ANATOMY. Bones and joints (Figure 20). The hand. The framework of the hand is formed by five metacarpal bones; the digits (four fingers and a thumb) are made up of small bones called phalanges. Each finger has three phalanges (proximal, middle, and distal); the thumb has two (proximal and distal). The digits and their metacarpal rays are numbered from one to five, starting with the thumb. The metacarpals and phalanges are long bones.
Each has a diaphysis or shaft, with slightly flaring ends. The joints of the hand and wrist are named for the bones which they connect. All of the IP and MCP joints have a similar arrangement of ligaments that bind the joint together. The metacarpal bones articulate with the wrist to form five carpometacarpal (CMC) joints. In contrast to the first metacarpal, the other rays of the hand have limited mobility. The wrist is not a single joint, but consists of multiple joints. Muscles and tendons (Figure 21). Nerves. Anterior view of Right Hand. Hand Anatomy. Hand Anatomy 101. Hand. A hand (med. /lat.: manus, pl. manūs) is a prehensile, multi-fingered extremity located at the end of an arm or forelimb of primates such as humans, chimpanzees, monkeys, and lemurs.
A few other vertebrates such as the koala (which has two opposable thumbs on each "hand" and fingerprints remarkably similar to human fingerprints) are often described as having either "hands" or "paws" on their front limbs. Fingers are some of the densest areas of nerve endings on the body, are the richest source of tactile feedback, and have the greatest positioning capability of the body; thus the sense of touch is intimately associated with hands. Like other paired organs (eyes, feet, legs), each hand is dominantly controlled by the opposing brain hemisphere, so that handedness, or the preferred hand choice for single-handed activities such as writing with a pencil, reflects individual brain functioning.
Structure[edit] The hand is located at the distal end of each arm. Areas[edit] Bones[edit] Arches[edit] Hand Anatomy. Introduction Few structures of the human anatomy are as unique as the hand. The hand needs to be mobile in order to position the fingers and thumb. Adequate strength forms the basis for normal hand function. The hand also must be coordinated to perform fine motor tasks with precision.
This guide will help you understand what parts make up the handhow those parts work together Important Structures The important structures of the hand can be divided into several categories. Bones and jointsligaments and tendonsmusclesnervesblood vessels The front, or palm-side, of the hand is referred to as the palmar side. Bones and Joints There are 27 bones within the wrist and hand. The main knuckle joints are formed by the connections of the phalanges to the metacarpals.
The three phalanges in each finger are separated by two joints, called interphalangeal joints (IP joints). The joints of the hand, fingers, and thumb are covered on the ends with articular cartilage. Ligaments and Tendons Muscles Nerves. Anatomy Home page.