Intramuscular communicating branches in the flexor digitorum profundus: dissection and Sihler's staining.
OBJECTIVE
This study was designed to clarify the anatomy of the intramuscular communicating branch (ICb) between the median and ulnar nerves in the flexor digitorum profundus (FDP), and morphologically demonstrate the location of connection.


METHODS
Twenty Korean cadavers were dissected and a further 8 were subjected to modified Sihler's staining to investigate the pattern of innervation of the ICb and the location of its communicating points in muscle.


RESULTS
The median and ulnar nerves divided into small branches before entering FDP muscle. Of these small branches, one or two met inside the muscle. This communicating pattern could be classified into three types: type I, communicating branches in both the proximal and distal regions; type II, at least one communicating branch in the proximal region; type III, at least one communicating branch in the distal region. Of 20 dissected specimens, no case of type I was observed, but 3 cases of type II and 15 cases of type III were found. No ICbs at all were found in two of the dissected specimens. In eight stained specimens, one was classified as type I, two as type II, and five as type III. The proximal communicating branches were located at 34.1% from the interepicondylar line, inside the third muscle bundle. The distal communicating branches were located at 66.0% from the interepicondylar line, between third and fourth muscle bundles.


CONCLUSIONS
These findings could provide critical anatomical information regarding the nerve distribution of FDP focused on the ICbs.
Division in Anatomy and Developmental Biology, Department of Oral Biology, Oral Science Research Center, BK 21 Projects, Yonsei University College of Dentistry, 250 Seongsanno, Seodaemun-gu, Seoul, 120-752, Korea.
Sung-Yoon
SY
Won
Da-Yae
DY
Choi
Jae-Gi
JG
Lee
Kwan-Hyun
KH
Yoon
Hyun-Ho
HH
Kwak
Kyung-Seok
KS
Hu
Hee-Jin
HJ
Kim
D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D004210:Dissection; D006801:Humans; D008475:Median Nerve / Q000033:anatomy & histology*; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000033:anatomy & histology / Q000294:innervation* / Q000601:surgery; D013194:Staining and Labeling / Q000379:methods*; D014459:Ulnar Nerve / Q000033:anatomy & histology*; D034941:Upper Extremity / Q000033:anatomy & histology / Q000294:innervation* / Q000601:surgery