To determine the 3D location of the intramuscular motor nerve endings of the biceps brachii and brachialis, we identified from 56 fresh cadaveric arms the regions where the intramuscular branches were most densely located in relation to a reference line connecting the medial epicondyle of humerus and the coracoid process. For the biceps, these points were most densely distributed at a length from 64.6 to 70.3% point of the reference line with the coracoid process as starting point, at a width of 21.6-32.6 mm lateral to the reference line. For the brachialis muscle, these points were located at a length of 75.4% point and width of 27.1-35.4 mm lateral to the reference line. At these points, the biceps was located at a depth of the upper two-third portion and the brachialis at the lower one-third portion of the upper arm, from skin to humeral bone.

The aim of this study was to elucidate the anatomical location of the motor entry point (MEP) and intramuscular motor point (IMP) of the tibialis posterior muscle for effective motor point block. Thirty-six fresh specimens from 20 adult Korean cadavers (11 males and 9 females) were investigated. The reference line between the most proximal-medial articular margin of the tibia (MPM) at the level of the knee joint and the most distal point of the malleolus of the tibia (MDM) on the surface were identified. The mean length of the reference line was 326.5 ± 27.1 mm. There were 82.5% of the total number of MEPs located at 10-30% and 67.9% of the total IMPs were 10-40% from the MPM. The safety zone for botulinum toxin (BTX) injections on the medial approach was 10-40% from the MPM. In addition, insertion of the needle to a depth of 3.5 cm from the surface of the skin was effective. These results may assist in determining more accurate localization of injection sites.

The parameters provided from this study should help increase the efficacy and precision of motor point injections to the hamstring muscles.

These findings may offer useful information for anatomists, physiologists, and clinicians.

This study examined the anatomic location of the motor entry point (MEP) and branching point at the proximal and distal points of the tendon of the peroneal muscle by visual observation. Forty-three fresh legs of 25 adult bodies which had been donated to science were investigated in this study. The mean length of the reference line between the most proximal point of the head of the fibula (PHF) and the most distal point of the malleolus of the fibula (DMF) was 33.4 ± 2.5 cm. The MEPs of the peroneus longus (PL) and peroneus brevis (PB) gathered from 20 to 40% (7.0-13.0 cm) and 40 to 60%, respectively. The branching point where the nerve was divided to innervate the PL and PB was 10% and 28% from the PHF, respectively. These anatomic results suggest appropriate areas where to inject phenol or other agents for a MEP block in the case of a spastic lower extremity as well as guidelines for an electromyography conduction test.