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Articles » Skeletal » Radial ray aplasia
2004-12-09-14 Radial ray aplasia © Manohar www.thefetus.net/

Radial ray aplasia

S. Manohar, MD, DMRD
Madurai, India

A Gravida 2, Para I was scanned at 31 weeks of gestation. The fetus showed:

  • an atrio-ventricular septal defect,
  • a short forearm in one of the upper limbs
  • intercalaray hemimelia (probably only the ulna was present)
  • radial deviation of the thumb on 2D images.

The 3D images demonstrated the characteristic shortened forearm and the radial deviation of the wrist and hand. The rendering of fingers was technically difficult. The patient opted for termination of the pregnancy. The postnatal photographs were not available. However, the external features were confirmed by the obstetrician. No karyotyping or fetal blood sampling was done. The following are the ultrasound images:

Images showing discontinuity of the inter-ventricular septum, suggestive of atrio-ventricular septal defect:

Angled view showing the ostium primum defect:



Shortened forearm with only one bone. Acute medial deviation of the wrist and hand is also demonstrated.

3D surface rendered images demonstrating a shortened forearm with a prominent olecranon process.


Radial Ray Abnormalities (Radial hypoplasia or aplasia) may be seen in:

1. Holt-oram syndrome
2. Thrombocytopenia-absent Radius (TAR) syndrome
3. VATER Association
4. Trisomy 18
5. Robert"s phocomelia
6. Fetal valproate syndrome

Incidence:  in 30,000 live births.

Prenatal detection: The following features may be seen on ultrasound:
1. Absent or abnormal radius,
2. Radial hypoplasia – usually involves the distal portion and is often associated with radial deviation of the thumb or hand.
Amniocentesis and fetal blood sampling are indicated for karyotype analysis & hematologic evaluation in cases such as TAR syndrome.

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