Shira is a term used collectively for blood vessels (the arteries, the veins and the capillaries). In simple language, dhamani denotes the artery; which carries pure or oxygenated blood. This is also referred to as the arterial system and forms integral part of the circulatory system. Preliminary knowledge of dhamani is very important for physicians as well as surgeons.
Classification of Shira (blood-vessels)
The cardiovascular system comprises of the heart and blood-vessels with their contained fluid, blood. The heart is basically a muscular organ pumping blood to all parts of the body by its contraction.
- Pure or oxygenated blood is carried by the arteries away from the heart,
- Impure or deoxygenated blood is carried by the veins. The veins carry the blood from the capillaries back toward the heart,
- There is another group of blood vessels known as capillaries which carry lymph. The capillaries ensure the exchange of chemicals and water between the blood and the body-tissues.
Dhamani (Artery) as per Sushruta Samhita
Sushruta calculated that there were about seven hundred, siras (veins), two hundred, dhamanis (arteries). The number of the minute sira and dhamani was equal to same as the number of the hair-follicles. Sushruta Samhita had used the word dhamanis (artery) to some of the mula sthanas of srotas (origin of the channels of the circulations), but he had not used any siras as the mula sthana of a srotas (channels of the circulations).
Relation of dhamani with srotas (Relationship of arteries with the channels of the circulations)
A structure which has originated in the hollow organs or the vacant are found widespread throughout the human body. These structures are better understood as srotas (channels of circulation) and are distinct from dhamani (artery) and sira (vein).
According to Charaka Samhita, srotas (channels of circulation), sira (vein), dhamani (artery), rasavahini (capillaries), rasayani (lymphatic channels), marga (track), nadi (duct), pantha (passage), sariracchidra (spaces inside the body), samvritasamvrita (duct closed at one end and open at the other), sthana, ashaya and niketa (visible and invisible spaces inside the human body) are constant part of the human anatomy.
According to Charaka Samhita, some of the above described structures having pulsation, and are known as dhamani. Pulsation is described as 'dhmanaddhamanyah' (pulsating process) in Ayurvedic system of medicine. Some have hollow space and allow translocation of nutriments, liquid and blood and are known as srotas (channels of circulation). Some perform simple duty of simply carrying a substance from one place to another, are known as sira (veins).
Difference between veins, arteries and channels of circulation
According to Sushruta Samhita, the concept that there is no difference among sira (vein), dhamini (artery) and srotas (channels of circulations), as dhamini and srotas are only sira vikara (by-products) is wrong. Sushruta categorically says that shamini and srotas are different entities than sira. Sushruta describes following reasons for differentiation among sira (vein), dhamini (artery) and srotas (channels of circulations).
- Vyanjanayatvat (Differentiation in features): The colour of sira can be crimson red, red, blue or white. No such differentiation in seen in dhaminis and srotas.
- Mulasanniyamat (Point of origin): As regard point of origin, siras are 40 in number, dhamanis are 24 in number and srotas are 22 in number.
- Karmavisesyat (Specificity in functions): Sira owing to contraction and dilatation property, supply nutrients to the human body. Dhamanis owing to pulsating property are in a position or carry blood. On the other side, srotas carry oxygen, fluid and food.
- Agamcca (Text authority): The ancient texts of Ayurveda have mentioned sira, dhamani and srotas as separate entities. Hence dhamani should be considered as different from different from sira and srotas.
Similarities between veins, arteries and channels of circulation
- Paraspara sannikarshata (Close relationship): Sira, dhamani and srotas are situated in close proximity in the human body. Arteries and veins along with branches are found in close proximity in the human body.
- Sadhrusyagama (Inter-changeable): Since sira, dhamani and srotas are involved in transport of the nutrients, apparently there is no distinct difference between these structures. In Ayurvedic context, sira, dhamani and srotas are used for each as they are inter- changeable. Veins and arteries have identical anatomy as they are hollow inside.
- Sadhrusya karma (Similarity in functions): Transportation of the biological humours and tissue is a common function of sira, dhamani and srotas. Along with physiological similarity, sira, dhamani and srotas have some anatomical similarity also. Sira, dhamani and srotas are composed of akash mahabhuta (space or ether).
- Sukshamat (Minuteness): Sira, dhamani and srotas, all are minute. Owing to this property, differentiation among three is a bit difficult.
From above discussion, it can be concluded that the arteries can only act as moola sthana (point of origin) but not the veins because they carry impure blood. Further, veins are situated after the channels of circulation, hence veins cannot be considered as mula sthana (point of origin) of any channels of circulation.