Preferred Label : accessory XI nerve spinal component;
Uberon definition : The spinal root of accessory nerve (or part) is firm in texture, and its fibers arise
from the motor cells in the lateral part of the anterior column of the gray substance
of the medulla spinalis as low as the fifth cervical nerve. Passing through the lateral
funiculus of the medulla spinalis, they emerge on its surface and unite to form a
single trunk, which ascends between the ligamentum denticulatum and the posterior
roots of the spinal nerves; enters the skull through the foramen magnum, and is then
directed to the jugular foramen, through which it passes, lying in the same sheath
of dura mater as the vagus, but separated from it by a fold of the arachnoid. In the
jugular foramen, it receives one or two filaments from the cranial part of the nerve,
or else joins it for a short distance and then separates from it again. As its exit
from the jugular foramen, it runs backward in front of the internal jugular vein in
66.6 per cent. of cases, and behind in it 33.3 per cent. The nerve then descends obliquely
behind the Digastricus and Stylohyoideus to the upper part of the Sternocleidomastoideus;
it pierces this muscle, and courses obliquely across the posterior triangle of the
neck, to end in the deep surface of the Trapezius. As it traverses the Sternocleidomastoideus
it gives several filaments to the muscle, and joins with branches from the second
cervical nerve. In the posterior triangle it unites with the second and third cervical
nerves, while beneath the Trapezius it forms a plexus with the third and fourth cervical
nerves, and from this plexus fibers are distributed to the muscle.;
Uberon synonym : spinal part of the accessory nerve;
Uberon Homology note : Cranial nerves XI and XII evolved in the common ancestor to amniotes (non-amphibian
tetrapods) thus totalling twelve pairs.[well established][VHOG];
Origin ID : 0009674;
branching part of
- part of
The spinal root of accessory nerve (or part) is firm in texture, and its fibers arise
from the motor cells in the lateral part of the anterior column of the gray substance
of the medulla spinalis as low as the fifth cervical nerve. Passing through the lateral
funiculus of the medulla spinalis, they emerge on its surface and unite to form a
single trunk, which ascends between the ligamentum denticulatum and the posterior
roots of the spinal nerves; enters the skull through the foramen magnum, and is then
directed to the jugular foramen, through which it passes, lying in the same sheath
of dura mater as the vagus, but separated from it by a fold of the arachnoid. In the
jugular foramen, it receives one or two filaments from the cranial part of the nerve,
or else joins it for a short distance and then separates from it again. As its exit
from the jugular foramen, it runs backward in front of the internal jugular vein in
66.6 per cent. of cases, and behind in it 33.3 per cent. The nerve then descends obliquely
behind the Digastricus and Stylohyoideus to the upper part of the Sternocleidomastoideus;
it pierces this muscle, and courses obliquely across the posterior triangle of the
neck, to end in the deep surface of the Trapezius. As it traverses the Sternocleidomastoideus
it gives several filaments to the muscle, and joins with branches from the second
cervical nerve. In the posterior triangle it unites with the second and third cervical
nerves, while beneath the Trapezius it forms a plexus with the third and fourth cervical
nerves, and from this plexus fibers are distributed to the muscle.
