Skeleton
in physiology, the framework of the body. The lower animals, as jellyfishes and worms, have no hard matter in their bodies that can be called a skeleton. Other animals, as the snail, starfish, crayfish, and the whole horde of insects, have a crusty protective outside covering, but it is an inconvenient arrangement. In order to grow, an animal of this sort must either burst its covering and produce a new one, or else, as in case of the snail, enlarge the free end and abandon the part first occupied.
The chief uses of a skeleton are three: 1. It gives shape and proper stiffness to the body. 2. It protects the delicate organs and the soft parts of the body. 3. Its parts act as levers to which the tendons of the muscles may be attached to produce motion.
The skeleton, or want of one, serves as a basis in the classification of animals. The human skeleton consists of over 200 distinct bones. Two of these, the hyoid to which the root of the tongue and the palate are attached, and the knee-cap, are not joined to any other bones. The human skeleton, being upright, is considered the most highly developed of all.
1. Head or Skull.
A. Cranium (8).
1 frontal.
2 parietal.
2 temporal.
1 occipital.
1 sphenoid.
1 ethnoid.
B. Face (14)
2 upper jaw.
2 nasal.
2 lachrymal.
2 palate.
2 turbinated.
2 malar.
1 vomer.
1 lower jaw.
II. Trunk.
A. Hyoid bone.
B. Spinal Column (26).
7 cervical vertebrae.
12 dorsal vertebrae.
5 lumbar vertebrae.
1 sacrum.
1 coccyx.
C. Ribs (24)
14 true ribs.
6 false ribs.
4 floating ribs.
D. Sternum (1).
E. Hip Bones (2).
III. Limbs.
A. Arms (32 each).
a. Upper Arm.
1 scapula or shoulder-blade.
1 clavicle or collar bone.
1 humerus or arm bone.
b. Fore-arm.
1 ulna.
1 radius.
c. Hand.
8 wrist bones.
5 metacarpal bones.
14 finger bones.
B. Legs (30 each).
a. Thigh.
1 femur.
b. Lower leg.
1 scutella or knee-cap.
1 tibia.
1 fibula.
c. Foot.
7 ankle bones.
5 instep bones.
14 toe bones.
See Animals; Vertebrates; Horse; Tortoise; Bone; URANG-UTAN.