Chapter 2: Thorax Flashcards
The breast is considered what type of modified gland?
modified sweat gland
What is the orange peel appearance of the breast caused by when a tumor is present?
peau’ de orange is caused by Cooper ligaments being stretched while lymphatics accumulate edema
Cooper ligaments?
suspensory ligaments that attach mammary gland to the skin and run from the skin to the deep fascia
What are the 2 prominent blood supplies to the mammary tissues?
- internal thoracic artery
- lateral thoracic artery
What part of the mammary gland does the internal thoracic artery supply?
medial aspect of the gland
What artery does the internal thoracic artery branch from?
subclavian artery
What artery is the lateral thoracic artery a branch of?
the axillary artery
Which part of the mammary gland does the lateral thoracic artery supply?
Bonus points if you can name another part of the body supplied by arter
contributes to the blood supply to the lateral part of the gland and lateral aspect of the chest wall
Which nerve does the lateral thoracic artery course with?
courses with the long thoracic nerve
The long thoracic nerves is superficial to what muscle?
the serratus anterior muscle
What is a symptom of a lesion where the long thoracic n is?
winged scapula and weakness of abduction of the arm above 90 degrees
During a mastectomy, which nerve supplying the latissimus dorsi muscle may be damaged?
thoracodorsal nerve
Damage to the thoraccodorsal nerve because of a mastectomy may lead to what symptoms?
weakness in extension and medial rotation of the arm
What are the 2 routes of lymphatic drainage of the breast?
laterally and medially
Describe lateral lymphatic flow of the breast?
drains from the nipple and the superior, lateral, and inferior quadrants of the breast to the axillary nodes initially to the pectoral group
Describe medial lymphatic flow of the breast.
drains to the parasternal nodes which accompany the internal thoracic vessels
Respiratory epithelium develops from what germ layer?
endoderm
Muscles, connective tissues and cartilages of the lower respiratory system develop from what germ layer?
mesoderm
During embyrological development the respiratory diverticulum enlarges distally to form what?
lung buds
What time in embyrological development concides with completion of formation of the bronchial tree? (main, secondary, and tertiary bronchi)
by month 6
What week of development does the lower respiratory system begin to develop? What are the parts of the respiratory system that begin to develop? and how do they begin to form ?
- week 4
- trachea, bronchi, and lungs
- they begin to form as a single respiratory laryngotracheal diverticulum of endoderm from the ventral wall of the foregut
What is the function of the tracheoesophageal septum?
to separate the esophagus from the trachea
What is the critical time in lung development? Why is this an important time in lung development?
25 -28 weeks
the Type I and II pneumocytes are present and gas exchange and surfactant production are possible
What is a tracheoesophageal fistula?
abnormal communication between trachea and esophagus caused by malformation of tracheoesophageal septum
What are some symptoms of tracheoesophageal fistula? (List 3)
esophageal atresia and polyhydramnios (increased volume of amniotic fluid)
regurgitation of milk
gagging and cyanosis after feeding
abdominal distention after crying
reflux of gastric content into lungs causing pneumonitis
Where is the tracheoesophageal fistula usually located?
between the esophagus and the distal third of the trachea
What is pulmonary hypoplasia?
a condition that occurs when lung development is stunted
What are 2 congenital causes of pulmonary hypoplasia?
congenital diaphragmatic hernia
bilateral renal agenesis
What is congenital diaphragmatic hernia?
a herniation of abdominal contents into the thorax which affects development of the left lung
What is bilateral renal agenesis? Moreso what does it cause?
“agenesis” absence or failure of development of both kidneys
this causes oligohydramnios which increases pressure on fetal thorax and Potter’s sequence (one feature of Potter’s sequence is bilateral pulmonary hypoplasia)
What are the characteristics of POTTERs sequence?
POTTER
Pulmonary hypoplasia
oligohydramnios
twisted facies
twisted skin
extremity defects
renal failure
Thoracic inlet
superior thoracic aperture
What is the thoracic inlet usually called?
thoracic outlet clinically
What is the thoracic cavity usually divided into?
- 2 lateral compartments (lungs and their covering serous membranes)
- central compartment the mediastinum
Why is passage of instruments through ICS done in the lower part of the space?
to avoid intercostal neurovascular structures (e.g during thoracocentesis)
What part of the ICS is an intercostal nerve block administered?
upper part
What are the 3 serous mesodermal derived membranes found in the thoracic and abdominal cavities?
lungs (pleura)
heart (pericardium)
abdominal viscera (peritoneum)
Where is costal parietal pleura found?
is lateral and lines the inner surfaces of the ribs and ICS
Where is diaphragmatic parietal pleura found?
lines the thoracic surface of the diaphragm
Label the image.
Refer to image.
Label image.
What is RDS caused by?
caused by deficiency of surfactant type II pneumocytes
What individuals are more likely to have RDS?
associated with premature infants, infants of diabetic mothers, and prolonged intrauterine asphyxia.
What treatments increase the production of surfactant?
thyroxine and cortisol
Surfactant deficiency may lead to what condition?
hyaline membrane disease
What is hyaline membrane disease characterized by histologically?
collapsed alveoli (atelactasis) and eosinophilic (pink) fluid covering the alveoli
In hyaline membrane disease, repeated gasping inhalations damage what structure/s?
alveolar lining
Where is mediastinal parietal pleura found?
is medial and lines the mediastinum.
Where is cervical parietal pleura found?
extends into the neck above the first rib where it covers the apex of the lungs
Where does the mediastinal pleura reflect and become continuous with the visceral pleura?
at the hilum
What is pleurisy?
inflammation of the parietal pleural layers
Where is costal inflammation pain felt?
local dermatome pain of the chest wall via intercostal nerves
Where is mediastinal pain felt?
produces referred pain via the phrenic nerve to the shoulder dermatomes of C3-C5
Which nerves supply the costal and peripheral portions of the diaphragmatic pleura?
intercostal nerves
Which nerve supplies the central portion of the diaphragmatic pleura and the mediastinal pleura?
phrenic nerve
The visceral pleura is supplied by what nerves?
visceral sensory nerves that course with the autonomic nerves
What is pneumothorax? What are symptoms?
introduction of air into the pleural cavity causing lung to collapse causing shortness of breath and painful respiration
Why does the lung collapse in pneumothorax?
due to loss of the negative pressure of the pleural cavity during a pneumothorax
When will open pneumothorax occur?
Occurs when air enters the pleural cavity following a penetrating wound of the chest cavity. Air moves freely through the wound during inspiration and expiration.
Describe the where the mediastinum moves during an open pneumothorax.
air enters chest wall and the mediastinum will shift toward the other side and compress the opposite lung
during expiration air exits the wound and the mediastinum moves back toward the affected side
When does tension pneumothorax occur?
when a piece of tissue covers and forms a flap over the wound
Describe the movement of the mediastinum with a tension pneumothorax.
During inspiration, air enters chest cavity which result in shift of mediastinum toward other side compressing opposite lung
During expiration, piece of tissue prevents air from escaping the wound, which increases the pressure and the shift toward the opposite side is enhanced, This severely reduces opposite lung function and venous return to the heart and can be life threatening
