Muscles Of The Thoracic Wall

Diaphram And Its Origins

Several muscles of the thoracic wall, including the most superficial ones that create some of the contours of the thoracic wall, are muscles that act on the upper extremity. Some of these muscles form important surface landmarks on the thorax, and others have relationships to vessels that communicate with the thorax. In addition to moving the upper extremity, some of these muscles also can play a role in movement of the thoracic wall and participate in respiration. The pectoralis major muscle...

Nerves Of The Thoracic Wall

Intercostal Nerves

The wall of the thorax receives its innervation from intercostal nerves Fig. 8 . These nerves are the ventral rami of segmental nerves leaving the spinal cord at the thoracic vertebral levels. Intercostal nerves are mixed nerves that carry both somatic motor and sensory nerves and autonomics to the skin. The intercostal nerves pass out of the intervertebral foramina and run inferior to the rib. As they reach the costal angle, the nerves pass between the innermost and the internal intercostal...

Internal Anatomy Of The Heart

Atrial Septal Anatomy

A cross section cut through the heart reveals three layers Fig. 7 1 a superficial visceral pericardium or epicardium epi upon heart 2 a middle myocardium myo muscle heart and 3 a deep lining called the endocardium endo within, derived from the endoderm layer of the embryonic trilamina . The endocardium is a sheet of epithelium called endothelium that rests on a thin layer of connective tissue basement membrane. It lines the heart chambers and makes up the valves of the heart. The myocardium is...

Blood Pressure Monitoring

Arterial Pressure Waveform

The cardiovascular system is most commonly assessed by monitoring arterial blood pressure. Blood pressure is proportional to the product of cardiac output and systemic vascular resistance BP CO x SVR CO HR x SV MAP 1 3 SBP 2 3 DBP where BP is blood pressure, CO is cardiac output, SVR is systemic vascular resistance, HR is heart rate, SV is stroke volume, MAP is mean arterial pressure, SBP is systolic blood pressure, and DBP is diastolic blood pressure. Stroke volume is dependent on preload,...

What If Heart Beat Goes Fast Frequently And Qt And Pr Intervals Are Not Normal

What Ventricular Fibrillation

The normal heartbeat is initiated by specialized cardiac cells (so-called pacemaker cells) located in the right atrium adjacent to its junction with the superior vena cava. These cells make up a specialized, albeit somewhat diffuse, region of the right atrium called the sinus node. The rate and regularity of activity in the sinus node (the cardiac pacemaker) is determined by both the intrinsic firing rate (automaticity) of the cells within the node and the influence of extrinsic factors on...

Cardiac Defibrillation

Implantable Cardioverter Defibrillator

Today, sudden cardiac arrest death is one of the most common causes of mortality in developed countries 3 million people experience sudden cardiac arrest worldwide, and the annual incidence in the United States is 300,000. Sudden cardiac arrest claims more lives in the United States each year than the combination of deaths from acquired immunodeficiency syndrome AIDS , breast cancer, lung cancer, and stroke 31 . Several studies have identified the primary risk factors for sudden cardiac arrest,...