The jugular processes are quadrilateral projections that extend laterally from the posterior half of each occipital condyle and are indented anteriorly by the jugular notches (the posterior parts of the jugular foramina).  The inferior surface gives attachment to rectus capitis lateralis, while the superior surface is deeply grooved by the sigmoid sinus.  Laterally, a roughened triangular (or quadrilateral) area is joined to the jugular surface of the temporal bone by a cartilaginous growth plate, which begins to ossify at 25 years of age.