axillary sheath

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ax·il·lar·y sheath

fibrous neurovascular sheath formed as an extension of the prevertebral layer of deep cervical fascia through the cervicoaxillary canal, that encloses the first part of the axillary artery, the axillary vein, and the brachial plexus.
References in periodicals archive ?
The axillary sheath and single-injection axillary block.
Pectoralis major and minor muscles were reflected and the clavipectoral fascia removed together with the axillary sheath which surrounded the axillary vessels and the brachial plexus.