3. Anatomy is the science of the structure of
the body. the term is applied usually to
human anatomy. The word is derived
indirectly from the Greek anatome, a term
built from ana, meaning "up," and tome,
meaning "a cutting" (compare the words
tome, microtome, and epitome) i.e. the
dissection"
4. it is necessary to learn some useful terms for
describing body structure. Knowing these
terms will make it much easier for us to
understand the content of the body in future
studies .
.
Three groups of terms are introduced here:
1- terms describing body cavities
2- Terms describing planes of the body,
3- Directional ( movements )terms,and
4- Terms of position,
5. Planes:
Medical professionals often refer to
sections of the body in terms of anatomical
planes (flat surfaces). These planes are
imaginary surfaces - vertical or horizontal -
drawn through an upright body. The terms are
used to describe a specific body part.
6.
7. 1- Coronal Plane (Frontal
Plane):
A verticle plane running
from side to side; divides
the body or any of its parts
into into dorsal and ventral
(back and front, or posterior
and anterior) portions.
8. 2- Sagittal Plane (Lateral Plane):
This term comes from Latin.
Sagitta means " an arrow ", A
vertical plane running from front (
anterior ) to back ( posterior );
divides the body or any of its parts
into right and left sides.It might be
called Median plane: Sagittal plane
through the midline of the body;
divides the body or any of its parts
into right and left halves
9. 3- Axial Plane (Transverse
Plane or horizontal ):
Is a horizontal plane; divides
the body or any of its parts into
upper and lower parts or
cranial and caudal (head and
tail). A transverse plane, also
known as an axial plane or
cross-section.
10. The Cavities:
The cavities, or spaces, of the body
contain the internal organs, or viscera. The
two main cavities are called the ventral and
dorsal cavities. The ventral is the larger
cavity and is subdivided into two parts
(thoracic and abdominopelvic cavities) by the
diaphragm, a dome-shaped respiratory
muscle.
11.
12. Thoracic cavity : The upper
ventral, thoracic, or chest
cavity contains the heart,
lungs, trachea, esophagus,
large blood vessels, and
nerves. The thoracic cavity
is bound laterally by the
ribs (covered by costal
pleura) and the diaphragm
caudally (covered by
diaphragmatic pleura).
13. 2- Abdominal and pelvic
cavity:
The lower part of the
ventral(abdominopelvic) cavity
can be further divided into
two portions: abdominal
portion and pelvic portion.
14. The abdominal cavity
contains most of
1-the gastrointestinal tract
as well as
2- the kidneys and
adrenal glands.
The pelvic cavity contains
most of
1- the urogenital system
as well as
2- the rectum.
15. II - Dorsal cavity:
The smaller of the two main
cavities is called the dorsal cavity.
As its name implies, it contains
organs lying more posterior in the
body. The dorsal cavity, again,
can be divided into two portions.
The upper portion, or the cranial
cavity, houses the brain, and the
lower portion, or vertebral canal
houses the spinal cord.
17. 3- Directional ( movements )terms
1-Adjusting angle between two parts:
A-Flexion - Bending movement that decreases
the angle between two parts. Bending the
elbow, are examples of flexion. When sitting
down, the knees are flexed. Flexion of the hip or
shoulder moves the limb forward (towards the
anterior side of the body).
18. B-Extension –
The opposite of flexion; a straightening
movement that increases the angle between
body parts.
19. 2- Adjusting relation to midline of body:
A-Abduction –
A motion that pulls a structure or part away from the
midline of the body (or, in the case of fingers and toes,
spreading the digits apart, away from the centerline of
the hand or foot). Abduction of the wrist is called radial
deviation. Raising the arms laterally, to the sides, is an
example of abduction.
20. B-Adduction –
A motion that pulls a structure or part towards the midline of the
body, or towards the midline of a limb. Dropping the arms to the
sides, or bringing the knees together, are examples of adduction. In
the case of the fingers or toes, adduction is closing the digits
together. Adduction of the wrist is called ulnar deviation.
21. 3- Rotating body parts:
A- Internal rotation (or medial
rotation) of the shoulder or hip would
point the toes or the flexed forearm
inwards (towards the midline).
B- External rotation (or lateral
rotation) is the opposite. It would
turn the toes or the flexed
forearm outwards (away from the
midline).
22. Anatomical position:
In this position the body is
straight in standing position
with eyes also looking
straight. The palms are
hanging by the sides close to
the body and are facing
forwards. The feet also point
forwards and the legs are
fully extended. Anatomical
position is very important
because the relations of all
structures are described as
presumed to be in anatomical
position.
25. Terms of position:
1-Ipsilateral (Latin ipse; self/same): on the
same side as another structure. Thus, the
left arm is ipsilateral to the left leg.
2-Contralateral (Latin contra; against): on
the opposite from another structure. Thus,
the left arm is contralateral to the right
arm, or the right leg.
3-Superficial (Latin superfacies; at the
surface or face): near the outer surface of
the body. Thus, skin is superficial to the
muscle layer. The opposite is "deep", or
"visceral".
26. 4-Deep: further away from the surface of the
organism. Thus, the muscular layer is deep to the
skin, but superficial to the intestines. This is one of
the few terms where the English vernacular is
prevalent. The proper anglicised Latin term would be
profound (Latin profundus; due to depth), but this
word has other meanings in English. In other
languages, the equivalent term is usually similar to
"profound" (e.g. profond, meaning deep, in French).
5-Intermediate (Latin intermedius; inter, between and
medius, middle): between two other structures. Thus,
the navel is intermediate to (or intermediate between)
the left arm and the contralateral (right) leg.
6-Visceral (Latin viscus; internal organs, flesh):
organs within the body's cavities. The stomach is
within the abdominal cavity, and is thus visceral
27.
28.
29.
30. Supine position:
In this position the body is
lying down with face pointing
upwards. All the remaining
positions are similar to
anatomical position with the
only difference of being in a
horizontal plane rather than a
vertical plane.
31. Prone position:
This is the position in which the
back of the body is directed upwards.
The body lies in a horizontal plane
with face directed downwards.
34. THE NERVOUS SYSTEM
is the most complicated and
highly organized of the
various systems which make
up the human body
35. Its mechanism is concerned with the
correlation and integration of
various bodily processes and the
reactions and adjustments of the
organism to its environment. In addition
the cerebral cortex is concerned with
conscious life.
36.
37. The central nervous system consists
1-of the encephalon or brain, contained within the
cranium, and
2- the medulla spinalis or spinal cord, lodged in the
vertebral canal; the two portions are continuous with
one another at the level of the upper border of the atlas
vertebra
38. The human brain has three major
subdivisions :
1-cerebrum :
the principal and most anterior
part of the brain in vertebrates,
located in the front area of the
skull and consisting of two
hemispheres, left and right,
separated by a fissure. It is
responsible for the integration of
complex sensory and neural
functions and the initiation and
coordination of voluntary activity
in the body.
39. 2-The Brainstem. The
brainstem is the core of the
brain. We consider it in three
parts--the hindbrainstem, the
midbrain stem, and the
forebrainstem. In general, the
brainstem is made up of many
nuclei and fiber tracts. It is a
primary coordinating center of
the human nervous system. 1-
The Mid-brain
2- The pons
3- The medulla oblongata
40. 3-The Cerebellum.
Over the hindbrainstem is the cerebellum. The
cerebellum is connected to both the midbrainstem
and the hindbrainstem. The cerebellum is the
primary coordinating center for muscle actions.
Here, patterns of movements are properly
integrated. Thus, information is sent to the
appropriate muscles in the appropriate sequences.
Also, the cerebellum is very much involved in the
postural equilibrium of the body.
41. The peripheral
nervous system
consists of a series
of nerves by which
the central nervous
system is connected
with the various
tissues of the body.
For descriptive
purposes these
nerves may be
arranged in two
groups,
cerebrospinal and
sympathetic,
42. The spinal cord
The spinal cord is a thin,
tubular structure that is an
extension of the central
nervous system from the
brain and is enclosed in and
protected by the bony
vertebral column within the
vertebral cavity. The main
function of the spinal cord is
transmission of neural inputs from
the periphery to the brain and vice
versa ,it is a vital structure for our
survival and functional capacity.
43. The spinal cord extends from
the medulla oblongata in the
brain and continues to the
conus medullaris near the
lumbar level at L1-2,
terminating in a fibrous
extension known as the filum
terminale. The adult spinal cord
is approximately 18 inches
long, ovoid-shaped, and is
enlarged in the cervical and
lumbar regions.
44. Spinal cord segments
The spinal cord is divided into 31
different segments, with motor
nerve roots exiting in the ventral
aspects and sensory nerve roots
entering in the dorsal aspects. The
ventral and dorsal roots later join to
form paired spinal nerves, one on
each side of the spinal cord.
There are 31 spinal cord segments:
8 cervical segments
12 thoracic segments
5 lumbar segments
5 sacral segments
1 coccygeal segment
45. There are two regions
where the spinal cord
enlarges:
1-Cervical enlargement -
corresponds roughly to the
brachial plexus nerves, which
innervate the upper limb. It
includes spinal cord segments
from about C4 to T1. The vertebral
levels of the enlargement are
roughly the same (C4 to T1).
46. 2-Lumbosacral enlargement -
corresponds to the lumbosacral
plexus nerves, which innervate the
lower limb. It comprises the spinal
cord segments from L2 to S3, and is
found about the vertebral levels of
T9 to T12.
47. In medicine, a lumbar puncture
(colloquially known as a spinal
tap) is a diagnostic and at times
therapeutic procedure that is
performed in order to collect a
sample of cerebrospinal fluid
(CSF) for biochemical,
microbiological, and cytological
analysis, or rarely to relieve
increased intracranial pressure.
50. The JOINTS
A site where two or more bones come
together, whether or not movement occurs
between them, is called a joint
51.
52. Joints are classified
according to the tissues that
lie between the articulating
bones:
1- fibrous joints,
2- cartilaginous joints, and
3-synovial joints.
53. joints can be further classified into two
general categories. These are :
1- those in which the skeletal elements
are separated by a cavity (i.e. synovial
joints);
2- those in which there is no cavity and
the components are held together by
connective tissue (i.e. solid joints).
54. 1- those in which the skeletal
elements are separated by a
cavity (i.e. synovial joints);
55. 2- those in which there is no cavity (
solid joints). and the components
are held together by connective
tissue : 1- fibres
2- cartilage
-
56. Synovial joints
Synovial joints are connections between
skeletal components where the elements
involved are separated by a narrow articular
cavity (Fig. ). In addition to containing an
articular cavity, these joints have a number of
characteristic features.
57. characteristic features
of synovial joints
1- The articular surfaces of the
bones are covered by a thin
layer of hyaline cartilage
separated by a joint cavity
2- The cavity of the joint is lined
by synovial membrane, which
extends from the margins of one
articular surface to those of the
other
58. 3-The synovial membrane is
protected on the outside by a
tough fibrous membrane
referred to as the capsule of
the joint.
4- The articular surfaces are
lubricated by a viscous fluid called
synovial fluid, which is produced by
the synovial membrane
59. 5- the presence of fibrous
ligaments .
6- fibrocartilage are interposed
between the articular surfaces
(articular discs ) . some of Synovial
joints like TMJ.
60. Synovial joints can be classified according
to the arrangement of the articular
surfaces and the types of movement that
are possible.
61. 1- Plane joints:
In plane joints, the
apposed articular
surfaces are flat or
almost flat, and this
permits the bones to
slide on one another.
Examples of these joints
are the sternoclavicular
and acromioclavicular
joints (Fig. ).
62. 2-Hinge joints:
Hinge joints resemble the hinge on a door,
so that flexion and extension movements are
possible. Examples of these joints are the
elbow, knee, and ankle joints
63. 3-Pivot joints:
In pivot joints, a
central bony pivot
is surrounded by a
bony ligamentous
atlantoaxial and
superior radioulnar
joints are good
examples
64. 4- Condyloid joints: Condyloid joints have two distinct
convex surfaces that articulate with two concave
surfaces. The movements of flexion, extension,
abduction, and adduction are possible together with a
small amount of rotation. The metacarpophalangeal joints
(Fig. ).
65. 5- Ellipsoid joints:
In ellipsoid joints, an elliptical convex articular surface
fits into an elliptical concave articular surface. The
movements of flexion, extension, abduction, and
adduction can take place, but rotation is impossible.
The wrist joint is a good example (Fig. ).
66. 6- Saddle joints:
In saddle joints, the articular surfaces are reciprocally
concavoconvex and resemble a saddle on a horse's
back. These joints permit flexion, extension,
abduction, adduction, and rotation. The best example
of this type of joint is the carpometacarpal joint of the
thumb (Fig. ).
67. 7- Ball-and-socket joints:
In ball-and-socket joints, a ball-shaped head of one bone fits
into a socketlike concavity of another. This arrangement
permits free movements, including flexion, extension,
abduction, adduction, medial rotation, lateral rotation, and
circumduction. The shoulder and hip joints are good examples
of this type of joint (Fig. ).
68.
69.
70.
71. The stability of a joint
depends on three main
factors:
1-the shape,
2-size, and
3-arrangement of the
articular surfaces;
4-the ligaments; and
the tone of the muscles
around the joint.
76. The Bone
Bone is a living tissue capable
of changing its structure as the
result of the stresses to which it is
subjected. Like other connective
tissues, bone consists of:
1- cells,
2- fibers, and
3- matrix.
77. Bone is hard because of the
calcification of its extracellular matrix
and possesses a degree of elasticity
because of the presence of organic
fibers.
78. Bone exists in two forms:
1- compact and
2- cancellous.
Compact bone appears as a
solid mass; cancellous bone
consists of a branching network
of trabeculae (Fig. ). The
trabeculae are arranged in such
a manner as to resist the
stresses and strains to which the
bone is exposed.
79. Functions of Bone in general:
1-a protective function; the
skull and vertebral column, for
example, protect the brain and
spinal cord from injury; the
sternum and ribs protect the
thoracic and upper abdominal
viscera (Fig. ).
80. 2-It serves as a
lever, as seen in
the long bones of
the limbs
81. 3- as an important storage
area for calcium salts.. The
storage of calciumThe bones
store and release calcium in
the bones is under hormonal
control.
82. 4- It houses and protects
within its cavities the
delicate blood-forming bone
marrow. The bones assist
the lymphatic system and
immunity
83. Classification of Bones
Bones may be classified
regionally or according
to their general shape :
1- long bones,
2- short bones,
3- flat bones,
4- irregular bones,
and
5- sesamoid bones.
84. 1- Long Bones:
Long bones are found in the limbs (e.g., the
humerus, femur, metacarpals, metatarsals, and
phalanges). Their length is greater than their
breadth.. The shaft has a central marrow cavity
containing bone marrow. The outer part of the
shaft is composed of compact bone that is
covered by a connective tissue sheath, the
periosteum.
The ends of long bones are composed of
cancellous bone surrounded by a thin layer of
compact bone. The articular surfaces of the
ends of the bones are covered by hyaline
cartilage.
85. 2-Short Bones:
Short bones are found in the hand
and foot (e.g., the scaphoid, lunate,
talus, and calcaneum). Their length
is equal to their breadth.. They are
roughly cuboidal in shape and are
composed of cancellous bone
surrounded by a thin layer of
compact bone. Short bones are
covered with periosteum, and the
articular surfaces are covered by
hyaline cartilage.
86. 3- Flat Bones:
Flat bones are found in the
vault of the skull (e.g., the
frontal and parietal bones).
They are composed of thin
inner and outer layers of
compact bone, the tables,
separated by a layer of
cancellous bone, the diploe.
The scapulae, although
irregular, are included in this
group.
87. 4- Irregular Bones:
Irregular bones include those not assigned to
the previous groups (e.g., the bones of the skull,
the vertebrae, and the pelvic bones). They are
composed of a thin shell of compact bone with
an interior made up of cancellous bone.
88. 5-Sesamoid Bones:
Sesamoid bones are small
nodules of bone that are found in
certain tendons where they rub
over bony surfaces.. The largest
sesamoid bone is the patella, which
is located in the tendon of the
quadriceps femoris. The function of
a sesamoid bone is to reduce
friction on the tendon; it can also
alter the direction of pull of a
tendon
91. Three types of muscles are
present in our body :
1-smooth,( Autonomic nervous
system control )
2- cardiac self contraction. and
3- skeletal ( motor supply)
voluntary muscles
94. Smooth muscle :
1- consists of long, spindle-shaped
cells closely arranged in bundles or
sheets
95. 1- In the tubes of the body the smooth muscles
provide:
a- the motive power for propelling the contents
through the lumen.
b- In the digestive system it also causes the
ingested food to be thoroughly mixed with the
digestive juices.
c - A wave of contraction of the circularly
arranged fibers passes along the tube, milking
the contents onward.
96. d- By their contraction, the
longitudinal fibers pull the wall of the
tube proximally over the contents.
This method of propulsion is referred
to as peristalsis.
97.
98. e- In storage organs such as the urinary
bladder and the uterus, the fibers are
irregularly arranged and interlaced with one
another. Their contraction is slow and
sustained and brings about expulsion of the
contents of the organs
99. 5- In the walls of the blood vessels the smooth
muscle fibers are arranged circularly and serve to
modify the caliber of the lumen. Depending on the
organ, smooth muscle fibers may be made to
contract by local stretching of the fibers, by nerve
impulses from autonomic nerves, or by hormonal
stimulation.
100.
101. II -Cardiac Muscle :
Cardiac muscle consists of striated muscle fibers
that branch and unite with each other. It forms the
myocardium of the heart. Its fibers tend to be
arranged in whorls and spirals, and they have the
property of spontaneous and rhythmic contraction.
Specialized cardiac muscle fibers form the
conducting system of the heart. Cardiac muscle is
supplied by autonomic nerve fibers that terminate in
the nodes of the conducting system and in the
myocardium for regulation of the rate contraction of
thr heart .
104. Skeletal muscles produce the movements of
the skeleton; they are sometimes called
voluntary muscles and are made up of striped
muscle fibers. A skeletal muscle has two or
more attachments ( origin and insertion ). The
attachment that moves the least is referred to
as the origin, and the one that moves the most,
the insertion (see figures ). Under varying
circumstances the degree of mobility of the
attachments may be reversed; therefore, the
terms origin and insertion are interchangeable.
105. The fleshy part of the muscle is referred to as
its belly (see figures ). The ends of a muscle
are attached to bones, cartilage, or ligaments
by cords of fibrous tissue called tendons (see
figures ).
106. Skeletal Muscle Action
All movements are the result of
the coordinated action of many
muscles. However, to understand
a muscle's action it is necessary
to study it individually.
A muscle may work in the
following four ways:
107. 1- Prime mover: A muscle is a prime mover when it
is the chief muscle or member of a chief group of
muscles responsible for a particular movement.
For example, the quadriceps femoris is a prime
mover in the movement of extending the knee joint
(see figures).
108. 2- Antagonist:
Any muscle that opposes the action of the prime mover
is an antagonist. For example, the biceps brachii
opposes the action of the Triceps when the elbow joint
is flexed (see figures). Before a prime mover can
contract, the antagonist muscle must be equally
relaxed; this is brought about by nervous reflex
inhibition.
109. 3- Fixator:
A fixator contracts isometrically (i.e., contraction
increases the tone but does not in itself produce
movement) to stabilize the origin of the prime mover so
that it can act efficiently. For example, the muscles
attaching the shoulder girdle to the trunk contract as
fixators to allow the deltoid to act on the shoulder joint
(see figures ).
110. 4- Synergist:
In many locations in the body the prime mover muscle crosses
several joints before it reaches the joint at which its main action
takes place. To prevent unwanted movements in an intermediate
joint, groups of muscles called synergists contract and stabilize
the intermediate joints. For example, the flexor and extensor
muscles of the carpus contract to fix the wrist joint, and this
allows the long flexor and extensor muscles of the fingers to
work efficiently (see figures).
111. These terms are applied to the action of a particular
muscle during a particular movement; many muscles can
act as a prime mover, an antagonist, a fixator, or a
synergist, depending on the movement to be
accomplished. Muscles can even contract paradoxically,
for example, when the biceps brachii, a flexor of the
elbow joint, contracts and controls the rate of extension
of the elbow when the triceps brachii contracts.
112. Nerve Supply of Skeletal Muscle
The nerve trunk to a muscle is a mixed nerve, about
60% is motor and 40% is sensory, and it also contains
some sympathetic autonomic fibers. The nerve enters
the muscle at about the midpoint on its deep surface,
often near the margin; the place of entrance is known
as the motor point. This arrangement allows the
muscle to move with minimum interference with the
nerve trunk.
115. 1- Anatomy of the Heart
, The heart is located in the thoracic cavity
between the lungs within the mediastinum. It is a
hollow, cone-shaped, muscularorgan about the
size of a closed – hand . Figure shows that the
base (the widest part) of the heart is superior to its
apex (the pointed tip), which rests on the
diaphragm. Also, the base is directed toward the
right shoulder, and the apex points to the left hip.
The base is deep to the second rib, and the apex is
at the level of the fifth intercostal space.
116. The human heart is an organ that pumps blood
throughout the body via the circulatory system,
supplying oxygen and nutrients to the tissues and
removing carbon dioxide and other wastes. In humans,
the heart is roughly the size of a closwd- hand and
weighs between about 280 to 340 grams in men and 8
to 230 to 280 grams in women,
117. Facts about the human heart
1- A human heart is roughly the size of a
closed- hand.
2- The heart weighs between about 280 to 340
grams in men and 230 to 280 grams in women.
3- The heart beats about 100,000 times per
day (about 3 billion beats in a lifetime).
4- An adult heart beats about 60 to 80 times
per minute.
5- Newborns' hearts beat faster than adult
hearts, about 70 to 190 beats per minute.
6- The heart pumps about 6 quarts (5.7 liters)
of blood throughout the body.
7- The heart is located in the center of the
chest, usually pointing slightly left.
118. Chambers of the Heart
The heart has four hollow
chambers: two superior atria
(sing., atrium) and two inferior
ventricles (Fig. ). Each atrium
has a wrinkled anterior pouch
called an auricle. Internally, the
atria are separated by the
interatrial septum, and the
ventricles are separated by the
interventricular septum.
119. The heart has a left and a right side.
The thickness of a chamber’s
myocardium is suited to its
function. The atria have thin walls,
and they send blood into the
adjacent ventricles. The ventricles
are thicker, and they pump blood
into blood vessels that travel to
parts of the body. The left ventricle
has a thicker wall than the right
ventricle; the right ventricle pumps
blood to the lungs, which are
nearby. The left ventricle pumps
blood to all the other parts of the
body.
120. 2- The Blood vessels
are of three types:
1- arteries,
2- veins, and
3- capillaries,
4- Sinusoid.
121. 1- Arteries :
Are blood vessels that transport blood from the
heart and distribute it to the various tissues of
the body by means of their branches (Fig. ) .
The smallest arteries, <0.1 mm in diameter, are
referred to as arterioles. The joining of
branches of arteries is called an anastomosis.
Arteries do not have valves.
122. 2-Veins :
are vessels that transport blood back to the heart; many of
them possess valves. The smallest veins are called venules (Fig.
). The smaller veins, or tributaries, unite to form larger veins,
which commonly join with one another to form venous
plexuses. Medium-size deep arteries are often accompanied by
two veins, one on each side, called venae comitantes. Veins
leaving the gastrointestinal tract do not go directly to the heart
but converge on the portal vein; this vein enters the liver and
breaks up again into veins of diminishing size, which
ultimately join capillary-like vessels, termed sinusoids, in the
liver (Fig. ). A portal system is thus a system of vessels
interposed between two capillary beds.
125. 4-Sinusoids :
resemble capillaries in that they are thin-walled blood
vessels, but they have an irregular cross diameter and are wider
than capillaries. They are found in the bone marrow, the spleen,
the liver, and some endocrine glands. In some areas of the body,
principally the tips of the fingers and toes, direct connections
occur between the arteries and veins without the intervention of
capillaries. The sites of such connections are referred to as
arteriovenous anastomoses (Fig. ).
126. Arteriovenous Anastomosis (Shunt):
Arteriovenous anastomosis (shunt) is the
communication between an artery and a
vein. It serves the function of phasic
activity of the organ. When the organ is
active these shunts are closed and the
blood circulates through the capillaries.
However, when the organ is at rest, the
blood bypasses the capillary bed and is
shunted back through the arteriovenous
anastomosis. The shunt vessel may be
straight or coiled, possesses a thick
muscular coat, and is under the influence
of sympathetic nervous system.
