THORAX OS powerpoint

Is an irregularly shaped cylinder with a narrow opening superiorly and relatively large opening inferiorly

Boundaries: root of the neck superiorly and diaphragm inferiorly, thoracic wall laterally Has flexible musculoskeletal wall consists of vertebrae, ribs, muscles and the sternum

Left and right pleural cavity each surrounding a lung Separated from each other by the mediastinum Mediastinum A thick soft tissue partition oriented longitudinally in a median sagittal position Contains the heart, esophagus, trachea, major nerves and systemic blood vessels

1. Breathing 2. Protection of vital organs 3. Conduit

A. Thoracic Wall Consists of skeletal elements and muscles Boundaries: Posteriorly T1-12 vertebrae and IV discs Laterally 12 ribs on each side Anteriorly sternum

B. Superior thoracic aperture Boundaries: Posteriorly body of T1 vertebra Laterally medial margin of rib 1 Anteriorly manubrium IV disc between T2-T3 – same horizontal plane with the superior margin of the manubrium

Inferior thoracic aperture large and expandable Boundaries: Posteriorly body of T12 vertebra Posterolaterally 12th rib and distal end of 11th rib Anterolaterally distal cartilaginous ends of 7th -10th ribs Anteriorly xiphoid process IV disc between T9-T10 – same horizontal plane with the joint between the coastal margin and sternum

D. Diaphragm - Closes the inferior thoracic aperture - Is not flat but has a dome shape: right dome ( reach up to 5th rib ) is higher than the left -During its contraction, there is a decrease on the height of the dome and an increase on the volume of the thorax

E. Mediastinum - A thick midline partition Boundaries : Anteriorly Sternum Posteriorly thoracic vertebra Superiorly superior thoracic aperture Inferiorly inferior thoracic aperture

Divisions: horizontal plane passing from sternal angle to IV disc of T4-T5 A . Superior mediastinum B. Inferior mediastinum • subdivided by the pericardium: I. anterior mediastinum – lies between the sternum and the pericardium II. middle mediastinum – consists of the pericardium and heart III. posterior mediastinum – lies between the pericardium and the thoracic vertebra

F. Pleural Cavities - Situated on either side of the mediastinum - Lined by a mesothelial membrane called the pleura A. Parietal pleura – lining the walls of the thoracic cavity B. Visceral pleura – lines those that reflected from the mediastinum and onto the surfaces of the lungs Costodiaphragmatic recess – the largest and clinically most important; it lies inferiorly between thoracic wall and diaphragm

IV disc between T4-T5: one of the most significant structure at its horizontal plane • Passes through the sternal angle anteriorly, marking the position of the anterior articulation of the coastal cartilage of the 2nd rib with the sternum • Separates the superior and inferior mediastinum, marks the position of the superior limit of pericardium • Marks where the arch of the aorta begins and ends • Passes through the site where the superior vena cava penetrates the pericardium to enter the heart • Is the level at which the trachea bifurcates into right and left main bronchi • Marks the superior limit of the pulmonary trunk

Arteries Thoracic aorta, internal thoracic arteries, interior and posterior intercostal arteries B. Nerves Intercostal nerves – innervates the wall, related parietal pleura and associated skin C. Dermatomes - T2-T12

• External to the thoracic wall and anchors the upper limb to the trunk • Consists of: A superficial compartment containing skin, superficial fascia and breasts A deep compartment containing muscles and associated structures

Arterial supply axillary artery branches Internal thoracic artery branches 2 nd -4 th intercxostal arteries Lymphatic drainage axillary nodes Venous Drainage axillary, internal thoracic and intercostal veins Innervation Breasts -2 nd -6 th intercostal nerves Nipple – 4 th intercostal nerve

MUSCLES: pectoralis major Pectoralis minor Subclavius originates from the ant. Thoracic wall and inserts into bones of the upper limb

CLINICAL CONDITION: Breast Cancer F > M one of the most common malignancies in women Develops in the cells of the acini, lactiferous ducts and lobules of the breast Mastectomy surgical removal of the breast might damage the long thoracic nerve that innervates the SA causing paralysis  Winged scapula

Is a broad central partition that separates the two laterally placed pleural cavities It contains: thymus gland Pericardial sac Heart Trachea Major Arteries and Veins DIVISIONS: 1. Superior Mediastinum 2. Inferior Mediastinum a. Anterior b. Middle c. Posterior

MIDDLE MEDIASTINUM - Contains the pericardium, heart, origins of the great vessels, various nerves and smaller vessels PERICARDIUM - Is a fibroserous sac surrounding the heart and the roots of the great vessels Consists of: 1. Fibrous pericardium 2. Serous pericardium

I. FIBROUS PERICARDIUM - Is a tough connective tissue outer layer that defines the boundaries of the middle mediastinum - Is a cone-shaped bag with its base on the diaphragm and its apex continuous with the adventitia of the great vessels Attachments: Base – attached to the central tendon of the diaphragm and to a muscular area of the diaphragm on the left side Anteriorly – attached to the posterior surface of the sternum by sternopericardial ligaments phrenic nerves and pericardiacophrenic vessels

II. SEROUS PERICARDIUM - Is thin and consists of: A. Parietal layer • Lines the inner surface of the fibrous pericardium B . Visceral layer • Adheres to the heart and forms its outer covering Pericardial Cavity – a narrow space that contains a small amount of fluid between the two layers of serous pericardium allows the uninhibited movement of the heart

CARDIAC ORIENTATION • apex of this pyramid projects forward, downward and to the left • base is opposite the apex and faces in a posterior direction

• Is quadrilateral and directed posteriorly • It consists of: The left atrium A small portion of the right atrium The proximal parts of the great veins (sup. And inf. Vena cava, pulmonary veins) Is fixed posteriorly to the pericardial wall , opposite to the bodies of T5-T8 or when standing T6-T9

• Is formed by the inferolateral part of the left ventricle • Positioned deep to the left 5th intercostal space

Anterior Surface • Faces anteriorly and consists mostly of the right ventricle with some of the right atrium on the right and some of the left ventricle on the left

Diaphragmatic Surface • Faces inferiorly, rests on the diaphragm • Separated from the base of the heart by the coronary sinus and extends from the base to the apex of the heart • Consists of the left ventricle and the small portion of the right ventricle separated by the posterior interventricular groove

Left pulmonary surface • Faces the left lung • Is broad and convex and consists of the left ventricle and a portion of the left atrium Right pulmonary surface • Faces the right lung • Is broad and convex, consists of the right atrium

Right and Left margins • Same as the right and left pulmonary surfaces of the heart Inferior margin • The sharp edge between the anterior and diaphragmatic surfaces of the heart • Formed by the right ventricle and small portion of the left ventricle near the apex Obtuse margin • Separates the anterior and left pulmonary surfaces • It is round and extends from the left auricle to the cardiac apex • Formed by the left ventricle and superiorly by a small portion of the left auricle

• Are external grooves I Coronary sulcus  Circles the heart, separating the atria from the ventricles  It contains the right coronary artery, the small cardiac vein, the coronary sinus, and circumflex branch of the left coronary artery II. Anterior and Posterior Interventricular Sulci  Separates the 2 ventricles A. Anterior interventricular sulcus  Located on the anterior surface of the heart  Contains the anterior interventricular artery and the great cardiac vein B. Posterior Interventricular sulcus  Located on the diaphragmatic surface of the heart  Contains the posterior interventricular artery and the middle cardiac vein

THORAX OS powerpoint

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THORAX OS powerpoint