The first pattern of the WWII Army Nurses visored service cap had a fabric bow at the front and initially was worn without any insignia. However, some nurses pinned the ANC collar insignia above the middle of the bow.  The pattern of the service cap was revised a few months later. The fabric bow at the front was omitted and approval was given to nurses' requests for the same regulation United States Coat of Arms on their service caps as male officers wore.

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Cap Device: Regulation Coat of Arms of the United States

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At first, Army Nurses wore their caduceus collar branch insignia on the left front of their overseas caps.  Later, in 1943, it was ordered to wear a rank pin only on the left side one inch from the front center of their overseas caps, thus adopting the same wear authorized for male officers.

A letter was superimposed on the staff of the caduceus to distinguish special Medical Service Corps of the Army (for example "D" for Dental Corps, "V" for Veterinary Corps, "S" for Sanitary Corps, PT for Physical Therapists). A superimposed "N"  indicated the Army Nurse Corps.

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Left: Caduceus with white enameled N Middle: Caduceus with brown enameled N Right: Caduceus with black N

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It was very common to use contrasting coloration on the superimposed letters, in order to highlight the exact branch of the Medical Service Corps being served. For example, a bronze and a brown enameled N was already adopted during the 1920s, white and black during the 1930s.

The caduceus was worn on both lapels of the WWII service uniforms.  The cut-out US letters were worn on the collar of the service uniform. Rank insignia were attached to the shoulder loops.	.........	Placement of Insignia  on the Service Uniform
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Additionally, the caduceus was worn on the left side of the collar on capes, hospital uniforms and shirtwaists (if the jacket was removed).  A rank pin was worn on the right side of the collar. On hospital uniforms where the rank pins could be worn on shoulder epaulets, the US letters were worn on the right side of the collar instead of the rank pin.
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On the Off-Duty dress, the caduceus was worn on the left side of the collar, the cut-out US letters on the right side and rank insignia on the shoulder loops.  The insignia were placed the same way on the brown and white seersucker uniform when worn with the matching jacket.		Placement of Insignia  on the Off-Duty Dress

Flight Nurse Wings
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Flight Nurses wore a flight nurse's wing above their left sleeve pocket. The first flight nurse wing was authorized in December 1943. The gold color of the first wing version was changed to silver at the end of 1944. 
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Regular gilt US Coat of Arms Button

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Army Nurses wore regular gilt US coat of Arms buttons on their service uniforms and off-duty dresses. Detachable white mother-of-pearl buttons were worn on the white hospital uniform. Detachable blue mother-of-pearl buttons were worn on the blue hospital uniforms.

Overseas stripes made of gold embroidery

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Overseas stripes made of gold colored braid

. Placement of sleeve stripes above the sleeve braid

. Placement of sleeve stripes on the  wool field jacket (Ike jacket)

Army Nurses could wear a sleeve patch on their left upper sleeve of their service and field jacktes, overcoats, utility coats, raincoats and waists to indicate the Army force to which they were assigned. The Army was divided in three forces, the Army Service Force, the Army Air Force and the Army Ground Force. The patch could be that of a General Headquarters or a special higher-level formation or command. Army Nurses serving with the Ground Forces were formally assigned at the level of army groups or armies, but seldom within corps or combat divisions. 

To make a complete and accurate survey of all sleeve patches worn by Army nurses, one would have to possess all the unit assignment and attachment orders of all nurses during World War II. This would be an impossible task. Many orders were destroyed or captured by enemy offenses (i.e., Japanese advance in the Philippines, German counterattacks at Anzio and the Ardennes, etc.). Furthermore, many orders were destroyed during the war or accidentally burned during the 1973 loss of personnel records at the St. Louis depository in postwar America. In other words, in most cases, the required orders simply no longer exist. http://www.archives.gov/st-louis/military-personnel/fire-1973.html

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In the following, some examples of United States Army Sleeve Patches 
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General Headquarters

Examples of some headquarters patches