Ligamentary structure of the base of the nail

Deviation of the Nail Lamina after Unilateral Partial Matricectomy

Deviation of the nail plate in the transverse plane has traditionally been regarded as a postoperative complication following the definitive surgical treatment of ingrown toenails, particularly when only a single nail fold is addressed. The quantification and longitudinal comparison of the operated versus non-operated nail folds could elucidate potential transverse deviations of the nail plate. The objective of this study was to assess the presence or absence of transverse nail plate deviation following ingrown toenail surgery on a single nail fold.

METHODS

A cohort of 11 patients (three males, eight females) with recurrent ingrown toenails undergoing unilateral partial matricectomy were included in this study. Preoperative measurements were compared to those taken at 7, 14, 21, 28, and 35 days postoperatively.

RESULTS

The analysis revealed no statistically significant differences in measurements between the operated and non-operated nail folds, nor were there significant changes in the measurements over time within each group (p > 0.05).

CONCLUSIONS

Despite the absence of visible deviations in the orientation of the nail plate, the angular measurements post-surgery at 35 days showed no statistically significant alterations. The angular values observed across all time points appeared to be influenced by the intrinsic morphological characteristics of each nail plate.

Surgical anatomy of the nail

Knowledge of nail anatomy is a prerequisite for both diagnostic and therapeutic purposes. The nail apparatus is a highly specialized structure, but is in close relationship to the distal phalanx which supports it and to the pulp which carries the sensory receptors and is involved in pinching. It can be divided by the nail plate into the perionychium underneath, and the paronychium above. The perionychium includes, from proximal to distal: the nail matrix, the sole structure responsible for the growth of the nail plate; the nail bed, mostly responsible for adhesion of the plate; and the hyponychium, which is the most distal part, where the nail plate loses its adhesion. The paronychium comprises three nail folds, one proximal and two lateral, that embed the nail plate. The nail apparatus is richly vascularized, with three main sources, and richly innervated, which explains why trauma and surgery are so painful.

Nail Ultrasound in Psoriasis and Psoriatic Arthritis-A Narrative Review

Ultrasonography has advantages for assessing psoriatic arthritis (PsA) due to its ability to evaluate several targets, including joints, entheses, and tendons, but also skin and nails. Although ultrasound is widely used in PsA, nail ultrasound, despite its potential as a non-invasive method for the early detection of inflammation in the nail apparatus, has low applicability in medical practice, as probes with a higher frequency are needed compared with the frequency of probes usually used. In the present article, we have narratively evaluated the studies published in the last 5 years (19 February 2018-18 February 2023) on nail ultrasound value in the diagnosis and monitoring of PsA. The studies published during this period share common measurement parameters, such as the OMERACT definition of enthesis published in 2018. We included original articles published in PubMed and Web of Science using the following search terms in all possible combinations: psoriatic arthritis, psoriasis, ultrasound, and nail. Articles were declared relevant if they presented data on nail morphology, power Doppler evaluation and nearby structure evaluation, while focusing on digitorum extensor enthesitis. In most of the studies, common morphological parameters were generally increased in patients with psoriasis or PsA and were demonstrated to change with medication. The thickness of the extensor tendon was greater in patients with PsA and psoriasis versus controls and it was correlated with nail clinical changes, especially the presence of onycholysis. The presence of PD showed large variability in healthy individuals. The link between enthesitis and nail involvement is still a subject of controversy, taking into account the latest histological findings. The use of ultrasound in the evaluation of nail and DIP enthesitis remains a challenge and an area of research in the coming years.

The Membrane-Like Structure From Extensor Tendon to the Nail in the Distal End of Digits: An Anatomical Study of Structure, Function, and Utility

METHODS

The nail structures of 6 cadavers were investigated in each of the 10 digits of the hand. In the histological study, the thickness, length, and location of the SEP were measured in each digit of 3 cadavers. In the other 3 cadavers, the moving distance of the SEP was measured macroscopically with the distal interphalangeal joint in flexion at 0 to 60 degrees for confirmation of the function. This moving distance could be considered as an indicator of the SEP straining the surrounding (retaining) structure and improving the stability of the nail in pinches.

RESULT

The SEP was recognized in all the digits. The average length of the SEPs was 2.38 ± 0.11 mm (mean ± SE). The average thickness of the SEPs was 0.35 ± 0.02 mm. The nail matrix and its feeding artery were found beneath the SEP in all digits. The average moving distance of the SEP was 1.38 ± 0.06 mm. This moving distance could be considered sufficiently large to support the role of SEP in the pinches compared with the excursion of the extensor tendon at the DIP joint in a previous report.

CONCLUSIONS

The SEP has been shown to play an essential role in fingertip stabilization in pinches. It can serve as an anatomical marker to avoid iatrogenic damage to the nail matrix in surgical approaches.

Congenital malalignment of the great toenail: Conservative and definitive treatment

Congenital malalignment of the great toenail, or ungual malalignment, is a rarely recognized disorder. It is characterized by lateral deviation of the longitudinal axis of the nail plate with respect to the distal phalanx, and if untreated, complications in the late teens and adulthood may arise. In this study, we have reviewed conservative and definitive treatments for this disorder.

Anatomic and Histological Features of the Extensor Digitorum Longus Tendon Insertion in the Proximal Nail Matrix of the Second Toe

Background: Anatomic and histological landmarks of the extensor digitorum longus (EDL) tendon insertion in the proximal nail matrix may be key aspects during surgery exposure in order to avoid permanent nail deformities. Objective: The main purpose was to determine the anatomic and histological features of the EDL’s insertion to the proximal nail matrix of the second toe. Methods: A sample of fifty second toes from fresh-frozen human cadavers was included in this study. Using X25-magnification, the proximal nail matrix limits and distal EDL tendon bony insertions were anatomically and histologically detailed. Results: The second toes’ EDLs were deeply located with respect to the nail matrix and extended superficially and dorsally to the distal phalanx in all human cadavers. The second toe distal nail matrix was not attached to the dorsal part of the distal phalanx base periosteum. Conclusions: The EDL is located plantar and directly underneath to the proximal nail matrix as well as dorsally to the bone. The proximal edge of the nail matrix and bed in human cadaver second toes are placed dorsally and overlap the distal EDL insertion. These anatomic and histological features should be used as reference landmarks during digital surgery and invasive procedures.

To Study the Outcome of Three-Flap Technique in the Management of Pincer Nail

CONTEXT

Pincer nail deformity is a transverse overcurvature of the nail. Though various conservative and surgical techniques have been described in the literature, very few studies are based on objective measurements. This study was undertaken to evaluate the outcome of three-flap technique in the management of pincer nail.

AIM

To study the outcome of three-flap technique in the management of pincer nail.

SETTINGS AND DESIGN

Prospective interventional study.

SUBJECTS AND METHODS

Fifteen patients with pincer nail deformity, fulfilling inclusion and exclusion criteria were enrolled for the study. Routine X-ray was carried out for all patients to detect underlying bony abnormalities such as exostoses. Width and height indices were calculated before the procedure. A three-flap technique was performed on all affected toe nails and outcome was assessed at the end of 6 months and 1 year.

STATISTICAL ANALYSIS USED

Paired t-test and P value.

RESULTS

Satisfactory cosmetic outcome and statistically significant improvement (P < 0.0001) were achieved in all patients.

CONCLUSIONS

Three flap technique is an useful technique in the management of pincer nail.

Anatomic Association of the Proximal Fingernail Matrix to the Extensor Pollicis Longus Tendon: A Morphological and Histological Study

BACKGROUND

Extensor tendon disorders may cause severe functional impairments, and there is a lack of knowledge about their anatomic associations with the proximal fingernail matrix.

OBJECTIVE

To delineate the association between the distal extensor pollicis longus tendon (EPLT) insertion and the limit of the fingernail matrix in the thumb.

METHODS

The limit of the fingernail matrix and the distal bony insertion of the EPLT were identified in five thumbs from fresh-frozen human cadavers. An additional five thumbs were fixed and the longitudinal thumb sections were histologically analyzed.

RESULTS

The terminal limit of the matrix and fingernail was dorsal and overlapped to the EPL tendon, which was located between the fingernail matrix and the phalanx, and extended dorsally to the distal section of the terminal phalanx in all ten thumb bodies.

CONCLUSION

The fingernail matrix is not directly inserted into the periosteum of the dorsal section of the base to the distal phalanx, because this anatomic relationship is separated by the deep fibers of the EPLT.

Anatomic relationship of the proximal nail matrix to the extensor hallucis longus tendon insertion

BACKGROUND

The purpose of this study was to delineate the relationship of the terminal extensor hallucis longus tendon insertion to the proximal limit of the nail matrix of the great toe.

MATERIAL AND METHODS

Fifty fresh-frozen human cadaver great toes with no evidence of trauma (average age, 62.5 years; 29 males and 21 females) were used for this study. Under 25X magnification, the proximal limit of the nail matrix and the terminal bony insertion of the extensor hallucis longus tendons were identified. The distance from the terminal tendon insertion to the nail matrix was ascertained using precision calipers, an optical microscope, and autocad(®) software for windows. Twenty-five great toes were placed in a neutral formalin solution and further analysed by histological longitudinal-sections. The specimens were stained with haematoxylin and eosin and examined microscopically to determine the presence of the extensor hallucis longus tendon along the dorsal aspect of the distal phalanx of each great toe.

RESULTS

The main result we found in great toes was that the extensor tendon is between the matrix and the phalanx and extends dorsally to the distal aspect of the distal phalanx in all, 100%, specimens. The nail matrix of the great toe is not attached to the periosteum of the dorsal aspect of the base of the distal phalanx as is the case for fingers, because the extensor hallucis tendon is plantar or directly underneath the nail matrix and the tendon is dorsal to the bone.

CONCLUSIONS

We have found that the extensor tendon is between the matrix and the phalanx and extends dorsally to the distal aspect of the distal phalanx. The nail matrix of the great toe is not attached to the periosteum of the dorsal aspect of the base of distal phalanx as is the case in fingers, because the extensor hallucis tendon is plantar or directly underneath the nail matrix and the tendon is dorsal to the bone. Our anatomic study demonstrates that the proximal limit of the matrix and nail bed of the human great toe are dorsal and overlapping the terminal extensor hallucis longus tendon until its distal bony insertion in all specimens.

Benefits of an ungual prosthesis in traumatology and reconstructive surgery of the nail

Lesions of the nail apparatus can leave esthetic and sometimes functional sequelae. Many sequelae are the result of incorrect growth of the nail plate. During the acute phase, in the absence of a nail plate, the nail bed may keratinize or form a pyogenic granuloma, compromising harmonious regrowth of the nail plate. The ideal is to reinsert the plate if it is available, but if it has been lost, an ungual prosthesis must be inserted to act as a temporary implantable splint. This implant must have the same shape and structure as the nail plate. Many ideas have been used in the past, including suture pack, infusion tubing, or x-ray film. However, these techniques are no longer acceptable, as, in many countries, all types of implants require a documented recorded identification or "traceability." The implants we use are packed individually in sterile packaging. They are therefore immediately available in traumatology departments treating Hand Emergencies. These prostheses are also very useful in reconstructive surgery of the digit in the hand and feet, particularly when the nail bed has to be reconstructed. In this case, the implant is used to flatten the nail bed, whether it is sutured, grafted, or reconstructed with flaps, during the slow regrowth of the nail plate. The author reports his experience in emergency or secondary repair of the nail complex.

Controversies in the treatment of ingrown nails

Ingrown toenails are one of the most frequent nail disorders of young persons. They may negatively influence daily activities, cause discomfort and pain. Since more than 1000 years, many different treatments have been proposed. Today, conservative and surgical methods are available, which, when carried out with expertise, are able to cure the disease. Packing, taping, gutter treatment, and nail braces are options for relatively mild cases whereas surgery is exclusively done by physicians. Phenolisation of the lateral matrix horn is now the safest, simplest, and most commonly performed method with the lowest recurrence rate. Wedge excisions can no longer be recommended.

Joint appendages: the structures which have historically been overlooked in arthritis research and therapy development

Rheumatologists have largely conceptualised joint disease in inflammatory and degenerative arthritis in terms of bone, cartilage and the synovial lining, but have tended to overlook other integral components of the joints which are attached close to joint margins. We discuss these structures under the umbrella term of 'appendages'. These structures include ligaments, tendons, entheses or joint insertions, regional fibrocartilages, bursae and other peri-articular joint structures including fat pads and nails. In this review, we highlight how these structures play key pathophysiological roles in inflammatory arthritis and we emphasise how an understanding of these structures is collectively important for both clinical practice and future rheumatological research.

Nail biology and nail science

The nail plate is the permanent product of the nail matrix. Its normal appearance and growth depend on the integrity of several components: the surrounding tissues or perionychium and the bony phalanx that are contributing to the nail apparatus or nail unit. The nail is inserted proximally in an invagination practically parallel to the upper surface of the skin and laterally in the lateral nail grooves. This pocket-like invagination has a roof, the proximal nail fold and a floor, the matrix from which the nail is derived. The germinal matrix forms the bulk of the nail plate. The proximal element forms the superficial third of the nail whereas the distal element provides its inferior two-thirds. The ventral surface of the proximal nail fold adheres closely to the nail for a short distance and forms a gradually desquamating tissue, the cuticle, made of the stratum corneum of both the dorsal and the ventral side of the proximal nail fold. The cuticle seals and therefore protects the ungual cul-de-sac. The nail plate is bordered by the proximal nail fold which is continuous with the similarly structured lateral nail fold on each side. The nail bed extends from the lunula to the hyponychium. It presents with parallel longitudinal rete ridges. This area, by contrast to the matrix has a firm attachment to the nail plate and nail avulsion produces a denudation of the nail bed. Colourless, but translucent, the highly vascular connective tissue containing glomus organs transmits a pink colour through the nail. Among its multiple functions, the nail provides counterpressure to the pulp that is essential to the tactile sensation involving the fingers and to the prevention of the hypertrophy of the distal wall tissue, produced after nail loss of the great toe nail.

Dizygotic twins with congenital malalignment of the great toenails: Reappraisal of the pathogenesis

Congenital malalignment of the great toenails (CMGTN) is a heritable disorder, in which the longitudinal axis of the nail plate is not parallel to the corresponding axis of the distal phalanx of the hallux, but laterally deviated. We describe a pair of 1(1/2)-month-old dizygotic twins with laterally deviated nail plates of the great toenails since birth. By the time the infants were 10 months of age, significant realignment was observed. Adult pedigree members also showed slight similar deviations of the nail plates. We suggest that desynchronization of growth between the nail and the adherent end-phalanx of the hallux may result in temporarily larger nail plates, which are gliding outwards, in order to fit into the underlying bony space. During postnatal life, spontaneous realignment is usually observed, probably as a result of a faster growing end-phalanx.

Surgical Anatomy of the Nail Apparatus

Nail surgery is an integral part of dermatologic surgery. An in-depth knowledge of the anatomy, biology, physiology, and gross pathology of the entire nail unit is essential. In particular, knowledge of nail histopathology is necessary to perform diagnostic nail biopsies and other nail procedures correctly.

Congenital malalignment of the great toenails in a pair of monozygotic twins

Congenital malalignment of the great toenails is the lateral deviation of the long axis of nail growth relative to the distal phalanx. The nails grow slowly, with thickening, curving, and transverse ridging. We describe a pair of 3-year-old monozygotic female twins with congenital malalignment of the great toenails complicated by ingrowing and paronychia. Although there are a few cases without any family history, congenital malalignment is believed to be inherited through an autosomal-dominant gene of variable expression. This report provides further evidence of the heritability of the disease.

The physical basis of cosmetic defects of the nail plate

Cosmetic defects of the nail cover a range of changes. Some are variants of normal which are considered unattractive, others are part of the normal ageing process and some changes are manifestations of local or systemic disease. Interpretation of these changes relies on recognition of the specific characteristics in question and an understanding of the anatomy and biology of nails. In many instances, therapies are limited and explanation of the changes represents one of the most useful contributions the professional can make to the affected individual. This article covers some of the most common cosmetic defects of nail involving colour, surface, brittleness and behaviour of surrounding tissues. Understanding of the physical basis of these defects is limited in many cases, but current thinking is recorded.

Subungual myxoid cysts: clinical manifestations and response to therapy

BACKGROUND

Myxoid cysts located beneath the nail are very different from those within the nailfold and there is no established literature on their diagnosis and therapy.

OBJECTIVE

Thirty-five cases of subungual myxoid cyst are described in which the diagnosis was confirmed by magnetic resonance imaging, surgical exploration, or both.

METHODS

The clinical characteristics of all cases of subungual myxoid cysts confirmed in 3 specialist nail clinics are reported. Twenty cases were confirmed by magnetic resonance imaging. Histologic details were recorded in 4 cases.

RESULTS

Thirty-four patients (22 female, 12 male) presented with a subungual tumor of the thumb (n = 25) or finger (n = 10). The 3 main clinical variables were color of the lunula, transverse nail curvature, and integrity of the nail. In 26 cases the lunula was discolored; it was red in 22 cases, blue in 3, and as part of a longitudinal leukonychia in one. Transverse curvature was increased in 29 cases and was normal in 5 cases; in one case the nail was destroyed. In 11 cases, the change in curvature led to lateral ingrowing. Surgery (n = 22), sclerosant (n = 1), and spontaneous discharge (n = 2) all resulted in resolution. Ten patients had no treatment.

CONCLUSION

This study describes 35 subungual myxoid cysts having characteristic features that allow clinical diagnosis. They respond to a range of treatments.

Examination of the anatomic relationship of the proximal germinal nail matrix to the extensor tendon insertion

The purpose of this study was to delineate the relationship of the terminal extensor tendon insertion to the proximal limit of the germinal nail matrix. Sixteen fresh-frozen human cadaver fingers without any evidence of trauma (average age, 55 years; 3 males and 1 female) were used for this study. Under x25 magnification the proximal limit of the germinal nail matrix and the terminal bony insertion of the extensor tendon were identified. The distance from the terminal tendon insertion to the germinal nail matrix was ascertained using precision calipers. The average distance from the terminal extensor tendon insertion to the proximal edge of the germinal nail matrix was found to be 1.2 mm. We conclude that the proximal limit of the germinal matrix is extremely close to the terminal extensor tendon bony insertion. When the extensor tendon insertion is visualized during operative exposures of the dorsum of the distal phalanx, care should be taken to avoid damaging the germinal matrix. Conversely, when the nail bed is being completely excised, visualization of the insertion of the extensor tendon will indicate that further proximal dissection is not required.

Etiology and treatment of nail malalignment

BACKGROUND

There are three main types of nail malalignment. These are: congenital nail malalignment of the big toenail, traumatic nail malalignment, and iatrogenic malalignment of the nail plate.

OBJECTIVE

Treatment is only of benefit in the first two conditions, and specific surgical approach to each condition is outlined. The probable mechanism of iatrogenic malalignment is discussed.

RESULTS

Nail rotation for congenital malalignment produces its best results in early childhood.

CONCLUSION

Surgery is of benefit in congenital malalignment and traumatic malalignment and is worthwhile in selected cases. Iatrogenic malalignment that is the consequence of wide lateral nail biopsies or similar excisions does not respond to treatment.