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Saturday, 16 April 2011

Info Post

Characteristics

Symmetrical
In the trunk of the body consist of parietal and visceral branches
Shortest possible course
Run on flexor surfaces
Usually do not pass directly through muscles, avoiding compression
Together with the veins and nerves in a sheath of fascia to form neurovascular bundle

Arteries of pulmonary circulation

Pulmonary trunk Arises from right ventricle
Runs up, back ,and to the left
Bifurcates inferior to aortic arch into right and left pulmonary arteries, one for each lung


Ductus arteriosus

is a shunt connecting the pulmonary artery to the aortic arch. It allows most of the blood from the right ventricle to bypass the fetus' fluid-filled lungs
The DA begins to close when breathing is established, and is completely sealed after four to ten days to become the ligamentum arteriosum



Arteries of systemic circulation

Aorta
Ascending aorta
Aortic arch
--Brachiocephalic trunk
right common carotid a.
right subclavian a.
Left common carotid a.
Left subclavian a.

Descending aorta
Thoracic aorta
Abdominal aorta


Arteries of systemic circulation

The aorta is usually divided into 3 sections:

Ascending aorta—the section between the heart and the arch of aorta . The only branches of the ascending aorta are the right and left coronary arteries that supply the heart.

Arch of aorta— ending on the left side at level of vertebral T4/5. From right to left side at its convexity the aortic arch give off three branches for the head and upper limbs, namely the brachiocephalic trunk, left common carotid artery and the left subclavian artery.


Descending aorta—the section from the arch of aorta to the point where it divides into the common illiac arteries at level of L4

Thoracic aorta—the half of the descending aorta above the diaphram. this part of the aorta sends numerous branches to serve the thoracic wall and organs.

Abdominal aorta—the half of the descending aorta below the diaphram. It sends many branches to the abdominal wall and organs. And finally, it bifurcates into the right and left common iliac arteries in front of the L4 for the pelvis and lower limbs.


1.Arteries of the neck and head

The neck and head are supplied by the common carotid arteries and three branches from each subclavian artery.
(1)Common carotid arteries
They are the main source of the blood supply for the neck and head.
The right originates from the brachiocephalic trunk, and the left arises directly from the aortic arch .
At the upper border of the thyroid cartilage the arteries divide into the external and internal carotid arteries



1)External carotid arteries supply most tissues in the face and in the anterior area of the neck.

Superior thyroid a. - to supply upper pole of thyroid gland and larynx

Lingual a. - to supply the tongue

Facial a.

Occipital a. -- to the back of the scalp

Posterior auricular a. - supplies the skin of the back of the ear

Maxillary a. - supplies the upper and lower jaws, nasal cavity and the muscles of mastication

Superficial temporal a. - to supply the most part of the scalp

2) internal carotid arteries

Ascend and pass through the carotid canal to the skull.
They send branches to supply the brain and the eyes.
The arteries have no branches in the neck.

(2) Subclavian artery

Origin
Brachiocephalic trunk on right
Aortic arch on left
Becomes axillary artery at lateral border of first rib

Branches

Vertebral a. passes through the foramen magnum to the skull and supply the brain and the spinal cord .
Internal thoracic a.
Thyrocervical trunk
Inferior thyroid artery -supplies inferior pole of thyroid gland
Costocervical trunk



Arteries of the upper limb

1)The axillary artery
It is the continuation of the subclavian arteries at the lateral border of the first rib ,serves the large part of the upper limb, and ends at the lower border of teres major.

2)Brachial artery
The brachial artery is continuation of the axillary artery, it descends along the medial side of the humerus,divides into the radial and ulnar arteries at the level of the neck of radius.


3)Radial and Ulnar arteries

The radial artery

descends along the medial margin of the brachioradialis to the level of styloid of the radius.
it lies just lateral to the tendon of the flexor carpi radialis in diatal forarm and is easy to palpate
A superficial palmar branch enters the hand and anastomoses with the superficial palmar arch formed by the ulnar artery.


The ulnar artery

passes down the medial side of the forearm
In distal regions of the forearm ,it leaves the forearm, enters the hand by passing lateral to the pisiform bone
A major branch is the common interosseous artery, it splits immediately into the anterior and posterior interosseous arteries to supply the flexor and extensor muscle of the forearm

(4)Palmar arches

In the palm, the branches of the radial and the ulnar arteries anastomose each other to form the two arches.
The superficial palmar arch is formed by the anastomosis of the terminal part of the ulnar artery and the superficial palmar branch of the radial artery.
It gives off three common palmar digital arteries that finally split into two proper palmar digital arteries to supply the fingers.



The deep palmar arch

is formed by the anastomosis of the terminal part of the radial artery and the deep palmar branch of the ulnar artery.
The main branches of the arch include the principal thumb artery that supplies mainly the thumb and three palmar metacarpal
arteries that join to the three common palmar digital arteries.

Arteries of thorax

(1) Arteries of thoracic wall
The anterior wall of the thorax is supplied mainly by the internal thoracic artery.
It gives off the anterior intercostal arteries that anastomoses with the posterior intercostals arteries to supply the intercostals muscles.


(2) Arteries of thoracic viscera

The thoracic aorta give off the visceral branches to all the organs of the thorax except the heart.
These include the bronchial arteries to the bronchi and lung, the esophageal arteries to the esophagus, and the pericardial arteries to pericardium.
These arteries are ususlly very small and vary in their numbers and origins.





Arteries of abdomen

The abdominal aorta is the main source of blood supply of the abdomen.

It gives off 1)parietal branches to the abdominal wall and 2)visceral branches to the organs in the abdominal cavity.

1)Parietal branches

These include the inferior phrenic arteries, the lumbar arteries and the median sacral artery.
The inferior phrenic arteries supply the inferior surface of the diaphragm
The lumbar arteries supply the posterior abdominal wall
The median sacral artery supplies the sacrum and coccyx





(2)Visceral branches
They are divided into two groups: the paired branches that supply the paired abdominal organs, and the unpaired branches that serve the unpaired abdominal organs.

The paired branches of the abdominal aorta include the middle suprarenal arteries, the renal arteries, and the testicular/ovarian arteries.

The unpaired visceral branches include the celiac trunk, and the superior and inferior mesenteric arteries

1)Celiac trunk

It divides almost immediately into the left gastric, splenic and the common hepatic arteries.
These branches supply the alimantary canals from the stomach to the decending part of duodenem proximal to the great duodenal papilla.
They also supply the liver ,pancrease, gall bladder and spleen.


2)Superior mesenteric artery

It arises from the front of the aorta at the level of the L1
From its left side it sends many jejunal arteries and ileal arteries to the jejunum and ileum;
from its right side sends the ileocolic artery to the terminal part of the ileum, the cecum, the appendix and the lower part of the ascending colon; the right and middle colic arteries to the upper part of the ascending colon and the transverse colon.


3)Inferior mesenteric artery

arises from the front of the aorta at the level of L3
it gives off the left colic artery, sigmoid arteries, and superior rectal arteries.
These branches supply the the last part of the transverse colon, descending colon, sigmoid colon and the upper part of the rectum。


Arteries of pelvis and lower limb

Both of them are the branches of the common iliac arteries

The two common iliac arteries start at L4 from the end of aorta and splits into the internal and external iliac arteries in front of the sacroiliac joint.


Arteries of pelvis

Supplied by the internal iliac arteries

Main branches include:
parietal branches
a)Superior and inferior gluteal arteries -- supply the gluteal muscles
b) Obturator artery-- descends through the obturator foramen to the thigh to supply the adductor muscles



2) Visceral branches
a) Internal pudendal artery-- supply the anus, perineal muscles and external genitalia
b) Inferior rectal artery to the lower part of the rectum
c) Uterine artery supplies the uterus and vagina.

Arteries of lower limb

Supplied by the extenal iliac arteries

Femoral artery

is the continuation of the external iliac artery under the midpoint of the inguinal ligament
the largest branch is called the femoral profunda artery
It supplies the muscles of thigh
It terminates by passing through the hiatus in adductor magnus to become the popliteal artery




Popliteal artery

It is the continuation of the femoral artery, and descends through the popliteal fossa .
It gives off several branches to the knee joint and nearby muscles.
Just below the lower border of the popliteus, the popliteal artery splits into the anterior and
posteror tibial arteries.

Posterior tibial a.

is the continuation of the popliteal artery and descends downwards , branches to supply the flexor muscles of the leg.
Inferiorly, it passes behind the medial malleolus of the tibia and enters the planta. There it divides into the medial and lateral plantar arteries to serve the sole and the toes.
Another branch is the peroneal artery supplying the lateral group muscles of leg and giving a nutrient branch to the fibula.


Anterior tibial artery

pierces the interosseous membrane into the anterior surface of the leg
It then descends lateral to the tibia and sends branches to the extensor muscles of the leg.
Passing the anterior surface of the ankle joint, it becomes the dorsal pedal artery that supplies the dorsum of foot and toes.

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