All of the following statements about Sibson's fascia are true, expect (2018)

Sibson's fascia or suprapleural membrane is triangular in shape. Its apex is attached to the tip of the transverse process of the seventh cervical veebra and the base to the inner border of the first rib and its cailage. Morphologically it is regarded as the flattened tendon of the scalenus minimus (pleuralis) muscle.The inferior surface of the membrane is fused to the cervical pleura, beneath which lies the apex of the lung. Its superior surface is related to the subclan vessels and other structures at the root of the neck . Ref:- BD chaurasia volume 1, pg num:-183