Vertebra Prominens

Introduction

Vertebra prominens is the name of the seventh cervical vertebra. The most distinctive characteristic of this vertebra is the existence of a long and prominent spinous process which is palpable from the skin surface, hence the name.

Spinous process

The spinous process is thick, nearly horizontal in direction, not bifurcated, but terminating in a tubercle to which the lower end of the ligamentum nuchae is attached.

Other structures

The transverse processes are of considerable size, their posterior roots are large and prominent, while the anterior are small and faintly marked; the upper surface of each has usually a shallow sulcus for the eighth spinal nerve, and its extremity seldom presents more than a trace of bifurcation.

The transverse foramen may be as large as that in the other cervical vertebrae, but is generally smaller on one or both sides; occasionally it is double, sometimes it is absent. On the left side it occasionally gives passage to the vertebral artery; more frequently the vertebral vein traverses it on both sides; but the usual arrangement is for both artery and vein to pass in front of the transverse process, and not through the foramen.

Anomalies

Sometimes the anterior root of the transverse process attains a large size and exists as a separate bone, which is known as a Cervical Rib. These ribs are usually small, but may occasionally compress blood vessels (such as the subclavian artery or subclavian vein) or nerves in the Brachial Plexus, causing pain, numbness, tingling, and weakness in the upper limb, a condition known as Thoracic Outlet Syndrome.