Costal groove - Sulcus costae
Between a ridge on the internal surface of the rib and the inferior border is a groove, the costal groove, for the intercostal vessels and nerve.
At the back part of the bone, this groove belongs to the inferior border, but just in front of the angle, where it is deepest and broadest, it is on the internal surface.
The superior edge of the groove is rounded and serves for the attachment of an Intercostalis internus; the inferior edge corresponds to the lower margin of the rib, and gives attachment to an Intercostalis externus.
Within the groove are seen the orifices of numerous small foramina for nutrient vessels which traverse the shaft obliquely from before backward.
This definition incorporates text from a public domain edition of Gray's Anatomy (20th U.S. edition of Gray's Anatomy of the Human Body, published in 1918 – from http://www.bartleby.com/107/).
General Anatomy > Bones; Skeletal system > Axial skeleton > Thoracic skeleton > Rib > Body of the rib; Shaft of the rib > Costal groove