Lowered hyoid bone overlapping the thyroid cartilage in CT angiograms

Area of Science:

• Anatomy
• Radiology
• Medical Imaging

Background:

• The ventral enclosure of the thyroid cartilage by a collapsed hyoid bone (CHB) is an infrequently researched anatomical variant.
• Previous research has not extensively detailed this malformation.

Purpose of the Study:

• To investigate the occurrence and anatomical details of CHB in a series of computed tomography (CT) scans.
• To document the variations in CHB and their relationship with surrounding structures.

Main Methods:

• Systematic review of 200 archived CT angiograms.
• Explicit observation for the presence of the CHB anatomical variant.

Main Results:

• CHB variations were identified in 6 out of 200 cases (3% prevalence).
• Observed variations included symmetrical and asymmetrical overlapping of the thyroid cartilage by the hyoid bone.
• Associated findings in some cases included ossified anterior longitudinal ligament, fused triticeal cartilage, and retropharyngeal positioning of thyroid cartilage horns.

Conclusions:

• Collapsed hyoid bone (CHB) represents a potential atavism that can significantly alter standard anatomical and surgical landmarks.
• The hyoid bone's anatomical components can descend unilaterally or bilaterally, leading to CHB variations.