lumbar plexus

In short, man as a microcosm is the all-pervading Spirit (which most purely manifests in the Sahasrara) vehicled by Sakti in the form of mind and matter, the centres of which are the sixth and following five Chakras respectively.
The six Chakras have been identified with the following plexuses commencing from the lowest, the Muladhara; the sacrococcygeal plexus, the sacral plexus, the solar plexus, (which forms the great junction of the right and left sympathetic chains Ida and Pingala with the cerebro-spinal axis). Connected with this is the lumbar plexus. Then follows the cardiac plexus (Anahata), laryngeal plexus, and lastly the Ajna or cerebellum with its two lobes. Above this is the Manas-Chakra or middle cerebrum, and finally, the Sahasrara or upper cerebrum. The six Chakras themselves are vital centres within the spinal column in the white and grey matter there. They may, however, and probably do, influence and govern the gross tract outside the spine in the bodily region lateral to, and co-extensive with, that section of the spinal column in which a particular centre is situated. The Chakras are centres of Sakti as vital force. In other words these are centres of Pranasakti manifested by Pranavayu in the living body, the presiding Devatas of which are names for the Universal Consciousness as It manifests in the form of those centres. The Chakras are not perceptible to the gross senses. Even if they were perceptible in the living body which they help to organise, they disappear with the disintegration of organism at death. Just because post-mortem examination of the body does not reveal these Chakras in the spinal column, some people think that these Chakras do not exist at all, and are merely the fabrication of a fertile brain. This attitude reminds us of a doctor who declared that he had performed many post-mortems and had never yet
discovered a soul! The petals of the lotuses vary, being 4, 6, 10, 12, 16 and 2 respectively, commencing from the Muladhara and ending with Ajna. There are 50 in all, as are the letters of the alphabet which are in the petals; that is, the Matrikas are associated with the Tattvas; since both are products of the
same creative Cosmic process manifesting either as physiological or psychological function. It is noteworthy that the number of the petals is that of the letters leaving out either Ksha or the second La, and that these 50 multiplied by 20 are in the 1000 petals of the Sahasrara, a number which is indicative of infinitude.