Pacinian Corpuscles in the Human Fetal Finger and Thumb: A Study Using 3D Reconstruction and Immunohistochemistry

Area of Science:

• Developmental Anatomy
• Neuroscience
• Histology

Background:

• Pacinian corpuscles are mechanoreceptors crucial for tactile sensation.
• Their detailed distribution and morphology in the developing human hand are not fully understood.
• Previous studies have primarily focused on adult anatomy.

Purpose of the Study:

• To meticulously map the distribution of Pacinian corpuscles in fetal hands and thumbs.
• To characterize the morphology and arrangement of these corpuscles in various digital and interdigital locations.
• To identify any unique fetal-specific structures or arrangements of Pacinian corpuscles.

Main Methods:

• Analysis of transverse sections from eight fetal hands (gestational age 28-33 weeks).
• Serial sectioning and 3D reconstructions of nerve elements in selected fingers.
• Immunohistochemical staining for S100 protein and nestin to characterize corpuscle components.

Main Results:

• Pacinian corpuscles were found in digital skin, tendon sheaths, and nail beds of fetal hands.
• Distal phalanges contained 45-75 corpuscles, measuring 0.2-1.0 mm in length.
• Unique fetal arrangements included bouquet- and tree-like clusters along neurovascular bundles, and corpuscles within tendon sheaths and nail beds.

Conclusions:

• The distribution and morphology of Pacinian corpuscles in fetal hands exhibit distinct features not observed in adults.
• The presence of corpuscles in tendon sheaths and nail beds, along with specific cluster arrangements, appears to be a fetal-specific characteristic.
• These findings contribute to a deeper understanding of the developmental trajectory of tactile sensory structures in the human hand.