Unit 14 Pleura and Lungs

Quiz

Clinical Case A 55 year old man reported to his family physician that he had a solid swelling in his scrotum. There was no ulceration of the scrotal skin and a red glow could not be seen using transillumination. The lump was diagnosed as an advanced carcinoma of the testis.

Plate 242 Three divisions to the thorax: 2 Pleural Cavities and a Mediastinum The 2 Pleural Cavities are closed and separate spaces M P P

Directions: 1. Make a horizontal cut from the xiphisternal junction laterally to midaxillary line Plate STERNUMSTERNUM Saw Cuts

2. Cut through the ribs in a superior direction to rib 2 – midaxillary line 4. Pry the rib cage upward and separate any pleura 3. Saw through the sternal angle and use a scalpel to cut through muscles in the intercostal spaces Plate STERNUMSTERNUM Saw Cuts

Remember, the Internal Thoracic artery terminates as the Musculophrenic and Superior Epigastric arteries Superior Epigastric Musculophrenic Internal Thoracic Artery Anterior Intercostal Arteries SternumSternum Identify the Internal Thoracic artery and any Parasternal lymph nodes Plate 191 Internal Thoracic Cage Subclavian Artery

If the parietal pleura was freed intact from the thoracic wall, incise it parasternally and reflect it laterally to expose the lungs in their respective pleural cavities. The visceral pleura is a covering on the surface of the lungs. The parietal pleura lines the pleural cavity. The space between the two membranes is the pleural cavity. The visceral and parietal pleura are continuous with one another at the root (hilum) of the lung.

Lung bud expands into primitive pleural cavity-5th week; this is the first of 3 body cavities Identify the parts of the parietal pleura MEDIASTINUMMEDIASTINUM Pleura and Cavity Serous fluid Pleura

Locate the Costodiaphragmatic and Costomediastinal Recesses Pleura-lined “gutters” Plate 196 Right and Left Costodiaphragmatic Recesses Costomediastinal recess Cardiac Notch of Left Lung Pleura and Cavity Anterior View

Plate 197 Pleura and Cavity Left Costodiaphragmatic Recess Right Costodiaphragmatic Recess Posterior View

Plate 196 Cardiac Notch of Left Lung Lingula Apex Base Identify Cardiac Notch Lingula Apex Base

Retract the lungs laterally to expose the Mediastinal pleura covering the Fibrous Pericardium Plate 193 Mediastinal Part of Parietal Pleura Fibrous Pericardium of Heart Sac Lungs

If you separate the Mediastinal pleura from the heart sac you will find the Phrenic Nerve and the Pericardiacophrenic vessels anterior to the ROOT of the LUNG Plate 211 Phrenic Nerve Pericardiacophrenic Vessels Lungs

Left Phrenic Nerve C3 C4 C5 Ventral Rami Diaphragm Mediastinal Part of Parietal Pleura C345 keeps the diaphragm alive! Plate 193

There may be adhesions Transect the root of the each lung and remove the lungs from the pleural cavities

What is in the Root of the lung? Identify: Pulmonary Artery Bronchi Pulmonary Veins Lymph Nodes Pulmonary Ligament Plate 199B Lungs Apex Base Lingula Superior Lobe Inferior Lobe Superior Lobe Oblique Fissure Cut Pleura Anterior Pulmonary Ligament Left Pulmonary Artery Left Main Bronchus Left Superior Pulmonary Veins Hilar Lymph Nodes Left Inferior Pulmonary Vein

Superior Lobe Middle Lobe Inferior Lobe Identify the same components on the right lung and on the corresponding mediastinal surface Plate 199A Lungs Oblique Fissure Horizontal Fissure Rt. Lobar Bronchi Rt. Pulmonary Artery Rt. Superior Pulmonary Veins Hilar Lymph Node Rt. Inferior Pulmonary Vein Anterior

Identify the Vagus Nerve as it passes behind the root of the lung Note that the Phrenic nerve passes in front of the root of the lung Plate 231 Lungs Vagus Nerve Phrenic Nerve Diaphragm Posterior Left Side Mediastinal Pleura

Phrenic Nerve Vagus Nerve Posterior Diaphragm Do the same on the right side Plate 230 Lungs Right Side Posterior Mediastinal Pleura

Plate 198 Lungs Three lobes: Superior, Middle, Inferior Two fissures: Horizontal and Oblique Two lobes: Superior, Inferior One fissure: Oblique S M I S I Lingula Cardiac Notch Horizontal Fissure Oblique Fissure Base Oblique Fissure Right lung – shorter and wider due to liver Identify Apex extends into the neck

The Primary Bronchi divide into Lobar Bronchi which divide into Segmental Bronchi (~10 for each lung); a bronchopulmonary segment is that portion of lung supplied by a segmental bronchus and pulmonary artery branch This is the bronchial tree Plate 202 Trachea Primary Bronchi Lobar Bronchi Segmental Bronchi T4-T5

Bronchopulmonary Segments Plate 201 Bronchopulmonary segments are surgically separable: important in removal of tumors or abscesses Lungs A bronchopulmonary segment contains a segmental bronchus, a branch of the pulmonary artery, and a branch of the bronchial artery which run together in the central part of the segment. Lymphatics and veins drain along the borders Arteries run with Airways

If a person inhales a foreign object, it lodges in the right bronchus. Why? 1. Shorter in length 2. Wider in diameter 3. More vertical 2545 Plate 202 Lungs Right

Plate 202 Lungs Typical Pathway of a Foreign Body

Atelectasis of the right lung – total homogeneous opacity of right side. Atelectasis of the right middle and lower lobes of the lung – the intermediate bronchus leads to dilated and occluded branches in the shrunken middle and lower lobes. The rest of the right side is occupied by branches of upper lobe. AP of right lung Lateral of right lung U

Bronchoscopic view of the carina and left and right primary bronchi Distortions in the position of the carina may indicate metastasis of bronchogenic carcinoma into the tracheobronchial lymph nodes Carina

Air in Trachea Pulmonary Artery Diaphragm Rib V Plate 213 Left Primary Bronchus

In order for inspiration to occur, the lungs must expand. This increases lung volume and decreases the pressure in the lungs to 758 mm Hg or below atmospheric pressure (760 mm Hg). The lungs expand because the diaphragm increases the vertical diameter of the thorax and the external intercostals elevate the ribs. Air will flow into the lungs because of this pressure difference. Expiration is a passive process and occurs when the pressure in the lungs is greater than the pressure in the atmosphere. Elastic recoil of the chest wall and lungs occurs. Intrapleural pressure (in the pleural space) is 4 mm Hg below atmospheric pressure. This acts like a “suction” and keeps the alveoli inflated.

Bucket Handle - LateralPump Handle - APPlus diaphragm movements Movements of the thoracic cage which increase or decrease the intrathoracic volume resulting in pressure changes causing inspiration or expiration. Page 89 Moore

The entry of air into the pleural cavity is called a pneumothorax. As a result, the lung collapses and the pleural cavity becomes a real space. The pneumothorax can be spontaneous due to a rupture of a bleb or bulla on the lung surface - seen in men years Moore page 118

Typically in a patient with no known lung disease, but can occur secondary to diseases of the lung.

Simple Pneumothorax Detail Common presentation: Tall, thin male teenager Abrupt onset dyspnea Chest pain Hyperresonant percussion on affected side Breath sounds diminished

This is another type of pneumothorax - an open pneumothorax; air flows easily in and out of the open wound. Mediastinal structures are pushed to the opposite side with inspiration but return with expiration.

In a tension pneumothorax, the wound is covered by skin, muscle or clothing. The air becomes trapped in the pleural space and Mediastinal structures are pushed to the opposite side. One lung is collapsed and the other lung is compressed. Trachea deviates away from the lesion. This is a lethal condition. Pressure must be relieved! Clinical signs: distended neck veins, shifted trachea, decreased breath sounds in both lungs, hypotension, agitation

Classic signs of a tension pneumothorax: Deviation of trachea away from side of tension Shift in mediastinum Depression of hemi- diaphragm Post-mortem chest X-ray of left tension pneumothorax Cardiovascular function compromised due to venous obstruction of heart

Tension pneumothorax identified on CT scan

Moore, page 119

To remove blood or other fluids, a needle is inserted closer to the upper border of the rib below to avoid nerves. The 9th interspace in the midaxillary line during expiration is a safe place - above the diaphragm. Hydrothorax: due to a pleural effusion (escape of fluid into the pleura space) Hemothorax: blood entering the pleural space – e.g., from a chest wound Page 119 Moore 9 10

CLINICAL CASE A woman was stabbed in the right side of her lower neck. The stab wound was approximately 2.5 cm superior to the medial third of the clavicle. Shortly after the bleeding was controlled, the woman began breathing rapidly and was given oxygen by the paramedics. Physical examination revealed a significant shift of mediastinal structures and poor breath sounds were heard on the right side of the chest.

Laboratory