Ultrasound identification of nerve cords in the infraclavicular fossa: a clinical study.

BACKGROUND: This study aimed to analyze nerve trunk anatomy in the infraclavicular fossa and to correlate these data with the most common anthropometric parameters.

METHODS: A Mylab 30 Gold (Esaote) and the linear transducer LA523 (7.5 MHz frequency) were used. The probe was oriented according to a parasagittal plane, parallel to the lateral chest wall and immediately medial to the coracoid process underneath the clavicle. Measurements included the distance between the artery and the cutaneous surface (mm) and the apical corner of the ultrasound image (mm), the number of identified nervous cords and their position related to the axillary artery, and the position and number of axillary veins. Sex, age, height, weight, body mass index (BMI), biceps girth, and breast size were recorded. Statistical analysis included calculation of linear Pearson correlation coefficient and Student's t test.

RESULTS: Two hundred and two consecutive patients were enrolled. The position of the three cords was highly variable around the artery. In a small but significant percentage of patients (8.9%), the medial and the lateral cords were located together at the top of the artery. The visibility of the trunks and the distance between the upper part of the artery and the apical corner of the ultrasound image correlated with anthropometric characteristics. The vein position with respect to the artery and nerves was markedly variable.

CONCLUSION: Sono-anatomic study of the infraclavicular region adds important data that is useful when conducting nerve blocks to improve safety and likelihood of success.