Asthi Dhatu (अस्थी धातु)
The term 'Asthi' (अस्थिः) in samskrit refers to a 'Bone'. Thus Asthi dhatu (अस्थि धातुः) 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.
अस्थिधातु विशिष्टलक्षणानि ॥ 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 ॥
तस्माच्चिरविनष्टेषु त्वङ्मांसेषु शरीरिणाम् | अस्थीनि न विनश्यन्ति साराण्येतानि देहिनाम् ॥
मांसान्यत्र निबद्धानि सिराभिः स्नायुभिस्तथा | अस्थीन्यालम्बनं कृत्वा न शीर्यन्ते पतन्ति वा ॥ (Sush. Samh. 5/21-23)[1]
abhyantaragataiḥ sārairyathā tiṣṭhanti bhūruhāḥ | asthisāraistathā dehā dhriyante dehināṁ dhruvam ॥
tasmācciravinaṣṭeṣu tvaṅmāṁseṣu śarīriṇām | asthīni na vinaśyanti sārāṇyetāni dehinām ॥
māṁsānyatra nibaddhāni sirābhiḥ snāyubhistathā | asthīnyālambanaṁ kr̥tvā na śīryante patanti vā ॥ (Sush. Samh. 5/21-23)
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.
पांचभौतिकत्वम् ॥ 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.
अस्थिधातु उत्पत्तिः॥ 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]
अस्थि उपधातु॥ 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.
अस्थि मलाः॥ 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]
अस्थिसारता लक्षणानि॥ 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]
अस्थिधातु स्थानानि तथा भेदाः॥ Location and types of asthi dhatu
Asthi dhatu is present everywhere in the body mainly forming the skeleton of the bones. There are five types of Asthi in human body. [Su .Sa Sharira Sthana 5/20] These 5 types are as below,
| Type | Site | |
|---|---|---|
| 1. | Kapala (कपाल Flat bones) | Knee (Janu), jaghana(pelvic), shoulder(amsa),
Cheek(ganda),palate(talu),temples(shankha),skull(shiras) |
| 2. | Ruchaka (रुचक Teeth) ruchaka | Teeth |
| 3. | Taruna (तरुण Cartilages ) | Nose(Ghrana), Ear(karna), Neck(griva),orbit of the eye(akshikosha) |
| 4. | Valaya (वलय curved/Annular bones) | Ribs(Parshuka), vertebrae (prushthakasheruka) |
| 5. | Nalaka (नलक Tubular bones) | All other long bones |
अस्थिवहस्रोतसम् ॥ Asthivaha Srotas
Channels for transportation and transformation of asthi dhatu are known as asthivaha srotas. Acharya Charaka has mentioned meda dhatu and buttocks (jaghana) as the chief sites of this system. [Cha. Sa. Vimana Sthana 5/8]
There are various other anatomical structures related to asthi dhatu. These can be included in the system.
अस्थिजालानि ॥ Asthi Jala
There are four types of network-like structures (jala) in body including, bone network (asthijala). There are four such networks formed from each of these types. They are present in wrist and ankle joints and interlinked together.[Su. Sa. Sharira Sthana 5/12].[3]
अस्थिसंघातानि ॥ Asthi sanghata
The places where many bones are present is called confluences. The confluences of bones are fourteen in number. They include ankle(gulpha), knee(janu), and groin(vankshana) in lower limbs and their counter parts wrist(manibandha), elbow(kurpara) and axilla(kaksha) in upper limbs on each side. One is in the lower back(trika) and the other on the skull(shira) [Su. Sa. Sharira Sthana 5/16][3]
अस्थिमर्माणि ॥ Asthi Marmas
There are eight vital points formed from bones (asthi marma). [Su. Sa. Sharira Sthana 6/4] Katikataruna, Nitamba, Ansaphalaka and Shankha are those 4 marmas.[3]
कार्यम्॥ Functions
Asthi dhatu performs the major function of providing support to the body. The skeleton formed by asthi gives shape, stability and protection to the vital soft organs. The locomotor function of a person is dependent on the health and state of Asthi dhatu. Apart from this it provides nourishment to the succeeding Majja dhatu and indirectly supports its function. [Su. Sa. Sutra Sthana 15/5]
अस्थिधातुदुष्टिहेतवाः॥ Causes of vitiation
Various diet and lifestyle related factors that adversely affect asthi dhatu have been listed by Ayurveda acharyas. They cause imbalance in the levels as well as quality of the asthi dhatu, cause disturbance in the channels of its transport across the body and thus affect its function. [Cha. Sa. Vimana Sthana 5/17]
आहारहेतवाः ॥ Dietary causes
- Food items that aggravate Vata dosha (वातल आहारसेवनम्) in body lead to asthi dhatu imbalance in the body. This includes the dietary items which possess properties like laghu (लघु), ruksha (रुक्ष), sheeta (शीत), khara (खर), chala (चल) etc.
विहारहेतवाः ॥ Lifestyle causes
- Excessive physical exercise (अतिव्यायाम)
- Excessive jerks to the body or jerky movements (अतिसंक्षोभात)
- Excessive pressure on bones. (अतिविघट्टनात्)
अस्थिधातु॥ Importance in preservation of health and prevention
Asthi is that dhatu of body which provides framework in the form of skeleton which is responsible for providing shape to body and protection to inner organs. Thus the human body is held and sustained due to asthi. The locomotory activities or voluntary movements of body are possible due to presence of strong and firm asthi. Along with this asthi dhatu is also responsible for overall strength, endurance, firmness and in general for enthusiasm and longevity of body.