Table 5. Twelve articles recommending sites for deltoid intramuscular injections.

AXN: axillary nerve; IMI: intramuscular injection

Sr. no.	Authors and publication year & country of publication	Study design	Number of participants & gender	Participants age group	Ethnicity of participants	Proposed site/technique
1	Davidson et al., 2007 [12]; USA	Case report	Male	26 years old	American Indian population	Site is 1–3 fingerbreadths (5 cm) below the mid-acromion, and it is frequently used in clinical settings in Japan. The site is shown in a self-generated image in Figure 3
	Beyea and Nicoll, 1995 [32]; UK	Integrative review	Literature of last seven decades	Not applicable	White population
2	Kozieret al., 2010 [33]; Australia	Nursing manual	Not applicable	Not applicable	White population	The student nurse should use four fingers, placing the little finger on the acromion process, and three fingers below
3	Treas and Wilkinson, 2014 [34]; USA	Based on multi-cultural, multi-generational, Asian-American family case studies			Asian-American population	A triangular injection site is proposed. The apex is directed at a point of intersection between the line connecting the upper ends of the anterior and posterior axillary lines and a vertical line extending from the mid-acromion point. The base is formed by a horizontal line positioned 1–3 fingerbreadths (5 cm) below the acromion. The site is shown in a self-generated image in Figure 4
	Gray et al., 2009 [35]; UK	Pragmatic Review	Not applicable	Not applicable	White population
	Rodger and King, 2000 [36]; UK	Literature review	Not applicable	Not applicable	White population
4	Funnell et al., 2005 [37]; Australia	Nursing manual	Not applicable	Not applicable	Australian–New Zealand white population	Site is at the middle third of the deltoid muscle, with acromion as the origin of the deltoid and the deltoid tuberosity as the insertion of the deltoid muscle. This site is the densest part of deltoid. The site is shown in a self-generated image in Figure 5
5	Kim et al., 2017 [20]; Korea	Review study	Not applicable	Not applicable	Asian population	A mid-deltoid site is proposed, with the acromion as the origin of the deltoid muscle and the deltoid tuberosity as the insertion of the deltoid muscle. The site is shown in a self-generated image in Figure 6
6	Cocoman and Murray, 2008 [38]; Ireland	Review study	Not applicable	Not applicable	White population	An injection site is recommended approximately 3–5 cm below the lower edge of the acromion, but this site is also unsafe due to the presence of the AXN
7	Nakajima et al., 2017 [1]; Japan	Prospective study	30 (15 male, 15 female)	Age > 17 years	Asian population	A new site is proposed: divide the superolateral margin of acromion into three points: posterior (a); mid-portion (b); and anterior (c). Draw a line between the upper corners of anterior and posterior fold line (line AB). Finally, draw a perpendicular line from both points (a) and (b) of acromion to AB line. The zone between the halfway point of the a-AB line and the lower one-third of the b-AB line may be safe for IMIs. The site is shown in a self-generated image in Figure 7
8	Cook, 2011 [14]; Australia	Cadaveric study	Not available	Adults > 65 years	White population	A safer IMI site is recommended that is 7.4 cm below the mid-acromion in both sexes due to the course of the AXN and position of the subacromial/subdeltoid bursa. The site is shown in a self-generated image in Figure 8
9	Lammon et al., 1995 [39]; UK	Nursing manual	Not applicable	Not applicable	White population	Many nursing textbooks illustrate no AXN but do show a radial nerve, and state: “You must inject the medication into the densest part of deltoid to avoid the radial nerve and artery”