Vertebra prominens
Encyclopedia
Vertebra prominens is the proper name for 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. This 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.
The seventh cervical vertebra (C7) has the most prominent spinous process only in about 70% of people; in the remainder, either C6 or T1 (the first thoracic vertebra) is the most prominent.
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 foramen transversarium 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.
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
.
The seventh cervical vertebra (C7) has the most prominent spinous process only in about 70% of people; in the remainder, either C6 or T1 (the first thoracic vertebra) is the most prominent.
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
Spinal nerve
The term spinal nerve generally refers to a mixed spinal nerve, which carries motor, sensory, and autonomic signals between the spinal cord and the body...
, and its extremity seldom presents more than a trace of bifurcation.
The foramen transversarium 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
Vertebral artery
The vertebral arteries are major arteries of the neck. They branch from the subclavian arteries and merge to form the single midline basilar artery in a complex called the vertebrobasilar system, which supplies blood to the posterior part of the circle of Willis and thus significant portions of the...
;
more frequently the vertebral vein
Vertebral vein
The vertebral vein is formed in the suboccipital triangle, from numerous small tributaries which spring from the internal vertebral venous plexuses and issue from the vertebral canal above the posterior arch of the atlas....
traverses it on both sides;
but the usual arrangement is for both artery
Artery
Arteries are blood vessels that carry blood away from the heart. This blood is normally oxygenated, exceptions made for the pulmonary and umbilical arteries....
and vein
Vein
In the circulatory system, veins are blood vessels that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood to the heart...
to pass in front of the transverse process, and not through the foramen.
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
Cervical rib
A cervical rib is a supernumerary rib which arises from the seventh cervical vertebra. It is a congenital abnormality located above the normal first rib. A cervical rib is present in only about 1 in 500 of people; in even rarer cases, an individual may have two cervical ribs...
.