Diagnostic ultrasound ( PDFDrive )

CHAPTER 40 The Fetal Musculoskeletal System 1403
FIG. 40.30 Amputation of the Hand. Upper extremity ends abruptly
distal to the wrist, in the midcarpal region (arrows). (Courtesy of Ants
Toi, MD, University of Toronto.)
Limb pterygium, or webbing of the skin across a joint, can
involve a single joint or several joints 102 and etiologically is a
heterogeneous disorder. Popliteal pterygium is the most common
dominantly inherited pterygium syndrome and is associated with
mutations in the IRF6 gene. 103
Asymmetrical limb enlargement may be caused by hemihypertrophy,
cutaneous hemangioma or lymphangioma,
elephantiasis secondary to a constricting band, arteriovenous
malformations, neuroibromatosis, or Beckwith-Wiedemann
syndrome.
Hereditary lymphedema type 1 (Nonne-Milroy lymphedema)
is a rare autosomal dominant condition secondary to deicient
lymphatic drainage, typically afecting the lower extremities. he
subcutaneous tissues of the afected extremity appear difusely
thickened. Associated ascites and pleural efusions may be seen.
here is variable expressivity and age of onset 104 (Fig. 40.35).
A
B
FIG. 40.31 Amputation of Right Lower Extremity. (A) Ultrasound image demonstrates abrupt ending of the right lower limb (arrow).
(B) Comparison ultrasound image shows normal left lower limb.
A
B
C
D
FIG. 40.32 Amniotic Band Sequence. Constriction rings with distal elephantiasis. (A) Ultrasound lateral image of the distal forearm and hand
demonstrates the two constriction rings with elephantiasis. (B) Ultrasound of the digits demonstrates the distal tapering of the digits. (C) Radiograph
demonstrates the two constriction rings in the distal forearm and hand. (D) Correlative specimen photograph.