Topographical Analysis of Pacinian Corpuscle in the Pulp of Human Cadaver Finger Tip Pulp: A Pilot Cadaver Study.

Background: The human hand is a specialised organ for fine motion and sensation and has a relatively large representation in the homunculus. The pathway of sensation starts from information sent by mechanoreceptors in the hand. This study reports the topography of the Pacinian corpuscle in the fingertips of a human cadaver. Methods: All 10 digits from both hands of a fresh-frozen cadaver were examined. Glabrous skin distal to the distal interphalangeal joint was harvested superficial to the periosteum including fat and subcutaneous tissue. The glabrous skin were divided into 10 sections that included five distal and five proximal sections. Modified gold chloride staining was performed. Sectioned specimens were observed under a light microscope and the density of Pacinian corpuscles was determined in each segment. The density of the corpuscles was compared between the radial/ulnar and proximal/distal segments and also between digits from the right hand versus those from the left hand. Results: Pacinian corpuscles were observed only in the subcutaneous tissue. There was no significant difference in density of the corpuscles between the distal and proximal segments or between the right and left hands. There was a statistically significant greater density of Pacinian corpuscles on the radial segments of all digits except the thumb. Conclusions: There is a greater density of Pacinian corpuscles on the radial side of the human fingertip in all digits except the thumb.

Distribution of sole Pacinian corpuscles: a histological study using near-term human feet.

INTRODUCTION: Fast-adapting afferent input from the sole Pacinian corpuscles (PCs) is essential for walking. However, the distribution of PCs in the plantar subcutaneous tissue remains unknown. MATERIALS AND METHODS: Using histological sections tangential to the plantar skin of eight near-term fetuses, we counted 528-900 PCs per sole. RESULTS: Almost half of the sole PCs existed at the level of the proximal phalanx, especially on the superficial side of the long flexor tendons and flexor digitorum brevis. Conversely, the distribution was less evident on the posterior side of the foot. The medial margin of the sole contained fewer PCs than the lateral margin, possibly due to the transverse arch. In contrast to a cluster formation in the anterior foot, posterior PCs were almost always solitary, with a distance greater than 0.5 mm to the nearest PC. DISCUSSION AND CONCLUSION: Because a receptive field of PCs is larger than that of the other receptors, fewer solitary PCs might cover the posterior sole. In infants, the amount of anterior sole PCs seemed to determine the initial walking pattern using the anterior foot without heel contact. Anterior PCs concentrated along flexor tendons might play a transient role as tendon organs during the initial learning of walking. During a lesson in infants, mechanical stress from the tendon and muscle was likely to degrade the PCs. In the near term, the sole PCs seemed not to be a mini-version of the adult morphology but suggested an infant-specific function.

The sensory innervation of the human nipple.

Nipples represent a highly specialized skin with capital importance in mammals for breastfeeding and additionally in humans due to sexuality. The histological studies regarding this region are scarce, so 42 human nipples were studied to describe the morphology of the nipple innervation. Our results exclude the presence of a rich innervation on nipple's skin or superficial dermis, thus definitely excluding nipple skin from the concept glabrous skin. The presence of mechanoreceptors is limited to scarce Merkel cells on the epidermis and some corpuscular capsulated and non-capsulated structures in the dermis; Merkel cells progressively decrease with ageing. No Meissner corpuscles were found and the rare Pacinian corpuscles identified were close to vascular structures and embroidered in the mammary fatty tissue. The great sensitivity observed functionally on the breast and especially in the nipple can be morphologically explained by two elements; on the one hand there is a rich smooth muscle innervation present in the deep dermis; on the other hand the mammary gland demonstrate Piezo2 expression in many glandular cells, with two differentiated patterns in the ductal and in the acinar tissue of the breast. The role of Piezo2 in the normal mammary gland is discussed.

Pacinian corpuscles in the human fetal foot: A study using 3D reconstruction and immunohistochemistry.

PURPOSE: Our group had recently described human hand Pacinian corpuscles (PCs): the hand PCs are not simply arranged along the digital palmar nerves but often exhibited specific morphologies known uncommonly. However, there is still no or few information about human foot PCs. MATERIALS AND METHODS: We observed transverse sections of all five toes including the interdigital area obtained from 12 feet of eight fetuses at 28-33 weeks (crown-rump length 230-290mm). Serial sections were prepared for 3D reconstructions and measurement. RESULTS: Foot PCs were characterized by (1) a dense distribution in the interdigital area in contrast to a few PCs in the distal tip of the all five toes; (2) abundant dorsal PCs including those in the nail bed and: (3) a long chain of PCs in the flexor tendon sheath of all five toes. Therefore, a distal dominance was not evident in the foot in contrast to the hand and, a tendon sheath contained much greater numbers of PCs than the hand. A tree-like or bouquet-like arrangement of PCs along a short perforating artery to the palmar digital skin was seen in the foot as we had described in the hand. The tree of foot PCs was sometimes seen laying transversely along the digital skin surface, not toward the skin. CONCLUSION: It is still unknown that, in utero, how the PCs distribution became different between the hand and foot: it might be determined genetically in a region-specific manner.

Tree of Vater-Pacinian corpuscles in the human finger and thumb: a comparison between the late fetal stage and old age.

Using histological sections of 12 hands from 12 human fetuses at 20-34 weeks of gestation (150-290 mm) and 14 fingers (index and small) from seven donated cadavers of elderly individuals (aged 78-95 years), we compared the features of Vater-Pacinian corpuscles between these two stages of life. Corpuscles with thin, tightly packed lamellae appeared to undergo a change to thick, loosely packed lamellae at 23-32 weeks. The typical fetal corpuscle had two parts: (1) a rod-like proximal part (0.2-0.6 mm in length) extending along the proximodistal axis of the finger, and (2) a distal end (0.1 mm) after acute bending of the proximal part. Corpuscles were associated with palmar digital nerves in the fingers, but were also present along the dorsal nerves in the thumb. A flower bouquet- or tree-like arrangement including 5-10 corpuscles extended to the dermis of the skin along a perforating artery. Serial sections of the thumb and fifth finger revealed approximately 80-180 corpuscles in the distal phalangeal segment. In elderly individuals, the corpuscles were distributed along the palmar digital nerve, but (1) their density was much lower than in fetuses and (2) a bouquet- or tree-like arrangement was rarely seen. In the distal segment, there were fewer than 40 adult corpuscles, being 0.2-0.5 mm thick and 1.0-2.5 mm long. Wavy or coiled corpuscles were evident. Because of the considerable differences in the distribution and number of corpuscles between the fetus and adult, they appear to undergo considerable depletion with age, especially along thin, superficial nerve branches.

Immunocytochemical characterization of pacinian-like corpuscles in the labia minora of prepubertal girls.

STUDY OBJECTIVE: To better understand the precise role of sensory corpuscles within the female external genitalia. DESIGN: After IRB approval, waste tissue samples were obtained from 10 normal girls (aged 2-9 years) who underwent surgery for labial fusion. Immunocytochemistry against protein gene product 9.5 (PGP 9.5), neuron-specific enolase (NSE), vasoactive intestinal peptide (VIP), 5-hydroxytryptamine transporter (5HTT), 5-hydroxytryptamine receptor 1A (5HT1A), Neuronal Peptide Y (NPY), neuronal nitric oxide synthase (nNOS), and estrogen receptors (ER) α and ß was performed. RESULTS: Pacinian-like corpuscles were identified in epithelium of labia minora of prepubertal girls. A central structure composed of an axon surrounded by a central core, outer core, external capsule, surrounded by encapsulated stroma, and a subsidiary innervation in the outer aspect of the corpuscle stroma stained for PGP 9.5 in the outer core and layers of the external capsule, NSE positive cells in layers of the outer core, 5HTT in stroma of the corpuscle and cells located in layers of the outer core, 5HT1A in cells of outer core, NPY in stroma of the corpuscle, and nNOS in external core and external capsule of the central structure. ERα was present in stroma, external core, and external capsule, and ERß in stroma of the corpuscle with subsidiary innervation in the stroma positive to PGP 9.5, VIP, and NPY. CONCLUSION: PGP 9.5, NSE, ERα, nNOS, and 5HTT immunoreaction detected in the outer core and external capsule could indicate these areas may play an important role in the functional aspects of the Pacinian-like corpuscle.

Ovoid geometry of the Pacinian corpuscle is not the determining factor for mechanical excitation.

Static displacements in Pacinian corpuscles (PCs) were measured using video microscopy. Mechanical stimuli of 10-40 microm steps were applied to the PC capsule surfaces using cylindrical contacts with different diameters. Displacements parallel to the stimulation axis were measured at various locations in the focal plane of the optical setup. In contrast to previous data in the literature, the displacements within the corpuscle were found to be linearly related to the indentation amplitude. Displacements decreased as a function of lamella depth, with a more negative slope close to the surface and less negative slope at deeper locations. The experimental data were compared to the predictions of a previous mechanical model, and to the results of two new models: (1) elastic semi-infinite continuum model; (2) ovoid isotropic finite-element model. Although the previous model did not specify displacement boundary conditions, it predicted the current experimental results well. On the other hand, the experimental displacements were found to be smaller than those predicted by the semi-infinite continuum and finite-element models. However, both semi-infinite continuum and finite-element models yielded close results, which show that the three-dimensional ovoid geometry of the corpuscle is not the primary factor for determining the displacements in physiological conditions. Furthermore, simulations with the finite-element model using a wide range of material properties yielded similar results. This supports the hypothesis that a homogeneous isotropic model for the PC cannot predict experimental results. The modeling analyses suggest that the experimental results are largely affected by the displacement of the incompressible interlamellar fluid and the layered structure of the corpuscle.

Decrease in the numbers of mechanoreceptors in rabbit ACL: the effects of ageing.

It is proposed that there is a positive correlation between the numbers of mechanoreceptors and proprioceptive function. On the other hand, normal aging process is associated with deficits in proprioception. This study is designed to test the hypothesis that aging resulted in decreased numbers of mechanoreceptors. Anterior cruciate ligaments of 14 male rabbits (2 months, n=5; 12 months, n=4 and 60 months, n=5) were extracted and the total numbers of Ruffini, Pacini and Golgi tendon-like receptors were accounted. As a result, the numbers of mechanoreceptors, especially Ruffini receptors, decreased with aging (p<0.05). Increased age was associated with changes in the morphology of mechanoreceptors. In conclusion, aging results in both diminished numbers and changed morphology of mechanoreceptors.

Differences in the presence of mechanoreceptors and nerve structures between wrist ligaments may imply differential roles in wrist stabilization.

The purpose of this study was to analyze human wrist ligaments with regard to presence of general innervation and mechanoreceptors. The ligaments studied were: dorsal radiocarpal (DRC), dorsal intercarpal (DIC), long radiolunate (LRL), radioscaphocapitate (RSC), ulnocarpal (UC), scapholunate interosseous (SLI) and lunotriquetral interosseous (LTI) ligaments. Specific immunohistochemical markers were used to target neural/perineurial structures. Both Ruffini and Pacini-like mechanoreceptors (sensory corpuscles) as well as nerve fascicles/free nerve fibers were identified. Ruffini corpuscles were primarily identified via their dendritic intracapsular nerve endings, whereas the Pacini-like corpuscles were identified through their thick perineurial capsules with marked p75 immunoreaction. The wrist ligaments were found to vary in innervation, the DIC, DRC and SLI being richly innervated, whereas the LRL being almost without innervation. The difference in innervation between the ligaments might reflect differential function. Ligaments without innervation might act as structures of passive restraint, whereas ligaments with rich innervation are proposed to also provide proprioceptive information. Wrist ligament injuries should, therefore, be regarded as a disturbance not only of the intrinsic carpal kinematics, but also of the coordination and proprioception of the entire wrist joint.

Pacinian corpuscle in the juxtaoral organ of Chievitz.

The juxtaoral organ of Chievitz (JOOC) is a normal permanent anatomical structure located within the soft tissue overlying the angle of the mandible in the buccotemporal space. Although the sensory organ nature of JOOC, repeatedly mentioned in German publications, has been neglected in the last decade by the American anatomists and pathologists, we incidentally found JOOC-type squamous epithelium accompanied by Pacinian corpuscles. This fortuitous finding appears to be the first report of the authentic Paciniform nerve endings within JOOC, supporting its mechanosensory function.

Topography of corpuscular mechanoreceptors in the shoulder joint region of monodelphis domestica.

The topography and structure of corpuscular mechanoreceptors in the shoulder joint capsule and periarticular connective tissue of a small laboratory marsupial (monodelphis domestica) were studied using light and electron microscopy. This animal is known to use its upper extremities for a wide range of activities like climbing and manipulating food. Thus, the shoulder joint of this animal species has a similar wide range of movement as the human shoulder joint, but is small enough for serial sectioning in its entirety. Silver stained serial paraffin sections were examined under the light microscope and the distribution of the different types of mechanoreceptors was reconstructed using three-dimensional image processing. In addition, selected mechanoreceptors were studied electron microscopically. Approximately 100 small lamellated corpuscles were found in the dense connective tissue of the joint capsule close to the insertion on the scapula and in the thickening of the joint capsule close to the glenoid labrum. Ruffini corpuscles were found in much smaller numbers in the moderately dense connective tissue of the axillary region. Only very few Vater-Pacinian corpuscles were seen in the soft periarticular connective tissue. The large number and localization of mechanoreceptor corpuscles in the shoulder joint capsule especially close to the glenoid labrum suggests, that these specialized nerve endings are likely to play an important role in control of joint movement. They can induce protective reflexes during extreme movements in the shoulder joint preventing shoulder luxation by increasing the tone of muscles pressing the humerus head into the glenoid cavity.

Innervation of the metacarpophalangeal and interphalangeal joints: a microanatomic and histologic study of the nerve endings.

Six pairs of fresh human cadaver hands were dissected under the surgical microscope at x28 to x32 and selectively silver stained. In addition, 18 proximal interphalangeal and metacarpophalangeal joints of fresh cadaver hands were processed with protein gene product 9.5 for measurement and analysis of nerve endings in those joints. The results demonstrated that the proximal interphalangeal joints are innervated by 2 palmar articular nerves (mean diameter, 0.21-0.53 mm). Each metacarpophalangeal joint of the second through fifth fingers is predominantly supplied by 1 palmar articular nerve (mean diameter, 0.41-0.59 mm), which comes from the deep branches of the ulnar nerve, as well as by 2 dorsal articular nerves (mean diameter, 0.11-0.24 mm). The metacarpophalangeal joint of the thumb also had 2 dorsal articular nerves (mean diameter, 0.18-0.24 mm) and 2 palmar joint nerves (mean diameter, 0.29-0.31 mm). The mean densities of the type IV free nerve endings and the mean numbers of the encapsulated endings in the palmar capsules were consistently much greater than in the dorsal or lateral capsules. The majority of encapsulated endings were pacinian corpuscles. The anatomic and histologic information may help the surgeon avoid damaging these small joint nerves during operative procedures and to reconstruct or de-innervate them if necessary. (J Hand Surg 2000; 25A:128-133.

Distribution of human Pacinian corpuscles in the hand. A cadaver study.

The subcutaneous distribution and number of Pacinian corpuscles were studied in ten fresh cadaver hands. They were found to cluster close to nerves and vessels at the metacarpophalangeal joints and the proximal phalanx. The total mean number in the hand was 300 (192-424). The percentage of the total was 44 to 60% in the fingers, 23 to 48% in the metacarpophalangeal area and 8 to 18% in the thenar and hypothenar regions. Corpuscles in palmar skin overlying the distal phalanx were smaller than receptors in the metacarpophalangeal area. The lowest density of corpuscles was along the nerves and vessels of the middle phalanx.

[The longitudinal muscle of the anal canal]. / Der longitudinale Muskel des Analkanals.

The longitudinal muscle (LM) represents a strong muscular structure of the anal canal situated between the internal (IAS) and the external anal sphincter (EAS). Terminal fibres of this muscle insert at the submucosa of the anal canal, representing the m. canalis ani. Others cross the subcutaneous part of the EAS to become the m. corrugator ani. Thus, the LM connects the visceral and somatic parts of the anal sphincter complex. Histologically ganglionic cells and as Vater-Pacinian corpuscles can be identified inside the LM. Morphology, topography and histology of the LM suggest that this muscle participates in maintaining anorectal continence. It is mandatory that the exact functions of this muscular structure be to elaborated upon, if we are to understand the mechanism of anorectal continence.

Sensory nerve supply in the human subacromial bursa.

The subacromial bursa is the major component of the subacromial gliding mechanism. The neural elements of the subacromial bursa obtained from specimens that underwent autopsy and surgery were investigated by the silver impregnation and immunohistochemical methods with antisera to substance P and calcitonin gene-related peptide; which are considered to be involved in nociceptive transmission, and protein gene product 9.5. Free nerve endings, Ruffini endings, Pacinian corpuscles, and two kinds of unclassified nerve endings were observed. Most of these receptors were observed of the roof side of the coracoacromial arch, which is exposed to stress because of the impingement. A delta and C fibers, thought to be nerve fibers of free nerve endings, were immunoreactive to substance P and calcitonin gene-related peptide. On the other hand, thick fibers thought to originate in encapsulated mechanoreceptors were not immunoreactive to substance P. The subacromial bursa receives nociceptive stimuli and proprioception and seems to regulate appropriate shoulder movement.

Ontogeny of the cutaneous sensory organs.

The ontogeny of cutaneous sensory nerve organs is described in higher vertebrates, and includes the lamellated corpuscles of Meissner, Pacini and Herbst, and the Merkel cell-neurite complex with bird Merkel and Grandry corpuscles, and mammalian Merkel cells. The main common feature is that for most corpuscles there is an inside-out order of assembly around the nerve ending which is present from the beginning of end-organ ontogeny. The exception is the mammalian Merkel cell which is present in the epidermis before the entrance of nerve fibers, and could play a promotional role in the development of skin innervation. The developmental origin of Herbst and Merkel corpuscles in birds is reported as demonstrated using embryological experiments with cell markers. Conclusions are that inner bulb cells of Herbst corpuscles and bird Merkel cells are of neural crest origin, whereas other cells (inner space and capsular cells for Herbst corpuscle and capsular cells for Merkel corpuscles) are provided by the local mesenchyme. The question of the ontogeny of mammalian Merkel cells is discussed in relation to the two debated hypothesis of epidermal and neural crest origins. Morphogenetic interactions during the development of cutaneous sensory end organs are also discussed.

On the vegetative and sensitive innervation of the Retractor clitoridis muscle in some domestic animals.

The retractor clitoridis muscle originates from the coccygeal vertebrae in the cow, ewe, goat and mare, and from the anal musculature in the sow. It terminates at the base of the clitoris. In all the species considered, a vegetative innervation was found. This was represented by isolated or grouped ganglion cells. Nervous sensitive supply was also present. This was represented by Pacinian, Pacinian-like and Golgi-Mazzoni's corpuscles, and by Krauses's end bulbs. A notable difference was found in the amount and type of these receptors. They were numerous in the sow, ewe and goat, and rare in the cow and mare. Additionally, in the sow, ewe and goat, all the above mentioned receptors were found, while, in the cow and mare, only Pacinian and Pacinian-like corpuscles occurred. The morphology of these receptors was described and hypotheses were made concerning their probable functional role.