A large, four-bladed Finochietto retractor is primarily used in cardiothoracic surgery to spread the ribs and open the chest cavity for improved access to the heart and lungs. The instrument is self-retaining, meaning it holds the ribs apart without requiring a surgeon's hands, which provides a stable and clear view of the surgical field. 

Thoracotomy:

The Finochietto is a standard tool for a thoracotomy, a procedure to open the chest wall. It is essential for gaining wide access to the internal organs within the thoracic cavity.

Cardiac surgery:

Surgeons use the large retractor for various open-heart procedures, including coronary artery bypass grafting, valve replacement, and other repairs of cardiovascular structures.

Lung surgery:

It provides access to the lungs for procedures such as lung resection (removing a portion of the lung), lung lobectomy (removing an entire lobe), or biopsy.