Ultrasonographic Evaluation of the Optimal Needle Position in the Supinator Muscle

Background@#and Purpose Investigating the supinator muscle (SUP) is important for diagnosing radial neuropathy or cervical radiculopathy in needle electromyography (EMG). However, different authors have proposed several locations for needle EMG placement in the SUP.This study aimed to determine the optimal needle insertion position for examining the SUP via needle EMG under ultrasonographic guidance. @*Methods@#This study included 16 male (32 upper limbs) and 15 females (30 upper limbs). In the supine position, the line connecting the midpoint of the dorsal wrist to the upper margin of the radial head (RH) (RH_WRIST line) was measured while the forearm was pronated.Under ultrasonographic guidance, the thickness of the SUP was measured at 1-cm intervals from the RH to 4 cm along the RH_WRIST line. Moreover, the horizontal distance (HD) from the RH_WRIST line to the posterior interosseous nerve (PIN) and the distance from the RH to the point where the RH_WRIST line and the PIN intersected (VD_PIN_CROSS) were measured. @*Results@#VD_PIN_CROSS was 51.25±7.0 mm (mean±SD). The muscle was the thickest at 3 cm (5.6±0.8 mm) and 4 cm (5.4±1.0 mm) from the RH. The distances from the PIN to these points were 14.1±3.9 mm and 9.0±4.3 mm, respectively. @*Conclusions@#Our findings suggest that the optimal needle placement is at 3 cm from the RH.

Branching Patterns and Anatomical Course of the Common Fibular Nerve

OBJECTIVE: To present the branching patterns and anatomical course of the common fibular nerve (CFN) and its relationship with fibular head (FH).METHODS: A total of 21 limbs from 12 fresh cadavers were dissected. The FH width (FH_width), distance between the FH and CFN (FH_CFN), and thickness of the nerve were measured. The ratio of the FH_CFN to FH_width was calculated as follows: < 1, cross type and ≥1, posterior type. Angle between the CFN and vertical line of the lower limb 5 cm proximal to the tip of the FH was measured. Branching patterns of the lateral cutaneous nerve of the calf (LCNC) were classified into four types according to its origin and direction as follows: type 1a, lateral margin of the CFN; type 1b, medial margin of the CFN; type 2, lateral sural cutaneous nerve (LSCN); and type 3, CFN and LSCN.RESULTS: In the cross type (15 cases, 71.4%), the ratio of FH_CFN/FH_width was 0.83 and the angle was 13.0°. In the posterior type (6 cases, 28.6%), the ratio was 1.04 and the angle was 11.0°. In the branching patterns of LCNC, type 2 was the most common (10 cases), followed by types 1a and 1b (both, 5 cases).CONCLUSION: Location of the CFN around the FH might be related to the development of its neuropathy, especially in the cross type of CFN. The LCNC showed various branching patterns and direction, which could be associated with difficulties of electrophysiologic testing.