Titles, Legends, and Labels
4.2.7 Titles, Legends, and Labels
Many journals, including JAMA, use both titles and legends to describe and clarify figures. Others, like the Archives Journals, combine the title and legend underneath the figure.
The figure title follows the designation “Figure” numbered consecutively (ie, Figure 1, Figure 2) and does not appear in the figure itself. Articles that contain a single figure use the designator “Figure” (not “Figure 1”). The title is a succinct clause or phrase that identifies the specific topic of the figure or describes what the data show. Each major word in a figure title is capitalized and follows the same rules as for article titles (see 3.9.1, References, Titles, English-Language Titles). Some publications print the figure title under the figure, in sentence style, followed immediately by the legend.
Titles of figures, including diagrams, photographs, and line drawings, generally should not begin with a phrase identifying the type of figure.
Photograph Showing Prominent Physical Signs of Familial Hypercholesterolemia
Prominent Physical Signs of Familial Hypercholesterolemia
However, a description of the type of figure may be required in certain circumstances to provide context and avoid confusion.
Figure 3. Fluorescein Angiogram Showing Widespread Retinal Capillary Nonperfusion and Marked Optic Nerve Head Leakage
Figure 4. Autoradiograph Demonstrating Loss of Heterozygosity at the 3p25 Locus in Preneoplastic Foci and Corresponding Invasive Cancer
The figure legend or caption is written in sentence format and printed below or next to the figure. The legend contains information that identifies and describes the figure, and it should provide sufficient detail to make the figure comprehensible without reference to the text. Although the recommended maximum length for figure legends is 40 words, longer legends may be necessary for figures that require more detailed explanations or for multipart figures. Figure legends should contain expansions of abbreviations and footnotes for information too cumbersome to include in the figure itself.
Composite figures consist of several parts and should have a single legend that contains necessary information about each part. The legend should begin with a brief description that pertains to all of the components. Each component of the figure is then described, usually by a separate sentence beginning with the designation for the part, followed by a comma. If the parts share much of the same explanation, parenthetical mention of each part is appropriate. Such information should be clearly specified by designations corresponding to the figure components. However, the designations must be consistent in all legends.
For composite figures with 2 or more panels, capital letters (A, B, C, D, etc) should be used to label the parts of the figure. These letters should be placed in a small insert box that is positioned in the same place in each figure. The figure legend should refer to each of the figure components and the letter designators in a clear and consistent format (Example F23).
Information About Methods and Statistical Analyses.
Statements regarding methodologic details are unnecessary for each figure if this information is provided in the “Methods” section of the article and the text that refers to the figure clearly indicates the source of the data. Reference to the “Methods” section or to other figures that contain this information may be appropriate. At times, brief inclusion of methodologic details in the legend may be necessary for understanding the figure.
For data that have been analyzed statistically, pertinent analyses and significance values may be included in the figure or its legend.17 Values for data displayed in the figure (eg, mean or median values) should be indicated in the figure or in the legend. The meaning of error bars should be explained in the legend (Example F7).
Legends for photomicrographs should include details about the type of stain used and the degree of magnification. If the original illustration has been modified (enlarged or reduced), the original magnification should be noted. In figures with 2 or more parts, the stains or magnifications relevant to each individual part should be noted after its description.
A, Histological section of the vertebral specimen showing the typical “cookie-bite” tunneling osteoclasia of the vertebral trabeculae (unstained, original magnification ×400). B, For comparison, a bone tissue section of a recent case of hyperparathyroidism demonstrates very similar defects at the trabecular surface (hematoxylin-eosin, original magnification ×400).
Electron micrograph legends may specify magnification, without information about the stain.
Haemophilus influenzae microcolonies of middle ear mucosa 24 hours after inoculation (×5000).
Visual Indicators in Illustrations or Photographs.
Visual indicators provided in illustrations or photographs, such as a reference bar or ruler denoting a measure of dimension (eg, length) in a photomicrograph, arrows, arrowheads, or other markers, should be clearly defined in the figure or described in the figure legend (Example F23).
Capitalization of Labels and Other Text.
Capitalization should be kept to a minimum within the body of the figure.2 Axis labels in figures are akin to column headings in tables, so each word should be capitalized (except minor words such as prepositions of less than 4 letters). In nonaxis areas of the figure, capitalizing each major word can make comprehension difficult, especially when phrases or clauses are used. Using sentence-style capitalization is easier to read1 and takes less space.
Abbreviations in figures should be consistent with those used in the text and defined in the title or legend or in a key as part of the figure. Abbreviations may be expanded individually in the text of the legend or may be expanded collectively at the end of the legend.
Arachidonic acid is the precursor molecule from which all eicosanoids are synthesized. Products of the cyclooxygenase 1 (COX-1) enzyme include the potent stimulator of platelet activation and aggregation thromboxane A2, as well as prostaglandin E2 (PGE2).
If several illustrations share many of the same abbreviations and symbols, full explanation may be provided in the first figure legend, with subsequent reference to that legend. This practice works relatively well in print but can make understanding figures in online articles more difficult because readers may have to open separate figure files to find the legend.