THE HUMAN SKELETON DIAGRAMS LABELED and PARTS
THE HUMAN SKELETON is composed of 37 (men) or 38 (women) vertebrae, and of appendages, which include the upper and lower extremities.
There are :
4 vertebrae ; the nasal, the frontal, the parietal, the occipital
7 cervical vertebrae
12 dorsal vertebrae
5 lumbar vertebrae
5 sacral vertebrae
4 or 5 coccygeal vertebrae
The number of the cranial and of the cervical vertebrae remain the same, with but two exceptions,throughout the mammalian class ; but the number of the dorsal vertebrae, or of those vertebrae from which long pleurapophyses, or ribs, arch forwards, varies in different animals, so as to give as much support to the viscera as is compatible with the mobility Of the trunk.
The human skeleton can be divided into the axial skeleton and the appendicular skeleton. The axial skeleton is formed by the vertebral column, the rib cage, the skull and other associated bones. The appendicular skeleton, which is attached to the axial skeleton, is formed by the shoulder girdle, the pelvic girdle and the bones of the upper and lower limbs.
The axial skeleton is the part of the skeleton that consists of the bones of the head and trunk of a vertebrate. In the human skeleton, it consists of 80 bones and is composed of six parts; the skull bones, the ossicles of the middle ear, the hyoid bone, the rib cage, sternum and the vertebral column. The axial skeleton together with the appendicular skeleton form the complete skeleton. Another definition of axial skeleton is the bones including the vertebrae, sacrum, coccyx, ribs, and sternum.
The appendicular skeleton is the portion of the skeleton of vertebrates consisting of the bones or cartilage that support the appendages. Appendages appeared as fins in early fishes, and subsequently evolved into the limbs of tetrapods. The appendicular skeleton includes the skeletal elements within the limbs, as well as supporting pectoral and pelvic girdles in the case of tetrapods (these are lacking in fish). The word appendicular is the adjective of the noun appendage, which itself means a part that is joined to something larger.