Page 4 - Carotid and peripheral vascular interventions textbook
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                    CAROTID ARTERY                                      The ECA is readily identif ed, because of its many
                                                                    branches to the scalp, face, and thyroid (Fig. 6-4).
                        The right CCA arise from the bifurcation of the     These branches include:
                    brachiocephalic (innominate) artery, whereas the left CCA      •  superior thyroid artery
                    generally origins directly from the aortic arch. The CCAs       •  ascending pharyngeal artery
                    ascend through the mediastinum, lying posterior to the      •  lingual artery
                    sternoclavicular joints and medial to the internal jugular      •  facial artery
                    veins in the neck. The CCAs are in the carotid sheath,      •  occipital artery
                    caudal (posterior) to the sternocleidomastoid muscle.      •  posterior auricular artery
                        At the level of the superior border of the thyroid      •  internal maxillary artery
                    cartilage (normally at the C3-C4 vertebral level), each      •  superf cial temporal artery.
                    CCA bifurcates into an internal carotid artery (ICA) and      Several of these ECA branches (i.e., occipital and
                    external carotid artery (ECA) (Fig. 6-3). During diagnostic   internal maxillary) supply the dura of the lateral and basal
                    angiography, the mandible angle serves as a useful landmark    brain surfaces. The ECA may supply essential intracranial
                    for the carotid bifurcation, even though signif cant     f ow if there is severe ICA stenosis or occlusion.
                    differences in the level of carotid bifurcation are common.
                                                                    INTERNAL CAROTID ARTERY
                    EXTERNAL CAROTID ARTERY

                                                                        The proximal ICA contains a bulbous dilatation,
                        After dividing, the ECA leaves the sheath to provide   which is clinically signif cant because it functions as
                    blood supply to the neck and face, while the ICA proceeds   the place of the "carotid sinus," a baroreceptor , and the
                    in the carotid sheath to go into the carotid canal in the   "carotid body," a chemoreceptor. The carotid body
                    temporal bone. Understanding the anatomy of the ECA   chemoreceptor can be affected by increased PCO 2,
                    is essential because this vessel together with its branches   decreased PO 2, as well as decreased pH in the blood, and
                    are usually wired while performing a carotid intervention.   manages alerts to the brain to adjust respiratory rate.

                                          Left ECA
                                                                                                  Superficial temporal

                                      Right ECA           Left ICA                  ECA
                     Right ICA                                                                       Internal maxillary
                                                                      Posterior auricular
                        Right common
                        carotid artery                Left common    Ascending pharyngeal
                      Right subclavian                carotid artery                                  Facial

                                                   Left subclavian
                          Brachiocephalic          artery
                          (innominate)                                                                Lingual
                          artery                                              ICA
                                                                                                 Superior thyroid


                                                                    Figure 6-4. External carotid artery and its branches. CCA, common
                                                                    carotid artery; ECA, external carotid artery; ICA, internal carotid artery.
                    Figure  6-3.  Anatomy of bilateral carotid artery with bifurcation   (Adapted from Cho L, Mukherjee D. Basic cerebral anatomy for the
                    into the internal carotid artery (ICA) and external carotid artery (ECA)     carotid interventionalists: The intracranial and extracranial vessels.
                    at the C3-C4 vertebral level.                   Catheter Cardiovasc Interv. 2006;68:104-111.)
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