Clinical Anatomy of the Thorax PDF

Clinical Anatomy of the Thorax Application of anatomical knowledge to clinical reality Thoracic respiratory system Lungs, Bronchi, Trachea and Pleura  Penetrating traumatisms in the neck The severity of neck trauma can be determined depending on the zone:  Zone I: from the clavicles-...

Clinical Anatomy of the Thorax Application of anatomical knowledge to clinical reality Thoracic respiratory system Lungs, Bronchi, Trachea and Pleura  Penetrating traumatisms in the neck The severity of neck trauma can be determined depending on the zone:  Zone I: from the clavicles- manubrium to the cricoid cartilage. It contains the root of the neck:  Cervical pleurae  Apices of lungs  Thyroid gland  Parathyroid glands  Trachea  Esophagus  Common carotid arteries  Jugular veins  Cervical vertebral column  Penetrating traumatisms in the neck  Zone II: from the cricoid cartilage to the angle of mandible  Superior part of thyroid gland  Thyroid cartilage  Cricoid cartilages  Larynx  Laryngopharynx  Carotid arteries  Jugular veins  Esophagus  Cervical vertebral column  Zone III: superior to the angle of mandible:  Salivary glands  Oral and nasal cavities  Oropharynx  Nasopharynx  Penetrating traumatisms in the neck Injuries in zones I & III:  They obstruct the airway  Highest risk of mortality and morbidity  The surgery at these levels have many complications  The structures injured are hard to watch and repair  The vascular damage is hard to control Injuries in zone II:  More common  Mortality and morbidity are less important because with direct pressure you can control the hemorrhages  It is also easy to identify the damaged structure and repair it  Radical dissections of the neck  The deep cervical nodes are involved in the spread of abdominal and thoracic cancer  So they are normally the cervical sentinel nodes  In the radical dissection the objective is to remove all the deep cervical nodes and the surrounding structures in a whole, as completely as possible  Preserved:  Vagus and Phrenic nerves  Brachial plexus  Major arteries  Not preserved:  Cutaneous branches of cervical plexus  Deep cervical nodes  Pleural pain  Visceral pleura: insensitive to pain due to its lack of sensory nerves  Parietal pleura: very sensitive to pain due to its innervation:  Intercostal nerves  Phrenic nerves  Main referred pain areas:  Pain from costal and peripheral part of diaphragmatic pleura: referred to the thoracic and abdominal wall  Pain from mediastinal and central part of diaphragmatic pleura: referred to the root of neck and shoulder  Injuries of pleura  Remember that the cervical pleura and apex of the lung extends to the neck, so they can be injured in cervical wounds causing a pneumothorax  In children, is more severe because the apex is in a higher level than adults  Remember that also the abdominal incisions can enter in the pleural cavity, specially in three areas in which the pleura is below the costal margin:  Right infrasternal angle  Both last costovertebral angles: very common in surgery of kidney Injuries of pleura Check in yellow the infrasternal and costovertebral angles  Pulmonary collapse  Think about the lungs as inflated balloons: if the Visceral pleura distension is not maintained, their elasticity will make them collapse  Atelectasis: can be primary or secondary  Primary: the lung does not inflate at birth  Secondary: collapse of a previously inflated lung  The pleural cavities have a negative pressure -2/-8 mmHg  Normal lungs remain distended even when the trachea or bronchi are open because the visceral pleura adhere to the parietal pleura of the surface of the thoracic walls thanks to the surface tension provided by the pleural fluid Parietal pleura  Pulmonary collapse The man of the picture has received a shot in the thorax, and the bullet has pierced by order:  Thoracic wall  Endothoracic fascia  Parietal pleura  Pleural cavity  Visceral pleura  Lung  Pulmonary collapse  If a penetrating wound opens the thoracic wall, air will be sucked into the pleural cavity due to the negative pressure  The surface tension of the pleura will be broken, transforming the potential interpleural space into real space  Lung will collapse expelling most of its air because of its inherent elasticity  As both pleural cavities are not communicated, the collapse of one lung may no affect the other one  In open-chest surgery, lung inflation must be maintained by intubating the trachea and using a positive-pressure pump  Pulmonary collapse Radiological signs:  Elevation of the diaphragm above its usual levels  Intercostal space narrowing  Displacement of the mediastinum toward the affected side  Lung whiter and surrounded by a black halo  Segmental atelectasis  If a segmental bronchus is blocked by an obstruction, its segment will not receive air  This means that when the air of this segment it is absorbed by the blood, it will collapse  This segment acts like a dead space  The adjacent segments will expand to compensate the reduced volume of this collapsed segment In this case we have a long- course atelectasis because of a tumor Pneumothorax and hydrothorax  Pneumothorax: entry of air into the pleural cavity, which results in collapse of the lung. Many causes:  Penetrating wound  Fractured ribs  Rupture of a pulmonary lesion, such a fistula, into the pleural cavity  Hydrothorax: liquid in pleural cavity, normally produced by a pleural effusion  If the liquid is blood, we have an hemothorax, normally caused by the injury of an intercostal or internal thoracic vessel Hemothorax  Inhalation of carbon particles  Normal color of the lungs: light pink  Smokers and people that live in urban and industrial places normally have dark and mottled lungs due to the accumulation of carbon, dust and irritants  Don’t panic: lungs can accumulate a lot of carbon particles without being adversely affected thanks to the phagocytes of the lymph  Phagocytes remove carbon from the alveoli and deposit it in the connective tissue or in the lung lymph nodes  Pulmonary embolism Pulmonary embolism: Obstruction of a pulmonary artery by:  Blood clot  Fat globule  Air bubble  They travel through the blood, cross the right side of the heart and achieve the lung by the pulmonary arteries until they occlude one of its branches  Result: block of the blood flow at this area of the lung, causing decrease in the oxygenation of blood, acute respiratory distress, and overload of the right heart  Pulmonary embolism  The heart’s overload cause dilatation because it can’t pump all the incoming blood through the blocked pulmonary circuit, causing cor pulmonale  The embolus may also produce a pulmonary infarct, but normally we have collateral circulation with branches from the bronchial arteries  Pulmonary infarct is more often in sedentary people or patients with chronic congestion  The area of pleura deprived of blood may inflame causing pleuritis, very painful. The pain is referred to the thoracic or abdominal walls  Hemoptysis Hemoptysis: Blood when coughing, or blood in the sputum  Due to bronchial or pulmonary haemorrhage  95% of cases the origin is the bleeding of bronchial arteries or their branches  Causes:  Tuberculosis  Bronchitis  Lung cancer  Pneumonia  Bronchiectasis  Pulmonary embolism  Lung carcinoma  Main cause: smoking  The cancer arise in the mucosa of the bronchi and produce a persistent cough and hemoptysis  Radiologically you can see a lung mass that become larger along the time  Lung carcinoma  Metastasis arise first the bronchopulmonary lymph nodes and later to other thoracic nodes  Hematogenous spread can happen to brain, bones, lungs, and suprarenal glands, when the tumor cells invade the wall of a venule Nose & Larynx Superior airway  Nasal fractures  Fractures of the nasal bones are common in automobile accidents and contact sports, specially in those that face guards or helmets are not worn  Results:  Deformation of the nose, that may be more important if the impact has a lateral direction  Epistaxis  Displacement of the nose  Fracture of the ethmoid bone  Deviation of nasal septum  The nasal septum may deviate to one side due to a birth injury or for a trauma during adolescence or adulthood  Consequences:  Nasal septum is in contact with the lateral wall of the nasal cavity  Obstruction of the breathing  Exacerbation of snoring  The deviation can be corrected surgically  Rhinitis  The nasal mucosa becomes swollen and inflamed during infections or allergic reactions  Swelling of the mucosa occurs easily because of its vascularity  Infections may spread to:  Anterior cranial fossa through the cribriform plate  Nasopharynx  Middle ear through the Eustaquian tube  Paranasal sinuses  Lacrimal apparatus and conjunctiva  Epistaxis Epistaxis: bleeding from the nose  Very frequent due to the rich blood supply of the nasal mucosa  Most common origin of bleeding: Kiesselbach area, located in the septum  Causes:  Traumatism  Infections  Hypertension  Nose picking  Inflammatory Epistaxis Treatment:  Normally it ends by itself, we can help tilting anteriorly the head pressing the nose wings  If bleeding persists we would need some procedures:  Anterior nasal pack  Posterior nasal pack  Surgical embolization Epistaxis Treatment:  Anterior nasal pack: inserting gauzes through the nose or self-inflating balloons  Posterior nasal pack: the gauzes are introduced through the mouth  Surgical embolization of the bleeding vessel  Sinusitis  Remember that the paranasal sinuses are continuous with the nasal cavities through the meatus  This means that the infection may spread from the nasal cavities to the sinus  The inflammation and swelling of the mucosa of the sinuses is very painful and the swelling may block one or more meatus  Transillumination of sinuses  Exploration produced in a dark room  You put a light on one side of the hard palate or against the cheek  The light passes through the maxillary sinus to the inferior part of the orbit, like in the drawing  This glow is decreased when we have edema or swelling Transillumination of sinuses In this picture, the transillumination is performed in the frontal sinus  Fractures of the laryngeal skeleton  Two typical mechanism of laryngeal fractures are:  Traumatism in sports  Compression by the seat belt during a car accident  In sports such as hockey or baseball you can see that the players wear on their helmets laryngeal protection  Consequences:  Submucous hemorrhage and edema  Respiratory obstruction  Hoarseness  Inability to speak  Valsalva Maneuver  The vestibular and vocal folds have an sphinteric function that is very important to keep the glotis closed during the Valsalva maneuver  In this maneuver, we have a forced expiratory effort against a closed airway  Cough  Sneeze  Dive  Weight lifting  Valsalva Maneuver  Stage of the deep inspiration, both folds are opened  At the forced expiration they adduct tightly  The anterolateral abdominal muscles then contract strongly to increase the intrathoracic and intraabdominal pressures  The diaphragm is relaxed, so the increased abdominopelvic pressure is passively transmited to the thoracic cavity  The high intrathoracic pressure avoids the venous return to the right atrium, so this maneuver is also used to study cardiovascular diseases  Valsalva Maneuver  Italian anatomist, he was specialized in the internal and middle ear  He put the name to the Eustaquian tube, and to the aortic sinuses  He described the valsalva maneuver in “De aure humana tractatus”, 1704  His teacher was Marcello Malpighi  Then he became anatomy teacher in Bologna, and taught to important students as Giovanni Battista Antonio María Valsalva Morgagni Imola 1666 – Bologna 1723  Heimlich Maneuver  There is an spam that tenses the vocal folds when a foreign object enters inside the laryngeal vestibule  This closes the rima glottidis for avoid the entry of air to the trachea. As a consequence:  The person cannot breath → asphyxia → Death in 5 minutes  The person cannot speak → important for diagnosis  If the person can cough, let it cough  Backs laps: with the patient bended  If persists, you can perform the Heimlich maneuver  Heimlich Maneuver The lungs still contain air, so a sudden compression on the abdomen can elevate the diaphragm and expel the air inside to the larynx:  Place yourself behind the patient, embracing him  Close the fist with the base of the palm as in the picture  Put it between the umbilicus and the xiphoid process of the sternum  Push inward and superiorly for elevate the diaphragm  Do it several times until the object is expelled  Heimlich Maneuver  In child and babies it is better to sit and hold the chest face down with one hand  With the other hand we make 5 quick backslaps  If the foreign body goes into the mouth, remove it with your fingers  Cancer of larynx  Very high incidence in smokers  Main sympthoms:  Dysphagia: difficulty in swallowing  Hoarseness (broken voice)  Otalgia: pain in the ear  Enlarged pretracheal or paratracheal lymph nodes  Cancer of larynx  In severe cases, may be indicated the laryngectomy  After laryngectomy, the patient may need vocal rehabilitation:  Electrolarynx  (listen one real example: https://www.youtube.com/watc h?v=riHLUOXt1Aw)  Tracheo-esophageal prosthesis  Esophageal speech regurgitating air  Age changes in Larynx  0-3 years: larynx grow steadily  3 to 12 years: larynx growth slightly, but it does not have differences between male and female  In pubertal females, the enlargement of the larynx is not very significant  In pubertal males, testosterone make the walls of the larynx strengthen and the cavity enlarges  The anteroposterior diameter of the rima glottidis doubles its measurement  The vocal folds lengthen  This produces a deep change in the voice of the males, almost one octave  Age changes in Larynx  However, the artificial administration of testosterone does not produce a lower voice in:  Eunuchs  Agonadal males  Men whose testicles have been surgically removed for a cancer  The thyroid, cricoid, and arytenoid cartilages often ossify as age advances and are frequently visible in radiographies  Peak Expiratory Flow Rate (PEFR)  It measures how much air can the patient blow out in a single breath  PEFR is not as accurate as spirometry, but is cheaper, easier to perform and more accessible  The patients can also use it by themselves at home: useful in asthmatic patients  First step is to connect a clean mouthpiece Peak Expiratory Flow Rate (PEFR)  Be sure that the marker is set to ZERO  Stand up or sit upright  Take a very deep breath and hold it  Place the mouthpiece in your mouth and seal it with your lips  Peak Expiratory Flow Rate (PEFR)  Breathe out as hard as you can  Observe and record the reading  Repeat the process 3-4 times and record the highest reading  Note down the reading in a diary to allow comparison with readings on other days. Thyroid and parathyroid  Sinus tract from piriform fossa  In some people there is a tract from the piriform fossa to the thyroid gland  This causes recurring thyroiditis  Its origin seems to be a remnant of the thyroglossal duct  For removing this tract, normally is needed a partial thryroidectomy because the piriform fossa lies deep to the superior pole of the gland  Aberrant thyroid glandular tissue It may be found anywhere on the path of the thyroglossal duct:  Root of the tongue: Lingual thyroid gland, next to foramen cecum  At the neck: inferior to the hyoid bone  Lateral to the thyroid cartilage on the thyrohyoid muscle  Pyramidal lobe of thyroid gland  It appears in about 50% of the people  It extends superiorly from the isthmus of the thyroid gland  The isthmus may be incomplete or absent like in the picture  Goiter Goiter: enlargement of the thyroid gland  Its main cause is the lack of iodine  It is very common in areas with a lack of iodine in the water  The enlargement can happen in all directions except superiorly, due to the attachments of sternothyroid and sternohyoid muscles  The enlarged gland may cause a compression in:  Trachea  Esophagus  Recurrent laryngeal nerve 51  Thyroidectomy Thyroidectomy: removal of part of the thyroid or the whole gland. The main indications are:  Malignant tumour  Hyperthyroidism: in this case the posterior part of each lobe can be preserved for avoid the damage to the recurrent laryngeal nerves. It is called near-total thyroidectomy  A bleeding after the surgery may be lethal because the blood collects within the fibrous capsule causing compression of the trachea  Inadvertent removal of parathyroid  Parathyroids are hard to find due to their variable position and number, which makes very common their unconscious removal during a surgery of the neck  For prevent it, many surgeons preserve the posterior part of the lobes of the thyroid  If you need to perform a complete thyroidectomy, it is mandatory to localize and isolate the parathyroid  Parathyroid glands can also be transplanted, not only in the neck, also in the arm  Consequences:  Tetany: the decrease of calcium causes muscle twitches and cramps  If you have tetany in the respiratory muscles it can cause the death  Injury of the phrenic nerve  Injury of a phrenic nerve results in paralysis of the corresponding half of the diaphragm  For the lung surgery, normally we need to block the phrenic for a short period of time  The anesthetic is injected around the nerve at the level of the middle portion of the anterior scalene muscle  Injury of the phrenic nerve  A surgical phrenic nerve injury or compression produces a longer period of paralysis  At the picture we can see a displacement of diaphragm as a result of phrenic nerve injury  Bibliography  Moore clinically oriented anatomy 7th edition, Moore, Dalley, Agur  Anatomía: estructura y morfología del cuerpo humano, 4ª Edición, Lippert  Gray’s anatomy 3rd edition, Richard L. Drake, A. Wayne Vogl, Adam W. M. Mitchell  OSCE (Objective Structured Clinical Examination) Skills e-courses