Chasaignac tubercle is
The anterior tubercle of the sixth cervical veebra is known as the carotid tubercle or Chassaignac tubercle. This separates the carotid aery from the veebral aery and the carotid aery can be massaged against this tubercle to relieve the symptoms of supraventicular tachycardia . The carotid tubercle is also used as a landmark for anasthesia of the brachial plexus and cervical plexus . Ref - pubmed.com
Erbs point
Carotid tubercle on C6 veebra
Found on 1st rib
Medial condyle of humerus
Head and neck