial, esophageal, bronchial arteries

Aneurysm and coarctation of the aorta Aortic aneurysm:

•The arch of the aorta lies behind the manubrium sterni.

•A gross dilatation of the aorta (aneurysm) may show itself as a pulsatile swelling in the suprasternal notch.

Coarctation of the aorta: A congenital narrowing of the aorta just proximal, opposite, or distal to the site of attachment of the ligmentum arteriosum.

•This condition is believed to result from an unusual quantity of ductus arteriosus muscle tissue in the wall of the aorta. When the ductus arteriosus contracts, the ductal muscle in the aortic wall also contracts, and the aortic lumen becomes narrowed. Later, when fibrosis takes place, the aortic wall also is involved, and permanent narrowing occurs.

Clinically; absent or diminished pulses in the femoral arteries of both lower limbs

Collateral circulation develops

The dilated intercostal arteries erode the lower borders of the ribs. Leading to Notching in Chest X-ray

Aneurysm and coarctation of the aorta

Large arteries of the thorax • Pulmonary trunk The pulmonary trunk is contained within the pericardial sac (Fig. 3.77), is covered by the visceral layer of serous pericardium and is associated with the ascending aorta in a common sheath Leaves the upper part of the RV and runs upward, backward, and to the left and terminates at concavity of the aortic arch.

At approximately the level of the intervertebral disc between 5th & 6th vertebrae opposite the left border of the sternum and posterior to the 3rd left costal cartilage, the pulmonary trunk divides into the:

right pulmonary artery, which passes posterior to the ascending aorta and the superior vena cava, to enter the right lung; left pulmonary artery, which passes inferiorly to the arch of the aorta and anteriorly to the descending aorta to enter the left lung.

Patent ductus arteriosus

Failure of the ductus arteriosus to

close shortly after birth results in a

shunt of blood from the aorta into

the pulmonary trunk, which may

lead to CHF.

PDA occurs in approximately 1 in

2000–2500 births (10% of

congenital heart defects) and can

be treated medically, or surgically

if necessary. The latter treatment

is by direct surgical ligation or via

a less invasive catheter-based

device

Large arteries of the thorax • Ligamentum arteriosum Fibrous band connects the bifurcation of the pulmonary trunk to the lower concave surface of the aortic arch It is the remains of the ductus arteriosus The left recurrent laryngeal nerve hooks around lower border

Lymph nodes and Lymph vessels • Thoracic wall Anterior axillary nodes: anterior thoracic wall Posterior axillary nodes: posterior thoracic wall Internal thoracic nodes: anterior intercostal spaces Posterior intercostal nodes: posterior intercostal spaces

Lymph nodes and vessels of the thorax • Mediastinum Disease and enlargement of these nodes may exert pressure on important neighboring mediastinal structures, E.g. trachea & SVC

Lymph nodes and vessels of the thorax • Thoracic duct Begins in the abdomen as cisterna chyli Ascends through the aortic opening in the diaphragm Crosses the median plane behind esophagus at sternal angle Runs upward along the left edge of esophagus Enter the beginning of the left brachiocephalic vein

At the root of the neck receives:= Left jugular Subclavian Bronchomediastinal lymph trunks

Conveys to the blood all lymph from Lower limbs, pelvis, abdomen, Left side of (thorax, head, neck,

arm)

Lymph nodes and vessels of the thorax • Right lymphatic duct Opens into the beginning of right brachiocephalic vein

Conveys to the blood all lymph from right side of (thorax, head, neck, arm)