Location
Moultrie, GA
Start Date
17-4-2026 12:00 PM
End Date
17-4-2026 1:00 PM
Description
Introduction
Congenital hand anomalies may arise from intrinsic malformations of limb development or extrinsic disruptive processes. Distinguishing symbrachydactyly—a failure-of-formation malformation—from amniotic band sequence (ABS)—a constrictive disruption—is essential, as pathogenesis, prognosis, and management differ substantially. Although both may present with absent digits, characteristic morphologic patterns allow reliable clinical differentiation. We present a term neonate with unilateral central hand deficiency to highlight key diagnostic features distinguishing these entities in the newborn period.
Methods
A retrospective descriptive case review was conducted of a term male neonate with an isolated upper extremity anomaly. Prenatal records, delivery documentation, newborn examination findings, and postnatal radiographic imaging were analyzed. Clinical morphology was compared against established diagnostic criteria for symbrachydactyly and ABS using contemporary congenital upper extremity classification frameworks.
Results
The patient was born at 39 weeks via scheduled repeat cesarean section to a 21-year-old now G2P2 mother with adequate prenatal care. Pregnancy was largely uncomplicated; a 21-week anatomy ultrasound was reported as normal, and the limb anomaly was not detected prenatally. There was no history of teratogenic exposure or family history of limb anomalies.
At birth, physical examination revealed isolated left-hand involvement characterized by absence of digits 2–5. Small distal soft-tissue nubbins were present without visible nail beds on the central digits; the thumb was intact with a nail plate. No circumferential constriction rings, distal edema, webbing, or amputation scars were observed. The right hand and all other extremities were normal. Birth weight was 3.99 kg (89th percentile), and systemic examination was unremarkable.
Postnatal radiographs confirmed congenital absence of phalanges of digits 2–5 with rudimentary proximal phalanges of the 2nd and 5th digits and a relatively preserved thumb. Outpatient pediatric orthopedic referral was arranged at the 4-day well-child visit. No genetic consultation was deemed necessary given isolated findings.
Discussion
The smooth central ray deficiency, unilateral involvement, intact thumb, and absence of constrictive or amputative features support a diagnosis of symbrachydactyly rather than ABS. ABS typically presents with circumferential constriction rings, distal lymphedema, irregular amputation patterns, or visible fibrous bands—findings absent in this case. Under the Oberg–Manske–Tonkin framework, this presentation is best classified as a failure-of-formation malformation.
Importantly, the anomaly was not detected on the routine mid-trimester anatomy scan, underscoring that isolated intrinsic limb malformations may be subtle prenatally. Accurate postnatal morphologic assessment is therefore critical to avoid misclassification and to guide appropriate counseling and management. Functional treatment planning for symbrachydactyly differs fundamentally from the urgent constriction release procedures required in ABS. Early involvement of pediatric hand specialists ensures individualized care focused on long-term function and reconstruction options when indicated.
Embargo Period
5-27-2026
Included in
Isolated Unilateral Central Ray Deficiency in a Term Newborn: Distinguishing Symbrachydactyly from Amniotic Band Sequence
Moultrie, GA
Introduction
Congenital hand anomalies may arise from intrinsic malformations of limb development or extrinsic disruptive processes. Distinguishing symbrachydactyly—a failure-of-formation malformation—from amniotic band sequence (ABS)—a constrictive disruption—is essential, as pathogenesis, prognosis, and management differ substantially. Although both may present with absent digits, characteristic morphologic patterns allow reliable clinical differentiation. We present a term neonate with unilateral central hand deficiency to highlight key diagnostic features distinguishing these entities in the newborn period.
Methods
A retrospective descriptive case review was conducted of a term male neonate with an isolated upper extremity anomaly. Prenatal records, delivery documentation, newborn examination findings, and postnatal radiographic imaging were analyzed. Clinical morphology was compared against established diagnostic criteria for symbrachydactyly and ABS using contemporary congenital upper extremity classification frameworks.
Results
The patient was born at 39 weeks via scheduled repeat cesarean section to a 21-year-old now G2P2 mother with adequate prenatal care. Pregnancy was largely uncomplicated; a 21-week anatomy ultrasound was reported as normal, and the limb anomaly was not detected prenatally. There was no history of teratogenic exposure or family history of limb anomalies.
At birth, physical examination revealed isolated left-hand involvement characterized by absence of digits 2–5. Small distal soft-tissue nubbins were present without visible nail beds on the central digits; the thumb was intact with a nail plate. No circumferential constriction rings, distal edema, webbing, or amputation scars were observed. The right hand and all other extremities were normal. Birth weight was 3.99 kg (89th percentile), and systemic examination was unremarkable.
Postnatal radiographs confirmed congenital absence of phalanges of digits 2–5 with rudimentary proximal phalanges of the 2nd and 5th digits and a relatively preserved thumb. Outpatient pediatric orthopedic referral was arranged at the 4-day well-child visit. No genetic consultation was deemed necessary given isolated findings.
Discussion
The smooth central ray deficiency, unilateral involvement, intact thumb, and absence of constrictive or amputative features support a diagnosis of symbrachydactyly rather than ABS. ABS typically presents with circumferential constriction rings, distal lymphedema, irregular amputation patterns, or visible fibrous bands—findings absent in this case. Under the Oberg–Manske–Tonkin framework, this presentation is best classified as a failure-of-formation malformation.
Importantly, the anomaly was not detected on the routine mid-trimester anatomy scan, underscoring that isolated intrinsic limb malformations may be subtle prenatally. Accurate postnatal morphologic assessment is therefore critical to avoid misclassification and to guide appropriate counseling and management. Functional treatment planning for symbrachydactyly differs fundamentally from the urgent constriction release procedures required in ABS. Early involvement of pediatric hand specialists ensures individualized care focused on long-term function and reconstruction options when indicated.