This answer discusses how combat and non-combat officers fit into a military hierarchy, how this impacts the ability of one to command the other, and how that fits into the ST:TOS hierarchy.

However, at least at two separate times (in Voyager; possibly elsewhere as well) it is stated that in medical matters, the chief medical officer outranks the captain of the ship. That's Starfleet Medical Protocol regulation 121 section A.

• When is that protocol first established and/or stated, in-universe? (Comparisons to real world situations are welcome as well, but are not the focus of this question.)
• What are the specific limits to this protocol? Is it, for example, possible for a properly skilled physician to outrank an admiral?

This answer discusses how combat and non-combat officers fit into a military hierarchy, how this impacts the ability of one to command the other, and how that fits into the ST:TOS hierarchy.

However, at least at two separate times (in Voyager; possibly elsewhere as well) it is stated that in medical matters, the chief medical officer outranks the captain of the ship. That's Starfleet Medical Protocol regulation 121 section A.

• When is that protocol first established and/or stated, in-universe? (Comparisons to real world situations are welcome as well, but are not the focus of this question.)
• What are the specific limits to this protocol? Is it, for example, possible for a properly skilled physician to outrank an admiral?

This answer discusses how combat and non-combat officers fit into a military hierarchy, how this impact the ability of one to command the other, and how that fits into the ST:TOS hierarchy.

However, at least at two separate times (in Voyager) it is stated that in medical matters, the chief medical officer outranks the captain of the ship. That's Starfleet Medical Protocol regulation 121 section A.

• When is that protocol first established and/or stated, in-universe? (Comparisons to real world situations are welcome as well, but are not the focus of this question.)
• What are the specific limits to this protocol? Is it, for example, possible for a properly skilled physician to outrank an admiral?

This answer discusses how combat and non-combat officers fit into a military hierarchy, how this impacts the ability of one to command the other, and how that fits into the ST:TOS hierarchy.

However, at least at two separate times (in Voyager; possibly elsewhere as well) it is stated that in medical matters, the chief medical officer outranks the captain of the ship. That's Starfleet Medical Protocol regulation 121 section A.

• When is that protocol first established and/or stated, in-universe? (Comparisons to real world situations are welcome as well, but are not the focus of this question.)
• What are the specific limits to this protocol? Is it, for example, possible for a properly skilled physician to outrank an admiral?