Lamellar (Pacinian) corpuscle
Corpusculum lamellosum
Also known as: Pacinian corpuscle, Vater–Pacini corpuscle, RA2 receptor, FA2 receptor
Lamellar (Pacinian) corpuscles are large, onion-like encapsulated mechanoreceptors in the deep dermis and hypodermis that adapt very rapidly and detect high-frequency vibration and deep pressure changes.
Overview
Pacinian corpuscles are the largest cutaneous receptors — ovoid bodies ≈1–4 mm long, visible to the naked eye. A single unmyelinated terminal of an Aβ axon occupies the central core, surrounded by an inner core of tightly packed Schwann cell lamellae and an outer capsule of 20–70 concentric lamellae of flattened perineurial (fibroblast-like) cells separated by fluid-filled spaces — giving a cut section the appearance of an onion.
The lamellae act as a mechanical high-pass filter: a sustained indentation is dissipated by fluid redistribution within the capsule, so the nerve terminal is only deformed at the beginning and end of a stimulus. The corpuscle therefore adapts extremely rapidly (RA2/FA2) and is exquisitely sensitive to vibration of ≈200–300 Hz, detectable as amplitudes of a few nanometres. Receptive fields are large and poorly defined. Pacinian corpuscles allow us to sense vibrations transmitted through tools and objects held in the hand.
- Location
Deep dermis and hypodermis of the palms, soles and digits; also periosteum, interosseous membranes, joint capsules, mesentery, pancreas and external genitalia.
Anatomy
- Innervation
Single Aβ myelinated afferent; dorsal column–medial lemniscus pathway.
- Histology
Large ovoid corpuscle in hypodermis; central axon surrounded by many concentric lamellae with interlamellar fluid — "onion bulb" appearance.
Function
- Detection of high-frequency vibration
- Detection of rapid changes in deep pressure
- Perception of distant events transmitted through held objects (tool use)
- Physiology
Very rapidly adapting; large receptive field; frequency range ≈40–1000 Hz with peak sensitivity ≈200–300 Hz.
Clinical significance
Vibration sense testing
A 128-Hz tuning fork applied to the distal interphalangeal joint of the great toe tests vibration sense, which relies largely on Pacinian afferents and the dorsal columns. It is lost early in diabetic peripheral neuropathy, vitamin B12 deficiency (subacute combined degeneration) and tabes dorsalis.
Test yourself
A 128-Hz tuning fork placed on a bony prominence tests vibration sense. Which receptor is principally responsible for detecting high-frequency vibration?
- Merkel cell–neurite complex
- Ruffini ending
- Lamellar (Pacinian) corpuscle
- Free nerve ending
Answer: Lamellar (Pacinian) corpuscle
Pacinian corpuscles are very rapidly adapting receptors whose onion-like lamellae filter out sustained pressure, making them most sensitive to vibration around 200–300 Hz. Signals ascend in the dorsal columns; vibration sense is lost early in peripheral neuropathy.
Compiled from standard anatomy and physiology references — see the Integumentary System sources. For education only; not medical advice.