The aim of this study was to elucidate the distribution of the accessory nerve within the sternocleidomastoid muscle (SCM) to aid identifying the optimum sites for botulinum neurotoxin (BoNT) injections and applying chemical neurolysis. Thirty SCM specimens from 15 Korean cadavers were used in this study. Sihler's staining was applied to 10 of the SCM specimens. Transverse lines were drawn in 20 sections to divide the SCM into 10 divisions vertically, and a vertical line was drawn into the medial and lateral halves from the mastoid process to the sternoclavicular joint. The most densely innervated areas were 5/10-6/10 and 6/10-7/10 along the lateral and medial parts of the muscle, respectively. We suggest injecting BoNT in the medial region 6/10-7/10 along the SCM prior to injecting in the lateral region 5/10-6/10 along the muscle to ensure safe and effective treatment. Clin. Anat. 33:192-198, 2020.

The aim of this study was to use ultrasonography to determine the locations and distributions of the superior labial artery (SLA) and the inferior labial artery (ILA) relative to the vermilion border (VB). Sixty healthy Korean volunteers (35 males, 25 females; age, 21-36 years) were investigated using ultrasonography. The participants had not received any noninvasive treatment or surgical procedure in the facial regions during the previous 6 months. Based on the VB, the overall thicknesses of the upper and lower lips were 9.4 AE 0.4 mm (mean AE SD) and 10.9 AE 0.7 mm, respectively. In most cases, the labial arteries were located in the wet mucosal layer on both the upper (35-57%) and lower lips (28-55%), respectively. In the upper lip, the SLA was in the intramuscular layer in 20-45% of cases, making it the second most common type. At some of the measuring points, the SLA was observed more often in the intramuscular layer than in the wet mucosal layer. In the lower lip, the ILA was also located in the dry mucosa (5-27%). The dry-wet mucosal junction is unclear in the lip area, and the ILA was commonly observed at the dry-wet mucosal junction. The arterial depth was 5.3 AE 0.3 mm in the upper lip and 4.2 AE 0.4 mm in the lower lip. The SLA and ILA are evenly distributed over all parts of the oral mucosa. Injection procedures for lip augmentation should therefore use very superficial approaches. Clin. Anat. 33:158-164, 2020.

Introduction To detect ideal locations for botulinum toxin (BoNT) injection by exploring the intramuscular nerve arborization of the psoas major and iliacus muscles. Method A modified Sihler's method was performed on the psoas major and iliacus muscles (16 specimens each). Intramuscular nerve arborization was recorded according to the most prominent point of the anterior superior iliac spine (ASIS), the posterior superior iliac spine (PSIS), the lesser trochanter (LT), and the transverse process of the 12th thoracic vertebra. Results Intramuscular nerve arborization of the psoas major muscle was the largest from 1/5 to 3/5 the distance from the transverse process of the 12th thoracic vertebra to the PSIS, and the tendinous portion of the muscle occupied from 3/5 to 5/5 this distance. In terms of the plane of the ASIS, the PSIS, and the LT, the arborization of the iliacus muscle was the largest from 1/5 to 3/5 the horizontal distance and 0 to 1/3, the distance longitudinally, and from 1/5 to 2/5, the horizontal distance and 1/3 to 2/3, the longitudinal distance. Discussion These results suggest that an injection of BoNT to the psoas major and iliacus muscle should be applied in specific areas. Additionally, the posterior approach is an ideal method for targeting only the psoas major because the injection point is above the PSIS. However, when treating both the psoas major and iliacus muscles, the proximal anterior approach is an ideal method according to the arborization patterns.

Investigating and verifying the vascular structure regarding its interactions with the facial artery and infraorbital artery will provide critical information to physicians performing facial surgery and cosmetic procedures.