Arteries of the neck Common carotid artery Beginning: On the right, the CCA arises from the brachiocephalic artery as it passes behind the sternoclavicular joint. On the left, it arises directly from the arch of the aorta in the superior mediastinum. End: upper border of the thyroid cartilage, by dividing into ECA and ICA. Branches: it gives no branches except its terminal branches(ECA and ICA). Internal carotid artery Beginning: from CCA lateral to the upper border of the thyroid cartilage. End: in the cranial cavity by dividing into anterior and middle cerebral arteries. External carotid artery Beginning: from CCA lateral to the upper border of the thyroid cartilage. End: in the substance of the parotid gland behind the neck of the mandible, by dividing into superficial temporal and maxillary arteries. Course: At its origin, it lies in the carotid triangle and lies anteromedial to the ICA. It later becomes anterior, then lateral, to the internal carotid as it ascends. It first ascends forwards and then inclines backwards and laterally, to pass midway between the tip of the mastoid process and the angle of the mandible. Relations: Superficial relations Deep relations - skin and superficial fascia. - lateral wall of the pharynx. - cervical branch of the facial n. - internal carotid artery. - sternocleidomastoid muscle. NB: ICA sparated from ECA - posterior belly of digastric ms. by: - posteromedial surface of the - styloid process. parotid gland. - styloglossus ms. - stylopharyngeus muscle. - glossopharyngeal nerve. - pharyngeal br. of vagus n. - part of the parotid gland. Branches of ECA: 1- Superior thyroid artery: just below the level of the greater cornu of the hyoid bone to supply thyroid gland. 2- Ascending pharyngeal artery: It arises near ECA beginning. to supply the pharynx and tonsils. 3- Lingual artery: arises opposite the tip of greater cornu to supply the tongue and the floor of the mouth. Mid. cerebral a. Ant. cerebral a. Cavernous sinus containing ICA Branches of ECA: 4- Facial artery: it arises above the greater cornu of the hyoid bone. It supplies the neck and face 5- Occipital artery: It passes backwards, up deep to posterior belly of digastrics to supply mastoid and occiput. 6- Posterior auricular artery: it arise just above digastric and stylohyoid muscles to supply digastric, stylohyoid, sternocleidomastoid and the parotid gland. Branches of ECA: A- branches from anterior surface: 1- superior thyroid A. 2- lingual A. 2- facial A. B- branches from posterior surface: 1- occipital A. 2- posterior auricular A. C- branches from medial surfac 1- ascending pharyngeal A. D- branches from termination: 1- maxillary A. 2- superficial temporal A. Veins of the neck(jugular veins): 1- Internal jugular v. 2- External jugular v. 3- Anterior jugular v. Internal jugular vein Beginning: at the base of the skull (at jugular foramen) as a continuation of sigmoid sinus. End: by union with the subclavian vein to form the brachiocephalic vein. Course: descends in the carotid sheath on the side of the neck. Relations : # Deep relations: - transverse process of the atlas. - cervical plexus, phrenic n. and thyrocervical trunk. - vertebral v. and 1st of the subclavian artery. # Medially: ICA, CCA and vagus nerve. # Superficial relations: - sternocleidomastoid - parotid gland. - styloid process & accessory n. - posterior belly of digastrics. - sup. belly of omohyoid. - posterior auricular and occipital arteries. Tributaries : 1- inferior petrosal sinus 2- Common facial vein 3- lingual vein 4- superior thyroid vein 5- middle thyroid vein 6- pharyngeal veins. External jugular vein(EJV) - Beginning: Posterior auricular vein + posterior branch retromandibular vein within substance of parotid. - Course: runs vertically downwards, superficial to sternomastoid muscle, 1 inch above midclavicular point it end. - End: in the subclavian vein - Tributaries: 1- transverse cervical vein. 2- suprascapular. 3- anterior jugular vein. Anterior jugular vein (AJV) Beginning: union of a few small veins near the hyoid bone. End in (drain into): EJV. Course: it runs downwards paramedian till suprasternal notch. CAROTID SHEATH Definition: It is a tube of connective tissue around the main vessels of neck. Attachments: 1- Above: to base of skull around carotid and jugular foramens. 2- below: blends with adventitia of arch of aorta. 3- anteriory: continuous with pretracheal facia. 4- Posteriory: continuous with prevertebral facia. Relations: Superficial Deep relations - skin, superficial and - transverse processes of deep facias. cervical vertebrae. - sternomastoid ms. - lateral vertebral muscles. - posterior belly of - 1st part of subclavian digastric. artery. - infrahyoid ms. Contents: - In the upper part (above level of posterior belly of digastric). - ICA(anteromedially). - IJV(posterolaterally). - Lower 4 cranial nerves (in between them). - In the lower part (below the level of posterior belly of digastric) - CCA(anteromedially). - IJV(posterolaterally). - vagus nerve(in between them). NB: sympathetic chain: embedded in the posterior wall of carotid sheath. Ansa cervicalis, embedded in the anterior wall of carotid sheath. .