Carpal tunnel syndrome and associated nail changes: Review and examples from the author's practice.

Carpal tunnel syndrome (CTS) is commonly seen by general practitioners and often presents with neurologic symptoms of nocturnal pain and paresthesia along the median nerve distribution. Approximately 20% of patients also present with cutaneous findings (ulcerations, blistering, sclerodactyly, nail dystrophy) characterizing a severe form called necrotic CTS. Necrotic CTS can also be associated with bone changes (acro-osteolysis). In the author's practice, combined nail and skin findings are not an uncommon presentation of CTS, although this form remains overlooked and underreported in the dermatological textbooks and studies. This manuscript aims to review the literature on CTS cases, with a specific focus on using associated nail findings as diagnostic clues. The literature review along with a few additional recent cases from the author's practice demonstrate that CTS is frequently accompanied by a variety of nail changes including koilonychia, longitudinal fissuring, Beau's lines, onychomadesis, melanonychia, nail thickening, hyperkeratosis, and ischemic ulcerations with paronychia. Furthermore, when these changes are limited to the second and third fingernails, they should prompt the diagnosis of CTS. Once suspected, diagnostic evaluation is not difficult and surgical management can resolve cutaneous findings and prevent irreversible changes such as acro-osteolysis.

Does nerve repair influence the outcome of reconstruction of a digital nail defect using a free composite flap taken from the great toe?

We describe reconstruction of a nail unit defect in the finger using a free composite flap taken from the great toe, comparing the outcome in patients in whom neurorrhaphy between the dorsal digital nerve of the great toe and the dorsal branch of the proper digital nerve of the injured finger was performed to those in which no nerve repair was made. From January 2002 to March 2009, 47 patients with traumatic fingernail defects were treated. Twenty-two patients before February 2005 had no nerve repair and subsequently 25 patients had nerve repair. The mean size of the germinal matrix and sterile matrix defects was 9 × 8 mm, and the mean size of the nail bed flaps was 9 × 9 mm. The mean length of the arteries used for the flap was 2.2 cm. Outcomes were rated. In the nerve repair group, full flap survival was achieved in 24 patients. At the mean follow-up period of 25 months, there were 12 excellent, seven very good, four good, and two fair results. In the comparison group without nerve repair, there were seven excellent, four very good, four good, five fair, and two poor results. Donor site morbidities were similar in both groups. The use of a free composite flap taken from the great toe is a useful technique for reconstructing nail unit defects in the finger. Innervated nail flap reconstructions tended to show better outcomes than those in which no nerve repair was performed. There is no difference in function or donor site between those in whom the nerve was repaired compared with those in whom it was not repaired.

Nail anatomy.

The nail unit comprises the nail plate, the surrounding soft tissues, and their vasculature and innervation based upon the distal phalanx. The nail plate is a laminated keratinized structure lying on the nail matrix (15-25%), the nail bed with its distal onychodermal band (75-85%), and the hyponychium at its free edge. The distal part of the matrix, the lunula characterized by its half-moon shape, can be observed in some digits. The nail plate is embedded by the proximal and lateral folds. From the proximal nail fold, the cuticle (also known as the eponychium), adheres to the superficial surface of the proximal nail plate. The nail unit possesses a complex and abundant vascular network to ensure adequate blood supply. Finally, both the periungual soft tissues and the nail folds are innervated. The shapes, structure, and inter-relationships of these tissues are factors in the way nails present with disease and how we understand and manage those diseases. In particular, an understanding of the surgical anatomy is important for those undertaking diagnostic or curative operations on the nail. With this knowledge, the most appropriate surgery can be planned and the patient can be provided with accurate and clear guidance to enable informed consent.

Slowly adapting mechanoreceptors in the borders of the human fingernail encode fingertip forces.

There are clusters of slowly adapting (SA) mechanoreceptors in the skin folds bordering the nail. These "SA-IInail" afferents, which constitute nearly one fifth of the tactile afferents innervating the fingertip, possess the general discharge characteristics of slowly adapting type II (SA-II) tactile afferents located elsewhere in the glabrous skin of the human hand. Little is known about the signals in the SA-IInail afferents when the fingertips interact with objects. Here we show that SA-IInail afferents reliably respond to fingertip forces comparable to those arising in everyday manipulations. Using a flat stimulus surface, we applied forces to the finger pad while recording impulse activity in 17 SA-IInail afferents. Ramp-and-hold forces (amplitude 4 N, rate 10 N/s) were applied normal to the skin, and at 10, 20, or 30 degrees from the normal in eight radial directions with reference to the primary site of contact (25 force directions in total). All afferents responded to the force stimuli, and the responsiveness of all but one afferents was broadly tuned to a preferred direction of force. The preferred directions among afferents were distributed all around the angular space, suggesting that the population of SA-IInail afferents could encode force direction. We conclude that signals in the population of SA-IInail afferents terminating in the nail walls contain vectorial information about fingertip forces. The particular tactile features of contacted surfaces would less influence force-related signals in SA-IInail afferents than force-related signals present in afferents terminating in the volar skin areas that directly contact objects.

Neural pattern in the human pollical distal phalanx.

A morphological study of the neural pattern in the human ungual region of the pollical distal phalanx was carried out on eight male cadavers. The dissections showed a palmar neural arrangement consisting of four designated ungual nerves, two proximal and two distal, for each of the ulnar and radial palmar digital nerves at the lateral sides of the thumb. This neural configuration was associated with the compartmentalization of its ungual pulp, the difference between the type of sensory receptors within the ungual pulp, the overlapping of the tactile composition at the thumb tip, seen clinically after laceration of one of the palmar digital nerves, and the sensory supply to the nail bed in the dorsal portion of the thumb. The proximal ungual pulp compartment had a single proximal medial ungual nerve, which did not appear, as far as visually possible, to overlap at the midline of the proximal ungual pulp. In contrast, the distal ungual pulp compartment was supplied by a medial and a lateral ungual nerve, both of which did appear to overlap to their contralateral sides in the thumb tip. A single proximal dorsal sensory nerve branched dorsally from each of ulnar and radial palmar digital nerves at the level of the proximal ungual pulp to supply the nail bed on the dorsum of the thumb.

Anatomy and physiology of the perionychium.

The nail is a unique structure in the human. Its anatomy and physiology are not well understood by many physicians caring for nail problems. The perionychial anatomy is described along with the physiology pertinent to care of the nail and its surroundings.

The nails and diagnosis in homoeopathy

The nails are continuously growing structures which reflect many aspects of the body's functions. The anatomy and physiology of the nails is described. Abnormal appearances of the nails are described in terms of: General appearance, form, colour, structural abnormalities and nail biting. The implications of various appearances of the nails of different digits for prescribing are described

Merkel cells in ontogenesis of human nails.

Digital skin of human fetuses is known to contain a particularly high concentration of Merkel cells. Using antibodies against the simple epithelial cytokeratins (CK) 18 and 20, which are sensitive and specific Merkel cell markers, we studied immunohistochemically the main adnexal structure of digital skin, the nail anlage, in human fetuses (9-22 weeks of gestation) for the presence of Merkel cells. As early as week 9 some clustered Merkel cells were detected in the early matrix primordium. In specimens of week 12-15, abundant Merkel cells were found in the nail anlagen, particularly in the epithelium of the proximal nail-fold and the dorsal and ventral side of the apex region. In contrast, Merkel cells were essentially absent from the epithelium of the ventral matrix (surface-near portion), lunula and nail bed. Correspondingly, in these region, the adjacent dermis contained hardly any nerve fibres, whereas such fibres, as detected by neurofilament antibodies, were quite numerous adjacent to the proximal nail-fold epithelium. At week 22, the Merkel cell number in the nail anlage had decreased, and in adult nail matrix such cells were very rare. No Merkel cells were found in the dermal tissue surrounding the nail anlage while finger-tip skin of week 15, and particularly of week 22, exhibited single Merkel cells in the upper dermis next to clusters of such cells in the glandular ridges. We also found that Merkel cells were negative for CK 17.(ABSTRACT TRUNCATED AT 250 WORDS)

Anatomy and physiology of the perionychium.

It is essential that practitioners, especially surgeons, understand the anatomy and physiology of the tissues they are treating. It is especially important in the nail bed because most practitioners know little about the specific anatomy and physiology of the nail bed. Only if such information is known and considered can new techniques and research in the anatomy, physiology, and care of the nail bed be used. In addition to the individual parts of the nail bed, developmental physiology, embryology, vasculature, lymphatics, and nerve supply are discussed.

[Trophic disorders following primary nerve sutures of the upper extremity]. / Trophische Störungen nach primären Nervennähten an der oberen Extremität.

The frequency of different trophic alterations was examined in 120 patients with 143 primary nerve sutures. Trophic alterations are dependent on the age of the patients and the quality of sensory recovery.