EXTERNAL CAROTID ARTERY. 301 



Additional Relations of the Left Common Carotid. 

 In Front. Behind. Internally. Externally. 



Left vena innominata. Trachea, Arteria innominata, Pleura. 



Thoracic duct. (Esophagus. 



EXTERNAL CAROTID ARTERY. 



The External carotid artery ascends nearly perpendicularly from op- 

 posite the upper border of the thyroid cartilage, to the space between 

 the neck of the lower jaw and the meatus auditorius, where it divides 

 into the temporal and internal maxillary artery. 



Relations. In front it is crossed by the posterior belly of the 

 digastricus, stylo-hyoideus, and platysma myoides muscles ; by the 

 hypoglossal nerve near its origin ; higher up it is situated in the sub- 

 stance of the parotid gland, and is crossed by the facial nerve. Be- 

 hind it is separated from the internal carotid by the stylo-pharyngeus 

 and stylo-glossus muscles, glosso-pharyngeal nerve, and part of the 

 parotid gland. 



Plan of the Relations of the External Carotid Artery. 

 In Front. 



Platysma, 

 Digastricus, 

 Stylo-hyoid, 

 Hypoglossal nerve, 

 Facial nerve, 

 Parotid gland. 



External Carotid Artery. 



Behind. 



Stylo-pharyngeus, 

 Stylo-glossus, 

 Glosso-pharyngeal nerve, 

 Parotid gland. 



Branches. The branches of the external carotid are eleven in 

 number, and may be arranged into four groups, viz. 



Anterior. Posterior. 



1. Superior thyroid, 4. Mastoid, 



2. Lingual, 5. Occipital, 



3. Facial, 6. Posterior auricular. 



Superior. Terminal. 



7. Parotidean, 10. Temporal, 



8. Ascending pharyngeal, 11. Internal maxillary. 



9. Transverse facial. 



