Tórax

Understanding the Thorax in Canines

Overview of the Thoracic Region

• The thorax consists of 13 ribs in dogs, with part of it obscured by the forelimb's placement.

• The thoracic region is examined starting from the caudal aspect at the 13th rib and moving cranially towards the sternum, which serves as a boundary for this area.

Rib Structure and Intercostal Spaces

• Palpation reveals both external and floating ribs; specifically, the 13th rib is a floating rib that does not connect to the costal arch.

• Important intercostal spaces are identified due to their relevance to heart and lung topography, particularly noting that the heart lies between the 3rd and 6th intercostal spaces.

Heart Location and Valve Auscultation

• The heart's position is primarily located at approximately the 5th intercostal space, with specific valves positioned as follows:

• Pulmonary valve at 3rd intercostal space,

• Aortic valve at 4th,

• Mitral valve at 5th.

• These auscultation points are crucial for assessing cardiac function in canines. The pulmonary auscultation zone is limited by limb presence and cardiac mass.

Pleural Cavity Dynamics

• The pleural cavity allows for lung expansion and contraction within a variable space defined by pleura reflections from diaphragmatic to costal areas, marking an important anatomical reference point.

• Accessing this cavity requires understanding its boundaries relative to lung borders and pleura reflections around the thoracic wall.

Diaphragm Anatomy

• The diaphragm's costal insertion occurs along internal rib surfaces forming an arch; its central dome projects upwards towards the caudal sternum, significantly influencing thoracic volume dynamics.