The Pericardium Posteriorly

 Boundaries: superior –incisura jugularis, clavicle, acromion, spina scapulae and proc. spinosus of C7 inferior – proc. xiphoideus, costal arch, XI and XII rib to proc. spinosus of T12 Posterior axillary line divides it:  Pectus, chest  Dorsum, back 1 2 3

 Regions: 1. Regio infraclavicularis 2. Regio mammalis 3. Regio axillaris  The axilla is the region between the pectoral muscles, the scapula, the arm, and the thoracic wall.  It is a region of passage for vessels and nerves that course from the root of the neck into the upper limb.

 Axillary vessels and their branches  Lymph nodes –  pectoral  lateral  subscapular  central  apical  Brachial plexus – branches - n. intercostobrachialis  Axillary vessels and their branches  Lymph nodes –  pectoral  lateral  subscapular  central  apical  Brachial plexus – branches - n. intercostobrachialis  Axillary vessels and their branches  Lymph nodes –  pectoral  lateral  subscapular  central  apical  Brachial plexus – branches - n. intercostobrachialis  Axillary vessels and their branches  Lymph nodes –  pectoral  lateral  subscapular  central  apical  Brachial plexus – branches - n. intercostobrachialis  Surface Anatomy:

 Skin  Subcutaneous tissue  Pectoral fascia  Muscles  Thoracic cavity

 Surface Anatomy:

 Skin  Subcutaneous tissue  Pectoral fascia  Muscles  Thoracic cavity

 Skeleton of the thorax - Sternum - Ribs - Vertebrae  The thoracic skeleton forms the thoracic cage, which protects the thoracic viscera and some abdominal organs.  The thoracic skeleton includes: Sternum - Ribs - Vertebrae  Intercostal Spaces - three layers of muscle fill the intercostal space

Intercostal Muscles: external intercostal muscle, internal intercostal muscle, innermost intercostal muscle. m. transversus thoracis subcostal muscles Intercostal Muscles: external intercostal muscle, internal intercostal muscle, innermost intercostal muscle. m. transversus thoracis subcostal muscles Intercostal Muscles: external intercostal muscle, internal intercostal muscle, innermost intercostal muscle. m. transversus thoracis subcostal muscles Intercostal Muscles: external intercostal muscle, internal intercostal muscle, innermost intercostal muscle. m. transversus thoracis subcostal muscles

 Intercostal spaces – 11. The interval between adjacent ribs.

 Structures in the intercostal space:

• Intercostal v. • Intercostal a. • Intercostal n. There are two neurovascular bundles: - Posterior –post. intercostalis a., v. and intercostal n. - Anterior –ant. intercostal a., v. and intercostal n.

They are connected at the midclavicular line.  The anterior rami of nerves T1-T11 form the intercostal nerves that run along the extent of the intercostal spaces. Herpes zoster - The diaphragm is a double-domed, musculotendinous partition separating the thoracic and abdominal cavities.

– central tendon – muscular part  muscular part is divided into three parts :

 Sternal part  Costal part  Lumbar part

 Lumbar part • right crus • left crus • lig. arcuatum mediale • lig. arcuatum laterale

 Costal part • trigonum lumbocostale

 Sternal part • trigonum sternocostale

Diaphragmatic apertures: • caval opening • esophageal hiatus • aortic hiatus

– small apertures in each crus – sternocostal triangle Diaphragmatic apertures: • caval opening • esophageal hiatus • aortic hiatus

– small apertures in each crus – sternocostal triangle  Actions of diaphragm • only the domes of the diaphragm descend • increases intra-abdominal pressure

* *  Innervation – phrenic nerves * (C4, and C3, C5)

Includes :

 Organs • the primary organs of the respiratory and cardiovascular systems  Vessels • blood vessels • lymph nodes  Nerves • somatic • autonomic  The thoracic cavity is divided into three major spaces:

 the right and left pulmonary cavities housing the lungs.  mediastinum that houses the thoracic viscera  Pleura – serous membrane. Each lung is invested by and enclosed in a serous pleural sac. Pleura consists of two continuous membranes: the parietal pleura, which lines the pulmonary cavities the visceral pleura, which invests all surfaces of the lungs forming their shiny outer surface The pleural cavity • the potential space between the layers of pleura • contains a capillary layer of serous pleural fluid  Parietal pleura consists of three parts: – costal part – diaphragmatic part – mediastinal part

– pleural cupula The potential pleural spaces:

• costodiaphragmatic recesses • costomediastinal recesses • phrenicomediastinal recesses • interlobar recesses Inspiration Expiration If a penetrating wound opens through the thoracic wall or the surface of the lungs, air will be sucked into the pleural cavity because of the negative pressure and the lung will collapse. Mediastinum – the region between the two pleural cavities. The boundaries of the mediastinum are: ― superior - superior thoracic aperture ― inferior – diaphragm ― anterior - sternum ― posterior - bodies of vertebrae T1 to T12 ― lateral – mediastinal pleurae (left and right)  The mediastinum is divided into four parts:

• superior mediastinum • inferior mediastinum – anterior – middle – posterior  Structures are distributed into three groups: – retrosternal – intermediate – prevertebral  Retrosternal group includes: – lymph nodes – thymus – brachiocephalic veins – superior vena cava  Retrosternal group includes: – lymph nodes – thymus – brachiocephalic veins – superior vena cava  Intermediate group:

– Aortic arch and its branches – Vagus nerves (right and left) – Left recurrent laryngeal nerve – Phrenic nerves (right and left) – Plexus cardiacus - rami and nervi cardiacae *  Intermediate group:

– Aortic arch and its branches – Vagus nerves (right and left) – Left recurrent laryngeal nerve – Phrenic nerves (right and left) – Plexus cardiacus - rami and nervi cardiacae  Prevertebral group: – trachea – esophagus – tracheal and tracheobronchial lymph nodes – thoracic duct The anterior mediastinum, the smallest subdivision of the mediastinum, lies between the body of the sternum and the pericardium posteriorly. It consists of: ‒ loose connective tissue – sternopericardial ligaments – internal thoracic a. and its branches – lymph nodes – sternal and diaphragmatic – thymus – inferior part (in children)  The pericardium and its contents (heart and roots of its great vessels) constitute the middle mediastinum.

– heart – ascending aorta – pulmonary trunc – superior vena cava – inferior vena cava – pulmonary arteries – phrenic nerves – pericardiacophrenic a.  The pericardium is a fibroserous membrane that covers the heart and the beginning of its great vessels.

It is a closed sac composed of two layers. • parietal layer, fibrous pericardium • visceral layer, epicardium The serous pericardium is composed mainly of mesothelium. The pericardial cavity is the potential space between opposing layers of the parietal and visceral layers of serous pericardium.  The visceral layer extends onto the beginning of the great vessels, becoming continuous with the parietal layer of serous pericardium. 1) where the aorta and pulmonary trunk leave the heart - porta arteriosa 2) where the SVC, inferior vena cava (IVC), and pulmonary veins enter the heart - porta venosa The pericardial reflection surrounding them forms recesses:  transverse pericardial sinus  oblique pericardial sinus  The visceral layer extends onto the beginning of the great vessels, becoming continuous with the parietal layer of serous pericardium. 1) where the aorta and pulmonary trunk leave the heart - porta arteriosa 2) where the SVC, inferior vena cava (IVC), and pulmonary veins enter the heart - porta venosa The pericardial reflection surrounding them forms recesses:  transverse pericardial sinus  oblique pericardial sinus