Bones are traditionally classified as long, short, flat, or mixed based on appearance. However, this classification does not account for differences in structure, function, and development between bones of the same group. A more accurate classification should consider form, function, and development. The document then presents an alternative classification system that divides bones into tubular, spongy, flat, and mixed groups based on their composition, functions in the skeleton, and locations.

1. BONE CLASSIFICATION
Bones are classified according to appearance: long, short, flat and mixed. Bones entirely
different in structure , function and origin form a single group . The group of flat bones,
for instance, includes both the parietal bone, a typical membrane bone, which undergoes
intramembranous ossification and the shoulder blade which is concerned with the
functions of support and movement, ossified from cartilage and formed of ordinary
spongy substance. A pathological process in the phalanges also differs in its course from
that in the carpal bones, although both types of bones are referred to as short bones; the
same applies to the thigh bone and rib included in the group of long bones.
It is therefore more proper to classify bones according to the three principles on which
any anatomical classification should be based, i.e. form (structure), function and
development. The following classification of bones can be suggested according toM.G.
Prives:
I. Tubular Bones: These are composed of spongy and compact substance forming a
tube with a marrow cavity; they perform all three functions of the
skeleton(support,protection and movement).
a) Long Tubular Bones(arm bone, forearm bones, thigh bone and leg bones)
b)Short Tubular Bones(metacarpal, metatarsal, phalanges)

2. II. Spongy Bones: they consist mainly of spongy substance covered with a thin layer
of compact substance.
a)Long Spongy Bones(ribs and sternum)
b)Short Spongy Bones(vertebrae, carpal, tarsal)

3. c)Sesamoid bones i.e. bones which resemble sesame seeds in shape, hence their
name(the knee cap or patella, the pisiform bone)

4. III. Flat Bones
a)Flat Bones of the skull(frontal and parietal): They perform a function that is mainly
protective.Their structure is dipole and they ossify from connective tissue.
b)Flat Bones of the girdles(shoulder blades, pelvic bones): Perform supportive and
protective functions. Their structure is primarily spongy substance.

5. IV. Mixed Bones( bones of the base of the skull) are formed by the fusion of several
parts, which differ in function, structure and development.
Kamal Umar Labaran(Med.)
Donetsk National Medical University
2014.