EXTERNAL CAROTID ARTERY

External carotid artery
- Course and relations
  - begins in the carotid triangle
    - at the level of upper border of thyroid cartilage
      - opposite the disc between
        
        third and fourth cervical vertebra
  - runs upwards and backwards
    - terminates behind mandible
      - dividing in to
        
        MAXILLARY ARTERY
        
        superficial temporal artery
  - slightly curved course
    - anteromedial to ICA in lower part
    - anterolateral to ICA in upper part
  - IN THE CAROTID TRIANGLE
    - superficial
      - superficial to ECA artery
        
        lies under cover of anterior border of sternocleidomastoid muscle
        
        crossed superficially by cervical branch of facial nerve , hypoglossal nerve
        
        crossed also by facial nerve and hypoglossal nerve
        
        crossed by facial , lingual , and superior thyroid veins
      - deep to ECA - artery
        
        wall of pharynx
        
        superior laryngeal nerve
        
        ascending pharyngeal artery
  - ABOVE THE CAROTID TRIANGLE
    - lies deep inside parotid gland
      - superficial to artery
        
        retromandibular vein
        
        facial nerve
      - deep to artery
        
        ICA
        
        Structures passing between ICA and ECA
        
        Styloglossus
        
        stylopharyngeus
        
        pharyngeal branch of vagus nerve
        
        superior laryngeal nerve
        
        superior cervical sympathetic ganglion
- Branches
  - Anterior
    - Superior thyroid
      - course
      - arises just below greater cornu of hyoid bone
        
        runs downwards and forwards parallel to external laryngeal nerve
        
        deep to infrahyoid muscles
        
        reaches upper pole of lateral lobe of thyroid gland
      - clinically
        
        ligation is done near to gland
        
        due to relationship with nerve
      - branches
        
        superior laryngeal artery
        
        pierces thyrohyoid membrane
        
        sternocleidomastoid branch
        
        cricothyroid branch
    - LINGUAL ARTERY
    - Facial Artery
  - posterior
    - Occipital
    - Posterior auricular
  - Medial
    - Ascending pharyngeal
  - Terminal
    - MAXILLARY ARTERY
    - Superficial Temporal