Lachmans Back and Thorax Unit 2 Flashcards
(41 cards)
Which axillary lymph nodes are in the most likely pathway of lymphatic drainage from the breast?
Anterior nodes receive the initial drainage - -> Central and apical nodes.
What 3 nerves pass through the axilla and are most susceptible to injury in an axillary node dissection, and what do these nerves innervate?
The long thoracic nerve (medial wall of the axilla)
The thoracodorsal nerve (posterior wall of the axilla)
Intercostobrachial nerve traverses the axilla from medial to lateral and provides sensory innervation to the medial arm.
Why is a dye injected into the region of the breast tumor before a sentinel lymph node biopsy is done?
The dye is picked up by the lymphatic system and will travel to the axillary lymph nodes or nodes to which the tissue around the tumor drains.
This allows the identification of the first lymph nodes to which cancer cells form the tumor would metastasize. The biopsy of this node then provides a good indication of whether there has been any metastasis of the cancer from the breast to the axilla.
What muscles form the wall of the axilla?
Anterior wall- Pectoralis major, and minor
Posterior wall- Subscapularis, teres major and latissimus dorsi
Medial wall- serratus anterior
What is the role of the parasternal lymph nodes in the lymphatic drainage from the breast?
A significant portion of the lymphatic drainage from the medial portion of the breast goes to the parasternal lymph nodes, which are in the anterior intercostal spaces near the internal thoracic (mammary) vessels. These nodes drain to the supraclavicular nodes. They are lymphatic communications between the parasternal lymph nodes of the right and left side that provide a pathway for metastasis from one breast to the other
What is the functional and structural unit of the lung?
The functional unit of the lung is the bronchopulmonary segment.
This is the region of a lobe that is supplied by one segment (tertiary) bronchus and one segmental branch of a pulmonary artery. Disease processes may be restricted to a single bronchopulmonary segment.
Why is an aspirated foreign body more likely to pass into the right main bronchus than the left?
At the tracheal bifurcation, the right main bronchus takes a more vertical course and is wider. Therefore, an aspirated body is more likely to pass into the right main bronchus.
At what point does the common aerodigestive tract divide into separate airway and digestive tracts?
The oropharynx is a common aerodigestive tract, at the level of about the C4 vertebra, the opening into the larynx is the upper end if the dedicated airway, and the laryngopharynx is dedicated as a food pathway. The pharynx continues downward as the trachea, and the laryngopharynx continues as the esophagus.
What vascular structures are used surgically as landmarks to identify the boundaries between bronchopulmonary segments?
Branches of the lobar pulmonary veins lie in the connective tissue planes between adjacent bronchopulmonary segments. These intersegmental veins are used as the landmarks to identify the boundaries between the segments.
What is the role of the soft palate during swallowing?
During swallowing, the soft palate is elevated to occlude the opening between the nasopharynx and the oropharynx. This prevents food in the oropharynx from passing upward into the nasopharynx when the pharynx constricts.
What is the piriform recess, and what is its role in swallowing?
The piriform recess is that portion of the laryngopharynx that is posterolateral to the larynx. During swallowing, food is diverted from the midline by the epiglottis and directed into the piriform recess. From there, it returns to the midline to enter the esophagus. This pathway keeps the food out of the airway.
What is the role of the vocal folds in the cough reflex?
Supraglottic mucosa is stimulated, the:
- vocal folds adduct to close the glottis.(This prevents a foreign body from entering the infraglottic space. With the glottis closed)
- the intrathoracic pressure is increased by contraction of the abdominal muscles. When the pressure gradient between the infraglottic space and the supraglottic vestibule is high enough
… the vocal folds rapidly abduct to open the glottis, and a high-velocity blast of air moves upward to clear the vestibule.
What four congenital defects are found in tetralogy of Fallot?
Pulmonary stenosis
Over-riding aorta
Ventricular septal defect,
Right ventricular hypertrophy
What embryonic structure us responsible for the formation of the ascending aorta and the pulmonary trunk?
The aorticopulmonary septum forms in the truncus arteriosus and divides it into the ascending aorta and the pulmonary trunk. It normally forms in the center of the truncus arteriosus, this creating two equal-sized vessels.
Why does a child with tetralogy of Fallot squat when having a cyanotic episode?
It is believed that the squatting causes a kinking of the arterial supply to the lower limbs and thus increases the peripheral resistance of the systemic circulation. This increases to the left ventricular pressure, reducing the pressure gradient between the right and left ventricle and thereby reducing the shunting of deoxygenated blood into the systemic circulation.
What structures pass through the hilum of the lung?
All of the structures of the root of the lung ass through the hilum. These include the bronchus, the pulmonary artery, usually two pulmonary veins, the bronchial artery and vein, and the lymphatics of the lung. The pulmonary veins are the most inferior and most anterior structure passing through the hilum. The bronchus is the most posterior structure passing through the hilum. The position of the pulmonary artery is slightly different on the right and left side.
What is the pathway of lymphatic drainage from the lung?
All lymphatic drainage in the lung is toward the hilum.
Pulmonary lymph nodes (Lung) –> bronchopulmonary lymph nodes (hilum) –> tracheobronchial lymph nodes (at the bifurcation of the trachea) –> paratracheal lymph node –> bronchomediastinal lymph trunk.
What are the portions of the parietal pleura?
The portions of parietal pleura are given names according to their location. The costal pleura is attached to the ribs of the chest wall. The diaphragmatic pleura is attached to the upper surface of the diaphragm. The mediastinal pleura is attached to the lateral surface of the mediastinum. The cervical pleura is the parietal pleura that ascends above the first rib and is in the neck.
Where does the parietal pleura become continuous with the visceral pleura?
The visceral pleura is fused to the surface of the lung. The parietal pleura is continuous with the visceral pleura at the hilum of the lung. This pleural reflection surrounds the structures of the root of the lung: the bronchus, the pulmonary artery, the pulmonary veins, the bronchial arteries and veins, and the lymphatics and nerves of the lung.
Why does the lung collapse when there is a pneumothorax?
Normally, there is a negative pressure in the pleural cavity (ie. Less that atmospheric pressure). The pressure inside the lung is atmospheric. This pressure gradient keeps the lung expanded against the elastic recoil of the lung. With a pneumothorax, air enters the pleural cavity and raises the pressure in the cavity. This disrupts the pressure gradient that resists the elastic recoil of the lung, allowing the lung to collapse
How does a tension pneumothorax compromise the circulatory system?
In a tension pneumothorax, the intracranial pressure rises above atmospheric pressure. This results in a pressure gradient between the two pleural cavities that pushes against the mediastinum and displaces it away from the side with the pneumothorax. This causes a kinking of the vena cava, resulting in a reduction in venous return. Additionally, the compression of the heart reduces diastolic filling of the ventricles, causing a decrease in cardiac output.
What is the anatomical pathway for pain from the heart?
The sensory nerve fibers that convey the sensation of pain from the heart travel with the sympathetic nerves that innervate the heart. They travel in the cardiac nerves to reach the sympathetic chain, then pass through the sympathetic ganglia and white rami communicants to reach the upper thoracic spinal nerves. They continue through the dorsal roots of these spinal nerves and have their cell bodies in the dorsal root ganglia.
To which dermatomes is cardiac pain referred?
Pain arising from the heart is referred to the dermatomes that correspond to the spinal nerve levels through which the sensory fibers from the heart reach the spinal cord. These are the upper thoracic spinal nerves. The corresponding dermatomes are found in the upper chest and the medial side of the arm.
What sensory functions are served by the sensory nerve fibers from the heart that travel in the vagus nerve?
The sensory fibers from the heart that are in the vagus nerve carry the sensory information necessary for the control of cardiac reflexes. This sensory information reaches the brain stem but does not ascend to conscious levels.
