The hand is an incredibly dexterous part of our upper limb which allows us to perform precise and accurate movements essential for us to interact with our environment. It is finely adapted to be extremely versatile, with a mixture of joints and muscles allowing us to move our fingers in a wide variety of ways. To understand how the hand works, it is important to understand the structures that give it its flexibility.
The hand consists of several different structures which are key to this area's flexibility and dexterity. The main joints in the hand are the Metacarpo-phalangeal (MCP) joints, Proximal inter-phalangeal joints (PIP) and the Distal inter-phalangeal joints (DIP). In addition to these joints, the hand also has several muscles, some of which are intrinsic and some of which are extrinsic.
The extrinsic muscles enter the hand via the carpal tunnel and are responsible for many of the hand's movements. These muscles are largely responsible for flexion and extension of the digits, abduction and adduction of the digits and opposition of the thumb and little finger. The intrinsic muscles of the hand are also important for more subtle and precise movements.
The thenar and hypothenar muscles of the hand are both intrinsic muscles and are important for finer movements such as the reposition of the thumb and little finger. These muscles are essential for fine hand control, allowing us to perform delicate tasks.
In addition to the muscles and joints of the hand, it is important to recognize the role that ligaments play in providing stability. Each joint in the finger is reinforced by a medial and lateral collateral ligament. In addition, the metacarpo-phalangeal joints have palmar plates which provide additional stability.
The combination of many different structures allows the hand to be highly versatile and extremely stable. This versatility and stability combined with the precision and accuracy provided by the muscles and joints of the hand make it an amazing tool. The hand allows us to interact with our environment in a way that would not be possible without it.
