Rudimentary Digit Research Articles

Osteology and radiographic anatomy of the thoracic limb of the greater cane rat (Thryonomys swinderianus).

The greater cane rat (Thryonomys swinderianus) is mainly distributed in the humid and sub-humid regions of the sub-Saharan Africa. It is believed to be the second largest African rodent. The aim of this study was to describe the normal osteology and radiographic anatomy of the thoracic limb of the greater cane rat as a reference for teaching, clinical use, anatomical studies and biomedical research. Five intact dead greater cane rats were used for radiographic examination. Radiographic findings were correlated with bone specimens. The clavicle was seen in all animals. The scapula was wide with well-developed acromion and coracoid process. The major and minor tubercles did not extend higher than the head of the humerus. The deltoid tuberosity was very prominent. The medial epicondyle was larger than its lateral counterpart, and the supratrochlear foramen was present. The radial tuberosity was further distally located. The ulnar head was well-developed, and the olecranon tuber was square-shaped. The distal physes for the radius and ulna appeared transverse. The carpus had eight bones. The manus presented with five widely spread digits. The first digit was reduced in size and placed such that the dorsal and palmar surfaces face almost medial and lateral, respectively. Additionally, two rudimentary digits were seen. Variations exist in the normal osteology and radiographic anatomy of the thoracic limb in different species. Knowledge of the normal osteology and radiographic anatomy of the thoracic limb of individual species is important for species identification and diagnosis of musculoskeletal diseases involving the thoracic limb.

Unusual congenital polydactyly in mini-pigs from the breeding group of the Institute of Cytology and Genetics (Novosibirsk, Russia).

The article describes a new phenomenon in the breeding group of mini-pigs at the Institute of Cytology and Genetics (ICG, Novosibirsk): polydactyly (extra digits), which is unusual because the additional digits are situated at the lateral surface of legs or at the lateral and medial ones. This anomaly was f irst found here in 2017 in adult animals intended for culling due to incorrect positioning of the legs caused by f lexor tendon laxity and resulting in weight-bearing on the palmar surface of the proximal phalanges (“bear’s paw”). Therefore, the polydactyly of mini-pigs has a pronounced negative selection effect. A visual survey of the livestock was conducted, and a description of the detected anomaly was compiled. The polydactyly in mini-pigs is a stand-alone trait and is not part of any syndromes. Individuals with polydactyly may have extra digits either on pectoral or on pectoral and pelvic limbs. On thoracic limbs, there may be either one lateral digit or a lateral digit and a medially located rudimentary hoof let. On pelvic limbs, only lateral extra digits can occur. Anatomical and morphological analyses showed that the lateral extra digit is an anatomically complete (“mature”) structure, whereas the medial rudimentary digit consists of only a hoof let without other structures characteristic of normal digits. Cytological examination revealed no specif ic karyotypic features, except for Robertsonian translocation Rb 16;17 previously reported for the mini-pigs of the same livestock. Cytological f indings indicated that the polydactyly and Robertsonian translocation are not linked genetically. Genealogical analysis and results of crosses are consistent with a working hypothesis of recessive inheritance of the trait. Overall, the study shows that this type of polydactyly is anatomically and morphologically unique and not typical of Sus scrofa. In this species, only polydactyly types with medial accessory toes have been described and are usually inherited as a dominant trait with incomplete penetrance. In our case, the results of test crosses indicate recessive inheritance of the trait with varying expression and incomplete penetrance, because of which poorly expressed phenotypes are not visually detectable.

RETRACTED: Amniotic Band Syndrome With Pseudoarthrosis of Tibia and Fibula: A Case Report

Constriction of the lower limb by a congenital amniotic band has been proposed to explain the development of pseudoarthrosis of the tibia and fibula. We report a case of amniotic band syndrome in a preterm female infant with pseudoarthrosis of the tibia and fibula. She was born at 29weeks of gestation with congenital amniotic bands and was noted to have a severely edematous left foot distal to the constricting band with rudimentary digits. The skin was pink and well perfused with palpable pulses. Radiography demonstrated pseudoarthrosis of the tibia and fibula. The limb deformities were managed with splints, positioning, and physiotherapy. She underwent Z-plasty with soft tissue release on the left lower leg on day 7 of life. At 36weeks of postmenstrual age, a repeat radiograph showed markedly improved growth of the tibia and fibula with mature new bone formation, which avoided the need for further surgical intervention. During the follow-up period, she underwent left Syme's amputation at 18months. At 29months of age, the child was able to walk and run without support. The findings from our case confirm the potential for bone growth in patients with amniotic band syndrome, once the constricting band has been released. Simple release of the constriction band with Z-plasty resulted in growth of mature bone, replacing the pseudoarthrosis and, hence, the patient did not require surgical amputation. Thus, one should be cautious when deciding on surgical amputation, even in the presence of pseudoarthrosis, especially in preterm infants. Early limb-preserving surgery with release of the constricting band with an intention to salvage the limb appears appropriate.

Symbrachydactyly.

Background: Symbrachydactyly is a unilateral congenital hand malformation characterized by failure of formation of fingers and the presence of rudimentary digit nubbins. The management is variable and are investigated in this review. Methods: A detailed review of the literature was compiled into succinct clinically relevant categories. Results: Etiology, classification, non-surgical management, surgical intervention, and patient oriented outcomes are discussed. Conclusions: All interventions should prioritize realistic, evidence-supported appearance and functional gains. Studies of the baseline function and quality of life of children with symbrachydactyly would allow surgeons to better understand functional changes associated with various interventions and would help surgeons and parents to make the best treatment decisions.

Pallister Hall syndrome (PHS)

Major findings: Hypothalamic hamartoma: a nonenhancing mass in the floor of the third ventricle posterior to the optic chiasm that is isointense to grey matter on T1 and T2 pulse sequences of an MRI, but may have distinct intensity on FLAIR. (Neither cranial CT examination nor cranial ultrasound examination is adequate for diagnosis of hypothalamic hamartoma). Central polydactyly: The presence of six or more well-formed digits with a ‘Y’ shaped metacarpal or metatarsal bone. Postaxial polydactyly: Can be either PAP-A with a well shaped digit on the ulnar or fibular aspect of the limb, or PAP-B with a rudimentary digit or nubin in the same position. Bifid epiglottis: A midline anterior-posterior cleft of the epiglottis that involves at least two-thirds of the epiglottic leaf. It is a useful feature for clinical diagnosis because it appears to be very rare in syndromes other than PHS and is also rare as an isolated malformation. Other: Imperforate anus, renal abnormalities including cystic malformations, renal hypoplasia, ectopic ureteral implantation, and pulmonary segmentation anomalies such as bilateral bilobed lungs.

Complications of Suture Ligation Ablation for Ulnar Polydactyly: A Report of Two Cases

We report two cases resulting in complications following suture ligation treatment for ulnar polydactyly. One case consisted of bilateral, retained gangrene and cellulitis, and a second case consisted of a residual, sensitive skin tag. The case involving gangrene and cellulitis developed after an unsuccessful suture ligation of bilateral pedunculated duplicated digits. The second case developed after suture ligature ablation of a rudimentary digit in the nursery but presented 3years later with a residual symptomatic nubbin. Both cases were treated by surgical excision of the residual tissue in the operating room. The first case illustrates a morbid complication following unsuccessful ligature while the second case demonstrates the inevitable suboptimal long-term outcome associated with what has traditionally been considered "successful" suture ligation.

Ectopic dermal ridge configurations on the interdigital webbings and postaxial marginal portion of the hindlimb in Hammertoe mutant mice (Hm)

The effects of the hereditary malformation of Hammertoe mutant mice (gene symbol Hm) on the digital pads and dermal ridge configurations on their hindlimbs were examined. In the wild-type (+/+) mice with normally separated digits, dermal ridges developed only on the pads. Heterozygous (Hm/+) and homozygous (Hm/Hm) mutant mice, however, had a broad big toe, fused interdigital soft tissues, reduced claws, an extra rudimentary postaxial digit and camptodactyly. The dermal ridges appeared not only on the pads, affected in their number and configurations, but also on the ventral surface of the interdigital webbings and postaxial marginal area exhibiting an extra rudimentary digit and webbing. These aberrant configurations may be related to the abnormal occurrence of programmed cell death (PCD) in the interdigital zones and the postaxial marginal portion in Hm/+ and Hm/Hm mice. That is, the diminished cell death may fail to decrease the cell density in the interdigital zones and postaxial marginal portion and result in the webbing and an extra rudimentary digit and webbing, respectively. Simultaneously, it could also interrupt the migration of surviving cells of these areas toward the neighboring digits and the distal area of the sole and produce the ectopic dermal ridges on the way to the as yet unformed (presumptive) digital and plantar volar pads. The present findings suggest that normal interdigital and pre/postaxial PCD contributes not only to the separation of digits, the initial formation of individual digits of different sizes, and the inhibition of the extra digit but also to the development of the presumptive digital and plantar pads, including dermal ridges.

Raised limb bands developing in infancy

Congenital cutaneous constriction bands are rare and often occur with other abnormalities, including the presence of rudimentary digits. This diverse syndrome lacks a precise definition and a satisfactory explanation. We describe two unusual cases with features previously undescribed, in which predominantly raised, annular limb bands became apparent postnatally. One infant was also born with foreshortened digits and a constricting limb band, suggesting a shared aetiology with other congenital cases. The development of raised bands during infancy would be difficult to reconcile with the widely held 'amniotic band hypothesis', and would be more in keeping with a multifocal developmental abnormality in limb growth.

Lumbosacral parasitic rachipagus twin

A rare case of a newborn girl presenting with a mass representing an aborted parasitic twin attached to the back in the midline over the lumbosacral region (parasitic rachipagus) is reported. Rudimentary digits were attached to the mass, and in one area, the overlying skin resembled scrotal skin. A depression resembling an anal dimple was also present on the surface of the mass. Investigations showed a well-developed long bone and other small bones within the parasite, and sacral spina bifida in the autosite. Successful surgical excision of the parasitic mass was performed. A review of the literature pertaining to parasitic rachipagus twinning is presented.

The cheetah (Acinonyx jubatus) dewclaw: specialization overlooked

The cheetah Acinonyx jubatus is an atypical felid, well known for having blunt, only slightly curved, and only partly retractile claws, clearly an adaptation for high-speed locomotion in the pursuit of swift mammals. However, saying that prey ‘is usually knocked down by the force of the cheetah's charge’ (Nowak, 1999) is incorrect, because this predator actually relies on the claw of the first digit of the forepaw, the so-called dewclaw, to hook the fleeing prey off balance. Although (1) this was understood by Indian huntsmen through their use of tame cheetahs and published (Burton, 1950) in a natural history journal circulating well outside India, (2) wounds attributable to the dewclaws of cheetahs were later observed (Schaller, 1972) on prey animals in Africa, the area of most research on this felid, and (3) the information from India was finally reported (though with the wrong year in the citation) in an authoritative book on African mammals (Kingdon, 1977), no systematic study of the dewclaw itself, or of explicitly related questions, has been made. Perhaps the general connotation of the term ‘dewclaw’, as intended for a non-functional claw on a rudimentary digit as in the case of dogs, has masked the importance of what is not only a strongly curved and sharply pointed, but also a very large claw in the cheetah. In fact, this specialization of the cheetah has escaped the attention of behaviourists (Eaton, 1970), anatomists (Gonyea & Ashworth, 1975), and palaeontologists (Adams, 1979).

Pads and flexion creases on the plantar surface of hammertoe mutant mouse (Hm).

The purpose of the present work was to determine the effects of the hereditary malformation of Hammertoe mutant mice (gene symbol Hm) on the surrounding morphological structures and, specifically, on the volar pads, i.e., the sites of the epidermal ridge patterns (dermatoglyphics). The hindlimbs of the wild-type (+/+) Hammertoe mice show no anomalies and their major pad and flexion crease configurations correspond to those of normal mice. The heterozygous (Hm/+) and homozygous (Hm/Hm) mice display a fusion of the interdigital tissues involving all digits with the exception of digit I. In Hm/Hm mice, this webbing extends to the distal phalanx and the markedly flexed digits form a shape resembling a hammer. In Hm/+ mice, the interdigital webbing does not extend as far and the digits show moderate flexion compared to those of Hm/Hm mice. Both Hm/Hm and Hm/+ have a rudimentary extra digit in the postaxial area of the hindlimbs. The ventral volar skin of the flexed digits is incompletely developed. The more posterior digits show the more severe camptodactyly. These aberrant configurations are related to the abnormal occurrence of the programmed cell death (PCD) in the interdigital zones II-IV and the proximal part of the postaxial margin during hindlimb development. They are limited to the pads on the plantar surface of the postaxial area; the preaxial area is not affected. As a result of a severe camptodactyly of digit V, its volar skin is shifted into the distal portion of the hypothenar area. This shifting affects the number, size, and location of the pads, especially of the hypothenar pad, resulting in varying pad configurations, such as a displacement of the distal and proximal components of the hypothenar pad, or a fusion of the two components of the hypothenar pad, leading to a reduced final pad number. These pad modifications are induced by the postaxial plantar surface shifting proximally and are not affected by the presence of an extra rudimentary digit. The pad modifications in Hammertoe mice with webbed digits and postaxial polydactyly resemble closely those of the previously studied mice with genetic preaxial polydactyly.

A mutational analysis of the 5′ HoxD genes: dissection of genetic interactions during limb development in the mouse

Using gene targeting in mice, we have undertaken a systematic mutational analysis of the homeobox-containing 5' HoxD genes. In particular, we have characterized the limb defects observed in mice with independent targeted disruptions of hoxd-12 and hoxd-13. Animals defective for hoxd-12 are viable, fertile, and appear outwardly normal yet have minor autopodal defects in the forelimb which include a reduction in the bone length of metacarpals and phalanges, and a malformation of the distal carpal bone d4. The limb phenotypes observed in hoxd-13 mutant mice are more extensive, including strong reductions in length, complete absences, or improper segmentations of many metacarpal and phalangeal bones. Additionally, the d4 carpal bone is not properly formed and often produces an extra rudimentary digit. To examine the genetic interactions between the 5' HoxD genes, we bred these mutant strains with each other and with our previously characterized hoxd-11 mouse to produce a series of trans-heterozygotes. Skeletal analyses of these mice reveal that these genes interact in the formation of the vertebrate limb, since the trans-heterozygotes display phenotypes not present in the individual heterozygotes, including more severe carpal, metacarpal and phalangeal defects. Some of these phenotypes appear to be accounted for by a delay in the ossification events in the autopod, which lead to either the failure of fusion or the elimination of cartilaginous elements. Characteristically, these mutations lead to the overall truncation of digits II and V on the forelimb. Additionally, some trans-animals show the growth of an extra postaxial digit VI, which is composed of a bony element resembling a phalange. The results demonstrate that these genes interact in the formation of the limb. In addition to the previously characterized paralogous interactions, a multitude of interactions between Hox genes is used to finely sculpt the forelimb. The 5' Hox genes could therefore act as a major permissive genetic milieu that has been exploited by evolutionary adaptation to form the tetrapod limbs.

EXTRAPERIOSTEAL TOE PHALANX TRANSFER FOR CONGENITAL APHALANGIA: REFINEMENT OF TECHNIQUE

Toe phalanges with attached periosteum can be transferred to hands with congenital aphalangia, constructing rudimentary digits with growth potential. Using a volar technique, rather than the traditional dorsal method, allows stabilization of the constructed metacarpophalangeal joint and maximizes flexor function.

Transverse deficiency of the hand in one of monozygotic twins

In this paper, we report on one male infant of twins with a left hand anomaly. The hand deformities were diagnosed as so called "congenital amputation" which is a synonym of "transverse deficiency" in Swanson's classification. The left hand showed spontaneous amputation at the level of the palm. There were two rudimentary digits on the stump, and an extremely hypoplastic thumb and little finger. The other twin had no anomaly. The results of laboratory findings on blood groups and HLA types suggest that these twins are monozygotic. From these facts, we considered that environmental factors are more important than genetic ones in the pathogenesis of transverse deficiency and symbrachydactyly of the hand.

The Probable Mutation Effect

The Probable Mutation Effect

Phocomelus: A case of congenital malformation

A rare case of congenital abnormality, phocomelus, is reported. The stillborn monster showed abnormal extremities, rudimentary digits, complete absence of the upper palate, and complete harelip.

Rudimentary Digits in Primates

Rudimentary Digits in Primates

Notes on the Reproduction of Rudimentary Toes in Greyhounds

AT the present writing, I have under my observation a fine male, light clay-coloured, smooth haired greyhound, which at certain intervals well illustrates the reproduction of the rudimentary digits of its feet, after they have been accidentally amputated. To-day this dog has growing on the inner aspects of both its fore and hind feet, and situated some 9 centimetres above the soles, on each limb, a strong rudimentary toe. If we choose, say, this toe on the right hind foot as an example of them all, we find it to be loosely attached, rather more than a centimetre long to the base of the claw, which latter is large and strong, powerfully curved, and fully as big as any of the claws on the foot phalanges. I further find that this toe has a well-marked pad on its under side, but careful examination fails to detect any bone in the proximal joint, from which I also infer that the ungual phalanx likewise lacks one, though this is not so easily determined without cutting through the horny theca forming the claw. About four months ago this dog was coursing hares over the prairie of this region, which chances to be overgrown with a stiff growth of sage-brush, about 2 feet to 3 feet high. The wiry stems of this plant, as the dog bounded among them, snipped off all four of these rudimentary digits, close down to the leg in each case, as nicely as though it had been done with a knife, leaving linear wounds about half a centimetre long. Now, instead of the lips of these wounds healing across, as one would naturally suppose they would, they immediately form the basis, in each case, for the growth of another rudimentary clawed toe, fully as perfect as the one which originally sprang from the same site. These subsequent growths take about three months to attain their full size again, when they are very likely to be removed by a similar process, and once more grow out as before, and so on indefinitely.