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Labeling medical illustrations

Labeling is an integral part of creating clear and accurate medical illustrations. It should not be considered as an afterthought. There are many variables to consider and some conventional rules to follow.

Choose a font that does not distract from the illustration. I usually use a sans sari£ font, and, when I want to keep things simple, I use Helvetica. Times roman is the default sari£ font Choose a font carefully and deliberately. The intended audience will often determine the font choice.

The size of the font will largely be determined by the intended use of the illustration. For textbooks and journals, the font should be no larger than the body text and yet large enough to see clearly at a normal reading distance. For slides, the type needs to be larger, in order to reach a more distant audience.

I FOR TEXTBOOK I !FoR SLIDE I

Superior vestibular

Facial n.

n.

Silastic protector

The font size for website labels will be variable according to 'its readablilty on screen. The size of the font will also be determined by the number of labels needed. If there are only a few labels they can be larger than if there are many.

Normally the first letter of the first word in the label is in upper case, and the subsequent words begin with lower case letters.

Bold, italic, and underlining options can be used to highlight a label that is more important than another. Using different font styles can also help to distinguish one kind or category of structure from another.

Using abbreviations is standard in certain cases, e.g. "a." for artery, "nn." for nerves, or are used to minimize the overall amount of text.

Gluteus medius m.

I CATEGORIES I

Middle crus: Domal segment

Lobular segment

Columellar segment

Footplate segment

jEMPHASTSj

Vastus lateralis m.

Placement of the leader lines will determine the overall design of the illustratoin. When there are a lot of labels this c~m be a challenging task. The most aesthetically pleasing placement, in my opinion, is leader lines radiating from the center of the subject. Another common format is for all of the leader lines to be either horizontal or vertical. Sometimes these need to have angled additions so that the labels are evenly spaced.

I HORIZONJAL]

kidney

Upper lateral cartilage

Middle crus of illar cartilage

Premaxillary portion oi maxilla

. .r'--+'1----crus of penis

!+----spermatic cord

".---+1-----lpenis

ltr-----head of epididymis

+--- testis

'<JC- --tail of epididymis

jRADIATINGJ

Cribiform plate

Perpendicular plate of ethmoid bone

Nasal crest of palatine bone

Palatine bone

Palatine process of maxilla

HORIZONTAL Vv'ITH ANGLED ADDITIONS

~------- post. hum. circumflex

~--+------- brachial

Often the labels read more clearly if they are grouped rather than evenly spaced. Occasionally, curved leader lines can give a little flair to an illustration.

lcROUPING I

Anterior superior iliac spine-- __

Anterior inferior iliac spine -- - ----

Headache

Neck and shoulder stiffness '-,,

Backache '-

Pressure on discs and ligaments

Compression of internal organs

--Obturator foramen

Intertrochanteric line-' ',,Ischial ramus

Lesser trochanter -' ' "\.

Ischial tuberosity

!cURVED LINES!

Pressure on nerves and tendons

numbness and pain

Figure 1-1. The repercussions of sitting with your head forward

Lateral epicondyle,_ _-'

Adductor tubercle

- ---Medial epicondyle

Head of fibula ,--

,, :

When deciding where to place a leader line there are other things to consider as well. Will the background pattern interfere with the line, will the line disappear when it passes over a dark part of the illustration, will the line obscure another structure? One t~chnique for allowing lines to stand out on a dark background is to add a thin white line around the black line.

rigp.ta:-v orifice

WHITE AROUND BLACK LINE

A

Leader lines should be as thin as possible while still being easy to see. They should not overwhelm the illustration. Using a dot at the end of the leader line enhances the overall readability. Sometimes it makes sense to use a small arrowhead at the end of the line, pointing to, rather than touching, the structure. Using dashed or dotted leader lines is appropriate on a complicated line illustration.

When identifying a group of structures with one label, you can use one major leader line with short offshoots, or you can attach a circle around the structures at the end of the line.

I ARROWHEAD I Superior conjunctival I DASHED LINES I

To pnreni~

Dorsal scapula~

To subclavius 0\. I

I I

\

-- _.- From (4

cs __ _,-- -·--To longus calli m.

- / and scalene rn. <

/" J. C6

C7

lateral pectoral, Anterior divisions,

/1..\usculocutaneous

I OFFSHOOTS!

',

Radiar - ----

Median-- -

Ulnar ---

Flexor digitorum brevis tendon

Lumbrical muscles

Flexor hallucis brevis muscle

_ Abductor hallucis tendon

'',Medial pectoral

',,, ', Upper subscapular , ' Thoracodorsal

',, ',Lower subscapular ',,, ''Medial brachial cutarleous

' Medial antebrachial cutaneous

I ciRCLE I

---From T2

' Long thoracic

Medial plantar nerve and artery

Medial calcaneal nerve and artery

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FIG. 67.

Another approach to labeling is to superimpose a number or letter onto the structures and then to name them in a legend or insert.

Labels are not always used for identification. Sometimes they show direction or movement arid are critical to understanding the illustration

There are cases when, to create a particular style, you might want to use hand lettering.

!NUMBERS!

DORSAL VIEW OF THE BRAIN STEM I DIRECTION & MOVEMENT I

1 acoustic area 2 acoustic striae 3 anterior cerebellor

peduncle 4 clava 5 corpora quadrigemina 6 cut surface of thalamus

and corpus striatum 7 dorsal median sulcus

dorsolateral sui= fasciculus cuneatus

10 fasciculus gracilis 11 founh ventricle 12 habenular trigone 13 inferior colliculus 14 massa intermedia. 15 medial geniculate body 16 middle cerebellar

peduncle 17 opening of aqueduct 18 opening of central canal 19 pineal body 20 posterior cerebellar

peduncle 21 superior rolliculus 22 thalamus 23 third ventricle

C l;-<2:rn.o,.s1:eY'-1.c ·. 24 trochlear nerve 25 tuberculum cuneatum . . · ,.:.\• ..

c1oaaL1 membr>ane

i \

\ i i ·, I \

·\ .\

\ ~

i I

)/ I I

I i l supra.Tenai / / gl~;cd I I

I I I gonan //

I mesoneplwos /

kidney 1;· I )