Asthi Dhatu (अस्थी धातु)
The term 'Asthi' in samskrit refers to a 'Bone'. Thus Asthi dhatu mentioned in Ayurveda is similar to bony tissue in human body. In human beings Asthi dhatu performs the vital function of forming the skeleton, providing stability and shape. In a literal sense, the word Asthi means that entity which doesn't get destroyed easily and stays longer as compared to all other counterparts. It is well known that even after years of burial of human bodies, the remnant tissue which one can find is bone. Thus bone or asthi is that body component which is not easily destroyed naturally very rapidly. In human beings Asthi dhatu performs the vital function of forming the skeleton, providing stability and shape.
Characteristic feature of Asthi dhatu
Asthi dhatu is identified by Ayurveda acharyas by its peculiar feature of strength. Acharya Sushruta has beautifully explained the properties, role and importance of Asthi dhatu with example as follows,
अभ्यन्तरगतैः सारैर्यथा तिष्ठन्ति भूरुहाः | अस्थिसारैस्तथा देहा ध्रियन्ते देहिनां ध्रुवम् ||२१||
तस्माच्चिरविनष्टेषु त्वङ्मांसेषु शरीरिणाम् | अस्थीनि न विनश्यन्ति साराण्येतानि देहिनाम् |
मांसान्यत्र निबद्धानि सिराभिः स्नायुभिस्तथा | अस्थीन्यालम्बनं कृत्वा न शीर्यन्ते पतन्ति वा ||२३||
Meaning: Physical bodies of the humans are held stable by the strong asthi like the trees are held strong rooted to the ground due to their strong stem (heartwood). Since asthi are like the essence of the body those never decay and get destroyed long after decaying of mansa and twak (Muscular tissue and skin). Various sira (vessels, nerves) and snayu (tendons, ligaments) are attached to asthi and those are held in place because of asthi which themselves never decay or fall.
Thus Asthi dhatu is also termed as the extract (sara) of the body (Su.sha 5/21-22]
Panchabhautika constitution
Asthi dhatu is that tissue which is called as essence or extract of body. It is strong, hard and stable. Therefore it is clear that it has Prithvi mahabhuta dominance in it. At the same time it is also khara (dry and rough) in texture. (Cha chi 15/24,25) This property of Asthi is developed during its generation from meda dhatu by the action of Teja and Vayu along with Pruthvi. Also Asthi is one of the chief sites of vata residence. Thus Along with Pruthvi, Asthi dhatu has dominant vayu and teja mahabhuta as well.
Utpatti of Asthi dhatu
The asthi dhatu is formed from its predecessor meda dhatu. When meda dhatu is subjected to the process of micro-transformation (सूक्ष्मपचनम्), one processed part of it is specifically utilized to provide nourishment to the next dhatu in order i.e. Asthi Dhatu (धातु). This part is responsible for development and nourishment of asthi dhatu in body. Transformation of this fluid and unctuous form of meda dhatu into solid and tough (cha chi 15 24, 30) form of asthi dhatu happens due to action of Pruthvi, Teja and Vayu mahabhutas. In this process, there happens generation of excess dryness in the processed part. Such excess dryness and hardness are the distinguishing features of asthi dhatu from all other dhatus.
Saushiryam ( Porosity) in bones are due to actions of vayu and akasha mahabhuta. [Cha. Sa. Chikitsa Sthana 15/30]
Upadhatu of Asthi
Nakha (nails) and Danta (teeth) are considered to be the Upadhatus (metabolic byproducts) of Asthi Dhatu. Those develop during the process of metabolism and development of asthi dhatu, [Su. Sa. Sutra Sthana 46/529] [Sha. Sa. Purva khanda chapter 5] Therefore it is observed that those suffering from diseases affecting Asthi dhatu may present with symptoms related to teeth and nails. Changes in the levels of asthi dhatu in body can be easily observed from the overall health of nails and teeth.
Malas of Asthi
Kesha (Scalp hair) and Loma (body hair) are malas (waste products of metabolism) of asthi dhatu. [Cha.Sa. Sutra Sthana 15/18]
Characteristics of best quality or essence (asthisara)
पार्ष्णिगुल्फजान्वरत्निजत्रुचिबुकशिरःपर्वस्थूलाः स्थूलास्थिनखदन्ताश्चास्थिसाराः|
ते महोत्साहाः क्रियावन्तः क्लेशसहाः सारस्थिरशरीरा भवन्त्यायुष्मन्तश्च||१०७|| [Cha.Sa. Vimana Sthana 8/107]
Meaning: The persons with essence of asthi dhatu have prominent heels (parshni), ankles (gulpha), knee joint (janu), elbows (aratni), collarbones (jatru), chin (chibuka), head (shira), flanks (parshva) and joints and also bones and teeth. Such persons are highly enthusiastic, active, enduring, having strong and firm body as well as longevity.[Cha.Sa. Vimana Sthana 8/107]
Location of asthi dhatu
Asthi dhatu is present everywhere in the body mainly forming the skeleton of the bones. There are five types of bones in human body. [Su .Sa Sharira Sthana 5/20] Also,
These 5 types are as below,
| Type | Site | |
|---|---|---|
| 1. | Flat bones (kapala) | Knee (Janu), jaghana(pelvic), shoulder(amsa),
Cheek(ganda),palate(talu),temples(shankha),skull(shiras) |
| 2. | Teeth(ruchaka) | Teeth |
| 3. | Cartilages(taruna) | Nose(Ghrana), Ear(karna), Neck(griva),orbit of the eye(akshikosha) |
| 4. | curved/Annular bones(valaya) | Ribs(Parshuka), vertebrae (prushthakasheruka) |
| 5. | Tubular bones (nalaka) | All other long bo |
Channels for transportation and transformation of asthi dhatu (asthivaha srotas)
The channels originate from predecessor meda dhatu and buttocks (jaghana). [Cha. Sa. Vimana Sthana 5/8] There are various other anatomical structures related to asthi dhatu. These can be included in the system. The structures are as described below.
Functions
The important function of asthi dhatu is providing structure and support to the body. It also nourishes the successor bone marrow tissue (majja dhatu).[Su. Sa. Sutra Sthana 15/5]
Causes of vitiation
The following are causative factors for the vitiation of channels for transport and transformation of asthi dhatu (asthivahasrotasa). [Cha. Sa. Vimana Sthana 5/17]
Dietary causes
- Excessive consumption of food that aggravates vatadosha in body. This includes the dietary items which possess properties like light to digest (laghu), dry(ruksha), cold(sheeta), rough(khara), highly penetrating or subtle (sukshma), mobile(chala).
Lifestyle causes
- Excessive physical exercise
- Excessive jerks to the body or jerky movements
- Excessive pressure on bones.
Signs of decrease
- loss of scalp and body-hair, beard, nails and teeth
- fatigue
- loose joints
- pain in bones
- dryness
- breaking of teeth and nails
[Cha. Sa. Sutra Sthana 17/67], [Su. Sa. Sutra Sthana 15/9]
Signs of increase
- extra tooth and bony growth [Su. Sa. Sutra Sthana 15/14]
Importance in preservation of health and prevention
Bone tissue (asthi dhatu) is considered as the essence of body tissue which remains even after destruction of all other tissues. [Su. Sa. Sharira Sthana 5/21-22]
The enthusiasm, endurance, strength, body structure, firmness, and longevity depend upon quality of asthi dhatu. [Cha. Sa. Vimana Sthana 8/107]