Anatomical Variations of the Ansa Cervicalis: A Systematic Review and Meta-analysis of Cadaveric Studies.
Ananya Priya, Nadia Ahmad, Abhilasha Priya et al.
✦ AI-curated · Sources linked
In 30 seconds
This systematic review and meta-analysis assessed the prevalence and anatomical variation of the ansa cervicalis in cadaveric studies, including 20 studies and 1294 specimens. The nerve loop was present in nearly all specimens; absence was reported in 1%. It was significantly more likely to lie anterior rather than posterior to the carotid sheath. The review also described variation in its position relative to the central tendon of the omohyoid and internal jugular vein, with the external (lateral) configuration most common.
Key findings
- Across 20 studies and 1294 cadaveric specimens, the ansa cervicalis was absent in 1%.
- The ansa cervicalis was significantly more likely to be anterior than posterior to the carotid sheath.
- The central tendon of the omohyoid was most often superior to the ansa cervicalis; inferior positioning was least common.
- The external (lateral) relationship to the internal jugular vein predominated; the mixed configuration was rare.
Why it matters
The ansa cervicalis is used in laryngeal reinnervation and reconstructive neck surgery, and its course varies in relation to important anatomical landmarks. Knowing the common configurations as well as the possibility of variation can support anatomical orientation during neck procedures and help clinicians avoid assuming a uniform nerve position.
What to keep in mind
The evidence comes from cadaveric anatomical studies, so it describes structure rather than clinical outcomes or the effects of surgical approaches.