Common carotid artery
COMMON CAROTID ARTERY
- Chief artery supplying head & neck.
ORIGIN:
- Although the left and right common carotid arteries follow the same course through the neck, their origin differs.
- On the left, the common carotid arises directly from the aortic arch begins in thorax in front of trachea.
- On the right, the origin is from the brachiocephaic trunk begins behind right sternoclavicular joint
- The left common carotid artery can be thought of as having two distinct parts: thoracic and cervical.
- The right common carotid arises caudally, it only really has a cervical portion.
- In the thoracic section, the left common carotid travels upwards through the superior mediastinum to the level of the left sternoclavicular joint where it is continuous with the cervical portion.
- The cervical section of both common carotids follows a similar course lies in carotid sheath.
- Lies in front of transverse process of lower 4 cervical vertebrae.
- Each vessel passes obliquely upwards from behind the sternoclavicular joint to the level of the upper border of the thyroid cartilage.
- In the lower neck, the two common carotid arteries are separated from each other by the trachea.
- However, as the carotids rise in the neck, they diverge come to be separated by the thyroid gland, the larynx and pharynx.
- Each common carotid is contained within the carotid sheath which is derived from all 3 layers of the deep cervical fascia.
- In addition to containing the common carotid artery, the sheath also comprises the internal jugular vein and vagus nerve: the vein lies lateral to the artery, with the nerve in between the two.
- At the level of the fourth cervical vertebra, at the level of upper thyroid the vessel bifurcates into the external and internal carotids.
BRANCHES:
COMMON CAROTID ARTERY
↓
Carotid Bifurcation(behind it lies carotid body)
↓(Lateral to external carotid)↓
Internal Carotid Artery External Carotid Artery
↓ (Branches) ↓(Branches)
Cervical Part:no branches in neck Anterior
- Petrous Part → SUPERIOR THYROID
- CARDIO TYMPANIC→ LINGUAL
- PTERYGOID BRANCH → FACIAL
Cavernous Part Posterior
- BRANCHES TO TRIGEMINAL GANGLION → OCCIPITAL
- BRANCHES TO HYPOPHYSIS CEREBRI → POSTERIOR AURICULAR
Cerebral Part Medial
- OPTHALMIC → ASCENDING PHARYNGEAL
ANTERIOR CEREBRAL Terminal
- MEDIAL CEREBRAL→ MAXILLARY
- POSTERIOR CEREBRAL→ SUPERFICIAL TEMPORAL
ANTERIOR CHOROIDAL
APPLIED ANATOMY:
- Common carotid artery can be felt at the lower part of the medial border of sternocleidomastoid.
- Common carotid artery is palpated at upper border of cricoid cartilage.
- The commonest variation in the arteries arising from the arch of aorta is Left common carotid artery arising from brachiocephalic trunk.
- Hanging causes large amount of injury to common carotid artery.
- Dye is injected in common carotid in cerebral angiography.
Exam Question
- Common carotid artery ends at the level of upper border of the thyroid cartilage C4 (C3-C4 disc) where they bifurcate into internal & external carotid artery.
- The left common carotid arises directly from the aortic arch.
- Right common carotid artery arises from brachiocephalic trunk.
- Internal carotid artery at the bifurcation from the common carotid is Lateral to the external carotid.
- Common carotid artery can be compressed against anterior tubercle of transverse process of C6 vertebra, known as carotid tubercle(Chassaignac tubercle), at cricoid cartilage level.
- Common carotid artery can be felt along the anterior margin of sternocleidomastoid at the level of laryngeal prominence.
- Common carotid artery is palpated at upper border of cricoid cartilage.
- The commonest variation in the arteries arising from the arch of aorta is Left common carotid artery arising from brachiocephalic trunk.
- Hanging causes large amount of injury to common carotid artery.
- Dye is injected in common carotid in cerebral angiography.
- Right common carotid artery arises from brachiocephalic trunk.
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