Skeletal muscle Skeletal muscle Skeletal muscle is one of three major muscle types, the others being cardiac muscle and smooth muscle. It is a form of striated muscle tissue, which is under the voluntary control of the somatic nervous system. Most skeletal muscles are attached to bones by bundles of collagen fibers known as tendons. A skeletal muscle refers to multiple bundles (fascicles) of cells joined together called muscle fibers. The fibres and muscles are surrounded by connective tissue layers called fasciae. Muscle fibres, or muscle cells, are formed from the fusion of developmental myoblasts in a process known as myogenesis. Muscle
Second metacarpal bone Second metacarpal bone The second metacarpal bone (metacarpal bone of the index finger) is the longest, and its base the largest, of all the metacarpal bones. Its base is prolonged upward and medialward, forming a prominent ridge. It presents four articular facets, three on the upper surface and one on the ulnar side: The extensor carpi radialis longus muscle is inserted on the dorsal surface and the flexor carpi radialis muscle on the volar surface of the base. The shaft gives origin to the first palmar interosseus and the first and second dorsal interossei. This bone is often the most