This image, a poster I've seen in yoga studios, conveniently sums up the confusion in the modern yoga world around the teaching on the five koshas (Skt. kośa) or 'sheaths', also known as the five bodies or five layers of the human being.
The Vedāntic version of this teaching originates in a short passage found in the Taittirīya Upaniṣad, reproduced below. The Tantrik version is detailed in my book Tantra Illuminated and in my last blog post. Now, in the interpretation given in the image, the Prāṇa-maya-kośa is the 'energy body' of cakras and nāḍīs, different from the 'emotional body' (Mano-maya-kośa). This is completely wrong from a traditional point of view -- because in the traditional yogic understanding the energy body (sūkṣma-śarīra or puryaṣṭaka) and the mental/emotional body are ONE AND THE SAME.
Therefore, the 'energy blockages' attributed in the image to the Prānic Body and the 'lack of awareness of [habitual] thought patterns and emotional reactions' attributed to the Mental/Emotional Body are one and the same thing stated in two different ways! This is indeed a crucial point to grasp.
Having said that, the creator of the poster should be praised for correctly stating that thoughts and emotions are part of the same sheath or layer; this is true in ALL systems of yoga.
The Prānic Body, then, simply relates to the proper functioning of the five aspects of prāṇa -- for example, burping, farting, digesting, and getting hungry when the body needs food is all due to the movement of prāṇa. The Prānic Body is thus intimately interrelated with the Physical Body (anna-maya-kośa) on the one hand and the Mental-emotional Body (mano-maya-kośa) on the other, which is why it is positioned between the two in the Vedāntic model. (Note how when the mental-emotional body is disturbed, that affects the prāṇa which affects the physical body. An extreme example would be anorexia.)
By contrast, in the Tantrik model, the Prānic Layer is positioned between the Mental-emotional Layer and the Void (see diagram below) -- because that model arranges the layers of selfhood in order of coarse to subtle, ephemeral to permanent, less to more fundamental (and Prāna or Life-force is both subtler and more fundamental than Mind).
In NEITHER model is the Prānic Layer thought to be the energy body of nāḍīs, cakras, and bindus, since, again, the energy body and the mental-emotional body are one and the same thing (though, as already stated, movement of prāṇa affects the energy body). This, it need hardly be stated, is more in line with modern psychological understanding as well. The energy body, then, is a model for understanding the subtler aspects of our mental-emotional being and how it interpenetrates the tissues of the physical body.
What, in summary, are the other differences between these two parallel models? The Vedāntic model's anna-maya-kośa corresponds exactly to the body (deha) layer in the Tantrik model, but then the two systems diverge. As mentioned above, the Vedāntic model has the prāṇa layer in a different position from the Tantrik model. Furthermore, the Vedāntic model splits the mind into two layers, a thinking-feeling layer (mano-maya-kośa) and a discernment-perception layer (vijñāna-maya-kośa) whereas in the Tantrik model these are both part of the 'heart-mind' layer (citta), which is identical with the energy-body layer (puryaṣṭaka); this, then, is the 'thickest' -- but not the densest -- layer in the Tantrik model.
Finally, the Vedāntic model entirely lacks the Void (śūnya) layer which is so important to the Tantrik model; partially because the original form of Vedānta did not emphasize meditation compared to Tantra. The so-called Void simply refers to the experience of profound silence and stillness deep within, the 'place' of repose in simple spacious openness. Therefore, those yogis who regard meditation as important to their practice would do better to utilize the Tantrik model over the Vedāntic one.
So does ānanda-maya-kośa (the 'Bliss Body') in the Vedāntic model correspond to cit or saṃvit, Awareness, the innermost core in the Tantrik model? No! In the Vedāntic model it is the final 'sheath' (kośa), since the (unstated) core of the five sheaths is Ātman or Inner Self. This implies that bliss (ānanda) is not inherent to the ātman, which was a problem for later Vedāntic commentators, since in mature Vedānta, bliss is thought to be inherent to ātman-brahman.
In the Tantrik model, by contrast, the core Awareness is explicitly expressed, and that dynamic core (as opposed to the static one of Vedānta) inherently possesses the Five Powers described on p. 101 of my book, including ānanda. By contrast, the Vedāntic Self does *not* possess the Powers of Will, Knowledge, or Action. It is entirely passive, an inactive Witness.
Note the arrows in the diagram above, indicating both the dynamism of Awareness and the fact that each layer pervades those exterior to it. In both the Tantrik and Vedāntic models, whatever body/sheath/layer is more interior and essential pervades the layers that are more exterior to it. (See my last blog post as well as the passage cited below.) Diagrams of the koshas found in a Google image search generally fail to convey this key teaching.
The diagram below (also found in an image search) is more accurate than the one we started with -- in terms of the process of successive interiorization through spiritual practice -- but still does not succeed in representing the key teaching that each successively subtler layer suffuses and pervades the coarser ones.
Having discussed the issue in some depth, let's look now at the original Upanishadic passage that inspired the Vedāntic version of the teaching. Note that this passage was tied to a very ancient Vedic ritual culture that was jettisoned by the mature Vedānta of a thousand years later; so the meaning in the mind of the original author of this passage was considerably different from how it was interpreted in the mature Vedānta philosophy. It is interpreted even more differently in the syncretistic modern Vedānta of today (due, in fact, to the influence of Tantra).
From the Taittirīya Upaniṣad's second chapter (brahma-vallī), c. 500-400 BCE:
"Now, a man here is formed from the essence of food. This here is his head; this is his right side; this is his left side; this is his torso; and this is his bottom on which he rests.
Different from and lying within this man formed from the essence of food is the self consisting of life-breath (Prāṇa), which suffuses that man completely.
Of this self, the out-breath (prāṇa) is the head; the inter-breath (vyāna) is the the right side; the in-breath (apāna) is the left side; Space element is the torso/core; and Earth element is the bottom on which it rests.
Different from and lying within this self consisting of breath is the self consisting of mind, which suffuses this other self completely. Of this self, the head is simply the Yajus mantras; the right side is the Ṛg mantras; the left side is the Saman chants; the teachings (upadeśa) are the torso/core; and the bottom on which it rests is the Atharva-Āngiras.
Different from and lying within this self consisting of mind is the self consisting of perception/wisdom (vijñāna), which suffuses this other self completely.
Of this self, faith is the head; truth the right side; the real is the left side; yoga (lit., effective method) is the torso/core; and celebration is the bottom on which it rests.
Different from and lying within this self consisting of perception is the self consisting of bliss, which suffuses this other self completely. Of this self, the head is simply pleasure; the right side is delight; the left side is the thrill; the torso/core is bliss; and the bottom on which it rests is the brahman."
(Based on the translation of Patrick Olivelle)