(covers information from several alternate timelines)
"Unbelievable... do you recognize those uniforms?"
"Mid-twentieth century Earth. The nation-state called Nazi Germany."
- - Kirk and Spock, 2268
German SS uniforms
The German SS used two main uniforms. The first uniform was adopted in the 1930s and comprised a black jacket and cap. During the 1930s, the SS displayed itself at Nazi rallies in the black uniform; one such rally was seen through the Guardian of Forever in 2267. (TOS: "The City on the Edge of Forever")
The SS used the black uniform until the start of World War II, when the SS adopted a more practical grey field tunic. The rank insignia remained the same from the 1930s black uniform. (VOY: "The Killing Game")
SS members were granted the same medals of Nazi Germany as the Wehrmacht (German military). The standard form for the display of SS decorations was to pin large medals on the front of the left uniform pocket immediately below award ribbons. (ENT: "Storm Front")
At the end of World War II in 1945, the SS ceased to exist along with its uniforms; however historical data regarding the original SS uniforms was maintained by Earth historians and later maintained in the library computers of Federation starships.
On a mission to Ekos, the library computer of the USS Enterprise was able to patch into its uniform section and create a replica of a 1944 Gestapo Standartenführer's uniform for wear by Leonard McCoy. Although there were differences between the German SS and its re-born Ekos counterpart, McCoy's uniform was convincing enough that he was able to pass for an Ekosian SS officer. (TOS: "Patterns of Force")
A century later, the Hirogen were able to capture the USS Voyager and program its holodeck with a World War II scenario set in France. In the scenario, the Hirogen took on the role of German SS personnel and dressed in the appropriate grey SS uniforms. (VOY: "The Killing Game")
Standard SS form was to display rank insignia on one collar, and an SS unit patch on the other. Most of the SS wore a "lightning bolt" SS unit patch, however certain SS units were entitled to wear a Death's Head insignia (the Death's Head emblem was also the standard cap insignia for all SS personnel). SS colonels and generals wore rank insignia on both collars and did not display a unit insignia patch.
SS uniforms also incorporated cuffbands worn at the bottom of the left sleeve, with such cuffbands used to indicate membership in special sections of the SS or in specific regiments. For specialty branches of the SS, such as the SS Medical Corps or units of a Headquarters Guard Battalion, additional badges could be worn either in the form of a sleeve insignia or as a shoulder board lapel. (TOS: "Patterns of Force"; VOY: "The Killing Game"; ENT: "Storm Front")
Enlisted SS uniforms
Enlisted SS collar insignia was worn on the right hand collar opposite an SS unit insignia patch. Ordinary SS soldiers wore a borderless rank patch, while non-commissioned officers (NCOs) displayed rank patches with a thick white piping. Enlisted soldiers wore a bare shoulder strap while NCOs wore a strap with white borders and pips. The lance corporal grade wore the same strap as a Private, but also displayed a sleeve chevron.
|Enlisted rank||Insignia (collar/shoulder)||Example|
Officer SS uniforms
The field grey SS officer uniform displayed rank the same as enlisted personnel, although the rank collar patches were bordered in silver trim. As with enlisted personnel, SS officers wore rank with a matching set of shoulder boards.
|Officer rank||Insignia (collar/shoulder)||Example|
The black officer uniform also utilized a collar rank patch and shoulder board combination, however the shoulder boards worn on the black uniform were thinner and slightly longer than those of the grey field uniforms. Black uniform shoulder boards were also worn on the right shoulder only whereas the field uniforms had boards on both shoulders.
|SS rank||Insignia (collar/shoulder)||Example|
Ekosian SS uniforms
In 2268, Federation historian John Gill succeeded in creating a replica of Nazi Germany on the planet Ekos. The Ekosian Nazi Party also formed its own version of the SS with uniforms and insignia very similar to the original SS of 1940s Earth. The similarities were so close that Doctor Leonard McCoy, outfitted in a 1944 era SS colonel's uniform, was able to easily pass as an Ekosian SS officer even under the scrutiny of Ekos Nazi Party Chairman Eneg.
The Ekosian SS used at least four different types of uniforms, all of which were worn simultaneously by various branches and sub-branches of the SS. The military SS was outfitted in grey field tunics and helmets with insignia the same as their German SS counterparts. The security branch of the SS (the most commonly encountered branch of the Ekosian SS as a whole) wore light blue uniforms with similar insignia to the German SS but with some notable differences.
Black SS uniforms were also used by the Ekosians, in particular the Ekosian Gestapo. Additionally, black uniforms were worn by various special branches of the SS. In an attempt to infiltrate the Ekosian Chancellery, Captain James T. Kirk led an Ekosian/Zeon resistance cell disguised as black-uniformed SS soldiers from the "Führer's Special Documentary Corps".
A fourth and somewhat rare uniform of the Ekosian SS was a brown shirt worn with black tie and insignia. The sole observation of this uniform, during an away mission to Ekos by USS Enterprise personnel, was as seen on a public viewscreen during a news broadcast by an SS announcer.
One of the most notable differences between the Ekosian SS and the German SS was the lack of medals and awards displayed by Ekosian SS members. On Earth, SS uniforms were typically heavily adorned with all manner of medals, ribbons, and badges, yet on Ekos most of the SS encountered wore uniforms without any military decorations. The Iron Cross was an exception; however, this award appears to have been awarded more to members of the Nazi Party proper rather than to the SS. (TOS: "Patterns of Force")
The SS on Ekos wore rank insignia much the same way as the German SS did on Earth. All SS members wore an SS emblem on the left collar followed by a rank patch worn on the right. In addition to the standard SS runes, the Ekosian military SS wore SS runes with a number "1". The entire Ekosian SS wore a standardized cuffband reading "Adolf Hitler" in Gothic script.
Standard SS uniforms
The standard branch of the Ekosian SS was outfitted in a light blue uniform with soldiers wearing helmets and officers issued SS caps. All ranks displayed collar rank with officers wearing silver shoulder boards and soldiers displaying a bare soldier strap.
There existed at least one non-commissioned officer rank of corporal as well as commissioned officer ranks including such titles as major. The ranks of the SS soldiers also included a recruit type position which wore an SS uniform without any insignia.
|Approximate rank||Insignia (collar/shoulder)||Example|
Military SS uniforms
The military branch of the Ekosian SS wore uniforms very similar to the standard SS but the tunics were of a heavier darker grey fabric. Military SS members also wore helmets and some members displayed the numbered SS insignia. Officers wore silver shoulder boards as well as a rank collar patch.
|Approximate rank||Insignia (collar/shoulder)||Example|
The Ekosian Gestapo, as well as certain other branches of the Ekosian SS, wore black uniforms with insignia displayed much the same as the rest of the SS with the exception that enlisted personnel did not wear shoulder boards. Officers wore silver trimmed boards on the right uniform shoulder and all SS personnel wore a red swastika armband with this uniform.
|Approximate rank||Insignia (collar/shoulder)||Example|
General officer uniforms
When the USS Enterprise made contact with the planet Ekos, the only observed Ekosian SS generals were dressed in black uniforms worn with heavy gold shoulder boards and oak leaf collar patches in various patterns on both black and red colored collar tabs.
At a special speech given by John Gill, four SS generals were in attendance three of whom wore various patches indicating positions approximate to brigadier, general, and marshal. A fourth SS general wore an SS unit insignia on one collar and a gold piped rank patch on the other.
Special service uniforms
In addition to the uniforms of the regular SS encountered on Ekos, certain special branches of the SS existed which either did not follow the normal insignia pattern or wore uniforms not common for the rest of the Ekosian SS.
The first such group were SS guards and officers assigned to the Ekosian Chancellery. Chancellery guards wore light blue uniforms, the same as their regular SS counterparts, but the rank collar patches were trimmed in silver, the same style as SS officers. The SS officers assigned to the Chancellery also wore the standard SS uniform but displayed enlisted collar insignia paired with officer shoulder boards.
The SS also appeared to have a civilian branch, or at least a branch which wore Nazi Party brown uniforms instead of the standard SS attire. One such example was a national broadcast announcer who was observed giving a news report on a viewscreen.
|Weapons Lab Officer|
|Enlisted personnel||Commissioned officers||Generals and flag officers|
|ENS||LT JG||LT||LT CMDR||CMDR||CAPT||FCAPT||CDORE||RADM||VADM||ADM||FADM|
|2nd LT||1st LT||CAPT||MAJ||LT COL||COL||BRIG||MAJ GEN||LT GEN||GEN||MARSHAL|
|Positions:||Crewman • Technician • Chief||YMN||TAC • SO • 3rd • 2nd • 1st • CO • DD||Portmaster • Chief of Staff • CinC|
|Services:|| Andorian • Bajoran • Cardassian • Jem'Hadar • Klingon • Romulan • SS • Terran Empire Starfleet • Terran Empire MACO •|
United Earth MACO • United Earth/Federation Starfleet • United States • Vulcan
The first time SS uniforms ever appeared in Star Trek was during the episode "The City on the Edge of Forever", when a large group of SS were seen through the Guardian of Forever. The SS, however, were only seen from the rear and apart from a few shoulder boards none of the insignia is identifiable.
The four-pip rank of SS major (Sturmbannführer) has never been seen on screen, although an Ekosian SS major was seen wearing the insignia for colonel. The senior NCO ranks of Hauptscharführer (first sergeant) and Sturmscharführer (sergeant major) have also never been seen.
Another insignia pattern which has never been seen in any Star Trek production are the post-1942 SS general insignia which modified the existing "two leaf, three leaf" design into a standard three leaf collar patch with extra pips to determine the seniority level of the SS general. 
The only SS generals who have been seen on Star Trek were the Ekosian generals encountered in "Patterns of Force", and of these, only one wore historically correct SS insignia. The SS marshal, played by Frank da Vinci, wore an appropriate rank patch but another SS general wore an incorrectly placed pip and a third general wore a Nazi Gauleiter (political leader) patch instead of standard SS insignia. A fourth SS general can also be observed wearing an enlisted collar patch which has been modified with gold pips instead of silver. This insignia was an original creation of the Star Trek wardrobe department and no such insignia was ever used in the real SS.
While "The Killing Game" and "Storm Front" portray SS uniforms with correct badges and insignia, Star Trek fans and military historians alike have long observed insignia inconsistencies and costume production errors with regards to the SS uniforms portrayed in "Patterns of Force".
The most commonly observed inconsistency in "Patterns of Force" pertains to SS personnel who wear collar insignia which do not pair correctly with the uniform shoulder boards. One of the most cited examples of this is the "major" who arrests Kirk and Spock. The actor in the scene (Gilbert Green) is in fact wearing a modified version of an SS colonel's collar insignia with surviving script and costume notes indicating that this occurred due to the wardrobe department receiving an order for an SS major's uniform and basing the insignia on a United States major (gold oak leaf) instead of an SS major (four pips).
Further examples include the military SS lieutenant, encountered by Kirk and Spock at the start of the episode, who wears major shoulder boards and second lieutenant collar patches. SS personnel encountered at the Chancellery Detention Center, specifically the SS interrogator and an SS guard seen near the weapons lab, also wear officer shoulder boards with enlisted insignia. Thus, in all, there are four examples of SS personnel who wear historically incorrect uniforms.
In addition to insignia inconsistencies, "Patterns of Force" portrays at least four clear production errors. The first two occur when Spock and Kirk steal SS uniforms at the start of the episode. In both cases, the uniform insignia changes from the time that the uniform is stolen to when Kirk and Spock wear the uniform in a later scene. This was since the two scenes were shot independently and the uniforms worn by Leonard Nimoy and William Shatner were not the same ones as those worn by the actors who portrayed the original SS officers.
Of interest also is that the Gestapo insignia worn by Kirk is not an actual insignia of the SS. Kirk's insignia consists of three silver pips sewn in a straight line with the last pip sewn on top of a silver bar. No such insignia existed in the historical SS, but the insignia seen on Kirk may very well be unique to Ekos.
Additionally, a costume error occurs towards the end of the episode, where Kirk and company are hiding in the cloak room inside the Ekosian Chancellery. During this one scene, the bottom pip of Kirk's rank patch suddenly becomes gold where before all three pips were silver.
A final production error occurs at the end of the episode when Spock exits an automobile as part of the "Führer's Special Documentary Corps". In this scene, Spock wears a silver pip on his collar but is "pip-less" in the next scene when Kirk and company walk inside the Ekosian Chancellery. The reason for this was that the two scenes were filmed days apart, one outside and at night and the other indoors on a soundstage.
Other plot ambiguities include Kirk's knowledge of Ekosian SS ranks (he addresses the SS major by his proper title before the rank is said by anyone else) as well as the uniform worn by Doctor McCoy who is disguised as an SS colonel.
While McCoy's uniform and insignia are essentially correct, when McCoy beams down into the Ekosian cloak room, he can be seen wearing a German general's army overcoat. McCoy's uniform also appears to be of exactly the same fabric as the Ekosian version and, like most of the Ekosian SS, McCoy wears absolutely no military decorations. Historically, this is extremely inaccurate, since a 1944 era SS colonel would most certainly have displayed military decorations. There are explanations around this, however, such as a computer error or Kirk explaining off-camera that Ekosian SS uniforms were worn without medals.