Sagittal plane imaging of fetal heart showing origin of left common carotid artery from the innominate artery on B mode and on colour doppler imaging, suggestive of Bovine aortic arch. However, it is a misnomer and now identified as variant of aortic arch in humans.

Discussion:

Definition:

• In a bovine aortic arch, the brachiocephalic (innominate) artery and left common carotid artery arise from a common trunk
• This means instead of three separate branches from the aortic arch, there are only two distinct branches.

Diagnostic Significance:

1. Imaging Characteristics

·         Typically identified during detailed fetal echocardiography

·         Appears as a single trunk emerging from the aortic arch instead of the typical three-vessel branching pattern

·         Can be visualized in routine mid-trimester anatomical surveys

2. Clinical Implications

·         Generally considered a benign anatomical variant

·         Most cases are asymptomatic and do not require specific intervention

·         Incidence ranges from 10-25% in different population studies

3. Associated Considerations

·         Usually an isolated finding

·         Sometimes associated with other cardiovascular anomalies

·         Warrant careful detailed fetal cardiac assessment