1.ANATOMY AND MEDICINE. HUMAN ANATOMY DEPARTMENT OF
2. The
main anatomical terms. The role of anatomy in the medical education. Planes,
axes and surfaces. The bone structure. Periosteum. Trunk skeleton (general
data).
3. Vertebrae
(general data). Cervical, thoracic and lumbar vertebrae. Sacrum. Coccyx. THE
VERTEBRAL COLUMN AS a WHOLE
Lesson # 1
Theme 1. ANATOMY AND MEDICINE. HUMAN ANATOMY DEPARTMENT
OF
THE TERM human anatomy comprises a consideration of the various
structures which make up the human organism. In a restricted sense it deals
merely with the parts which form the fully developed individual and which can
be rendered evident to the naked eye by various methods of dissection. Regarded
from such a standpoint it may be studied by two methods: (1) the various
structures may be separately considered—systematic anatomy; or (2) the
organs and tissues may be studied in relation to one another—topographical
or regional anatomy.
It is, however, of much advantage to add to the facts
ascertained by naked-eye dissection those obtained by the use of the
microscope. This introduces two fields of investigation, viz., the study of the
minute structure of the various component parts of the body—histology—and
the study of the human organism in its immature condition, i.
e., the various stages of its intrauterine development from the fertilized
ovum up to the period when it assumes an independent existence—embryology.
Owing to the difficulty of obtaining material illustrating all the stages of
this early development, gaps must be filled up by observations on the
development of lower forms—comparative embryology, or by a consideration
of adult forms in the line of human ancestry—comparative anatomy. The
direct application of the facts of human anatomy to the various pathological
conditions which may occur constitutes the subject of applied anatomy.
Finally, the appreciation of structures on or immediately underlying the
surface of the body is frequently made the subject of special study—surface
anatomy.
SYSTEMATIC ANATOMY.—The various systems of which the human
body is composed are grouped under the following headings:
Osteology—the bony system or skeleton.
Syndesmology—the articulations or
joints.
Myology—the muscles. With the description
of the muscles it is convenient to include that of the fasciæ which are
so intimately connected with them.
Angiology—the vascular system, comprising
the heart, bloodvessels, lymphatic vessels, and lymph glands.
Neurology—the nervous system. The organs of
sense may be included in this system.
Splanchnology—the visceral system.
Topographically the viscera form two groups, viz., the thoracic viscera and the
abdomino-pelvic viscera. The heart, a thoracic viscus, is best considered with
the vascular system. The rest of the viscera may be grouped according to their
functions: (a) the respiratory apparatus; (b) the digestive
apparatus; and (c) the urogenital apparatus. Strictly
speaking, the third subgroup should include only such components of the
urogenital apparatus as are included within the abdomino-pelvic cavity, but it
is convenient to study under this heading certain parts which lie in relation
to the surface of the body, e. g., the testes and the external organs of
generation.
For descriptive purposes the body is supposed to be in the
erect posture, with the arms hanging by the sides and the palms of the hands
directed forward. The median plane is a vertical antero-posterior plane,
passing through the center of the trunk. This plane will pass approximately
through the sagittal suture of the skull, and hence any plane parallel to it is
termed a sagittal plane. A vertical plane at right angles to the median
plane passes, roughly speaking, through the central part of the coronal suture
or through a line parallel to it; such a plane is known as a frontal plane
or sometimes as a coronal plane. A plane at right angles to both the
median and frontal planes is termed a transverse plane.
The terms anterior or ventral, and posterior
or dorsal, are employed to indicate the relation of parts to the front
or back of the body or limbs, and the terms superior or cephalic,
and inferior or caudal, to indicate the relative levels of
different structures; structures nearer to or farther from the median plane are
referred to as medial or lateral respectively.
The terms superficial and deep are strictly
confined to descriptions of the relative depth from the surface of the various
structures; external and internal are reserved almost entirely
for describing the walls of cavities or of hollow viscera. In the case of the
limbs the words proximal and distal refer to the relative
distance from the attached end of the limb.
The Department of Human Anatomy of the
In August, 1959 department was transferred into modern morphological building on a street Ruska, 12. The educational rooms placed on the second level and
actuated 2 sectional halls on 7 workstations. In a dextral wing of a building the main division of department was equipped room for cadavers. The students had a
capability independently to make dispositions for practical classes using dry
and wet preparations, the fund of the lecture tables was augmented, were built
up a fundamentals for creation of an educational
Senior lecturer A.О.
Verisotskyy was first Head of Department in 1957. Professor М.Y.
Polyankin has written above 100 scientific articles, the majority of which
are dedicated to a circulatory system of the human and animal. He managed the
scientific researches of influencing on an organism of gravitational
overloading have begun. The pioneer of these researches was professor
V.H.Коvеshnikov.
In 1972 department
has headed MD Professor V.H. Коvеshnikov. During his management the exterior of
department has changed, the
The main scientific supervision
on department was and there is an analysis of influencing external and internal
environment at a skeletal system. For the initiatives Professor V.H.
Коvеshnikov on the basis departments were conducted scientific conferences,
workshops, congresses of the morphologists.
Since July, 1984 department has headed by
professor Y.I.Fedonyuk. He is Honoured Scientist of Ukraine, Academician of
New-York Academe of Sciences, Academician of International Academy of
Integrative Anthropology, and Academician of Academy of National Progress.
Professor Y.I.Fedonyuk prolongs the best traditions and scientific
investigations. He has written above 550 scientific articles and books and five
monographs. Under his management 15 candidate and 2 doctoral thesis realized.
His name is in the brief biographic data are included in 24-those biographic
issuing of the Cambridge International Biographic Centre (
Professor Y.I.Fedonyuk, associated
professors – I.Y.Herasymyuk, B.V. Holod, А.М. Pryshlyak, B.Y. Reminetskyy, P.P. Flekey, O.M.Kyrychok, V.V. Buryy, I.I. Boymistruk, M.V. Yushchak, R.V.Hovda, M.V.Samborskyy
work at the department. The staff of department participated in preparing
the Ukrainian version of the Anatomical Nomenclature, from department sends to the
public tutorials for the students of medical and nursing schools. Staff of the
department develops new educational methods with using anatomical preparations
and computer technique, including methods in English language medium.
Anatomy is the study
of the structure of the body. Derived from the Greek to cut up: the Latin 'to
cut up' gives us dissect. Anatomy has a very specialised vocabulary, much of it
inherited from Latin, Greek. There is a standard list of terms, in Latin, which
has the disadvantage that virtually no one uses it.
Major parts of the body
Anatomical
usage follows general for most of the main parts, head neck, and trunk. The
limbs are a little different. The Anatomist calls these the upper and lower
limbs, and arm means between shoulder and elbow, and leg between knee and
ankle. We subdivide the trunk into thorax, above the diaphragm and abdomen,
below it.
The anatomical position
For descriptive
purposes the body is always imagined to be in the anatomical position, standing
erect, arms by sides, palms of hands facing forwards. In this position
directions are given by superior, inferior, anterior, posterior. These are
equivalent to the zoologist’s cephalic, caudal, ventral and dorsal. Thus the
eyes are always superior to the mouth, even if the patient is lying down or
standing on his head. These terms are not quite equivalent to above, below, in
front of and behind. To a layman acrobats’ feet are above her head when she is
dangling from a trapeze: to an anatomist they are inferior.
Theme
2. Planes, axes and surfaces. The bone structure.
Periosteum. Trunk skeleton (general data)
|
Principal Axes Horizontal
(transverse)
axis is perpendicular (at a right angle) to the longitudinal axis and runs from
left to right. Longitudinal
(vertical) axis, this is a vertical axis through the body in the upright position. |
Lateral
view on right The
saggital (antero-posterior) axis runs from front to back which is why it is
also know as an antero-posterior axis. This axis is perpendicular (at
right angles) to the other 2 axes |
|
Other
dimensions are referred to the midline - median, medial or lateral, or to their
closeness to the body surface, superficial or deep. In the limbs structures near
the trunk are proximal, those further away are distal. We have a problem with
the hands and feet: the palms of the hands resemble the soles of the feet and
the thumb is equivalent to the great toe. But the palmar surface of the hand
faces anteriorly and the back is dorsal. In the foot we defy logic and call the
inferior surface plantar (equivalent to palmar) and the superior surface
dorsal, even though it faces upwards. But we are still not out of the wood
because the great toe is medial but the thumb is lateral. To get around this
the term preaxial is often used to describe the thumb or great toe side.
Postaxial is the little toe or little finger side. The axis referred to runs to
the tip of the middle finger or the second
toe.
The
other small problem, the penis, is described in its erect position, so that its
dorsal surface faces anteriorly and superiorly when detumescent.
We
also need to define planes, mutually at right angles. The horizontal plane is
clear enough: the other two are a little less so. The sagittal plane (L.
sagitta, an arrow) probably refers to the sagittal suture which runs from
anterior to posterior in the newborn skull, and has an arrowhead in the form of
the frontal fontanelle. Coronal is also difficult since it means crown, and I
always think of a crown as being horizontal. But this is an older usage, as in
the crown of an arch or a tooth, or the road, meaning something more like a
halo. Once again these refer to the anatomical position.
Now that we can describe the
body at rest we can also deal with movement.
abduction is movement of any part
away from the midline in the coronal plain
adduction is return to the midline
flexion is moving anything in the sagittal plane
extension is straightening it again.
lateral flexion is bending in the
coronal plane
opposition which brings its palmar surface in
contact with the palmar surface of the fingers.
rotation occurs around a vertical
axis, or the main axis of the limb. If we rotate the head to the right we end
up facing right. For the limbs we still use the displacement of the anterior
aspect i.e. lateral rotation moves the palm laterally. The shoulder is a good
joint to illustrate movement because it is so free. The slide shows what we can
do, and how we describe it.
Also see:
http://www.sohp.soton.ac.uk/biosci/anatomy2.htm
Hand and foot again pose
problems because of their distinctive orientation. The hand has a rather
unusual movement whereby the thumb can be brought to lie medially: in fact this
crosses the bones of the forearm. The anatomical position of the hand is called
supine, the reverse prone, so this movement is pronation reverse supination.
General anatomical terms:
Vertical Horizontal Median Frontal
(Coronal) Sagittal Intermediate Medial Peripheral Radial Peroneal |
Lateral Anterior Posterior Ventral Dorsal Frontal Occipital Axial External Internal Tibial |
Inferior Cranial
Palmar Plantar Flexor Extensor
Caudal Ulnar Fibular Proximal |
Rostral Apical Basal Basilar Middle Transverse Longitudinal
Superficial
Deep Central Distal |
In human body they
distinguish some levels of the organization:
1.
molecular level – object of
the biochemistry
2.
subcellular level – object
of the histology
3.
cellular level – object of
the histology
4.
tissues level – object of
the histology
5.
organs – object of the
anatomy
6.
systems – object of the
anatomy
7.
organism – object of the
anatomy
connective
tissue - less elasticity - wrinkles
cartilage - less elasticity -
degenerative changes such as osteo-arthritis with associated changes. Costal
cartilages often replaced by bone: bony spurs develop in unusual places.
bone - becomes brittle, reduced in
size with less activity
muscle - ditto, plus deposition of
fat.
heart and blood vessels - arteries
become tortuous, walls become furred up with atheroma. Left ventricle is
enlarged as consequence of load. Veins often varicose.
nervous system - Often small strokes
will cause paralysis and reduction in size of some muscles
The human body is composed of 206 bones
that perform five main functions:
1)
support
2)
protection
3)
body movement
4)
blood cell formation
5)
storage of inorganic salts
and lipid
II. Cells in Osseous tissue: osteocytes, osteoblasts, osteoclasts,
osteoprogenitor, cells.
III. Cellular matrix - 1/ calcium hydroxyapatite, 2/ collagenous fibers
Diaphysis -- shaft
epiphysis -- bone ends
epiphyseal line
nutrient foramen
medullary cavity
V. Types of bone:
a. lamellar or compact bone
1.
contains osteons composed of concentric lamellae
2.
each osteon has an osteonic canal (Haversian canal) which has blood vessels and
nerves
3.
osteocytes found within lacunae
4.
canaliculi connect osteocytes and function to diffuse nutrition to the
osteocytes
5.
communicating (also called perforating or Volkman's) canals, connect adjacent
osteons, and carry blood vessels.
6.
the diaphyses, or shafts of long bones, are composed mostly of lamellar bone
b. Cancellous, trabecular,
or spongy bone
1.
does not contain haversian canal systems (osteons)
2.
nerves and blood vessels run randomly through the loose meshwork of bone.
Structure and Physical Properties of the bone.—Bone is one of the hardest structures of the animal body; it possesses also
a certain degree of toughness and elasticity. Its color, in a fresh state, is
pinkish-white externally, and deep red within.
On examining a section of any bone, it is seen to be
composed of two kinds of tissue, one of which is dense in texture, like ivory,
and is termed compact tissue
The
other consists of slender fibers and lamellae, which join to form a reticular
structure; this, from its resemblance to lattice-work, is called spongious tissue. The compact tissue is
always placed on the exterior of the bone, the cancellous in the interior. The
relative quantity of these two kinds of tissue varies in different bones, and
in different parts of the same bone, according as strength or lightness is
requisite. Close examination of the compact tissue shows it to be extremely
porous, so that the difference in structure between it and the cancellous
tissue depends merely upon the different amount of solid matter, and the size
and number of spaces in each; the cavities are small in the compact tissue and
the solid matter between them abundant, while in the cancellous tissue the
spaces are large and the solid matter is in smaller quantity.
Bone during life is permeated by vessels, and is enclosed,
except where it is coated with articular cartilage, in a fibrous membrane, the periosteum, by means of which many of
these vessels reach the hard tissue. If the periosteum be stripped from the
surface of the living bone, small bleeding points are seen which mark the
entrance of the periosteal vessels; and on section during life every part of
the bone exudes blood from the minute vessels which ramify in it. The interior
of each of the long bones of the limbs presents a cylindrical cavity filled with
marrow and lined by a highly vascular areolar structure, called the medullary membrane.
Periosteum.—The periosteum adheres to the surface of each of the bones in nearly
every part, but not to cartilaginous extremities. When strong tendons or
ligaments are attached to a bone, the periosteum is incorporated with them. It
consists of two layers closely united together, the outer one formed chiefly of
connective tissue, containing occasionally a few fat cells; the inner one, of
elastic fibers of the finer kind, forming dense membranous networks, which
again can be separated into several layers. In young bones the periosteum is
thick and very vascular, and is intimately connected at either end of the bone
with the epiphysial cartilage, but less closely with the body of the bone, from
which it is separated by a layer of soft tissue, containing a number of granular corpuscles or osteoblasts, by which ossification
proceeds on the exterior of the young bone. Later in life the periosteum is
thinner and less vascular, and the osteoblasts are converted into an
epithelioid layer on the deep surface of the periosteum. The periosteum serves
as a nidus for the ramification of the vessels previous to their distribution
in the bone; hence the liability of bone to exfoliation or necrosis when
denuded of this membrane by injury or disease. Fine nerves and lymphatics,
which generally accompany the arteries, may also be demonstrated in the
periosteum.
Marrow.—The marrow not only fills up the cylindrical
cavities in the bodies of the long bones, but also occupies the spaces of the
cancellous tissue and extends into the larger bony canals (Haversian canals)
which contain the bloodvessels. It differs in composition in different bones.
In the bodies of the long bones the marrow is of a yellow color, and contains,
in 100 parts, 96 of fat, 1 of areolar tissue and vessels, and 3 of fluid with
extractive matter; it consists of a basis of connective tissue supporting
numerous bloodvessels and cells, most of which are fat cells but some are
“marrow cells,” such as occur in the red marrow to be immediately described. In
the flat and short bones, in the articular ends of the long bones, in the
bodies of the vertebrae, in the cranial diploë, and in the sternum and
ribs the marrow is of a red color, and contains, in 100 parts, 75 of water, and
25 of solid matter consisting of cell-globulin, nucleoprotein, extractives,
salts, and only a small proportion of fat. The red marrow consists of a small
quantity of connective tissue, bloodvessels, and numerous cells, some few of
which are fat cells, but the great majority are roundish nucleated cells, the true “marrow
cells” of Kölliker. These marrow
cells proper, or myelocytes,
resemble in appearance lymphoid corpuscles, and like them are ameboid; they generally
have a hyaline protoplasm, though some show granules either oxyphil or basophil
in reaction. A number of eosinophil cells are also present. Among the marrow
cells may be seen smaller cells, which possess a slightly pinkish hue; these
are the erythroblasts or normoblasts, from which the red
corpuscles of the adult are derived, and which may be regarded as descendants
of the nucleated colored corpuscles of the embryo. Giant cells (myeloplaxes,
osteoclasts), large, multinucleated, protoplasmic masses, are also to be
found in both sorts of adult marrow, but more particularly in red marrow. They
were believed by Kölliker to be concerned in the absorption of bone
matrix, and hence the name which he gave to them—osteoclasts. They excavate in the bone small shallow pits or
cavities, which are named Howship’s
foveolae, and in these they are found lying. but the great majority are
roundish nucleated cells, the true “marrow cells” of Kölliker. These
marrow cells proper, or myelocytes,
resemble in appearance lymphoid corpuscles, and like them are ameboid; they
generally have a hyaline protoplasm, though some show granules either oxyphil
or basophil in reaction. A number of eosinophil cells are also present. Among
the marrow cells may be seen smaller cells, which possess a slightly pinkish
hue; these are the erythroblasts or normoblasts, from which the red
corpuscles of the adult are derived, and which may be regarded as descendants
of the nucleated colored corpuscles of the embryo. Giant cells (myeloplaxes,
osteoclasts), large, multinucleated, protoplasmic masses, are also to be
found in both sorts of adult marrow, but more particularly in red marrow. They
were believed by Kölliker to be concerned in the absorption of bone
matrix, and hence the name which he gave to them—osteoclasts. They excavate in the bone small shallow pits or
cavities, which are named Howship’s
foveolae, and in these they are found lying.
Vessels
and Nerves of Bone. The bloodvessels of bone are very numerous. Those of the compact tissue
are derived from a close and dense network of vessels ramifying in the
periosteum. From this membrane vessels pass into the minute orifices in the
compact tissue, and run through the canals which traverse its substance. The
cancellous tissue is supplied in a similar way, but by less numerous and larger
vessels, which, perforating the outer compact tissue, are distributed to the
cavities of the spongy portion of the bone. In the long bones, numerous
apertures may be seen at the ends near the articular surfaces; some of these
give passage to the arteries of the larger set of vessels referred to; but the
most numerous and largest apertures are for some of the veins of the cancellous
tissue, which emerge apart from the arteries. The marrow in the body of a long
bone is supplied by one large artery (or sometimes more), which enters the bone
at the nutrient foramen (situated in most cases near the center of the body),
and perforates obliquely the compact structure. The medullary or nutrient
artery, usually accompanied by one or two veins, sends branches upward and
downward, which ramify in the medullary membrane, and give twigs to the
adjoining canals. The ramifications of this vessel anastomose with the
arteries of the cancellous and compact tissues. In most of the flat, and in
many of the short spongy bones, one or more large apertures are observed, which
transmit to the central parts of the bone vessels corresponding to the nutrient
arteries and veins. The veins emerge
from the long bones in three places (Kölliker): (1) one or two large veins
accompany the artery; (2) numerous large and small veins emerge at the
articular extremities; (3) many small veins pass out of the compact substance.
In the flat cranial bones the veins are large, very numerous, and run in
tortuous canals in the diploic tissue, the sides of the canals being formed by
thin lamellae of bone, perforated here and there for the passage of branches
from the adjacent cancelli. The same condition is also found in all cancellous
tissue, the veins being enclosed and supported by osseous material, and having
exceedingly thin coats. When a bone is divided, the vessels remain patulous,
and do not contract in the canals in which they are contained. Lymphatic vessels, in addition to those
found in the periosteum, have been traced by Cruikshank into the substance of
bone, and Klein describes them as running in the Haversian canals. Nerves are distributed freely to the
periosteum, and accompany the nutrient arteries into the interior of the bone.
They are said by Kölliker to be most numerous in the articular extremities
of the long bones, in the vertebrae, and in the larger flat bones.
A transverse section of
dense bone may be cut with a saw and ground down until it is sufficiently thin.
If this be examined with a rather low power the bone will be seen to be
mapped out into a number of circular districts each consisting of a central
hole surrounded by a number of concentric rings. These districts are termed
Haversian systems; the central hole is an Haversian canal, and the rings are
layers of bony tissue arranged concentrically around the central canal, and
termed lamellae. Moreover, on closer examination it will be found that between
these lamellae, and therefore also arranged concentrically around the central
canal, are a number of little dark spots, the lacunae, and that these lacunae
are connected with each other and with the central Haversian canal by a number
of fine dark lines, which radiate like the spokes of a wheel and are called
canaliculi. Filling in the irregular intervals which are left between these
circular systems are other lamellae, with their lacunae and canaliculi running
in various directions, but more or less curved ; they are termed
interstitial lamellae. Again, other lamellae, found on the surface of the bone,
are arranged parallel to its circumference; they are termed circumferential, or
by some authors primary or fundamental lamellae, to distinguish them from those
laid down around the axes of the Haversian canals, which are then termed
secondary or special lamellae.
The lamellae are thin plates of bony tissue encircling the
central canal, and may be compared, for the sake of illustration, to a number
of sheets of paper pasted one over another around a central hollow cylinder.
After macerating a piece of bone in dilute mineral acid, these lamellae may be
stripped off in a longitudinal direction as thin films. If one of these be
examined with a high power of the microscope, it will be found to be composed
of a finely reticular structure, made up of very slender transparent fibers,
decussating obliquely; and coalescing at the points of intersection; these
fibers are composed of fine fibrils identical with those of white connective
tissue. The intercellular matrix between the fibers is impregnated by
calcareous deposit which the acid dissolves. In many places the various
lamellae may be seen to be held together by tapering fibers, which run
obliquely through them, pinning or bolting them together; they were first
described by Sharpey, and were named by him perforating fibers.
The Lacunae are situated between the lamellae, and consist of a number
of oblong spaces. In an ordinary microscopic section, viewed by transmitted
light, they appear as fusiform opaque spots. Each lacuna is occupied during
life by a branched cell, termed a bone-cell
or bone-corpuscle, the processes
from which extend into the canaliculi.
The Canaliculi are exceedingly minute channels, crossing the lamellae and
connecting the lacunae with neighboring lacunae and also with the Haversian
canal. From the Haversian canal a number of canaliculi are given off, which
radiate from it, and open into the first set of lacunae between the first and
second lamellae. From these lacunae a second set of canaliculi is given off;
these run outward to the next series of lacunae, and so on until the periphery
of the Haversian system is reached; here the canaliculi given off from the last
series of lacunae do not communicate with the lacunae of neighboring Haversian
systems, but after passing outward for a short distance form loops and return
to their own lacunae. Thus every part of an Haversian system is supplied with
nutrient fluids derived from the vessels in the Haversian canal and distributed
through the canaliculi and lacunae.
The bone cells
are contained in the lacunae, which, however, they do not completely fill. They
are flattened nucleated branched cells, homologous with those of connective
tissue; the branches, especially in young bones, pass into the canaliculi from
the lacunae.
In thin plates of bone (as in the walls of the spaces of
cancellous tissue) the Haversian canals are absent, and the canaliculi open
into the spaces of the cancellous tissue (medullary spaces), which thus have
the same function as the Haversian canals.
Chemical
Composition.—Bone consists of an animal and an earthy part
intimately combined together.
The animal part may be obtained by
immersing a bone for a considerable time in dilute mineral acid, after which
process the bone comes out exactly the same shape as before, but perfectly
flexible, so that a long bone (one of the ribs, for example) can easily be tied
in a knot. If now a transverse section is made the same general arrangement of
the Haversian canals, lamellae, lacunae, and canaliculi is seen.
The earthy part may be separately obtained
by calcination, by which the animal matter is completely burnt out. The bone
will still retain its original form, but it will be white and brittle, will
have lost about one-third of its original weight, and will crumble down with
the slightest force. The earthy matter is composed chiefly of calcium
phosphate, about 58 per cent. of the weight of the bone, calcium carbonate
about 7 per cent., calcium fluoride and magnesium phosphate from 1 to 2 per
cent. each and sodium chloride less than 1 per cent.; they confer on bone its
hardness and rigidity, while the animal matter (ossein) determines its tenacity. Ossification.—Some bones are preceded by membrane, such as those forming the roof and
sides of the skull; others, such as the bones of the limbs, are preceded by
rods of cartilage. Hence two kinds of ossification are described: the intramembranous and the intracartilaginous.
According to
their structure bones are dividing into long
bone, short bone, flat bone, irregular bone, pneumatized
bone, sesamoid bone. Bone is covered
by periosteum. An individual bone is composed of bones tissue,
cartilage, fibrous connective tissue, blood and nerve tissue. Because most of
the bone is made of inorganic salts a bones seems nonliving, but the bone is a
system of tissues that form together and the bones make the skeletal system.
Example of long bone.
Example
of short bone
On
long bones, such as those in the arms and legs the large expanded portions are
called epiphyses. These are the regions of the bones that articulate with other
bones. The shaft of the bones between the epiphyses is called the diaphysis.
Except of the articular cartilage that covers the epiphyes the entire bones is
covered in a tough, vascular tissue called periosteum. Periosteum fibres
interlock with fibres of tendons and muscles that are connected to the bone.
The wall of the diaphysis is composed of a strong, tightly packed, resistant to
bending tissue called compact bone. The epiphyses, on the other hand, are
formed mostly by spongy bone. Spongy bone is made of many small bone plates
that have irregular interconnected spaces that help keep bones light but very
strong. The compact bone in the diaphysis of long bones forms a tube or channel
called the medullary cavity. This cavity is continuos through the length of the
diaphysis and then fades into the spongy bone. The medullary cavity is filled
with a special type of soft connective tissue called marrow.
Example
of flat bones
Example
of pneumatized bones
Bones
usually developed from separate centers of ossification termed epiphyses, and
consist of cancellous tissue surrounded by thin compact bone.
Example
of sesamoid
bone
The medullary canal and the spaces
in the cancellous tissue are filled with marrow. The long bones are not
straight, but curved, the curve generally taking place in two planes, thus
affording greater strength to the bone. The bones belonging to this class are:
the clavicle, humerus, radius, ulna, femur, tibia, fibula, metacarpals,
metatarsals, and phalanges. Short Bones.—Where a part of the skeleton is
intended for strength and compactness combined with limited movement, it is
constructed of a number of short bones, as in the carpus and tarsus. These
consist of cancellous tissue covered by a thin crust of compact substance. The
patellae, together with the other sesamoid bones, are by some regarded as short
bones. 6 Flat Bones.—Where the principal requirement is either
extensive protection or the provision of broad surfaces for muscular
attachment, the bones are expanded into broad, flat plates, as in the skull and
the scapula.
Example
of irregular
bone
These bones are composed of
two thin layers of compact tissue enclosing between them a variable quantity of
cancellous tissue. In the cranial bones, the layers of compact tissue are
familiarly known as the tables of the skull; the outer one is thick and tough;
the inner is thin, dense, and brittle, and hence is termed the vitreous table.
The intervening cancellous tissue is called the diploë, and this, in
certain regions of the skull, becomes absorbed so as to leave spaces filled
with air (air-sinuses) between the two tables. The flat bones are: the
occipital, parietal, frontal, nasal, lacrimal, vomer, scapula, os coxae (hip
bone), sternum, ribs, and, according to some, the
patella. 7 Irregular Bones.—The irregular bones are such
as, from their peculiar form, cannot be grouped under the preceding heads. They
consist of cancellous tissue enclosed within a thin layer of compact bone. The
irregular bones are: the vertebra, sacrum, coccyx, temporal, sphenoid, ethmoid,
zygomatic, maxilla, mandible, palatine, inferior nasal concha, and
hyoid. Surfaces of Bones.—If the surface of a bone be examined,
certain eminences and depressions are seen. These eminences and depressions are
of two kinds: articular and non-articular. Well-marked examples of articular
eminences are found in the heads of the humerus and femur; and of articular
depressions in the glenoid cavity of the scapula, and the acetabulum of the hip
bone. Non-articular eminences are designated according to their form. Thus, a
broad, rough, uneven elevation is called a tuberosity, protuberance, or
process, a small, rough prominence, a tubercle; a sharp, slender pointed
eminence, a spine; a narrow, rough elevation, running some way along the
surface, a ridge, crest, or line. Non-articular depressions are also of
variable form, and are described as fossae, pits, depressions, grooves,
furrows, fissures, notches, etc. These non-articular eminences and depressions
serve to increase the extent of surface for the attachment of ligaments and
muscles, and are usually well-marked in proportion to the muscularity of the
subject. A short perforation is called a foramen, a longer passage a
canal.
Development
of Bone
Bone formation is due to the osteoblasts which are specialized mesenchymal
cells. Osteobiasts secrete an intercellular substance, the osteoid, which consists initially of soft around substance and
collagen fibers. Osteobiasts develop into osteocytes,
the definitive bone cells. At the same time multinucleated osteoclasts develop, cells connected with resorbing and remodelling
bone. We distinguish direct or Intramembranous ossification from Indirect or
chondral ossification.
Intramembranous
ossification, osteogenesis membranacea
is the development of bone from connective
tissue. The latter contains many mesenchymal cells which develop via
osteobiasts into osteocytes. At the same time osteoclasts develop and collagen
fibers also appear. The original bone is fibrous and it is subsequently
remodelled into lamellar bone. The skull cap, the facial bones and the
clavicles develop as membranous bones. Preformed cartilaginous skeletal parts
are necessary for chondral ossKlcatlon, osreogenesis cartilaginea when they become replaced by bone. Growth is possible
only as long as cartilage still remains. The prerequisites for replacement bone
formation are chondroclasts,
differentiated connective tissue cells, which remove cartilage and enable the
osteobiasts to form bone. Two types of replacement bone formation are
recognized endochondral and perichondral.
Endochrondral
ossification begins within cartilage, and
occurs near the epiphyses. Just before ossification begins the mass is entirely
cartilaginous, and in a long bone, which may be taken as an example, the
process commences in the center and proceeds toward the extremities, which for
some time remain cartilaginous. Subsequently a similar process commences in one
or more places in those extremities and gradually extends through them. The
extremities do not, however, become joined to the body of the bone by bony
tissue until growth has ceased; between the body and either extremity a layer
of cartilaginous tissue termed the epiphysial cartilage persists for a definite
period.
The first step in the ossification of the
cartilage is that the cartilage cells, at the point where ossification is
commencing and which is termed a center of ossification, enlarge and arrange
themselves in rows. The matrix in which they are imbedded increases in
quantity, so that the cells become further separated from each other. A deposit
of calcareous material now takes place in this matrix, between the rows of
cells, so that they become separated from each other by longitudinal columns of
calcified matrix, presenting a granular and opaque appearance. Here and there
the matrix between two cells of the same row also becomes calcified, and
transverse bars of calcified substance stretch across from one calcareous
column to another. Thus there are longitudinal groups of the cartilage cells
enclosed in oblong cavities, the walls of which are formed of calcified matrix
which cuts off all nutrition from the cells; the cells, in consequence,
atrophy, leaving spaces called the primary areolae.
At the same time that this process is
going on in the center of the solid bar of cartilage, certain changes are
taking place on its surface. This is covered by a very vascular membrane, the
perichondrium, entirely similar to the embryonic connective tissue already
described as constituting the basis of membrane bone; on the inner surface of
this—that is to say, on the surface in contact with the cartilage—are gathered
the formative cells, the osteoblasts. By the agency of these cells a thin layer
of bony tissue is formed between the perichondrium and the cartilage, by the
intramembranous mode of ossification just described. There are then, in this
first stage of ossification, two processes going on simultaneously: in the
center of the cartilage the formation of a number of oblong spaces, formed of
calcified matrix and containing the withered cartilage cells, and on the
surface of the cartilage the formation of a layer of true membrane bone. The
second stage consists in the prolongation into the cartilage of processes of
the deeper or osteogenetic layer of the perichondrium, which has now become
periosteum. The processes consist of bloodvessels and cells—osteoblasts, or
bone-formers, and osteoclasts, or bone-destroyers. The latter are similar to
the giant cells (myeloplaxes) found in marrow, and they excavate passages
through the new-formed bony layer by absorption, and pass through it into the
calcified matrix. Wherever these processes come in contact with the calcified
walls of the primary areolae they absorb them, and thus cause a fusion of the
original cavities and the formation of larger spaces, which are termed the
secondary areolae or medullary spaces. These secondary spaces become filled
with embryonic marrow, consisting of osteoblasts and vessels, derived, in the
manner described above, from the osteogenetic layer of the periosteum.
Thus far there has been traced the
formation of enlarged spaces (secondary areolae), the perforated walls of which
are still formed by calcified cartilage matrix, containing an embryonic marrow
derived from the processes sent in from the osteogenetic layer of the
periosteum, and consisting of bloodvessels and osteoblasts. The walls of these
secondary areolae are at this time of only inconsiderable thickness, but they
become thickened by the deposition of layers of true bone on their surface.
This process takes place in the following manner: Some of the osteoblasts of
the embryonic marrow, after undergoing rapid division, arrange themselves as an
epithelioid layer on the surface of the wall of the space. This layer of osteoblasts
forms a bony stratum, and thus the wall of the space becomes gradually covered
with a layer of true osseous substance in which some of the bone-forming cells
are included as bone corpuscles. The next stage in the process consists in the
removal of these primary bone spicules by the osteoclasts. One of these giant
cells may be found lying in a Howship’s foveola at the free end of each
spicule. The removal of the primary spicules goes on pari passu with the
formation of permanent bone by the periosteum, and in this way the medullary
cavity of the body of the bone is formed.
This series of changes has been gradually
proceeding toward the end of the body of the bone, so that in the ossifying
bone all the changes described above may be seen in different parts, from the
true bone at the center of the body to the hyaline cartilage at the
extremities.
While the ossification of the
cartilaginous body is extending toward the articular ends, the cartilage
immediately in advance of the osseous tissue continues to grow until the length
of the adult bone is reached.
During the period of growth the articular
end, or epiphysis, remains for some time entirely cartilaginous, then a bony
center appears, and initiates in it the process of intracartilaginous
ossification; but this process never extends to any great distance. The
epiphysis remains separated from the body by a narrow cartilaginous layer for a
definite time. This layer ultimately ossifies, the distinction between body and
epiphysis is obliterated, and the bone assumes its completed form and shape.
The same remarks also apply to such processes of bone as are separately
ossified, e.g., the trochanters of
the femur. The bones therefore continue to grow until the body has acquired its
full stature. They increase in length by ossification continuing to extend
behind the epiphysial cartilage, which goes on growing in advance of the
ossifying process. They increase in circumference by deposition of new bone,
from the deeper layer of the periosteum, on their external surface, and at the
same time an absorption takes place from within, by which the medullary
cavities are increased.
The permanent bone formed by the
periosteum when first laid down is cancellous in structure. Later the
osteoblasts contained in its spaces become arranged in the concentric layers
characteristic of the Haversian systems, and are included as bone corpuscles.
The number of ossific centers varies in
different bones. In most of the short bones ossification commences at a single
point near the center, and proceeds toward the surface. In the long bones there
is a central point of ossification for the body or diaphysis: and one or more
for each extremity, the epiphysis. That for the body is the first to appear.
The times of union of the epiphyses with the body vary inversely with the dates
at which their ossifications began (with the exception of the fibula) and
regulate the direction of the nutrient arteries of the bones. Thus, the
nutrient arteries of the bones of the arm and forearm are directed toward the
elbow, since the epiphyses at this joint become united to the bodies before
those at the opposite extremities. In the lower limb, on the other hand, the
nutrient arteries are directed away from the knee: that is, upward in the
femur, downward in the tibia and fibula; and in them it is observed that the
upper epiphysis of the femur, and the lower epiphyses of the tibia and fibula,
unite first with the bodies. Where there is only one epiphysis, the nutrient
artery is directed toward the other end of the bone; as toward the acromial end
of the clavicle, toward the distal ends of the metacarpal bone of the thumb and
the metatarsal bone of the great toe, and toward the proximal ends of the other
metacarpal and metatarsal bones.
Parsons groups epiphyses under three
headings, viz.: (1) pressure epiphyses, appearing at the articular ends of the
bones and transmitting “the weight of the body from bone to bone;” (2) traction
epiphyses, associated with the insertion of muscles and “originally sesamoid structures
though not necessarily sesamoid bones;” and (3) atavistic epiphyses,
representing parts of the skeleton, which at one time formed separate bones,
but which have lost their function, “and only appear as separate ossifications
in early life.”
Epiphyses
are found at the ends of long bones, whilst the shafts are called diaphyses. Pericnondrai ossification,
which originates in the perichondrium. Is confined to the diaphysis. The epiphyslal disk (growth plate), which is
necessary for growth in length, forms a layer between the epiphysis and the
diaphysis. That part of the shall adjacent to the epiphysial disk is called the
melaphysis and develops fiist on an
endochondral basis. Within the epiphysial cartilage, the processes of
ossification occur in separate zones. First, in the epiphysis is the zone of the capping, hyaline cartilaginous
material, which has not been influenced by bone formation. Next to this area of
'resting cartilage' is the zone or cartilage
cell columns, the growth zone. Here cartilage cells divide and so increase
in number. The next layer, which lies nearer to the shaft, is the zone of large vesicular cartilage cells,
in which calcification is occurring. This is contiguous with the zone of cartilage destruction, where
cartilage is broken down by chondroclasts and replaced by bone-forming
osteobiasts. A cartilage remnant persists, which enables endochondral bone and
perichondral bone to be distinguished in the diaphysis. It Is secondarily
replaced by perichondral bone. Endochondral bone is destroyed by the immigrant
osteoclasts. In crease in thickness in the region of the diaphysis is brought
about by deposition of new bony materal on the outer surface beneath the
cellular layer of the periosteum. The bone marrow
cavity becomes larger as a result of bone destruction. Hormones regulate
all growth processes.
The
bony aniagen in the epiphyses first aappear after birth, except for those in
the distal femoral epiphysis and the proximal tibial epiphysis. In both of
these epiphyses. and in the cuboid bone, osteogenesis begins just before birth
in the tenth intrauterine month.
Bone
and joint health is a concern for almost everyone over the age of 30. Studies show that bone density is determined
by the mid-twenties for both men and women and that bone mineral loss occurs
naturally as we age. This is also true
for the “building blocks” that make-up our joints and connective tissue.
Flexibility:
Stretching can increase flexibility. Bone strength: Weight-bearing exercise strengthens
bones and helps prevent osteoporosis. Exercising on a regular basis can help build
your bones, but the kind of exercise is what makes a difference. There
are basically two kinds of exercise -
aerobic and weight-bearing. Some aerobic exercises, like swimming and
bicycling outdoors or on a stationary bike, are certainly good for you, but
they don't do much for your bones.
The
ones that help build and strengthen bone are the weight-bearing kind.
Weight-bearing exercises, some of which can be aerobic, are those that force
you to put weight, and therefore stress, on your muscles and bones.
Weight-lifting walking, hiking, and step aerobic classes are all activities
that require your muscles to work against gravity. For weights you can even use
soup cans and water bottles.See the list below for more good examples of this
kind of exercise. Weight-bearing exercises that may be right for you:
gardening, stair climbing, chair exercises, tennis, walking, weight
lifting erobics, dancing.
Ideally,
you should do some kind of weight-bearing exercise on a regular basis. In
addition, weight-bearing exercise stimulates
the formation of new bone. Exercise strengthens the muscles that pull or
tug on bones, an action that keeps bones strong. Exercise improves balance,
strength, and co-ordination, which reduces the risk of falling and breaking a
bone. Talk to your doctor about the best weight-bearing exercise for you. In
general, exercise is a good thing. However, if you already have osteoporosis,
or if you have any other medical conditions, some activities may not be good
choices for you. Have a discussion with your doctor or other healthcare
provider about the exercises and activities that would be best for you,
especially before starting any new exercise programme.
When
you start any new programme, start slowly and build gradually. If you develop
any pain, check with your doctor or other health care provider immediately.
Exercise to prevent falls. Exercise counts in fall prevention. You've probably
heard about the benefits of exercise. It helps make your bones stronger,
improves your overall health, and can even brighten your outlook. But did you
know that exercise might reduce your risk of falling by improving your balance,
muscle strength, and co-ordination? It may even help you avoid a serious injury
if you do fall. Tips for developing an exercise programme that works for
you
1. Talk to your healthcare provider before
you start. While the right exercise program offers great benefits, the wrong
exercises can lead to injury or serious illness. Discuss your exercise plan
with your healthcare provider and keep in mind these special precautions:
2.
Anyone more than age 40 should have a thorough medical exam before beginning an
exercise programme. If a woman has a significant amount of bone loss, some exercises may actually increase her risk
of fracture. For example, sit-ups and toe touches increase the risk of fracture
in women with osteoporosis of the spine. A woman at high risk for heart
disease may need a stress test before starting an exercise programme.
Tai
chi (a popular exercise using gentle, slow movements to relax muscles): This
improves balance, flexibility, and state of mind.
Weight-bearing,
low-impact aerobic exercises such as walking, dancing, and climbing stairs:
These increase muscle strength and co-ordination, improve balance, and make
bones stronger, without putting too much stress on joints and muscles.
Consider
one of the most natural forms of exercise - walking. This is an easy, effective
way to strengthen muscles, increase bone
strength, and improve overall health.
Theme
3. Vertebrae (general data). Cervical, thoracic and
lumbar vertebrae. Sacrum. Coccyx. THE VERTEBRAL COLUMN AS a WHOLE
Bone |
Description |
Notes |
|||
one of a series of irregular
bones that form the spine |
a vertebra has two parts: the
vertebral body and the vertebral arch; there are 33 vertebrae total: 7
cervical, 12 thoracic, 5 lumbar, 5 fused to form the sacrum, 4 coccygeal;
features of a typical vertebra include: body, pedicles, transverse processes,
laminae, articular processes, spinous process |
||||
the largest part of the
vertebra |
it is shaped like a short
cylinder; adjacent vertebral bodies articulate through a symphysis |
||||
the ring of bone formed by the
paired pedicles and paired laminae of the vertebra |
the transverse processes and
spinous process are attached to the neural arch; the neural arch protects the
spinal cord |
||||
short strong process that
extends posteriorly from the posterolateral surface of the vertebral body |
paired; it connects the body
with the transverse process; it is marked by superior & inferior
vertebral notches; |
||||
transverse process |
a lateral process the extends
from the junction of the pedicle and the lamina of the vertebra |
a site for muscle attachment
and rib articulation |
|||
a broad flat plats of bone located
between the transverse process and the spinous process of the vertebra |
paired; it is flattened
markedly in the anteroposterior direction; ligamenta flava span the interval
between the laminae of adjacent vertebrae (Latin, lamina =
thin plate) |
||||
articular processes |
processed that project
inferiorly and superiorly from the junction of the lamina and pedicle of the
vertebra |
two pair on each vertebra
(superior and inferior); the superior articular processes of one vertebra articulate
with the inferior processes of the adjacent vertebra through synovial joints |
|||
a notch on the superior and
inferior surface of the vertebral pedicle |
the superior intervertebral
notch of one vertebra combined with the inferior intervertebral notch of the
adjacent vertebra forms the intervertebral foramen |
||||
an opening between the pedicles
of adjacent vertebrae |
adjacent intervertebral notches
form the intervertebral foramen; an opening for passage of the spinal nerve |
||||
the opening formed by the
combination of the body and the vertebral arch |
it contains the spinal cord,
meninges, epidural fat and the internal vertebral plexus of veins |
||||
a posterior midline process
arising from the junction of the two laminae of the vertebra |
it projects downward and
inferiorly; it is an important site of muscle attachment; spinous processes of
cervical vertebra 2-6 are bifid |
||||
Bones form the skeleton that they divide into bones of
the trunk, skull, and limbs. Bones of the trunk include vertebrae, sternum and
ribs.
Vertebrae
The vertebral column consists of 33-34
vertebrae: 7 cervical, 12 thoracic, 5 lumbar, 5 sacral and 4-5 coccygeal
vertebrae. The sacral vertebrae fuse to form the sacrum and the coccygeal
vertebrae fuse to form the coccyx. Thus the sacral and coccygeal vertebrae are
false vertebrae while the others are true vertebrae.
Function of the
vertebrae: 1) Supporting and amortisation; 2) Defense; 3) Motor; 4) Metabolic;
5) Hoemeopoetic.
Each vertebrae has a vertebral body and vertebral arch. They border vertebral
foramen that forms the vertebral
canal when vertebrae lay each other in backbone.
A typical thoracic vertebra, viewed from above.
Vertebral arch carries 7 processes:
unpaired spinous process (projecting
dorsally), paired transverse processes (for articulation with the ribs and attachment
of muscles), the superior articular process and the inferior articular process processes (for articulation vertebrae
each other). The vertebral notches, one caudal and one cranial, together form
the intervertebral foramen which
serves the passage of the spinal nerves.
Peculiarities of the III-VII
Cervical Vertebrae
1.
Transverse process possesses foramen transversarium.
2.
Spinous process is bifurcated.
3.
The transverse process has an anterior tubercle and a posterior tubercle, between them we find
a groove, the sulcus for the spinal nerve.
4.
Articular surfaces lay in horizontal
plane.
1st Cervical Vertebra, the Atlas differs basically from the other
vertebrae:
It has not any vertebral body. In the
atlas we therefore describe a smaller anterior
arch and a larger posterior arch. Both arches have small
protuberances: the anterior and posterior tubercles. Lateral to the large vertebral
foramen of the atlas lie the lateral
masses, each of which has a superior
and an inferior articular facet. On
the inner side of the anterior arch is the articular facet for the dens, fovea dentis. From the foramen of the transverse process, which
is located in the processus transversus,
a groove, the sulcus arteriae vertebralis,
extends across the posterior arch for the reception of the vertebral artery.
2nd Cervical Vertebra. The Axis carries the dens or odontoid process.
On the cranial surface of the body
the axis carries a tooth-like process, the dens
axis, which ends in a rounded point, the apex dentis. The surfaces of the dens have a the anterior articular facet and the posterior articular facet.
The anterior tubercle of the 6th
cervical vertebra can be very large and is designated as the carotid tubercle.
The 7th cervical vertebra has a
particularly large spinous process, which is usually the highest palpable
spinous process of the vertebral column; it is therefore called the vertebra prominens.
Peculiarities of the Thoracic
Vertebrae
1. Laterally,
the vertebral body usually has two costal
facets, each of which is half of an articular facet for articulation with
the head of a rib.
2. Transverse processes
carry a costal facet for articulation
with the costal tubercle.
3. The
spinous processes of the 1-st through the 9th thoracic vertebrae overlap each
other like roof tiles.
4. Articular
surfaces lay in frontal plane.
The 1st thoracic vertebra
has a complete articular facet at the cranial border of its body and a half
facet at the caudal border. The 10th vertebra has only a half
articular facet, while the 11th has a complete articular facet at its cranial
border. The 12th thoracic vertebra has the articular facet for the head of the
rib in the middle of the lateral surface of the body. There may be an accessory
process and a mamillary processor each side.
Peculiarities of the Lumbar
Vertebrae
1. The
bodies of the are much larger than those of the other vertebrae.
2. The
spinous process is flat and is
directed sagittally.
3. The
flattened lateral processes of the lumbar vertebrae may be called costal processes, and since they
originate from rib aniagen.
4. Articular
surfaces lay in sagittal plane.
5. Arch
carries the mamillar and accessory processes.
Peculiarities of the Sacral
Vertebrae
The sacrum consists of the five fused
sacral vertebrae. It has a concave anterior or pelvic surface and a convex dorsal
surface. The sacrum has the base
(with promontory) and the apex. The pelvic surface has four paired
pelvic anterior sacral foramina and transverse lines. In the convex dorsal
surface there are posterior sacral
foramina and five longitudinal ridges, not always clearly developed, have
their origin in fusion of the corresponding processes of the vertebrae (median sacral, intermediate sacral and lateral sacral crests). The sacral canal is located in bone and it terminate by the sacral hiatus, bounded laterally by the
two sacral horns. Auricular surface for the articulation
with the hip bone and sacral tuberosity
can be seen in lateral parts.
Coccyx
The coccyx, which is usually formed
from three to four vertebrae, has body and cornua
or horns.
All
vertebrae compose vertebral column, which has cervical and lumbal curves forward
(lordosis), and thoracic and sacral
curves backward (kyphosis).
References:
1.Gray`s
Anatomy. Lawrence H. Bannister, Martin M. Berry, Patricia Collins and others.
Churchhill Livingstone, - 1999. 2092 p.
2.
W. Kahle, H. Leonhardt, W. Platzer. Colour atlas and Textbook of Human Anatomy.
–
3.
R.D. Lockhart, G.F. Hamilton, F.W. Fyfe. Anatomy of the human body. –
5. Synelnіkov R.D. The atlas of anatomy of the man. Іn the 4-th volumes. -: Medіcіna, 1991.
6. Lecture.
7. Colіn H. Wheatley, B.Kolz. Human anatomy and physіology. 1995.
8. Reminetskyy B.Y., Fedonyuk Y.I. Human anatomy.
Locomotory apparatus. Notes. ‘Ukrmedknyha’,
- 2002, - 136 p.