CRANIAL BONES part 2

Ethmoid and Facial Bones

Cribriform plate

• Multiple foramina for CN I (olfactory) filaments to olfactory bulb

• Fracture → CSF rhinorrhea, anosmia

Crista galli

Falx cerebri attachment (anterior)

Foramen cecum

(shared with frontal)

Emissary vein (variable)

Uncinate process

• Relates to hiatus semilunaris

• Key endoscopic sinus surgery landmark

Anterior ethmoidal foramen

Anterior ethmoidal nerve & vessel

Posterior ethmoidal foramen

Posterior ethmoidal nerve & vessels

ethmoiditis

is the most common cause of orbital cellulitis in children

ethmoid landmarks (uncinate process, ethmoidal bulla).

endoscopic sinus surgery relies heavily on

NASAL BONE

most commonly fractured facial bone

LACRIMAL BONE

smallest, most fragile skull bone

Lacrimal groove/fossa

Forms fossa for lacrimal sac

Posterior lacrimal

crest

Lacrimal part of orbicularis oculi

(Horner's muscle)

dacryocystitis

(lacrimal sac infection) presents with medial canthus swelling.

Lacrimal bone, frontal process of maxilla, and

inferior nasal concha.

Which three bones form the nasolacrimal canal

Temporal process

Forms zygomatic arch with temporal

bone

Frontal process

Articulates with frontal bone; lateral

orbital wall

Zygomaticofacial foramen

Zygomaticofacial nerve & vessels (CN

V2 branch)

Zygomaticotemporal

foramen

Zygomaticotemporal nerve & vessels

(CN V2 branch)

Zygomaticoorbital foramen

Communicates the above two canals

within the bone

Frontozygomatic suture, zygomaticomaxillary suture, and the zygomatic arch (zygomaticotemporal region).

Which three points classically fracture together in a "tripod fracture"

Infraorbital foramen

Infraorbital nerve (CN V2 terminal branch) & vessels

Infraorbital groove/canal

Courses infraorbital nerve/vessels

Anterior nasal

spine

Nasal septal cartilage, depressor septi

Incisive

fossa/canal

Nasopalatine nerve, greater palatine

vessels (terminal branches)

Canine fossa

Levator anguli oris origin

Alveolar process

Dental alveoli (tooth sockets)

Odontogenic infection spread

Maxillary

tuberosity

Posterior superior alveolar foramina (nerves/vessels); part of medial

pterygoid & buccinator origin

Posterior superior

alveolar nerve block

landmark

Palatine process

Forms anterior 3/4 of hard palate;

median & transverse palatine sutures

Maxillary hiatus

Semilunar hiatus is the true drainage route

Zygomatic

process

Articulates with zygomatic bone

Frontal process

Articulates with frontal, nasal, lacrimal

bones

Greater palatine foramen

Greater palatine nerve & vessels

Landmark for greater palatine nerve block (near 3rd molar)

Lesser palatine

foramina

Lesser palatine nerves & vessels

Posterior nasal spine

Musculus uvulae attachment

Orbital & sphenoidal processes

Contribute to orbital floor & pterygopalatine fossa

greater palatine nerve block

is used for posterior maxillary/palatal anesthesia

Mental foramen

Mental nerve (terminal branch of inferior alveolar nerve, CN V3) &

vessels

Mylohyoid line

Mylohyoid muscle

Submandibular fossa

Lodges submandibular gland

Sublingual fossa

Lodges sublingual gland

Digastric fossa

Anterior belly of digastric

Mandibular foramen

Entrance to mandibular canal — inferior alveolar nerve & vessels

Key landmark for inferior alveolar nerve block

Lingula

Sphenomandibular ligament attachment

Mylohyoid groove

Nerve to mylohyoid (CN V3

branch)

Pterygoid tuberosity

Medial pterygoid insertion

Masseteric tuberosity

(angle roughening)

Masseter insertion

Coronoid process

Temporalis insertion

Condylar process

(head & neck)

Head articulates at TMJ; pterygoid fovea on neck = lateral pterygoid

insertion

Mandibular canal

Inferior alveolar nerve, artery, vein

→ exits as mental nerve/vessels

Lesser horn of hyoid

Stylohyoid ligament (to styloid process of temporal bone)

Greater horn

Middle constrictor, hyoglossus, thyrohyoid membrane