There are three ranks within the pay grade of E9 - Sergeant Major, Command Sergeant Major, and Sergeant Major of the Army. There is only one Sergeant Major of the Army.
After the ranks of Sergeant Major come the commissioned officers, the first one being 2nd Lieutenant.
There is no such rank as Medic Sergeant Major of the Army. There is a Sergeant Major of the Army and regardless of his specialty, it is just SMA.
The first US Army Sergeant Major of hte Army was William O. Wooldridge.
No, there is no rank of "Major Sergeant" in the Army Rangers. The ranks in the U.S. Army Rangers follow the same structure as the rest of the Army, including ranks such as Private, Sergeant, Lieutenant, Captain, and Colonel.
FORSCOM does not have it's own Sergeant Major of the Army - there is only one SMA in the entire Army. The Command Sergeant Major of FORSCOM holds the rank of Command Sergeant Major, and this post is currently filled by CSM Ronald T. Riling. The current Sergeant Major of the Army is SMA Kenneth O. Preston.
It's Sergeant Major of the Army (there is no "Command" in the title), and the post is currently held by SMA Raymond F. Chandler.
The United States army consists of twelve ranks. They are, in order of rank, Private, Private First Class, Specialist, Corporal, Sergeant. Staff Sergeant, Sergeant First Class, Master Sergeant, First Sergeant, Sergeant Major, Command Sergeant Major, and Sergeant Major of the Army.
The rank of sergeant is denoted by three chevrons on the sleeve of the DPCU uniform (old style) or in the rank-slot on the front of the new design uniform.
The latest figures I can find online are for 2005. See the following link, page 32. See related link below for official Army document. There is more than one level of sergeant in the US Army, so I'll give a total, as well as the number by rank. I assume you mean active-duty US Army, and not US Army National Guard, and possibly not the US Army Reserve, but the document does not indicate whether the latter two organisations are included or not. In the US Army, ranks E-5 (NATO OR-5) to E-9 (OR-9) are all variants of a sergeant. It should be noted, for comparison to other armies, that this is not true of all armies. In the British Army, by example, only OR-6 and OR-7 are sergeants (Sergeant and Colour/Staff-sergeant, respectively). OR-8 and OR-9 in the British Army are Warrant Officers. While addressed as Sergeants-Major, they are not considered Non-Commissioned Officers, or Sergeants. Also, the role of fire-team leader, performed in the US Army by an OR-5 Sergeant is actually performed in the British Army by an OR-3 Lance-Corporal. The role of squad/section-commander, performed in the US Army by an OR-6 Staff-Sergeant, is performed in the British Army by an OR-4 Corporal. The British Army has no OR-5 grade. The role of second-in-command of a rifle platoon, which is performed in the British Army by a Sergeant, is performed in the US Army by a Sergeant First Class. The roles assigned to different ranks, and the number of NCOs to privates, will be different in non-infantry units. The total shown for ranks E-5 to E-9 is: 189,134 The totals by grades are below E-9 (Sergeant Major of the Army; Command Sergeant Major; Sergeant Major): 3,409 E-8 (First Sergeant; Master Sergeant): 10,692 E-7 (Sergeant First Class): 37,810 E-6 (Staff Sergeant): 59,885 E-5 (Sergeant): 77,338
Command Sergeant Major is the highest enlisted rank in the US Army
Edgar Allan Poe held the rank of Sergeant Major in the Army.