Asthi Dhatu

Overview

Ayurveda describes the body as built from seven tissues, the sapta dhatu. They are formed one from the next, in order, the way each course of a meal feeds the one after it. Asthi Dhatu is the fourth of these seven. It is the bone tissue, the dry and firm tissue that gives the body its frame.

The word is plain. Asthi means bone, and dhatu means a tissue, something that holds the body together. So Asthi Dhatu is simply the bone tissue, though the classical authors meant by it not only the bones but the hard, structural quality of the body as a whole.

Where it sits among the seven tissues

The seven tissues are formed in a set order, each from the one before. First comes rasa, the plasma or nourishing fluid. From it is made rakta, the blood. From blood comes mamsa, the muscle. From muscle comes medas, the fat. From fat comes asthi, the bone. From bone comes majja, the marrow. And from marrow comes shukra, the reproductive tissue.

The order matters. Each tissue is finer and deeper than the last, and each is fed by the one above it. Bone is the fifth in the line of making but the fourth tissue counted, and the texts are clear that it is built from the fat that comes before it. When the fat is well nourished, the bone is well made; when it is not, the bone suffers in turn.

The qualities of bone

Ayurveda reads every tissue by its qualities, and bone has the firmest of them all. It is ruksha (dry), kathina (hard), guru (heavy) and sthira (stable). These are the qualities of the earth element, and bone is the most earthy of the tissues, the one that holds its shape.

This dryness and firmness is what lets the body stand. The softer tissues that come before it, the plasma and blood and fat, are wet and yielding. Bone is the tissue that does not yield, and so it is the frame on which the rest of the body is hung.

Bone as the home of Vata

There is a point the classical texts make again and again, and it can seem strange at first. Bone, the hardest tissue, is the seat of Vata, the lightest and most moving of the doshas. The two seem opposite. But Ayurveda sees it this way: Vata is dry, and bone is dry, and like settles in like. So the dry, light quality of Vata makes its home in the dry, firm tissue of bone.

This is why the texts say that when Vata grows too high in the body, it is the bones that feel it first. As Vata rises, it draws on the dryness of bone, and the tissue can lose its firmness over time. The classical answer to rising Vata is therefore also the classical care of the bones: warmth, oil and a steady routine.

How bone is kept well

The texts give a simple picture of how bone is nourished. It begins, as everything does, with the digestive fire. Food that is well digested makes good plasma, good plasma makes good blood, and so down the line until good fat makes good bone. So the care of the bones is first the care of digestion, and only then anything applied to the bones directly.

Sesame, in seed and in oil, is the substance the texts name most often for the bones. It is warm and building, and the practice of abhyanga, the daily oiling of the body, is held to nourish the deep tissues through the skin. Bone grows more dry with age, as Vata naturally rises in the later years, and the classical regimen meets this with more oil, more warmth and less of the dry and the cold.

This entry describes the classical Ayurvedic understanding of the bone tissue. It is not medical advice, and anyone with a health condition should speak to a qualified practitioner.

Frequently asked

Why is bone called the seat of Vata when Vata is the lightest dosha? Because Ayurveda holds that like settles in like, and both bone and Vata share the quality of dryness. The dry, light Vata makes its home in the dry, firm bone, which is why disturbances of Vata are read first in the bones.

What feeds the bone tissue? The fat tissue, medas, that comes just before it in the order of the seven tissues. Bone is built from fat, so the texts hold that the bones are only as well made as the tissues above them in the line.

Why is sesame oil linked with the bones? Sesame is warm and building, and its oil is the classical medium of abhyanga, the daily self-massage. The tradition holds that this oiling reaches and nourishes the deep tissues, the bone among them, and steadies the dry Vata that sits there.