Thorax

bones of the thorax

bones of the thorax

-12 thoracic vertebrae -12 pairs of ribs -sternum

how many ribs are attached directly

7 pairs

how many ribs are attached indirectly

3 pairs

how many ribs are floating

2 pairs

classifications of ribs

typical and atypical

typical ribs are

ribs 3-9

Atypical ribs are

ribs 1,2, 10, 11 and 12

Most common rib fractures

Middle of ribs

cause of rib fractures

crushing injuries, or direct trauma

complications that arise from rib fractures

injury to lungs, spleen or diaphragm

Diaphragm

a dome-shaped, muscular partition separating the thorax from the abdomen

thoracic inlet

superior thoracic aperture

thoracic inlet boundary posteriorly

body of vertebra T1

thoracic inlet boundary medially

margin of rib 1 on each side

thoracic inlet boundary anteriorly

manubrium of sternum

thoracic outlet

inferior thoracic aperture

how does the diaphragm attach to the vertebrae posteriorly

by tendinous bands called crura

crura of the diaphragm

right crus and left crus

hiatus

a gap, opening, break

hiatus of diaphragm

-caval T8 -esophageal T10 -aortic T12

Caval hiatus of diaphragm

phrenic nerve Inferior vena cava

esophageal hiatus of diaphragm

esophagus vagus nerves

Aortic hiatus of diaphragm

aorta

why does paralysis of the diaphragm occur

due to injury to its nervous supply

site of injury that causes diaphragm paralysis

lesion of the phrenic nerve

causes of diaphragm paralysis

mechanical trauma such as ligation of nerve during surgery or compression due to tumour within chest cavity

symptoms of diaphragm paralysis

paradoxical movement produced, diaphragm moves upwards during inspiration and downwards during expiration

asymptomatic paralysis of diaphragm

unilateral paralysis

fatal paralysis of diaphragm

bilateral paralysis

management of diaphragmatic paralysis

-identify and treat underlying cause -non-invasive ventilation by CPAP machine

3 main muscles of the thoracic cage

-external intercostal -internal intercostal -innermost intercostal

where do muscles of the thoracic cage lie

in intercostal spaces between ribs

what is present between internal and innermost layer

neurovascular structures

function of muscles of thoracic cavity

act to change the volume of the thoracic cavity during breathing process

regions of thoracic cavity

-mediastinum -left pleural cavity -right pleural cavity

mediastinum

central partition that separates the two laterally placed pleural cavities

Mediastinum contains

-thymus gland -heart and pericardial sac -trachea -major arteries and veins

where is the mediastinum

extends from sternum to bodies of the vertebrae and from superior thoracic aperture to diaphragm

function of mediastinum

serves as passageway for structures as they traverse the thorax on the way to the abdomen

Divisions of Mediastinum

superior and inferior

divisions of inferior mediastinum

anterior, middle, posterior

where is the thymus in the mediastinum

superior and anterior inferior

where is the heart in the mediastinum

middle inferior

where is the trachea in the mediastinum

superior mediastinum

where is the descending aorta in the mediastinum

superior mediastinum and posterior inferior mediastinum

pleura

closed serous sac invaginated by the lung from its medial aspect

layers of pleura

parietal and visceral

parietal layer

the outer layer which lines thoracic wall from inside

visceral pleura

inner layer which covers the lung

pleural cavity

space between the folds of the pleura

appearance of pleural layers around root of long

continuous together

What does the pleural cavity contain?

pleural fluid

what does inflammation of the pleura cause

pleural surface becomes rough leading to pleural rub (friction)

how to detect pleural rub

by stethoscope

Pleural recesses are

narrow extensions of the pleural cavity

name the imaginary lines that physicians use as a reference point during a variety of procedures, such as a thoracentesis or an ECG

midaxillary and midclavicular line

function of pleural recesses

allows the lungs to expand during deep inspiration

name the pleural recesses

costomediastinal recess and costodiaphragmatic recess

where does the costodiaphragmatic recess lie

between the costal and diaphragmatic pleura along inferior margin of pleura

where does the costomediastinal recess lie

lies between the costal and mediastinal pleura along anterior margin of the pleura

costodiaphragmatic recess is also called

costophrenic angle

pleural effusion

accumulation of fluid in the pleural cavity that tends to gravitate towards the recesses obliterating the costophrenic angle

another name for pleural effusion

Hydrothroax

what is done in thoracocentesis to avoid the inferior border of the lung

needle inserted into 6th intercostal space in midaxillary/posterior axillary line during expiration

pressure inside pleural cavity

slightly below atmospheric

pressure inside the lungs

almost atmospheric

pneumothorax

air in the pleural cavity caused by a puncture of the lung or chest wall

pneumothorax results in

pressure inside pleural cavity becomes the same as pressure inside lungs causing lungs to collapse

symptoms of pneumothorax

shortness of breath and cyanosis

Chest tube function

removes air or excess fluid from pleural cavity

where is the Chest thighs wings tube placed

through a short incision made in 5th or 6th intercostal space in mid-axillary line

winged scapula

the muscles of the scapula are too weak or paralyzed

what causes winged scapula

Damage to the long thoracic nerve

Site of lungs

in the pleural cavity

what separates the lungs

mediastinum

shape of lungs

conical shaped with an apex, base, surfaces and borders

surfaces of lungs

costal and medial

borders of lungs

anterior, posterior and inferior

How many fissures does the left lung have and name them?

one / oblique

function of fissure of left lung

Separates upper and lower lobes

How many fissures does the right lung have and name them?

two / oblique and horizontal

function of the fissures of the right lung

separates lung into 3 lobes which are upper, middle, and lower

oblique fissure of left lung

oblique fissure of right lung

horizontal fissure of right lung

what is the hilum of the lung

site where structures enter or leave the lung

what is the root of the lung

structures passing through the hilum connecting mediastinum to the lung

hilum of the lung

bronchography

radiography of the bronchi after injection of a radiopaque substance

pulmonary embolism

obstruction of blood flow in a branch of the pulmonary artery by an embolus

embolus

moving blood clot

pulmonary infarction

area of dead tissue in the lung

what does pulmonary embolism cause

a lung sector ventilated with air but nor perfused with blood leading to decrease in oxygenation of blood

why is pulmonary infarction rare

because of the double supply of the lungs

what happens after embolic occlusion of pulmonary artery

collateral channels between bronchial and pulmonary artery open immediately