Sternal region

The sternal region corresponds to the ventral and median portion of the thorax, located between the presternal region cranially and the abdomen caudally. It covers the sternum, an unpaired and segmented bone composed of the manubrium, the sternebrae, and the xiphoid process, which forms the most caudal part of the sternum.

Anatomically, the sternal region includes the sternal bony structures, the costal cartilages that articulate with it, the ventral thoracic fasciae, portions of the transverse thoracic muscle, the rectus abdominis (at the level of the xiphoid process), and the superficial and deep pectoral muscles, as well as associated vascular structures.

Inter-species variations exist:

• In dogs and cats, the sternum is composed of well-individualized sternebrae and a relatively flexible xiphoid cartilage.

• In horses and ruminants, the sternum is more massive, with a prominent manubrium and a broad xiphoid process, which influences the ventral thoracic contour and palpation landmarks.