UNITS AND STRENGTH

At 0400 on Sunday, 25 June 1950, the Russian-trained North Korean Army swept south across the 38th Parallel in four major drives. The U.S. Government, which maintained a small military mission in South Korea at the time, reported the aggression to the U.N. (United Nations) Security Council.

On 27 June 1950, the Security Council recommended all member nations act to assist South Korea to repel the armed attack and restore peace. The same day, President Harry S Truman ordered U.S. military forces to assist in this effort, and on 1 July 1950, the first U.S. Army combat units landed in Korea.

During the 3 years of fighting and periods of peace negotiations, nearly half a million American soldiers served in Korea, including medical evacuees, those rotated to the United States, units moved out of Korea to Japan and other areas, and individuals discharged from the Army. This resulted in a turn-over of strength in the Eighth U.S. Army of almost three times the average monthly strength of approximately 208,000 men for the 37-month period- July 1950- July 1953.

Table 1 presents the U.S. Army monthly mean strength for the total U.S. Army in Korea as well as for U.S. Army division and non-division units. Eight U.S. Army divisions and two separate regimental combat teams served at one time or another in the Korean War in addition to the 1st U.S. Marine Division, the ground force contingents of other United Nations, and the Armed Forces of the Republic of South Korea. Twenty-two nations joined forces under the U.N. flag in providing ground, air, naval, or medical support to resist the Communist aggression. The major U.S. Army division units were as follows: the 24th Infantry Division, the first to enter Korea on 2 July 1950, fought until 4 February 1952 when it was ordered back to Japan; the 1st Cavalry Division returned to Japan on 30 December 1951 after serving in Korea from 18 July 1950; the 25th Infantry Division served from 9 July 1950; the 2d Infantry Division from 30 July 1950; the 15th Regimental Combat Team from 3 August 1950; the 187th Airborne Regimental Combat Team first entered Korea on 17 September 1950, left the war zone on 27 June 1951, and returned to Korea on two occasions- 12 May- 17 October 1952 and, again, on 22 June 1953; the 7th Infantry Division from 18 September 1950; the 3d Infantry Division from 10 November 1950 (although the 65th Regimental Combat Team, a part of the 3d Infantry Division, arrived in September 1950); the 45th Infantry Division, 5 December 1951; and the 40th Infantry Division), 11 January 1952.

Eighth U.S. Army headquarters completed its movement to Korea on 25 August 1950. The X U.S. Corps, previously activated to direct the amphibious landing at Inchon on 15 September 1950, acted as an independent force directly under the Supreme Commander. Upon the withdrawal from North Korea in December 1950 and the return of these units to Pusan, X Corps became a part of the Eighth U.S. Army and remained so throughout the period of the war.

The total U.S. Army strength in Korea represents midmonth averages of end-of-month strength as reported by The Adjutant General (1). The division and separate regimental combat team mean strengths included in table I and the breakdown by organic division units (table 2) are the average monthly strengths served as reported to the Army Surgeon General on summary health reports (2) received from separate units operating medical treatment facilities. The non-division average strength was derived by subtracting the division strength from the total.

After the buildup of the U.S. Army Forces, division units, which bad peaked at almost 90 percent of the strength in August 1950, averaged about one-half of the U.S. Army strength in Korea, while regimental units averaged almost one-third of the strength. Table 3 and figure 1 reflect these relative distributions by type of unit. Regimental troops, which consistently averaged 58 to 60 percent of division strength, ranged from a high of 51

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percent of total U.S. Army strength in Korea in August 1950 to a low of 26 percent in November 1951. The relative proportions for the organic division units show a fairly stable distribution over the complete period of the war.

BATTLE CASUALTIES AND ADMISSIONS

The responsibility of the Medical Department of the U.S. Army for battle casualties, as well as for nonbattle (disease and nonbattle injury) patients, lies in proper diagnosis and treatment and also in providing for the timely evacuation and hospitalization of these patients. Consequently, medical interest in battle casualty statistics relates directly to information needed (such as diagnosis, anatomical location, and nature of trauma) to provide medical care for personnel who become battle casualties. Inasmuch as this information can be obtained only from medical records, they are the basic source of data. Tabulations of these individual medical records, by day of occurrence, organizational element, diagnosis, causative agent, surgical operation, and anatomical location of wound, provide the chief source of the data presented. The official battle casualty counts, however, are compiled by The Adjutant General and are based on casualty reports forwarded through command channels. Obviously, because casualty information is derived from different source record systems, patient data on certain categories of battle casualty and the generally corresponding categories compiled from command channel casualty reports may differ slightly with respect to totals.

Records received by The Surgeon General show the following counts: 18,769 killed in action, 77,788 wounded in action and admitted to medical treatment facilities, and 14,575 slightly wounded in action and carded for record only- making a total of 92,363 wounded. The official totals included in The Adjutant General's report (3) show 19,585 killed in action (including 251 killed after capture) and 79,526 wounded in action. Although these differences are not significant in analysis for operations research, planning, or similar purposes, nevertheless for completeness, The Surgeon General's killed-in-action count was increased from 18,769 to 19,353 by matching serial numbers from The Surgeon General's individual records of death with The Adjutant General's records. With respect to the differences between the wounded-in-action counts, the command channel casualty reports were generally submitted only for those wounded in action who were "unit losses" (evacuated rearward and admitted to a medical treatment facility and for which next-of-kin notifications were required). However, at the very beginning of the Korean War, there was slight ambiguity concerning reporting requirements, and some of the wounded who were treated at division clearing stations and

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not lost to their units were inadvertently included in the command channel reports. On the other hand, medical records were submitted not only for the "unit losses" but also for all of the slightly wounded, even those who were not admitted but could be treated in the vicinity, usually at an aid or clearing station, and returned to their units before the close of the morning report day. The latter, not officially excused from duty for as much as 1 day for medical care, were, as previously noted, the CRO (carded for record only) cases.

The reporting of DNBI (disease and nonbattle injury) cases is solely the responsibility of the Medical Department, U.S. Army, and information pertaining to these cases relates directly to the complete episode of their respective periods of medical treatment. The term "admission" as used in both text and source tables refers to instances of medical treatment given on an excused-from-duty basis. These patients may have been treated in a hospital or infirmary bed or "in quarters" (in a dispensary bed, at an aid station or clearing company, or in the person's usual quarters). Admissions to all medical treatment facilities in Korea numbered 443,163 for all causes during the complete period of the war, July 1950-July 1953. In addition to the 77,788 wounded admissions, there were 365,375 nonbattle admissions, (82.4 percent of the total), of which 290,210 resulted from disease and 75,165 from nonbattle injury.

In terms of annual rates per 1,000 average strength, for the complete period of the war, the overall counts represent 30 per 1,000 for killed in action, 121 per 1,000 for wounded in action admissions, and 570 per 1,000 for disease and nonbattle injury admissions. All of these rates are lower than the corresponding annual rates for the June 1944-May 1945 period of operations in the European theater during World War II, where rates of 44 killed in action, 152 wounded admissions, and 859 DNBI admissions per l,000, respectively, occurred. Table 4 shows the decline, on a yearly basis, of approximately 90 percent from the high rates experienced in 1950 for both killed in action and wounded admissions for total U.S. Army, Korea, compared to the overall drop of about 46 percent for DNBI admissions. The decline for division units shows sharper drops for disease and nonbattle injuries, while non-division units experienced a much smaller decline in nonbattle patients.

Since this report is concerned chiefly with the presentation of combat medical statistics, both text and source tables that show admissions reflect data related mostly to division combat units. Data are given for non-division and for total U.S. Army, Korea, to achieve perspective. For example, while division units comprised slightly more than one half the average total U.S. Army strength in Korea, (table, 5), they suffered almost 95 percent of the killed and wounded in contrast to slightly less than one-half of the DNBI admissions. The differences are more pronounced at the regimental level, where units comprising only 31 percent of the average U.S. Army strength in Korea accounted for more than five-sixths of the killed and wounded compared to about one-third of the DNBI admissions. The respective unit annual rates also are highest at the regimental level, being 85 per 1,000 for killed in action, 337 per 1,000 for wounded admissions, and 641 per 1,000 for DNBI admissions. While these data cover all of the U.S. Army divisions and regiments, that fought in the Korean War, the figures for headquarters and service companies and for artillery, engineer, medical, and tank battalions reflect only the assigned organic division or attached units of the respective type. Separate combat units such as corps or army troops are included with non-division units which represent combat

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¹ An additional 135 admissions (130 disease and five nonbattle injury) occurred before July in calendar year 1950.
² An additional 10 disease CRO cases occurred before July in calendar year 1950.

support and communications zone troops as well. These non-division troops comprised about 48 percent of the average U.S. Army strength in Korea and provided slightly more than one-half of the admissions to medical treatment facilities for disease arid nonbattle injuries. The extremely low annual rates of 2 per 1,000 for killed in action and 16 per 1,000 for wounded admissions reflect the relatively low level of risk and exposure to combat for most of these non-division troops.

All of the detailed cross-tabulations of data included in the source tables presented for overall counts of disease and nonbattle injury cover admissions through December 1953 and, therefore, reflect a slightly larger number of admissions than does the shorter period through July 1953. The overall annual admission rates, however, are somewhat smaller. From the data presented in table 6, it may be seen that this reduced annual rate is due, largely, to the lower rates experienced during the August-December 1953 peacetime period. In addition, the changeover from combat permitted more nonbattle patients to be treated within the division medical service as CRO outpatients and, undoubtedly, contributed to the overall reduction of the division admission rate. Non-division troops, on the other hand, did not experience a comparable shift between inpatients and outpatient.

The most frequent traumatism diagnosed as the cause of battle admissions was wounds of all types (62 percent). Penetrating wounds were the most prevalent type, representing 57 percent of wounds of all types, and 35 percent of the total number of admissions to medical treatment facilities for wounds. Fractures accounted for 23 percent of the total wounded, with compound fractures amounting to 19 percent. The distribution of the balance of wounds (table 7) shows each of the other types of traumatisms, was less than 3 percent of the total wounded. For division and separate regimental combat teams, the relative distribution was identical to total U.S. Army, Korea. The nondivision units show slightly less proportionately for fractures and slightly more for other types of wounds, such as burns, contusions, and concussions. Figure 2 graphically depicts similar distributions for nonbattle injury admissions through December 1953. Fractures, amounting to 18 percent of the total, were the leading cause of admission for division units, followed by sprains, strains, and dislocations (17 percent), cold injury (16 percent), and wounds of all types (15 percent). Contusions contributed 12 percent of all nonbattle injury admissions for divisions. Although fractures caused 19 percent of all nonbattle injury, admissions in the non-division units, they ranked second to sprains, strains, and dislocations, which accounted for almost 25 percent of the total. Wounds of all types represented 16 percent of the total nonbattle injuries for non-division units, followed by contusions (13 percent). Cold injury, which was a leading cause of nonbattle injury admissions for

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division troops (16 percent), amounted to slightly less than 3 percent for non-division units. This latter phenomenon results from the degree of exposure to the elements required of combat troops.

The most important cause of disease admissions among U.S. Army troops in Korea was acute respiratory infections, which accounted for one-fifth of all disease admissions for all Army units. This condition was responsible for 15 percent of the disease admissions among division troops and 26 percent of the disease admissions in non-division units. The second most frequent cause of admission for divisions was symptoms and ill-defined conditions, closely followed by infective and parasitic disease. This latter diagnosis and diseases of the digestive system, with annual admission rates of 53 and 47 per 1,000, respectively, were the second and third leading causes of disease admissions for non-division units. Psychiatric conditions represented over 9 percent of disease admissions for division troops, producing a rate of 36 per 1,000 average strength per year. This compares with 5

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