Intramuscular nerve distribution pattern of the adductor longus and gracilis muscles demonstrated with Sihler staining: guidance for botulinum toxin injection.
BACKGROUND
The aims of this study were to clarify the intramuscular branching patterns and arborizing area of hip adductor muscles with reference to surface landmarks on the thigh and to thus suggest effective and safe injection points for botulinum neurotoxin (BoNT).


METHODS
Ten gracilis and 10 adductor longus specimens were subjected to Sihler staining to reveal intramuscular nerve arborization patterns, and findings were matched with and referred to surface landmarks. Using these results, we determined the optimal location for BoNT injection in hip adductors in relation to the long axis of the femur.


RESULTS
The corrected, most dense areas of innervation in adductor longus and gracilis were typically 30-50% and 40-50% from the anterior superior iliac spine (ASIS) along the vertical line of the femur, respectively.


CONCLUSIONS
The most effective and safest point for BoNT injection into adductor muscles appears to be between 35% and 50% from ASIS, where neuromuscular junctions are most densely distributed.
Division in Anatomy and Developmental Biology, Department of Oral Biology, Human Identification Research Center, Yonsei University College of Dentistry, Seoul, Korea.
Sung-Yoon
SY
Won
Dong-Wook
DW
Rha
Hong-San
HS
Kim
Sang-Hoon
SH
Jung
Eun Sook
ES
Park
Kyung-Seok
KS
Hu
Hee-Jin
HJ
Kim
D001905:Botulinum Toxins / Q000008:administration & dosage*; D006801:Humans; D007273:Injections, Intramuscular / Q000379:methods; D009128:Muscle Spasticity / Q000188:drug therapy; D018482:Muscle, Skeletal / Q000294:innervation*; D013848:Thigh
D001905:Botulinum Toxins