Costal arch
Arcus costalis
Definition
The costal arch is formed by the union of the costal cartilages of the 10, 11, and 12 ribs with the costal cartilage of the 9 pair of ribs.
The costal cartilages of the first three pairs of false ribs (10, 11, and 12) are long and thin, interconnected by connective tissue, and associated with the costal cartilage of the last pair of true ribs (9).
Together, they form on each side a ventrolateral cartilaginous arch that contributes to defining the thoracic wall and marks the transition between sternal ribs and asternal ribs.
References
Evans HE, de Lahunta A. Miller’s Anatomy of the Dog. 5th ed. St. Louis: Elsevier; 2013. Chapter 4, The skeleton; p. 80–157.
