surface anatomy of the head

• The internal carotid arteries supply oxygenated blood to the brain.
• The vertebral arteries are branches of the subclavian arteries that enter the cranial cavity through the foramina transversaria of C1-C6 vertebrae.
• muscles of the head and neck
• the muscles of mastication (chewing) include temporalis, masseter, medial pterygoid, lateral pterygoid, and digastric
• temporalis muscle is fan shaped with its origin on the temporal bone and insertion into the coronoid process of mandible
• masseter muscle has two origins from the zygomatic arch and sphenoid bone and one insertion onto the ramus of the mandible
• masseter muscle has two origins from zygomatic arch and mandibular ramus and one insertion onto the angle of the mandible
• masseter muscle has two heads - one from zygomatic arch and another from zygomatic process of maxilla; it inserts onto the ramus of mandible
• medial pterygoid muscle has origins at the medial plate of sphenoid bone and inserts into the medial aspect of the mandibular ramus
• medial pterygoid muscle has two origins from the maxilla and palatine bones and one insertion onto the medial aspect of the mandibular ramus
• medial pterygoid muscle has two origins from the maxillary tuberosity and sphenoid bone and one insertion onto the medial aspect of the mandible
• lateral pterygoid muscle has two origins from the lateral pterygoid plate and pyramidal process of palatine bone and one insertion onto the articular disc of TMJ
• digastric muscle has two heads - anterior belly originates from the xiphisternum and posterior belly originates from the styloid process of the temporal bone
• lateral pterygoid muscle has two origins from the lateral pterygoid plate of the spinenoid bone and one insertion onto the articular disc between the condyle and glenoid fossa
• medial pterygoid muscle has two origins from the maxilla and palate and one insertion onto the medial aspect of the mandible
• digastric muscle has two heads - anterior belly originates from the xiphisternum and posterior belly originates from the styloid process of temporal bone
• lateral pterygoid muscle has two origins from the lateral pterygoid plate and one insertion onto the articular disc
• medial pterygoid muscle has two origins from the medial plate of spinenoid bone and one insertion onto the medial aspect of the mandible
• lateral pterygoid muscle has two origins from the lateral pterygoid plate of spinenoid bone and one insertion onto the articular disc of TMJ
• digastric muscle has two bellies - anterior belly arises from the body of hyoid bone and posterior belly arises from styloid process of temporal bone; both insert onto the mandible
• lateral pterygoid muscle has origins at the lateral pterygoid plate of spinenoid bone and inserts into the articular disc of TMJ
• temporalis muscle has origin on temporal fossa, inserts onto coronoid process of mandible
• lateral pterygoid muscle has origin on the lateral pterygoid plate of spinenoid bone and inserts into the articular disc of temporomandibular joint
• digastric muscle has anterior belly that arises from the posterior surface of the body of the hyoid bone and posterior belly that arises from the styloid process of temporal bone
• anterior belly of digastric muscle inserts into the anterior border of the mandible while posterior belly inserts into the mastoid notch of temporal bone
• cranial nerves
• CN3 oculomotor nerve
• CN2 optic nerve
• CN1 olfactory nerve
• CN4 trochlear nerve
• CN5 trigeminal nerve
• CN6 abducens nerve
• CN7 facial nerve
• CN8 vestibulocochlear nerve
• CN9 glossopharyngeal nerve
• CN11 spinal accessory nerve
• CN12 hypoglossal nerve
• The external acoustic means also has several important structures such as the tragus, antitragus, lobule, helix, antihelix, concha, and fossa triangularis.
• It contains the auditory canal (external opening to the middle ear) and the tympanic membrane (eardrum).
• The external acoustic means is located on the lateral side of the skull, just above the ear.