The Study of Intramuscular Nerve Distribution Patterns and Relative Spindle Abundance of the Thenar and Hypothenar Muscles in Human Hand

Abstract

BackgroundThe intramuscular nerve distribution and relative spindle abundance of the human hand have not been well defined, although this is important in guiding hand surgery.MethodsForty human hands were dissected and subjected to modified Sihler’s stain and haematoxylin and eosin stain to investigate intramuscular nerve distribution and relative spindle abundance, respectively.ResultsThe flexor pollicis brevis (FPB), adductor pollicis (AP), and abductor digiti minimi (ADM) contain separate nerve compartments. Neural anastomoses were observed in the thenar and hypothenar muscles, including the Y-like, O-like, H-like, and U-like appearance. We found that U-like neural anastomoses may be the characteristic of the opponens muscles. The relative spindle abundance was the greatest in the opponens muscles which may coordinate fine movements.ConclusionExcept for the two opponens muscles, the rest of the thenar and hypothenar muscles could be used as whole muscle or half-muscle donors for muscle transplant. Our nerve map of the hand offers valuable guidance for hand reconstruction.

Transferring the Motor Branch of the Opponens Pollicis to the Terminal Division of the Deep Branch of the Ulnar Nerve for Pinch Reconstruction

“…These findings are similar to those reported by previous investigators. 19e21 In accordance with Xie et al, 22 we found a single motor branch to the opponens pollicis in all cases, although, in 2 dissections, that branch bifurcated before entering the muscle. We found the distribution of the TDDBUN to be similar to previous reports, 20,23 including that of Atkins et al, 24 with a single motor branch to the transverse head of the ADP; 1 or 2 branches to the oblique head, which also innervated the deep head of the FPB; and a final branch to the FDI muscle.…”

Skeletal muscle function underpins muscle spindle abundance

“…Specifically, we test if muscle spindle composition correlates with predicted muscle function based on our subject-specific muscle architecture data. In line with previous ideas [6,10,14], it is hypothesized (hypothesis 1) that displacement specialist muscles (composed of long extrafusal fibres and a small physiological cross-sectional area (PCSA)) would contain a greater composition of muscle spindles than those optimized to generate force (short muscle fibres and large PCSA).…”

“…There exists an inherent difficulty in the exploration of correlates of muscle spindle abundance and motor function, especially across human subjects where data are exclusively derived from serial muscle histology preparations [ 11 , 14 , 34 ]. This methodological approach limits the number of morphometric indices available and any potential to correlate muscle spindle abundance with muscle functional outputs.…”

“…Muscle spindle density as an indicator of spindle abundance has often been used to hypothesize the functional roles of muscles [ 14 , 34 ] despite no evidence of or tests for a correlation with muscle function. The data presented here begin to fill this gap in understanding.…”

Hip Adductor Intramuscular Nerve Distribution Pattern of Children: A Guide for BTX-A Treatment to Muscle Spasticity in Cerebral Palsy

“…The modified Sihler's whole mount nerve staining technique is an internationally acknowledged method for tracing the intramuscular nerves without damaging muscle integrity (25–27). The technique allows a clear three-dimensional display of terminal nerves (i.e., the site where an α-motor nerve ending attaches to the muscular fiber, namely, the motor end-plate) that cannot be observed by naked eyes.…”