Chapter 6 sectional anatomy

The bony thorax functions to protect organs of the thorax and to aid in respiration. It consists of the

thoracic vertebrae, sternum, ribs, and coastal cartilage.

The 12 thoracic vertebrae make up the ____ boundary of the thoracic cage.

posterior

The ___ boundary of the thoracic cage is created by the sternum.

anterior

A common landmark, the jugular notch, is located on the superior border of the manubrium at approximately the level of….

T2-T3

The sternal angle is located at approximately…

T4-T5

The xiphoid process is located on the inferior border of the ____ and is a site for muscular attachment

sternum

forming the lateral borders of the thoracic cage are the 12 pairs of ribs. all 12 articulate posteriorly with the….

spine

Between the ribs are the intercostal spaces, the facets of the head of the ribs articulate with the vertebral bodies and the

costovertebral joints.

Whereas the facets of the tubercles articulate with the transverse processes. Of the vertebrate to form the…

costotransverse joints

The lungs are the organs of respiration where a gaseous exchange occurs between the respiratory air and blood. They are composed of

a sponge like material, parenchyma, and surrounded by a layer of serous fluid

Large and conical shaped lungs extend up to or slightly above the level of the first rib at their apex and down to the Dome of the diaphragm at their white concave shape bases or

diaphragmatic surfaces.

Each lung has a mediastinal or medial surface that is opposed to the mediastinum and a coastal surface that is opposed at the

inner surface of the rib cage.

The lungs are divided into lobes fissures that are lined by pleura and may extend as far as the hilum.

Each lung has an opening on each medial surface called ___. It is where the entrance and exit of lymph vessels blood vessels, nerves and mainstem bonchi are located as well as nodes are often visualized there.

the hilum

The ___ lung has three lobes: the superior upper, the middle and the inferior lower.

right

The ___ lung has two lobes: the superior upper and inferior lower.

left

the inferior lobe of the right lung is separated from the middle and posterior by the oblique fissure, termed oblique because of its posterior superior to Anterior inferior angle separating the middle from the superior is the

horizontal fissure

Each lung lies within a single plural cavity that is lined by a serous membrane or pleura. The pleura can be divided into two layers. The parietal pleura, the outer layer, is continuous with the thoracic wall and diaphragm and moves with these structures during respiration. The visceral pleura is the inner layer that closely covers the outer surface of the lung and continues into the fissures to cover the individual Membranes secrete a small amount of pleural fluid that provides lubrication between their surfaces during breathing

The trachea bifurcates into the left and Right main stem primary bronchi at approximate approximately the level of ___ also known as the carina

T5

The trachea is anterior and slightly right to the esophagus. The aortic arch sits to the left of the trachea. The Carina, or bifurcation of the trachea is just inferior to the aortic arch. Or we should see both. The ascending arch and descending aorta, the lung windows, demonstrate the corona well. The corona bifurcation is at the same level as the pulmonary artery bifurcation directly interior to the esophagus.

The right main bronchus is wider, shorter and more vertical and orientation than the left. At the highland, the mainstem bronchi entered the lung and devoted to secondary or. The left and right main bronchi are easy to ID, especially on the lung windows and MRI. When blood is black, it's much more difficult because they look just like the blood vessels. The right if you. Remember, the right main bronchus is more vertical than the left.

the right main bronchus is more vertical than the left.

The mediastinum is the midline region of the thoracic cavity located between the two plank cavities of the lungs. It is projected on the anterior surface by the sternum and this image you can see that the mediastinum is broken into four different parts. We have this mediastinum which is separated from the other three categories right there by the sternal angle. Then you have the anterior mediastinum, which is anterior to the middle mediastinum. The heart is there and then you have the posterior mediastinum which is posterior to the heart.

The thymus gland can be found at the level of the aoritc arch and is posterioir to the sternum.

Throughout the course of the mediastinum the trachea runs anterior to the esophagus. In cross section the trachea appears as a round air filled structure to the point at which it bifurcates at the Caarina. Here you can see the trachea and the esophagus is full of muscles that moves food down and it appears closed off where the trachea appears open and air flow.

The esophagus appears as an Oval shaped structure that descends through the diaphragm to enter the stomach at the gastroesophageal junction. The esophagus is located just anterior to the spine. Sometimes you can see a little air in the esophagus. Their transit is very difficult to differentiate these emphasis from the surrounding nodes and the radiologist will request an oral contrast that could see esophagus.

Lymph nodes in the mediastinum are generally clustered around the great vessels esophagus, bronchi and Carina. Lymph nodes in cross section are difficult to visualize unless they are enlarged as a result or abnormality.

The supraclavicular lymph nodes are commonly referred to as a sentinel lymph nodes because

they're enlargement alerts the medical professional to the possibility of malignant disease in the thoracic or abdominal cavities.

If you can't identify it as a vessel or airway is probably a lymph node. Bundles include

lungs, esophageal and mammary

the lymphatic system consists of a network of lymphatic vesserls that carry lymph fluid (excess interstitial fluid.) The thoracic duct is the main vessel of the lymoh system, draining all of the lymh fluid from the tissues below he diaphragm and from the left side of the body above the diaphragm and from the left side of the body above the diaphragm.

the left thoracic duct begins inferior to the diaphragm at the level of L2 and passes from the abdominal cavity into the thorax through the aortic hiatus of the diaphragm. It originates in the abdomen, at the cisterna chyli

cisterna chyli

, a dilated sac or confluence of lymph trunks into which lymph from the intestinal and lumbar lymphatic trunks open. It ascends the thorax, between the azygos vein and te descending aorta, and empties into the left subclavian vein at the level of the clavicle.

right lymphatic duct

collects lymph from the right upper side of the body and is formed by the merging of carious lymphatic trunks near the right clavicle and empties into the right sublclavian vein.

The heart

a hollow, four-chambered muscular organ located within the middle mediastinum. It is approximately the size of a large clench fist and is situated obliquely in the chest with one-third of its mass lying to the right of the median plane and two thirds of its mass lying to the right of the median plane and two-thirds to the left.

the fibrous pericardium

is attached to the central tendon of the diaphragm and is pierced by the inferior vena cava.

serous pericardium

the inner suface of the fibrous pericardium consists of a doubled-layered ____. this includes the inner surface called the visceral layer (epicardium) which covers the outer surface of the heart and the roots of the great vessels.

pericardial cavity

is located between the parietal and visceral layer is a potential space that contains a thin film of serous fluid that acts as a lubricant to reduce friction to the tissues caused by heart movements.

Of the heart and the four chambers, the bottom two are the ventricles, and they are separated by the

interventricular septum

The right atrium forms the right border of the heart and receives deoxygenated blood from the from the body. Via this app. Carrier and inferior vena cava and from the coronary sinus in cardiac veins that drain the

myocardium, a small muscular embryonic appendage

The right Oracle projects upward and towards the left from the right atrium covering the roots of the

ascending aorta anteriorly.

The right ventricle lies on the diaphragm and comprises the largest portion of the anterior surface of the heart. It lies just posterior to the body of the sternum. It receives deoxygenated blood from the

right atrium and forces it into the pulmonary trunk for delivery to the lungs.

The left atrium lies posterior to the right atrium and is the most posterior surface of the heart. It also has an embryotic appendage, the left Oracle, that projects to the

left pulmonary trunk over the surface of the heart.

The left atrium receives oxygenated blood directly. From the lungs via 4 pulmonary veins, 2 on each side. It also has a large, thick wall, three times thicker than the

right atrium normally it is inferior to the to the carina.

The left ventricle forms the apex, left border, and most of the inferior surface of the heart. It recedes oxygenate. Blood from the left atrium and pumps it into the

aorta for distribution to the rest of the body.

4 valves are located in the heart. The function to maintain one way directional blood flow throughout the heart. The valve can be divided into two groups

atrial ventricle and semi lunar.

The atrial ventricle valves are found at the entrance of both ventricles and function to prevent

back flow of blood between the Atria and ventricles during ventricle contraction.

The right atrial ventricle valve with three leaflets is called the tricuspid valve and the left anterior ventricular valve with two leaflets is called the

bicuspid mitral valve. They are located at the junction where the ventricles meet the great vessels separating the ventricles from the circulatory system. These valves are called semi lunar because of their three Crescent shaped cusps and function to prevent the flow of blood back into the ventricles during ventricle relaxation.

The pulmonary semilunar valve is located at the junction of the right ventricle and pulmonary artery, and the aortic semilunar valve lies between the l

eft ventricle and ascending aorta.

Pulmonary semi lunar has to do with the right ventricle and pulmonary artery, while the aortic semilunar valve the ascending between

the ascending aorta and the left ventricle

Moving on to the aortic arch when viewing images from superior tp inferior, the great vessels of the arch will first be identified. As you move inferior, the arch will is seen as a large diagonal vessel from the anterior right to left posterior. As you move further inferior you are below the arch and can identify the ascending and descending aorta.

The ascending aorta begins at the base of the left ventricle, at the level of the sternal angle and then curves. And posteriorly as the aortic arch over the root of the left lung. The top of the arch is located at approximately T3. The arch continues as the descending aorta posterior to

the left bronchus and pulmonary trunk on the left side of the vertebral body of T4.

The descending aorta passes slightly anterior and to the left of the vertebral column as it descends through

the thoracic and abdominal cavities.

The descending aorta is called the thoracic aorta, and while in the abdominal cavity it's called the

abdominal aorta

the three main branches of the aortic arch are the

brachiocephalic trunk/artery, the left common carotid, and the left subclavian artery

brachiocephalic trunk

the first major vessel of in the largest branch arising from the aortic arch, it descends obliquely to the upper border of the right sternoclavicular joint, where it divides into the right common carotid and the right subclavian arteries.

The right common carotid artery ascends the neck lateral to the trachea to the level of C4, where it divides into

the right external and internal carotid arteries.

The right subclavian artery curves posterior to the clavicle into the axillary region, where it becomes

the right axillary artery.

The left common carotid artery is the second vessel to branch from the aortic arch. It arises just behind the left sternoclavicular joint and descends into the neck. It is located just posterior and to the left of

the brachiocephalic artery.

The left subclavian artery arises from the aortic arch posterior to the left common carotid artery and arches laterally towards the axilla. It is the third of the vessels off the arch and is located just to the left of the trachea and

posterior to the brachiocephalic vein.

The two main coronary arteries are the first vessels to branch off of the ascending aorta. The right coronary artery rises from the base or root of the aorta. The left coronary artery arises from the left aortic sinus and passes to the left posterior and laterally inferior to the pulmonary trunk and between

the left atrium and the left ventricle.

The pulmonary trunk is the origin of the right and left pulmonary arteries and lies entirely within the pericardial SAC. It arises from the right ventricle and ascends in front of the ascending aorta courses posteriorly into the left, where bifurcates the level of

the sternal angle T4 into right and left pulmonary arteries.

The left pulmonary artery, shorter and smaller than the right, is also the most sad. Carrier of the pulmonary vessels. It travels horizontally, arching over the left mainstem bronchus, and

enters the hilum

To the left, mainstem bronchus, located inferior to the pulmonary arteries are the far are the four pulmonary veins to each sub. Carrier and inferior extending from each lung to enter the left atrium, the right superior pulmonary vein collects blood in the upper lip segments of the right lung and passes anterior and inferior to the right pulmonary artery behind the superior cava. The right inferior pulmonary vein receives blood from the right lower lobes of the lung and crosses behind the right atrium to the left atrium.

The left Pulmonary vein receives blood from the upper lobe of the left lung and courses anterior and inferior to the left main bronchus as it enters the left atrium. The left inferior pulmonary vein drained their inferior low of the left lung and passes towards the left atrium anterior to the bronco the pulmonary veins course more horizontally than the pulmonary arteries and are

ultimately oriented toward the left atrium.

The superior and inferior vena cava are the largest veins of the body. The superior vena cava is formed by the junction of the brachiocephalic veins posterior to the right first coastal cartilage and carries blood from the thorax, upper extremities, head and neck. travels inferiorly and it is located

posterior and lateral to the ascending aorta before entering the upper portion of the right atrium.

The inferior vena cava is formed with the junction of the common iliac veins in the pelvis and ascend the abdomen to the right of the abdominal aorta and anterior to the vertebral column. It passes through the caval hiatus of the diaphragm and almost immediately enters the inferior portion of the right atrium

The superior vena cava receives blood from the head and neck via the internal and external jugular veins, and from the upper extremities via sub. save me anything next here's another image of the inferior vena cava.

The subclavian veins arrive arise from the axillary veins in course posterior to the clavicles. They receive blood from the external jugular veins before uniting with the internal jugular veins behind the sternoclavicular joints, where they continue as the brachiocephalic veins. The left brachiocephalic vein courses across the midline anterior to the aorta and great vessels of the arch posterior to the manubrium to unite with the right brachiocephalic vein just posterior to the coastal cartilage of the right first rib.  

Most of the venous return from the heart is carried by the coronary sinus as it runs along the posterior section of the coronary sulcus and terminates in the right atrium immediately to the left of the inferior vena cava.

The coronary sinus is a wide venous channel situated in the posterior part of the coronary sulcus and is the main vein of the heart. It allows venous drainage of the heart between the left atrium and left ventricle.

which provides collateral circulation between the inferior and superior vena cava could be divided into the Azygos and Hemiazygos veins. The larger Azygos vein ascends along the right side of the vertebral column, whereas the hemiazygos vein ascends along the left side.

Together they drain blood from most of the posterior thoracic wall and from the bronchi. Cardiac and esophagus. at a level above the kidneys, at approximately

T7-T9,

the hemiazygos vein crosses the vertebrae to the right behind the aorta to join azygos vein. from there they continue to ascend along the right side of the vertebrae. Where it will eventually arch over the hilum of the right lung to

empty into the posterior surface of the superior vena cava.  

The Pharynx is a funnel shaped fibromuscular tube approximately 12 centimeters long that acts as an opening for both the respiratory and the digestive systems It extends from

the base of the skull and ends inferiorly as a continuation of the esophagus. This goes from sphenoid to C5.

The pharynx is divided into three sections

nasopharynx, oropharynx and laryngopharynx.

The nasopharynx is the most superior portion of the pharynx from sphenoid to C1. It has a respiratory function .

to allow for the passage of air from the nasal cavity to the larynx posteriorly. The boundaries of the nasopharynx are the clivis and the upper cervical spine. It is bordered inferiorly by the soft palate and extends down to the level of the uvula which hangs inferior from the soft pellet at the midline. It also contains the hard palate which is created by the Palatine process of maxilla. In the roof and the posterior wall of the nasopharynx is a collection of lymphoid tissue. Known as the pharyngeal tonsils, the fungal tonsils have a protective immune function and when enlarged you're often referred to as the adenoids.

The oropharynx and is a posterior extension of the oral cavity and extends from the soft palate to the level of the highlight. It is separated from the larynx by the epiglottis. Two additional pairs of lymphoid tissue are found within the oropharynx. The Palatine tonsils at the level of C1 through C3,

which are located on the lateral wall on each side of the union of the base of the tongue and the epiglottis are two pouches like openings called vallecula 

The Vallecula are common sites for foreign objects to become lodged within

the neck. 

The larynx

is the Bony skeleton that surrounds and protects the vocal cords and is commonly called the voice box. It begins as the laryngopharynx and continues to the trachea and marks the beginning of the respiratory pathway by allowing for the passage of error to the trachea.

The larynx consists of an outer skeleton made-up of nine cartilages that extend from approximately the 3rd to the 6th cervical vertebrae. These cartilages are connected to one another by ligaments and move by multiple muscles. Three of the cartilages are unpaired and include the thyroid, epiglottis and cricoid. The cartilages each have a distinct shape. The epiglottis is leaf shaped, thyroid cartilage is triangular, formed by two flat Shields attached anterior and the cricoid cartilage is a complete ring that appears the roundest on the image and the tracheal rings are 1/2 circle with soft flat posterior elements. The three paired cartilages are the arytenoids, corniculate and cuneiform.  

thyroid cartilage

The largest of the larynx cartilages is the …. It consists of a right and a left lamina the unite anteriorly to form a shield to protect the vocal cords. The anterior union of the laminate forms a vertical projection known as the atom sample.

The anterior union of the laminate forms a vertical projection known as the atom sample. On the posterior aspect of this project projection is the attachment for the epiglottis. It appears like bone dense and superior to the thyroid gland. The cornea is the posterior inferior extensions that articulate on the cricoid And the notch is this superior anterior portion that At this point the thyroid looks like two separate Shields. As you move inferior, we see it becoming one complete cartilage.

The epiglottis differs from the other cartilages and that it is elastic and allows for movement. During swallowing, the epiglottis folds back over the larynx, preventing the entry of liquid or solid food into the respiratory pacifiers. Remember it is leaf shaped, extends obliquely upward from the tongue base, and forms in forms of anterior surface of the upper larynx position posterior to the anterior shield of the highway.

The paired arytenoids cartilages are shaped like pyramids and are situated at the posterior aspect of larynx, just on top of the cricoid cartilage articulating with the superior aspect of the arytenoids cartilages are the small horn shaped. Corniculate cartilages These cartilages are involved in the opening and closing of the epiglottis for the production of sound. The small curved cuneiform cartilages lie with the faults of tissue termed the aryepiglottic folds that extend between the lateral aspect of the arytenoid cartilage.  

The cricoid collage is a complete ring that forms the base of the larynx on which the other larynx cartilages rest. The cricoid cartilage marks the junction between the larynx and the trachea and the beginning of the esophagus. It is both thicker and smaller than the thyroid cartilage and it looks like a circle on axial images.

The inner structures is a larynx, include the false and true vocal cords and the aryepiglottic folds. The false and true vocal cords consist of two pairs of ligaments that extend from the arytenoid cartilages to the posterior laminal surface of the thyroid. Cartilage. This. Here your pair of ligaments are called the vestibular folds or false vocal cords because they are not directly concerned with the production of voice. The inferior pair are the true vocal cords, named accordingly for their involvement in the production of sound. The true vocal cords extend works, meddling in a closed position during phonation with quiet respiration. The true vocal cords are in relaxed position, creating an opening between them called the glottis. The false vocal cords are superior to the true vocal cords. The glottis is a part of the learnings most directly involved with voice production. The airy epiglottic folds consists of tissue projecting off of the arytenoid cartilage to the inferior margin of the epiglottis.

These folds from lateral margin of the entrance to the larynx. Located lateral to these folds between the larynx and thyroid cartilage are those two mucosal pouches, the Periform sinuses, whose medial borders from the lateral walls of the larynx.

The esophagus is a muscular tube that extends down from the from the laryngopharynx to the cardiac office of the stomach. It begins posterior to the frequent cartilage, then descends. View this thoracic cavity between the trachea and anterior longitudinal movement of the vertebrae. The esophagus then enters the abdominal cavity through an opening called the esophageal hiatus to meet the stomach.

The trachea, considered the airway extends from the larynx to the lungs and light immediately anterior to the esophagus. Considered an elastic tube, the trachea is reinforced by many sea shaped pieces of cartilage that maintain an open passageway for air. The cartilages are closed posteriorly by elastic connective tissue. It allows for passage of food through the esophagus. It fight for Kates at approximately T5.

The salivary glands collectively produce an empty saliva into the oral cavity by way of ducts. To begin the process of digestion, there are three large paired salivary glands. The parotid, the submandibular and sublingual glands.

The largest of the pairs are the parotid glands, which are situated in front of the Oracle, the ear in this nest wedged between the ramis of the mandible and the sternocleidomastoid muscle. The parotid glands extend inferiorly from the level of the external auditory meatus to the angle of mandible. Their appearance differs from that of the other salivary glands because of the amount of fat that they contain.

Moving on to these submandibular glands, they ordered the posterior half of the mandible extending from the angle of the mandible to the level of the hyoid bone.

The sublingual gland is the smallest of the salivary glands and lies under the tongue on the floor of the mouth. The thyroid gland is an endocrine gland that is located at the level of the cricoid cartilage, that's at the 2nd through 4th tracheal rings. It consists of two lobes that are joined together anteriorly by the isthmus. It enhances bright light with IV contrast, and the right lobe is often higher than the left side.

The common carotid artery and the internal jugular veins. The parathyroid gland are located on the posterior surface of the thyroid gland. And there are usually four of them. They are not normally visualized in CT or MRI.

The neck has extensive lymph nodes throughout, containing more than 1/3 of the body's total number of lymph nodes. Typically, as many as 75 lymph nodes are located on each side of the neck.

Here we have the pharyngeal and tongue muscles. The pharyngeal muscles include the circular layer of constructors and the inner longitudinal layers. All are responsible for either constructing the bearings, including peristaltic waves during swallowing, elevating the pharynx and larynx during swallowing and speaking or moving the tongue.