[Reprinted from the Boston Medical and Surgical Journal, 
July 5, 1888.] 
A METHOD OF DETERMINING THE ANGLE OF 
FLEXION OF THE DISEASED LEG IN HIP 
DISEASE. 
BY GEORGE L. KINGSLEY, A.B., HARVARD MEDICAL SCHOOL. 
The estimation of the amount of flexion of the leg 
upon the pelvis, in the acute stage of hip-disease, is of 
much importance as a matter of record and as an indi- 
cation of the progress of the case. The estimation of 
this angle is commonly made by the use of the goni- 
ometer. As one seldom has this instrument at hand, 
and as its use is attended with many disadvantages, 
the following method is offered: 
The object of this article is to furnish a ready and 
accurate method of estimating with a common tape- 
measure the angle of flexion of the leg, and is intended 
to be supplementary to the article by Dr. Lovett,1 on 
the estimation of adduction and abduction by a similar 
method. Lay the patient on his back on a table or 
any flat surface, and then raise the diseased leg by the 
heel until the lumbar vertebrae touch the table; this 
1 Boston Med. and Surg. Journ., March 8, 1888. 2 
shows that the pelvis is in the normal position and the 
angle which the leg makes with the table, the angle 
C A B, is the angle of flexion of the thigh, from the 
normal position. It is this angle which it is desired to 
measure. Having placed the child in this position, 
measure off two feet on the external aspect of the 
leg with a tape measure with the zero of the tape on 
the table at (A), and note the point (B), from hero 
measure the perpendicular distance in inches to the 
table (C), consult Table I and opposite the number of 
inches found by measuring B C, will be found the 
number of degrees representing the flexion of the 
diseased leg from the normal position. 
Now we have a right-angled triangle A B C, of which the 
sides A B (24 inches) and B C (by measurement) are known. 
= sine B AC (the angle of tiexion),or B C = A B sine B A C. 
Therefore, if we compute by this formula a table which shall 
give the angles corresponding to the various lengths of B C, 
having measured this perpendicular distance (B 0) w® °an by 3 
glancing down the table until we find the number correspond- 
ing to the distance measured, ascertain the number of degrees 
in the desired angle. 
Table I. 
In. 
Deg. 
In. 
Deg. 
In. 
Deg. 
In. 
Deg 
.5 
1 
6.5 
16 
12.5 
31 
18.5 
50 
1.0 
2 
7.0 
17 
13.0 
33 
19.0 
52 
1.5 
3 
7.5 
19 
13.5 
34 
19.5 
54 
2.0 
4 
8.0 
20 
14.0 
36 
20.0 
56 
2.5 
6 
8.5 
21 
14.5 
37 
20.5 
58 
3.0 
7 
9.0 
22 
15.0 
39 
21.0 
60 
3.5 
9 
9.5 
24 
15.5 
40 
21.5 
63 
-1.0 
10 
10.0 
25 
16.0 
42 
22.0 
67 
4.5 
11 
10.5 
27 
16.5 
43 
22.5 
70 
5.0 
12 
11.0 
28 
17.0 
45 
23.0 
75 
5.5 
14 
11.5 
29 
17.5 
47 
23.5 
80 
6.0 
15 
12.0 
30 
18.0 
48 
24.0 
90 
If the leg is so short that it is impracticable to measure off 
twenty-four inches we can measure to a point on the leg distant 
twelve inches from the table; ascertain the distance to the 
table in a perpendicular line just as before, double this distance 
and look in the table as before.