In all nine specimens we dissected the radial nerve and individualized its motor branches to the ECRL and ECRB.
Six out of nine specimens presented two branches to innervate ECRL emerging both from the radial nerve after the distal branch to the BR and before the bifurcation into superficial and deep branches, except for one specimen where the distal branch emerged from the deep branch of the radial nerve. Three specimens had only one motor branch for the ECRL emerging from the radial nerve.
All specimens except from one presented the origin of the motor branches to the ECRL before the nerve crossed the intercondylar line. The measured mean point of origin was -17,73mm ± 13,04. If we measure the mean point of origin only accounting for the specimens with two branches to ECRL, we obtain that the mean emergence point for the proximal and distal branches at -26,33mm ± 10,05 and -11,67mm ± 7,31 respectively.
Regarding its type of innervation according to Taylor’s classification, we classified the specimen with two branches to the ECRL as a Taylor type 3, two specimens with one motor branch to ECRL were classified as Taylor type 1, and one specimen was classified as Taylor type 2 (Table 1).
Table 1
ECRL innervation characteristics including: the specimen, number of branches, origin of motor branches, distance from the origin to the intercondylar line, length from its origin to the entrance into the muscle and Taylor type.
ECRL
|
|
Specimen
|
Number of branches
|
Origin
|
Distance (mm)
|
Length (mm)
|
Taylor type
|
|
1
|
2
|
Radial nerve
|
-28
|
20
|
3
|
|
-10
|
31
|
|
2
|
2
|
Radial nerve
|
-16
|
36
|
3
|
|
-7
|
42
|
|
3
|
2
|
Radial nerve
|
-24
|
60
|
3
|
|
Deep branch of radial nerve
|
-7
|
50
|
|
4
|
1
|
Radial nerve
|
-17
|
36
|
1
|
|
|
5
|
1
|
Radial nerve
|
10
|
43
|
1
|
|
|
6
|
2
|
Radial nerve
|
-15
|
36
|
3
|
|
-6
|
55
|
|
7
|
2
|
Radial nerve
|
-35
|
37
|
3
|
|
-15
|
66
|
|
8
|
1
|
Radial nerve
|
-31
|
57
|
2
|
|
|
9
|
2
|
Radial nerve
|
-40
|
50
|
3
|
|
-25
|
48
|
|
All specimens only had one motor branch to the ECRB. We found variability in its origin, emerging in seven specimens from the deep branch of the radial nerve, just before its division into the supinator motor branches and its entry into the Frohse’s arcade, and in two specimens emerging from the superficial branch.
In all the specimens the motor branch to the ECRB emerged distal to the intercondylar line, with a mean distance of 23,89mm ± 8,37.
All specimens were classified as Taylor type 1, except from one specimen that was classified as Taylor type 2 (Table 2).
Table 2
ECRB innervation characteristics including: the specimen, number of branches, origin of motor branches, distance from the origin to the intercondylar line, length from its origin to the entrance into the muscle and Taylor type.
ECRB
|
Specimen
|
Number of branches
|
Origin
|
Distance (mm)
|
Lenght (mm)
|
Taylor type
|
1
|
1
|
Deep branch of radial nerve
|
20
|
30
|
1
|
2
|
1
|
Deep branch of radial nerve
|
12
|
55
|
1
|
3
|
1
|
Deep branch of radial nerve
|
24
|
45
|
1
|
4
|
1
|
Superficial branch of radial nerve
|
26
|
55
|
1
|
5
|
1
|
Superficial branch of radial nerve
|
31
|
60
|
1
|
6
|
1
|
Deep branch of radial nerve
|
39
|
47
|
2
|
33
|
7
|
1
|
Deep branch of radial nerve
|
25
|
66
|
1
|
8
|
1
|
Deep branch of radial nerve
|
13
|
76
|
1
|
9
|
1
|
Deep branch of radial nerve
|
25
|
87
|
1
|
We measured the length of each motor branch to ECRL and ECRB to estimate with further studies the possibility of a tension free nerve transfer. For the motor branches to the ECRL we obtained a mean length of 44,47mm ± 12,26, measuring both the proximal and the distal branches apart we obtained a mean length of 37,80mm ±13,72 and 48,67mm ± 11,83 respectively. In reference to the motor branch to the ECRB we obtained a mean length of 55,40 ± 17,90 from its emergence point to its entrance into de muscle belly.