The 206 bones in the adult human skeleton are organized into a longitudinal axis i.e. axial skeleton, to which appendicular skeleton is attached.
AXIAL SKELETON
Axial skeleton consists of 80 bones in the head and trunk of body. It is composed of five parts.
(i) Skull contains 22 bones out of which 8 are cranial bones (enclosing the brain) and 14 are facial bones.
(ii) There are 6 middle ear ossicles (3 in each ear).
(iii) There is also a hyoid bone in neck.
(iv) Vertebral column contains 33 bones (vertebrae).
(v)The chest is made of a chest bone called sternum and 24 (12 pairs) ribs.
APPENDICULAR SKELETON
Appendicular skeleton is composed of 126 bones. Figure 13.5
(i) Pectoral
(shoulder) girdle is made of 4 bones. Arms have 6 bones. Both hands have 56 bones.
(ii) Pelvic girdle
(hips) has 2 bones. Legs have 8 bones. Both feet have 56 bones.