1-موضوعات
عامة
2-أشعارى
3-مختارات شعرية و قصصية
4-مقالات أدبية
5-مقالات تاريخية و سياسية
6-شخصيات
7-إسلاميات
8-عروض الكتب
9-القسم الطبى
10-طب الأسنان
11-مدوناتى الخاصة
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Anatomical Position
Before studying anatomy, a student should become aware of some of the
vocabulary that is used to describe various aspects of the human body. If
everyone uses the same terminology, then it is easier to understand what each
of us is trying to say. So, before learning the particulars about the anatomy
of a region, we will take a look at some of the terminology.
For the purpose of description, the body is considered as being in what is
called the. "anatomical position". We will use a skeleton to describe this
position. In this Anatomical Position, the body
is assumed to be standing, the feet together, the arms to the side, and the
head and eyes and palms of the hands facing forwards. To ensure consistency
of description it is important to keep the anatomical position constantly in
mind. This last point is an important one, since in a normal relaxed
position of the body, the thumb points anteriorly. In anatomical parlance,
the thumb is a lateral structure, not an anterior one. Here's the Anatomical
Position as shown by a skeleton:
Anatomical Position |
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Anatomical Planes of the Body
Second, you will consider the planes of the body. Understanding these will
facilitate learning terms related to position of structures relative to each
other and movement of various parts of the body.
FRONTAL (or coronal) separates the body
into Anterior and Posterior parts
MEDIAN (or midsagittal) separates body into
Right and Left parts
HORIZONTAL separates the body into Superior
and Inferior parts
SAGITTAL any plane parallel to the median
plane |
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After taking a look at the Anatomical Planes, you can then view some of the
terms related to the planes. These are listed in the following tables. You
will notice that most of these are in pairs of opposites.
Terms of relation or position
superior (closer to the head) |
inferior (closer to the feet) |
reference point -- horizontal plane |
posterior (dorsal) closer to the
posterior surface of the body |
anterior (ventral) closer to the anterior
surface of the body |
reference point -- frontal or coronal plane |
medial (lying closer to the midline) |
lateral (lying further away from the
midline) |
reference point -- sagittal plane |
proximal closer to the origin of a
structure |
distal further away from the origin of a
structure |
reference point -- the origin of a structure |
superficial |
deep |
reference point -- surface of body or organ |
median |
|
reference point -- along the midsagittal or median
plane |
intermediate |
|
between two other structures |
external |
internal |
refers to a hollow structure (external being
outside and internal being inside) |
supine |
prone |
face or palm up when lying on back, face or
palm down when lying on anterior surface of body |
cephalad |
caudad |
toward the head, toward the tail (feet) |
Terms of movement
flexion |
extension |
increasing angle with frontal plane
decreasing angle with frontal plane |
abduction |
adduction |
moving away from or toward the sagittal plane |
protraction |
retraction |
moving forward or backward along a surface |
elevation |
depression |
raising or lowering a structure |
medial rotation |
lateral rotation |
movement around an axis of a bone |
pronation |
supination |
placing palm backward or forward (in anatomical
position) |
circumduction |
|
combined movements of flexion,
extension, abduction, adduction
medial and lateral rotation
circumscribe a cone |
opposition |
|
bringing tips of fingers and thumb together
as in picking something up |
Table of Frequently Used Terms in Anatomy
Aditus |
an entrance or opening |
Ala |
a wing-like process |
Alveolus |
a deep narrow pit, such as a tooth-socket |
Ampulla |
used to describe the dilated part of a duct. |
Ansa |
a loop, usually referring to a nerve |
Antrum |
a cavity |
Aponeurosis |
a glistening sheet of fibrous connective tissue from which muscle
fibers arise or into which they run |
Artery |
a blood vessel which conducts blood from the heart |
Bone |
a special form of connective tissue in which calcium salts are
deposited and which provides a framework, or skeleton, for the other
tissues of the body. |
Bursa |
a membranous sac containing a small amount of viscous fluid. A bursa
is usually found in tissues where friction develops, such as where a
tendon crosses a bony prominence. A bursa may form synovial
sheaths to surround tendons as they cross other tendons or
bone. |
Canal |
a tubular and relatively narrow channel, or tunnel, often through a
bone. A canaliculus is a smaller canal. |
Capsule |
a fibrous or membranous envelope surrounding an organ. An
articular capsule surrounds each synovial joint, being attached
to the bones just beyond the limits of the joint cavity. |
Cartilage |
a firm white tissue, from which most parts of the bony skeleton are
formed and which persists to protect the surfaces of bones and joints. |
Caruncle |
a small fleshy eminence |
Cauda |
tail |
Cavity |
a hollow space (or potential space) within the body or its organs. |
Cervix |
means neck and is applied to the neck like portion of an organ (e.g.
cervix of uterus) |
Chiasma |
a crossing of fibers in the form of an X. Used primarily to describe
nerve fibers. |
Commissure |
a band of fibers which join corresponding right and left parts of a
structure across the median plane. |
Corpus |
means body |
Cortex |
outer part, or rind, or some organs as distinguished from their
inner part, or core usually called a medulla. |
Crest |
a projecting ridge, especially one which on a bone |
Crus |
means a leg and is applied to a structure that resembles a leg or
stalk |
Decussation |
same as a chiasma. A crossing of fibers in the form of an X. |
Digitation |
a finger like process of a muscle |
Disc |
a flat round structure usually applied to plates of cartilage in
joints. |
Duct |
a tube for the passage of fluid, especially secretions of glands. A
ductule is a small duct. |
Epithelium |
a layer of cells which forms the external surface of the skin, or
which lines the cavities of the digestive, respiratory and urogenital
organs, serous cavities, inner coats of blood and lymphatic vessels,
gland and cavities within the brain. The epithelium of the skin is the
epidermis. The epithelium of the digestive, respiratory
and urogenital organs is moistened by a film of mucus and is known as
the mucous coat. The epithelium lining bloods vessels
is known as the endothelium. Serous cavities are lined by epithelium
called mesothelium. |
Fascia |
tissue which lies immediately deep to the skin known as subcutaneous
tissue. It usually consists of a layer of connective tissue which
contains fat, and of a deep and more fibrous layer which adheres to the
surface of the underlying muscle and vessels. These layers are known as
superficial and deep fascia respectively. Fascia surrounds every muscle,
organ, vessel and nerve in the body. |
Fasciculus |
a small bundle. A term that is usually applied to collections of
nerve fibers. |
Filum |
literally mean a "thread". This name is given to several thread-like
structures such as the filum terminale, the lower
extension of the pia mater of the spinal cord. |
Fold |
a ridge formed where a membrane doubles back on itself |
Folium |
mean leaf. The plural "folia" is applied to the folds of the cortex
of the cerebellum. |
Foramen |
a hole, often in a bone or between adjacent bones. |
Fossa |
a "ditch", usually referring to a shallow depression or cavity. |
Fovea |
a small pit or fossa |
Frenulum |
a small fold of the mucous coat which limits the movement of the
structure to which it is attached |
Fundus |
used to denote the widest part of a hollow organ |
Ganglion |
a swelling on the course of a nerve. Usually corresponds to a
collection of nerve cells. |
Genu |
mean knee. Geniculum is sometimes applied to a bent
part of a structure. |
Gyrus |
a fold or convolution of the cerebral cortex. |
Hilum |
a depression or notch where blood vessels enter or leave an organ. |
Humor |
applied to fluids of the eye |
Infundibulum |
a funnel-shaped passage |
Interdigitate |
an interlocking of structures by finger-like processes, as when the
fingers of the two hands are interposed. |
Invaginate |
a process when part of a wall of a structure is pushed inwards to
that the structure which invaginates the membrane becomes partly
ensheathed by it. |
Isthmus |
a narrow part of a duct or other passage, or a narrow strip of
tissue connecting two wider parts of an organ |
Joints
places where bones meet each other (articulate). Where bones are
connected by fibrous tissue, the joint is known as a fibrous
joint (i.e. suture of skull). Where bones are united by
cartilaginous tissue, the joint is know as a cartilaginous joint
(i.e. symphysis pubis). Where a space intervenes between the
articulating ends of bones, the joint is called a synovial joint
(i.e. most of the joints of the body). In these joints, there is an
articular capsule the encloses the joint. This capsule
is lined by a synovial membrane which secretes a
lubricating fluid. |
|
Labium |
lip |
Lamina |
A thin plate of bone or cartilage or a thin layer of softer tissues.
A stratum is also used to denote a layer |
Ligament |
a band of fibrous connective tissue by which bones are connected to
each other. Sometimes bands of connective tissue which support the
viscera or the thorax or abdomen are also known as ligaments. |
Lobe |
a part of an organ, often separated from the rest by a fissure. A
lobule is a small lobe |
Meatus |
a passage or opening |
Muscle |
these structures vary in shape and size, but always consist of
masses of special contractile cells which are under nervous control. It
is usual to describe a muscle as possessing an origin
and insertion, in the sense that when the muscle
contracts, the insertion moves toward the origin. It is probably more
useful to regard a muscle as possessing attachments which are
approximated when the whole muscle contracts. The original of a muscle
is sometimes called the head and the contractile part
the belly. |
Nerves
the nerves of the body can be divided into twelve pairs of
cranial nerves, which arise from the brain and brainstem, 31-33
pairs of spinal nerves which arise from the spinal cord
in segmental series (8 cervical, 12 thoracic, 5 lumbar, 5 sacral and 1-3
coccygeal). The spinal nerves emerge from the intervertebral
foramina which lie along side of adjacent vertebrae. The pass
laterally into the neck or trunk.
A typical spinal nerve is formed by the union of a dorsal root,
which arises from the dorsal aspect of the spinal cord and a
ventral root which arises from the ventral aspect of the spinal
cord. The dorsal root consists of sensory (afferent) fibers and contains
a swelling called the dorsal root ganglion. This
ganglion contains the cells bodies of the sensory nerve fibers. The
ventral root consists of motor (efferent) nerve fibers.
The nerve trunk formed by the mergence of the two roots splits
immediately into a dorsal ramus and a ventral
ramus. The dorsal ramus supplies the deeper muscles of the back
the their overlying skin. The ventral ramus supplies muscles and skin on
the lateral and ventral aspects of the body. The nerve supply of the
limbs is derived entirely from the ventral rami of the spinal nerves. |
|
Sympathetic nerves |
Just at the point where the 12 thoracic and first 2 lumbar spinal
nerve trunks split into a dorsal and ventral ramus, two branches leave
the trunk that connect to the sympathetic chain ganglia,
and these are called the communicating rami. The gray
communicating ramus usually comes off first and connects to the ganglion
in the sympathetic chain. It carries post ganglionic neurons from the
ganglion back to the spinal nerve trunk and thence to its branches. The
white communicating ramus arises a little more distal than the gray one
and also connects to the sympathetic chain and its ganglia. This
connection carries pre ganglionic neurons from the spinal cord to the
sympathetic chain where synapses may occur at that level or past the
sympathetic ganglia into other sympathetic ganglia. |
Neuron |
The neuron or nerve cell is the functional unit of the nervous
system. Each is composed of a cell body (perikaryon) where the nucleus
of the cell is located, and one or more processes. One of the processes,
called the axon, is different from the others, which
are called dendrites. The dendrites and body are the
receiving part of the neuron and the axon is the distribution part of
the neuron. |
Node |
a swelling or protuberance. A nodule is a small
node. |
Notch |
an indentation or depression, usually on the border of a bone. |
Nucleus |
literally means a kernel or nut. In anatomy, nucleus is most often
used to describe an aggregation or cluster of nerve cells. |
Papilla |
a small nipple-shaped elevation |
Periosteum |
the fibrous covering of a bone. |
Plexus |
a network of nerve or vessel processes |
Pouch |
pockets of peritoneum in the abdomen |
Process |
an appendage or projection from the main part of a bone or organ |
Punctum |
a minute opening |
Ramus |
a branch, which, when translated, is used to describe smaller
arteries, veins and nerves arising from their parent vessels or nerves. |
Raphe |
a seam where two similar sheets of tissue unite. |
Rete |
a network, used to describe plexuses of small canals, nerves or
vessels |
Retinaculum |
a band of connective tissue, usually connected at both ends to bone,
which keeps tendons or other structures in place |
Rima |
a cleft or fissure that refers to a narrow oval or oblong opening |
Root |
the part of a nerve or organ which arises from another structure |
Sac |
a bag-like cavity or pouch |
Septum |
a dividing wall or partition |
Sinus |
a recess, a cavity or hollow space, a dilated channel for venous
blood or a small tunnel |
Space |
a clearly demarcated segment of tissue or potential cavity |
Spine |
a small, sharp-pointed projection from a bone |
Stria |
a streak or stripe, sometimes slightly elevated |
Stroma |
supporting fibrous framework of tissue |
Substantia |
means substance or matter |
Sulcus |
a groove |
Taenia |
a flat band or tape, applied to a narrow strip of muscle |
Tegmen |
roof |
Tela |
means a web and describes a thin web-like membrane. Loosely
translated, it can mean tissue |
Tendon |
a cord of connective tissue into which muscles fibers end by which a
muscle is attached to bone or other structures |
Trabecula |
means a beam or bar. |
Tract |
a bundle of fibers, often nerve fibers, having similar origins and
terminations |
Trigonum |
a triangular space or area |
Trochlea |
pulley |
Tuber |
an enlargement or swelling |
Tubercle |
an eminence on a bone, usually smoother than a tuberosity |
Tuberosity |
a rough eminence on a bone |
Tunica |
a covering or coat around muscle or hollow viscera |
Uvula |
means little grape, usually referring to the small fleshy appendage
that hangs from the soft palate. |
Vallecula |
a wide depression, furrow or valley |
Valve |
a fold in an artery, vein or duct which prevents reflux of its
contents |
Vas |
a tubular structure |
Velum |
means a veil or curtain. |
Veins |
vessels that return blood from capillaries to the heart |
Viscus |
any organ of the digestive, respiratory or urogenital systems, or
ductless gland. Viscera is the plural. |
TABLE OF COMMON ANATOMIC DERIVATIVES
a-(an-) |
G, without |
anemia, anencephalic |
|
delta |
G, triangle |
deltoid |
ab- |
L, away from |
abduct |
|
di- |
G, double, two |
digastric |
acro- |
G, tip |
acromion process |
|
dis- |
L, separation |
dissect |
ad- |
L, toward |
adduct |
|
duco- |
L, to lead |
abduct |
ambi- |
L, both |
ambidextrous |
|
ect- |
G, outside |
ectoderm |
ana- |
G, apart |
anatomy |
|
-ectomy |
G, excision |
hysterectomy |
ante- |
L, before |
anteversion, antebrachial |
|
end- (ent-) |
G, within |
endothelium |
anti- |
G, against |
antiseptic |
|
epi- |
G, upon |
epicondyle |
arthr- (arthro-) |
G, a joint |
arthritis |
|
ex- (exo-) |
G&L, out |
exocrine |
auto- |
G, self |
autonomic, autonomous |
|
extra- |
L, outward |
extracellular |
bi- |
L, two, double |
bilateral |
|
fossa |
L, ditch |
infraspinous fossa |
brachi- |
G, arm |
brachial artery |
|
gastr- (gastro-) |
G, belly |
gastritis, digastric |
brachium |
L, arm |
antebrachium |
|
glenoid |
G, socket |
glenoid fossa |
brevis |
L, short |
peroneus brevis |
|
glosso- (gloss) |
G, tongue |
styloglossus |
capit (caput) |
L, head |
semispinalis capitis |
|
hyper- |
G, above, over |
hypertrophy, hyperextension |
cauda |
L, tail |
cauda equina |
|
hypo- |
G, under, less |
hypotension |
cervix |
L, neck |
cervix of uterus |
|
infra- |
L, below |
hypotension |
chondro- |
L, cartilage |
chondrocyte |
|
inter- |
L, between |
intertubercular |
circum- |
L, around |
circumflex |
|
intr-
(intra-) |
L, within |
intravenous, intrahepatic |
condyle |
G, knuckle |
humeral condyles |
|
linea |
L, line |
linea aspera |
coracoid |
G, beak |
coracoid process |
|
lingua- |
L, tongue |
lingual artery |
corona |
L, crown |
coronary ligament |
|
meta- |
G, beyond |
metatarsal |
coronoid |
L, crows beak |
coronoid process |
|
myo- |
G, muscle |
myotome |
cornu |
L, horn |
greater cornu of hyoid |
|
-oid |
G, appearance |
glenoid |
costa |
L, rib |
intercostal |
|
omo |
G, scapula, shoulder |
omohyoid |
crus |
L, leg |
crus of penis |
|
-otomy |
G, to open |
craniotomy |
crux |
L, cross |
cruciate ligament |
|
para- |
G, beside |
paravertebral |
peri |
G, around |
perichondrium |
|
super- |
L, over, |
superficial |
peroneus |
G, fibula |
peroneus longus,
peroneal nerve |
|
supra- |
L, above |
supraorbital |
post- |
L, after, behind |
postnatal |
|
sym- (syn-) |
G, together |
symphysis, synthesis |
pre- |
L, before |
preganglionic |
|
teres |
L, round |
ligamentum teres |
ram- |
L, branch |
ramus |
|
trans- |
L, across |
transfusion |
re- |
L, again, back |
recurrent |
|
tome |
G, cutting |
anatomy |
rect- |
L, straight |
rectus femoris |
|
tuber |
L, swelling |
tubercle |
ren |
L, kidney |
renal |
|
ultra- |
L, beyond |
ultrastructure |
retro- |
L, back |
retroperitoneal |
|
vagina |
L, sheath, sleeve |
vaginal process |
sect- |
L, to cut |
dissect |
|
vas |
L, duct, vessel |
vas deferens |
serra |
L, saw-like |
serratus anterior |
|
vent- (ventr-) |
L, belly |
ventral |
splenius |
G, bandage |
splenius capitis |
|
versio |
L, a turning |
anteversion |
sub- |
L, under |
subdural |
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General Description of Body Layers
We shall approach the study of the upper limb as if you were going to dissect
it on a cadaver. Before removing the skin and superficial fascia from a
region, it is usually necessary to study the bony structures in the area. The
cadaver dissector (or the surgeon) should become aware of the layers that they
will encounter when cleaning a region. Below is a diagram of a cross section
through the upper limb to help point out the layers:
The superficial fascia varies as to thickness. In overweight persons, this
layer can become 4 to 5 inches thick. This is also the layer through which
the superficial (cutaneous) vessels and nerves travel. So when we talk about
cutaneous or superficial vessels and nerves, these are the ones we are
talking about.
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