Corpus: Palmar aponeurosis

The palmar aponeurosis is a fan-shaped tendon plate in the palm of the hand.

The palmar aponeurosis consists of a complex, three-dimensional arrangement of longitudinal, transverse, and vertical fibers. It is connected to the overlying skin through the superficial fascia, a dense layer of connective tissue. The terms palmar aponeurosis and palmar fascia are sometimes used interchangeably due to their close relationship.

The palmar aponeurosis spans the central palm, covering and protecting the short muscles of the hand. On the lateral sides, it merges with the fasciae of the thenar and hypothenar muscles. Some authors regard these lateral extensions as part of the palmar aponeurosis, referring to them as the medial and lateral sections. In addition, the fascia of the fingers may also be included, forming what is sometimes described as the palmar fascia complex.

2.1. Palmar aponeurosis in the narrower sense

The central portion of the palmar aponeurosis, often referred to in a narrower sense, has a triangular shape. Its proximal tip is anchored to the tendon of the palmaris longus muscle and connects to the transverse carpal ligament. Distally, the aponeurosis divides into four fiber bands that extend toward the fingers, integrating with the skin of the palm and fingers and interweaving with transverse ligamentous structures such as the superficial transverse metacarpal ligament.

The palmar aponeurosis plays a vital role in the hand's ability to grasp objects. By tightening the skin of the palm, it enhances grip and ensures secure contact with objects. Additionally, its fibrous structure provides protection for the underlying blood vessels and nerves.

Pathological thickening and fibrosis of the palmar aponeurosis can lead to Dupuytren's contracture.