Meru and its Dimensions

Meru, without doubt, refers to the primary portion of the tracheo-bronchial tree. Determining its limits and boundaries requires careful consideration of several key passages describing this central mountain.

The Puranas speak of the city of Brahma on the summit of Meru or on the “top” of Meru. This city has been identified by this author as the deep cardiac plexus on the carina surrounding which there are the “cities” of Indra (the Vagus nerve?) and the other “guardians of the world” (lokapalas).
According to the Brahma Purana, the city of Brahma (the deep cardiac plexus) is not situated on the summit of this great mountain but only at an elevation of 14,000 yojanas. This factoid regarding the location of “Brahma’s city” does not seem to exist in the other Puranas.
After careful observation, it is found that the trachea represents the “top” of Meru and the two principal bronchi the “base” or “root” (mula) of Meru[H1] . The top is of diameter 32,000 y. all throughout and the root is 16,000.
Sridhara Svami, in his commentary on the verses in the Visnu Purana, remarks that it is because of this characteristic—the extensiveness (vistrtatvan) at the top (murdhni) and constriction (sankucitatvad) at the bottom (mule)—that Meru is referred to as the pericarp (karnika) of the lotus of the earth.[1]
After due consideration of the relevant passages, it appears that it is purely the trachea, denominated as the “top” of Meru, that is said to be 1 lac yojanas in height. “Meru” is therefore only the “top of Meru” (the trachea) and in such a reckoning, the primary bronchi which are designated as the “base” of this grand mountain are not taken into consideration. They are not taken to be “Meru.”
16,000, out of this 1 lac yojanas, is said to be situated “below the earth.” The remaining 84,000 of the height of the trachea is said to constitute its visible portion. The Brahma Purana’s statement that the city of Brahma is situated at a height of 14,000 yojanas on the “summit” of Meru is therefore the same distance measured from the inferior boundary of the trachea—the carina—upwards[H1]  and does not include the primary bronchi.

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 [H1]By this definition, therefore, Brahma’s city would be below the level of the earth and not above it. It seems to be therefore very much confined to the terrestrial (thoracic) realm.

Conventionally, Brahma’s seat is in the top of the pericarp (karnika) of the divine lotus, the tracheo-bronchial tree. This pericarp, as we see, is the trachea and the two primary bronchi taken together. The trachea represents the top of this pericarp (which is also Meru). The deep cardiac plexus is found at the level of the carina which, being of the trachea, is  definitely on the top portion of the pericarp of the lotus of the earth. Brahma’s seat therefore is on the summit of Meru, the trachea, the top of the pericarp of the lotus of the earth. 

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[1] ataeva murdhni vistrtatvan mule sankucitatvat bhumadhyavasthanacca bhurupasya padmasya karnikakarena samsthitah // 9 //

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 [H1]Meru thus follows an inverted tree structure. It is the great asvattha tree of samsara referred to by Krsna in the Bhagavad Gita (vv. 15.2-3). The principal bronchi are, like the (central) tree, also inverted (sub) trees. They resemble Meru.

The Trachea: the Sun in the Puranas

The “sun” is the code for “trachea” in the Puranas. Strictly speaking, it must be the respiratory epithelium contained within the wall of hyaline cartilage that must be so called; the sun, the respiratory conduit, divides itself up into several parts in the form of bronchi; these constitute the rays of the sun. The respiratory epithelium rides, as it were, the “chariot” of the trachea and the bronchi. The walls of the tracheal and the bronchial airways constitute the chariot of the sun; however, for convenience’s sake, we may simply refer to the sun as “trachea” (and his rays as “bronchi”).

Figure 1 "Surya in chariot." https://www.rarebooksocietyofindia.org/postDetail.php?id=196174216674_10152421277051675

The two halves of the lungs may be considered to be the two portions of the earth-globe. The trachea (sun) is stationed right between these two halves in the mediastinum—the antariksa—which, apart from being the “solar sphere,” is also the realm of the “moon” (the left atrium of the heart) and the other “celestial luminaries!”

The symmetry of the lungs coupled with the central position of the heart provides the philosopher-scientists of the Puranas with a great opportunity to translocate astronomical concepts into the microcosm, the body of man.