(covers information from several alternate timelines)
Sickbay, also known as the dispensary, was the main medical center aboard Federation starships. The section was presided over by the chief medical officer (CMO), a senior staff member. The CMO was supported by various medical practitioners. The area was also used for certain analyses of new lifeforms a starship might encounter, and for developing treatments for unknown diseases or illnesses. When rendering aid to a stricken planet or spacecraft, the sickbay staff treated and cared for the wounded. On starbases, sickbay was typically called the infirmary.
Intensive care unit
Three or four biobeds generally lined the walls of sickbay's intensive care unit, or ICU; these were for patients receiving medical care and were equipped with biofunction monitors. On Galaxy-class starships, private rooms were available for long-term patients. (TNG: "Ethics")
Sickbays also had surgical beds, where major surgeries were performed and critical patients were treated. A large, sophisticated sensor cluster was usually installed directly above this bed. Working in conjunction with a medical tricorder, the sensor suite could give detailed information about a patient's condition. The bed was also designed to use a surgical support frame. This bed was often located in the center of the main sickbay room, although refit Constitution-class and Intrepid-class starships had separate spaces for their surgical beds, the former in a separate room, the latter in a small area that could be isolated by a force field. (Star Trek: The Motion Picture; VOY: "Caretaker", "Phage") Aboard Intrepid-class starship this surgical facility was named surgical bay. (VOY: "In the Flesh") If necessary, surgery could be conducted in the intensive care ward if there was an overflow of patients or if another patient was present to donate blood. (TOS: "Journey to Babel"; VOY: "Latent Image") Galaxy-class starships also had separate surgical rooms. (TNG: "Ethics")
Sickbays typically had small laboratory facilities attached to the ICU. The chief medical officer or other associated personnel could monitor experiments or run tests here during their duty shift. (TNG: "Evolution", "Clues", "The Game"; VOY: "Macrocosm") The laboratory was equipped with a full bioisolation field. (TNG: "Home Soil") Many starships also have separate, larger medlabs. Galaxy-class ships had at least four. (TNG: "Ethics"; Star Trek Nemesis)
The chief medical officer's office was also located in or near sickbay. As with the captain's ready room, it was an area for the CMO to work in privacy or conduct meetings with patients, staff, and others. Its close location allowed the CMO to be present in sickbay almost immediately. The space could be personalized, and the chief medical officer could use plants or paintings for decoration. Dr. Beverly Crusher had a large painting outside her office; it was an abstract representation of humanoid organs against the backdrop of space and several of the USS Enterprise starships. She also had a small potted palm tree on the floor beside her desk.
Other treatment facilities available in a Galaxy-class sickbay included physical therapy rooms, (TNG: "Ethics") OB/GYN and nursery areas, (TNG: "The Child", "Data's Day") and an emergency bio support unit. (TNG: "Transfigurations") A stasis unit was also available, used to temporarily place patients in suspended animation for later treatment. (TNG: "Genesis") Constitution-class starships had a decompression chamber, and may have had other features as well. (TOS: "Space Seed", "The Empath", "The Lights of Zetar")
A morgue facility was also part of sickbay. On Galaxy-class starships, there was a large separate morgue, (TNG: "Man of the People", "Suspicions") although autopsies were performed in the main sickbay. (TNG: "Realm of Fear", "Suspicions") The Intrepid-class had a tiny area for storage of the deceased just off the medical lab as well as a separate morgue area. (VOY: "Basics, Part II", "Emanations", "Renaissance Man")
Sickbays were well stocked with a variety of medical equipment and supplies. Much of it was left out on tables or benches for use by the medical crew, but some items were stored in cargo crates. (TNG: "Haven", "Starship Mine"; VOY: "Message in a Bottle") On 24th century starships, if a piece of equipment was needed but not available it could be replicated. A standard food replicator was also found in sickbay, (TNG: "Evolution", "Future Imperfect") although the quality of the food did not appear to have improved much since the twentieth century. (TNG: "Ethics")
Due to its critical importance, the primary sickbay was usually located deep within the saucer section of most Federation starships. Sickbays were well-protected, and generally had a phaser locker for defense of the facility in the event the ship was boarded. (TNG: "Starship Mine", "Timescape") However, on Constitution-class vessels, at least one sickbay was located near the exterior of the saucer section, and had a window. (ST: "Ephraim and Dot")
Sickbays could provide limited psychological services to a starship's crew. In the 23rd century, the ship's doctor often doubled as an informal counselor. (TOS: "The Cage") By the 24th century, counselors became a normal part of starship crews. Although not formally part of the medical staff, the counselor played an important role in the well-being of the crew. (TNG: "Relics") Counselors were not always assigned to starships, especially smaller vessels with limited missions. While the USS Voyager was stranded in the Delta Quadrant, the ship's Emergency Medical Hologram and morale officer Neelix informally filled the counselor roles. (Star Trek: Voyager)
When a large scale disaster was encountered by a starship, cargo bays and shuttlebays could be used as triage centers and even morgues if necessary. Generally, this was only feasible on larger ships with a sizable medical staff. On Galaxy-class ships, a chief medical officer could order all Starfleet crewmembers and civilians with medical training to assist during a major crisis. (TNG: "Night Terrors", "Ethics") Galaxy-class starships also carried large quantities of backup medical supplies in the event of disaster. (TNG: "Preemptive Strike")
Designated environmental shelters could also be converted for medical use, such as Ten Forward on the Galaxy-class. (TNG: "Night Terrors", "Disaster") On the Intrepid-class USS Voyager, the mess hall often served as a backup to sickbay. (VOY: "Macrocosm", "Before and After", "Year of Hell", "Memorial")
The Emergency Medical Hologram
The Emergency Medical Hologram was an asset to medical personnel introduced in 2370. It could be activated in the event of a major emergency or loss of the medical staff. Although its value was indisputable, many Starfleet doctors, including Beverly Crusher, were not fond of the program, and it was rewritten several times. (Star Trek: First Contact; DS9: "Doctor Bashir, I Presume"; VOY: "Life Line") One noteworthy EMH was The Doctor of the USS Voyager. He was activated shortly after the ship's disappearance in 2371, and served as their chief medical officer for nearly seven years, growing into a sentient being in the process. (VOY: "Caretaker", "Endgame")
Differences among starship classes
The NX-class had a single sickbay ward on E Deck. The facility was open-plan, with laboratory equipment in the main sickbay area. The room also contained a main operating table, as well as several side beds for recovery of patients and an imaging chamber. To either side of the imaging chamber were autoclaves. The room was easily capable of caring for non-humanoid patients. Aboard Enterprise NX-01, Dr. Phlox often kept various different species of animals in sickbay, which he sometimes used in the treatment of injuries in lieu of more traditional treatments. One such animal was an osmotic eel. (ENT: "These Are the Voyages...", "Fight or Flight", "A Night in Sickbay", "Broken Bow")
The Kelvin-type sickbay was a brightly white-lit room, furnished with at least one biobed. Next to the bed were a couple of free-standing consoles and two overhead monitors.
The Crossfield-class sickbay featured two biobeds on each side of the room, with a third in the center. Above each biobed was an imaging chamber. (DIS: "The Butcher's Knife Cares Not for the Lamb's Cry")
On Constitution-class starships, sickbay was located on Deck 5, and was considered the best protected part of the ship. (TOS: "Mirror, Mirror", "Elaan of Troyius") It was maintained and operated by the astro-medicine department. There were at least four wards. (TOS: "The Naked Time") They featured multiple body function panels. (Star Trek: The Original Series) One of the wards was an isolation ward. (TOS: "Turnabout Intruder") It was completely redesigned during the refit of the USS Enterprise, much to the chagrin of Dr. McCoy. (Star Trek: The Motion Picture; Star Trek VI: The Undiscovered Country)
Galaxy-class ships had at least three sickbay wards. (TNG: "Tapestry") Two sickbay wards were located on Deck 12 of the saucer module, with the primary facility on the starboard side of the ship and a backup on the port. (TNG: "A Matter of Perspective") Another sickbay was in the stardrive section. (TNG: "The Arsenal of Freedom"; Star Trek Generations) Galaxy-class ships had one of the largest medical care facilities in the fleet, taking up the majority of Deck 12.
In an alternate timeline, Captain Rachel Garrett marveled at the size and advancement of the Enterprise-D sickbay, stating that she had "never seen anything like it before, even on a starbase." (TNG: "Yesterday's Enterprise", "Remember Me") Galaxy-class ships normally had several doctors on board and at least four medical personnel on duty at all times. (TNG: "Remember Me", "Genesis")
On Intrepid-class ships, sickbay was on Deck 5. (VOY: "Tuvix", "Flashback") The entire medical staff consisted of a doctor and a nurse, supplemented by an EMH. (VOY: "Caretaker") Sickbays on the Intrepid-class were unable to handle heavy patient loads, much to the frustration of Voyager's EMH, who requested a larger facility at some point during Voyager's journey through the Delta Quadrant. (VOY: "Deadlock", "Waking Moments")
On Defiant-class ships, sickbay was on Deck 2. (Star Trek: Deep Space Nine Technical Manual) Sickbays were spartan, usually staffed with a single physician or medic. The room was equipped with limited surgical facilities and was primarily intended to stabilize patients until they could be delivered to a nearby friendly starbase medical facility. (DS9: "Waltz", "Valiant")
Aboard the Sovereign-class, sickbay wards could be found on Decks 8 and 16 (the latter of which was a smaller facility resembling the sickbay of an Intrepid-class ship). Sovereign-class sickbays were equipped with an EMH. (Star Trek: First Contact; Star Trek Nemesis)
Sickbays on the Prometheus-class were somewhat small, each containing a single surgical biobed and a spartan research area. However, the sickbays were stocked with the latest in medical technologies and were the first to test the EMH Mark II. (VOY: "Message in a Bottle")
In the script of "Where No Man Has Gone Before", sickbay is described as "the small 'Hospital', the pleasant and comfortably furnished room – not the usual Spartanish hospital type." The script goes on to describe the room's furnishings.
The sickbay set seen in Star Trek: The Motion Picture was originally built for the aborted Star Trek: Phase II television series. It was reused for Star Trek II: The Wrath of Khan and also became the seedy bar visited by Dr. McCoy in Star Trek III: The Search for Spock. (citation needed • edit)
The set was later revamped to serve as the USS Enterprise-D sickbay for Star Trek: The Next Generation. The sickbay set also doubled as the observation lounge set, during the first season of TNG. Its windows were covered with carpet when the set was used to represent sickbay. (Star Trek: The Next Generation Companion 3rd ed., p. 10) Outlines of where the windows were can be seen in sickbay scenes. There was a small medlab attached to this set, beyond the doors next to Dr. Crusher's office. It was crammed behind the transporter room and a difficult set to shoot, and ultimately only appeared three times: once as the Bio Lab in "Home Soil", again as Wesley's laboratory at the beginning of the third season, and in its final appearance as the tactical laboratory in "The Mind's Eye". This led to the creation of a new, separate multipurpose laboratory which appeared towards the end of the same season. Items and the layout in sickbay changed gradually as the series went on, including the removal of a brown-tinted window in front of the main bio-bed shown in "The Naked Now". (citation needed • edit)
It also appeared as the USS Enterprise-A sickbay in Star Trek V: The Final Frontier and Star Trek VI: The Undiscovered Country, in this same basic configuration. 24th century control panels and technology could be seen on the set in Star Trek V, but for Star Trek VI, the set was better redressed to hide the TNG-era elements.
The set was further retooled to become Voyager's sickbay for Star Trek: Voyager and the USS Enterprise-E sickbay in both Star Trek: First Contact and Star Trek: Insurrection. Elements from this incarnation of the set were incorporated in the USS Prometheus in "Message in a Bottle". The set was torn down after Voyager wrapped in 2001. (citation needed • edit)