A hanging apparatus is provided that facilitates the attachment of a medical instrument to a support structure. The mechanism includes a generally longitudinal, telescoping assembly that extends outward from the back of the medical instrument and positions a rotatable arm to serve as one face of a clamp, opposing the back of the medical instrument as the second face of the clamp. The mechanism assembly includes a cylindrical shaft that extends outward against the tension force of a spring from a housing component of the assembly. A cam mechanism within the hanging apparatus allows for locking and tightening of the clamp against the support structure after closure of the clamp under the influence of the tensioning spring.