The human hand is capable of both immense strength and intricate precision. When describing its various parts, common language often falls short of the precise terms used in anatomy. This difference can lead to confusion when naming the surface commonly referred to as the “back” or “top” of the hand. Anatomical nomenclature relies on specific Latin and Greek roots to ensure medical professionals worldwide can communicate without ambiguity.
The Official Term for the Top of the Hand
The scientifically correct term for the top or back of the hand is the Dorsum Manus. This term is derived from the Latin word dorsum, which translates to “back” or “upper surface.” The dorsum of the hand identifies the posterior surface, the side opposite the palm.
The primary role of the dorsum is facilitating movement and providing a protective covering for the underlying structures, rather than gripping. It acts as a smooth surface connecting the hand’s bones and muscles to the forearm. This positioning allows the tendons that straighten the fingers to travel unobstructed across the back of the hand. The skin on this surface is generally thinner and more pliable than the opposite side, which helps accommodate the wide range of motion involved in finger and wrist extension.
Contrasting Terminology: The Palmar Surface
Understanding the dorsum requires contrasting it with the opposite side, known as the Palmar Surface, or the palm. This area is also referred to as the Volar Surface or the anterior surface of the hand. Its structure is specialized for the hand’s primary functions of grasping, gripping, and receiving sensory input.
The skin covering the palmar surface is thick, hairless, and tightly bound to the tissues beneath it. This firm attachment provides stability for a secure grip and helps prevent excessive skin movement during finger flexion. The palm is characterized by unique creases, which are tethered points where the skin is anchored deep into the underlying fascia. Furthermore, the palmar surface contains a high concentration of sensory nerve endings, making it highly sensitive to touch and pressure.
Key Structures and Function of the Dorsum
The Dorsum Manus features several visible and functionally important components that distinguish it from the palm.
Extensor Tendons
Running just beneath the skin are the prominent extensor tendons. These tendons originate in the forearm muscles and are responsible for straightening the fingers and thumb. They are clearly visible when the hand is opened and the fingers are stretched out.
Bony Structures and Veins
The bony projections commonly known as the knuckles are formally identified as the heads of the metacarpal bones, forming the metacarpophalangeal (MCP) joints. These joints are easily seen and felt on the dorsum. Another distinct feature is the dorsal venous network, an arch-like arrangement of superficial veins visible just under the thin skin. This network drains blood from the hand and is frequently used for intravenous access due to its accessibility.