THORAX CLINICAL CASES

Question 1

role of costal cartilages

Answer 1

-prolong the ribs anteriorly and contribute to elasticity of the thoracic wall
-prevents many blows from fracturing the sternum and/or ribs
-in elderly people, costal cartilage undergo calcification making them radiopaque and less resilient

Question 2

rib fractures

Answer 2

-weakest part of rib is just anterior to its angle
-rib fracture commonly result from direct blows or indirectly from crushing injuries
-middle ribs are most commonly fractured
-direct violence may fracture rib anywhere
-broken ends may injury internal organs such as lung or spleen
-segmental

Question 3

flail chest

Answer 3

-occurs when a sizable segment of the anterior and/or lateral thoracic wall moves freely bc of multiple rib fractures
-condition allows loose segment of the wall to move paradoxically (inward on inspiration and outward on expiration)
-extremely painful
-impairs ventilation-> affecting oxygenation of blood
-during treatment the loose segment may be internally fixed with plates or wires to prevent movement
-greater pulmonary contusion with flail compared to segmental

Question 4

supernumerary ribs

Answer 4

-12 ribs on each side but the number may be increased by the presence of cervical and/or lumbar ribs or decreased by failure of 12th pair to form
-cervical ribs- articulate with C7 and are clinically significant bc they may compress spinal nerves C8-T1 or the inferior trunk of the brachial plexus suppling the upper limb
-tingling and numbness may occur along medial border of forearm
-may also compress subclavian artery resulting in ischemic muscle pain in the upper limb
-resection may be required to relieve pressure -> performed through transaxillary approach (incisions in axillary fossa/armpit
-lumbar ribs- less common than cervical ribs but have clinical significance bc you may confuse identification of vertebral levels in images

Question 5

thoracotomy, intercostal space incisions, and rib excision

Answer 5

-surgical creation of an opening through the thoracic wall to enter a pleural cavity -> thoracotomy
-anterior thoracotomy- may involve making H shaped cuts through perichondrium of one or more costal cartilages (4th and 5th) and then shelling out segments of costal cartilage to gain entrance to the thoracic cavity
-posterior thoracotomy- posterolateral aspects of 5th-7th intercostal spaces are important sites for incisions
-*lateral approach is most satisfactory for entry through thoracic cage with pt lying on contralateral side -> upper limb fully abducted, placing the forearm beside the pts head -> elevated and laterally rotates the inferior angle of scapular, allowing access as high as the 4th intercostal space

Question 6

single intercostal space thoracotomy

Answer 6

-inferior upper rib- VAN (vein, artery, nerve)
-superior lower rib- NAV
-rib retraction allows for single intercostal space
-care to avoid the superior neurovascular bundle
-if wider exposure is required -> surgeons use H shaped incisions to incise the superficial aspect of the periosteum that surrounds the rib, strip the periosteum from the rib, and then remove a wide segment to gain better example
-in ribs absence -> entry made through deep aspect of the periosteal sheath sparing the adjacent intercostal muscle
-after surgery missing pieces of ribs regenerate from the intact periosteum imperfectly
-intrathoracic surgery can be performed using minimally invasive endoscopic approach

Question 7

sternal biopsies

Answer 7

-used for bone marrow needle biopsy
-bc of its breadth and subcutaneous position
-needle first pierces the thin cortical bone and then enters the vascular trabecular (spongy) bone
-commonly used to obtain specimens of bone marrow for transplantation and detection of metastatic cancer

Question 8

surgical entry into thorax

Answer 8

-gain wide access to thoracic cavity for sugical procedures in mediastinum -> sternum divided in the median plane (median sternotomy) and retracted
-after surgery -> halves of sternum are reunited and held together with wire suture
-lateral thoracotomy through intercostal spaces provides wide access to the pulmonary cavities
-minimally invasive thoracic surgery (thoracoscopy) allows access to the thorax through small intercostal incision for many intrathoracic procedures

Question 9

thoracic outlet syndrome

Answer 9

-clinicians refer to the superior thoracic aperture as the thoracic outlet -> they are emphasizing the important nerves and arteries that pass through this aperture into the lower neck and upper limb
-various types of thoracic outlet syndromes exist ->
-costocalvicular syndrome- pallor and coldness of skin of the upper limb and diminished radial pulse resulting from compression of subclavian artery between the clavicle and 1st rib (particularly when angle between the neck and shoulder is increased)

Question 10

clavicle fracture

Answer 10

-treatment is sling
-arm weighs down fracture

Answer 11

-requires a tremendous amount of force
-force can be transmitted to vascular structures
-CAT scan with IV contrast (when appropriate)

Answer 12

T10 dermatome- abdominal pain

Question 13

subclavian steal

Answer 13

-if there is stenosis subclavian artery it steals blood from vertebral artery on ipsilateral side
-vertebral artery supplies the brain -> if it is not supplying the brain -> faint

Question 14

dislocation of ribs

Answer 14

-slipping rib syndrome
-dislocation of sternocostal joint
-displacement of a costal cartilage from sternum
-causes severe pain particularly during deep respiration
-injury produces lump like deformity at the dislocation site
-common in body contact sports
-possible complications are pressure on or damage to nearby nerves, vessels, and muscles
-rib separation refers to dislocation of costochondral junction- between rib and its costal cartilage
-separations of 3rd-10th ribs -> tearing of perichondrium and periosteum usually occurs -> rib may move superiorly, overriding the rib above and causing pain

Question 15

paralysis of diaphragm

Answer 15

-detected radiographically by noting its paradoxical movement
-you can auscultate the diaphragm excursion
-paralysis of half the diaphragm bc injury to its motor supply from the phrenic nerve does not affect the other half bc the domes are separately supply by right and left phrenic nerves
-instead of descending on spiration -> paralyzed dome is pushed superiorly by abdominal viscera that are being compressed by active side
-paralyzed dome descends during expiration as it is pushed down by positive pressure in the lungs

Question 16

sternal fractures

Answer 16

-not common
-crush injuries can occur during traumatic compression of thoracic wall
-concern in sternal injuries is not primarily for the fractures -> heart and/or lung injury
-myocardial contusion, cardiac rupture, tamponade

Question 17

breast quadrants

Answer 17

-divided into 4 quadrants
-axillary process- extension of mammary gland of superolateral quadrant

Question 18

change in breasts

Answer 18

-changes like branching of lactiferous ducts occurs throughout menstrual cycle during pregnancy
-mammary glans are prepared for secretion by midpregnancy -> they dont produce milk until shortly after baby is born
-colostrum- creamy white to yellowish premilk fluid- may be secreted during last trimester and during initial episode of nursing
-colostrum believed to be especially rich in protein, immune agents, and growth factor affecting infants intestines
-multiparous women (who have given birth two or more times)- breast often increase in size and pendulous
-breast in elderly usually small bc of decrease in fat and atrophy of glandular tissue

Question 19

supernumerary breasts and nipples

Answer 19

-supernumerary (exceeding 2) breasts (polymastia) or nipples (polythelia) - may occur superior or inferior to normal breasts
-consist of only a rudimentary nipple and areola
-may appear along a line extending from the axilla to the groin, the location of embryonic mammary crest (ridge)

Question 20

carcinoma of breast

Answer 20

-understanding lymphatic drainage -> predicting metastasis of cancer
-breast cancer takes a long time to develop -> screening
-usually adenocarcinomas arising from epithelial cells of lactiferous ducts in mammary gland lobules
-metastatic cancer cells enter lymphatic vessel and pass through 2 or 3 groups of lymph nodes before entering venous system
-breast cancer can spread via lymphatics and veins AND direct invasion
-interference with dermal lymphatics by cancer may cause lymphedema -> deviation of nipple and thickened leather like appearance of skin
-prominent/puffy skin between dimpled pores gives it an orange peel appearance -
-larger dimples result from cancerous invasion of the glandular tissue and fibrosis -> causes shortening or places traction on the suspensory ligaments
-subareolar breast cancer- may cause inversion of nipple involving lactiferous ducts

Question 21

spread of breast cancer

Answer 21

-spread by means of lymphatic vessels (lymphogenic metastasis)
-carry cancer cells from breast to lymph nodes -> usually axilla
-cells lodge in nodes -> nest of tumor cells (metastases)
-communication between axillary, cervical, parasternal nodes -> may cause to spread to supraclavicular lymph nodes, opposite breast, or abdomen
-axillary most common site
-absence of enlargement of axillary nodes does not mean metastasis from breast cancer has not occurred-> may have passed to other nodes such as infra and supra clavicular or directly into circulation
-removal of axillary nodes or damage via radiation/chemo -> lymphedema in ipsilateral upper limb
-posterior intercostal veins drain into azygos/hemiazygos system of veins along bodies of vertebrae and communicate with internal vertebral venous plexus surrounding spinal cord
-cancer cells spread via venous routes to vertebrae -> spinal cord -> brain
-when cancer invades retromammary space -> attach to or invade pectoral fascia overlying -> interpectoral nodes -> advanced cancer of breast
-can spread medially to substernal and paraspinal nodes

Question 22

visualizing breast structure and pathology

Answer 22

-mammography is radiographic study of breast, flattened to extend the area that can be examined and reduce thickness -> more uniform and increased visualizations
-primarily for screening for problems before evident
-carcinomas appear as large jagged density
-ultrasound is used for formation palpated but not clearly observed on mammo to gain more info about areas of interest or changes detected compared to previous images -> Especially dense breast tissue
-ultrasound is noninvasive way to distinguish fluid filled cysts or abscesses form solid masses
-u/s can be used for biopsy needle or enable fluid aspiration
-MRI with dedicated breast soils- further examine problems detected by mammo or u/s -> rules out false positive and to plan treatment

Question 23

surgical incisions of breast and surgical removal of breast pathology

Answer 23

-incisions are in inferior breast quadrants bc its less vascular than superior
-transition between the thoracic wall and breast is most abrupt inferiorly -> line/crease/skin fold -> inferior cutaneous crease -> hides incision!
-incisions that must be made near areola are usually directed radially to either side of nipple (langer tension lines run traversely here) or circumferentially
-mastectomy- not as common of a treatment
-simple mastectomy- breast removed from retromammary space, nipple and areola may be spared and immediate reconstruction performed in some cases
-radical mastectomy- more extensive involves removing breast, pectoral, fat, fascia, and as many lymph nodes as possible in axilla and pectoral region
-lumpectomy or quadrantectomy- (breast conserving surgery)- wide local excision followed by radiation

Question 24

breast cancer in men

Answer 24

-metastasizes not only to axillary lymph nodes but also bone, pleura, lung, liver, skin (like women)
-visible and/or palpable subareola mass or secretion from nipple may indicate malignant tumor
-tend to infiltrate pectoral fascia, pectorallis major, and apical lymph nodes in axilla
-consequences are serious bc they frequently are not detected until extensive metastases have formed

Question 25

herpes zoster infection

Answer 25

-shingles
-viral disease of spinal ganglia
-skin lesion with dermatomal distribution
-invades spinal ganglion and is transported along axon to skin -> produces infection that causes sharp burning pain in deramtome supplied by the nerve
-few days later skin of the dermatome becomes red and vesicular eruptions appear
-vaccination recommended adults starting at age 50

Question 26

dyspnea

Answer 26

-difficulty breathing
-when people with problems like asthma or heart failure struggle to breathe they use accessory respiration muscles to assist expansion of thoracic cavities
-recruitment of neck muscles (sternocleidomastoid, pecs, upper trapezius, scalene muscles) is visible and particularly striking
-may also lean on table or thighs to fix pectoral girdles (clavicles and scapulae) so muscles are bale to act on their rib attachments and expand thorax

Question 27

intercostal nerve block

Answer 27

-local anesthesia by injecting local anesthetic agent around intercostal nerves -> numbs intercostal space
-used in pts with rib fracture and sometimes after thoracic surgery
-involves infiltration of aesthetic around intercostal nerve and its collateral branches
-considerable overlap in innervation of contiguous dermatomes occurs
-anesthesia of any particular area of skin usually requires injection of two adjacent nerves
-ex. anesthesia for broken rib requires injection of anesthetic agent into region of intercostal nerves superior and inferior to rib, proximal to site of fracture

Question 28

pulmonary collapse

Answer 28

-if a sufficient amount of air enters pleural cavity -> surface tension adhering visceral to parietal pleura (lung to thoracic wall) is broke -> lung collapses because of its inherent elasticity (elastic recoil)
-when a lung collapse (atelectasis*) -> pleural cavity (normally potential space) becomes real space
-reduction in size will be evident radiographically on affected side by elevation on the diaphragm above its usual levels, intercostal space narrowing (ribs closer together), and displacement of mediastinum (most evident via the air filled trachea within it) toward the affected side
-collapsed lung will usually appear denser (whiter) and will be surrounded by more radiolucent (blacker) air
-one lung may be collapsed after surgery without collapsing the other bc the pleural sacs are separate

Question 29

pneumothorax, hydrothorax, hemothorax, and chylothorax

Answer 29

-entry of air into pleural cavity
-pneumothorax - resulting from penetrating wound of parietal pleura, tearing of parietal pleura from fractured rib, or rupture of lung from bullet > results in partial collapse of lung
-may occur as result of leakage from lung through opening in visceral pleura
-hydrothorax- accumulation of significant amount of fluid in pleural cavity may result from pleural effusion (escape of fluid into pleural cavity)
-hemothorax- chest wound blood may also enter pleural cavity results more often from injury to major intercostal vessel from laceration of lung
-chylothorax- lymph from a torn thoracic duct may also enter pleural cavity
-chyle is pale white or yellow lymph fluid in thoracic duct containing fat absorbed by the intestines

Question 30

pleuritis

Answer 30

-during inspiration and expiration smooth pleurae make no sound detectable by auscultation
-inflammation of pleurae makes lung surfaces rough -> friction (pleural rub) may be heard with stethoscope
-acute pleuritis is marked by sharp, stabbing pain, especially on exertion, when the rate and depth of respiration may be increased even slightly

Question 31

thoracentesis

Answer 31

-sometimes necessary to insert hypodermic needle through intracostal space into pleural cavity to obtain sample of pleural fluid or remove blood or pus
-to avoid damage to intercostal nerve and vessels -> needle is inserted superior to rib high enough to avoid the collateral branches
-9-10th ribs
-posteriorly

Question 32

aspiration of foreign bodies

Answer 32

-right bronchus is wider and shorter and runs more vertically than the left bronchus -> aspirated foreign bodies are more likely to enter and lodge in it or one of its branches
-potential hazard encountered by dentist is aspirated foreign body, such as a piece of tooth or filling material
-such objects are also most likely to enter right main bronchus

Question 33

lung resections

Answer 33

-knowledge of bronchopulmonary segments is essential for precise interpretations of dx images of lungs and surgical resection (removal) of diseased segments
-when resecting bronchopulmonary segment -> surgeons follow interlobar veins to pass between segments
-bronchial and pulmonary disorders like tumors or abscesses often localize in bronchopulmonary segment -> may be surgically resected
-treatment for lung cancer -> may be removal of whole lung (pneumonectomy), a lob (lobectomy), or one or more bronchopulmonary segments (segmentectomy)
-knowledge required for planning drainage and clearance techniques used in PT for enhancing drainage from specific areas (pts with pneumonia or cystic fibrosis)

Question 34

thoracoscopy

Answer 34

-diagnostic and sometimes therapeutic procedure in which the pleural cavity is examined with thoracoscope
-small incisions made into pleural cavity via an intercostal space
-biopsies can be taken and some thoracic conditions can be treated (disrupting pleural adhesions or removing pleural plaques, fibrous or calcified thickenings of pleura)

Question 35

pulmonary embolism

Answer 35

-obstruction of pulmonary artery by a blood clot
-common cause of morbidity and mortality
-embolus in pulmonary artey forms when blood clot, fat, globule, or air bubble travels in blood to the lungs from a leg vein
-passes through right side of heart to lung through pulmonary artery
-may block pulmonary artery or one of its branches
-immediate result is partial or complete obstruction of blood flow to lungs
-obstruction results in sector of lungs that is ventilated but not perfused with blood
-when large embolus occludes a pulmonary artery, blood flow through the lung is blocked and blood oxygenation significantly decreases, which may lead to acute respiratory distress
-medium sized -> may block artery supplying bronchopulmonary segment, producing pulmonary infarct -> area of necrotic lung tissue

Question 36

inhalation of carbon particles

Answer 36

-lymph from lungs carries phagocytes -> cells possessing the property of ingesting carbon particles from inspired air
-many people (especially cigarette smokers) particles color the surface of lungs and associated lymph nodes a mottled gray to block
-smokers cough results from inhalation of irritants in tobacco

Question 37

bronchogenic carcinoma

Answer 37

-a common type of lung cancer that arises from epithelium of bronchial tree
-lung cancer is mainly caused by cigarette smoking
-usually metastasizes widely because of arrangement of the lymphatics
-tumor cells probably enter systemic circulation by invading the wall of sinusoid or venule in the lung and are transported through the pulmonary veins, left heart, and aorta to all parts of the body, especially the cranium and brain

Question 38

bronchoscopy

Answer 38

-when examining bronchi with a bronchoscope (an endoscope for inspecting the interior of tracheobronchial tree for diagnostic purposes) you can observe a ridge, the carina, between the orifices of the main bronchi
-carina is a cartilaginous projection of the last tracheal ring
-if tracheobronchial lymph nodes in the angle between the main bronchi are enlarged because cancer cells have metastasized from bronchogenic carcinoma -> the carina is distorted, widened posteriorly, and immobile

Question 39

surgical significance of transverse pericardial sinus

Answer 39

-transverse pericardial sinus is important to cardiac surgeons
-after pericardial sac has been opened anteriorly -> finger can be passed thorough transverse pericardial sinus posterior to the aorta and pulmonary trunk
-by passing surgical clamp or placing ligature around these vessels -> inserting the tubes of a bypass machine and tightening the ligature, surgeons can stop or divert circulation of blood in large arteries while performing surgery like coronary artery bypass grafting
-cardiac surgery is performed while pt is on cardiopulmonary bypass machine

Question 40

pericarditis and pericardial effusion

Answer 40

-chest pain
-layers of serious pericardium mak eno detectable sound during auscultation
-percarditis makes surfaces rough and result in friction (percardial friction rub) -> sounds like rustle of silk when listening with stethoscope
-chronically inflamed and thickened pericardium may calcify -> seriously affects cardiac efficiency
-certain inflammatory diseases may produce pericardial effusion (passage of fluid from pericardial capillaries into pericardial cavity or accumulation of pus) -> heart becomes compressed (unable to expand and fill fully -> cardiac tamponade) and is ineffectual

Question 41

cardiac tamponade

Answer 41

-heart compression
-potentially lethal
-fibrous pericardium is tough and inelastic
-heart volume is increasingly compromised by fluids outside heart but inside the pericardial cavity
-when the heart slowly increases in size -> pericardium gradually enlarges -> allows enlargement of heart to occur without compression
-stab wounds through the heart cause blood to suddenly enter pericardial cavity (hemopericardium) -> cardiac tamponade
-hemopericardium also results from perforation of weakened area of heart muscle after heart attack
-blood accumulates -> compresses -> circulation fails
-high pressure involved and rapidity at which fluid accumulates -> lethal
-veins of face and neck become engorged bc backup of blood beginning where SVC enters pericardium
-drainage of fluid from pericardial cavity -> percardiocentesis -> necessary to relieve cardiac tamponade
-to remove fluid large bore needle may be inserted through left subcostal angle or 5th 6th intercostal space near sternum
-approach to the sac is possible bc the cardiac notch in the left lung is shallower notch in left pleural sac leave part of pericardial sac exposed
-can also be reached via xiphocostal angle by passing needle superoposteriorly

Question 42

levels of viscera in mediastinum

Answer 42

-level of viscera relative to mediastinal subdivisions depends on position of person
-anatomical description traditionally describe level of viscera as if person was supine
-supine-> viscera are positioned higher (more superior) relative to subdivisions of mediastinum compared to upright
-occurs because soft structures in mediastinum (heart, great vessels, abdominal viscera) supporting them sag inferiorly under the influence of gravity when vertical
-most be considered during physical and radiologic procedures

Question 43

VAT

Answer 43

-video assisted thoracotomy
-small incisions