Anatomy Demo - Bones of the Skull
Channel: Dr B Biology
Date: 29/04/2020

An overview of the following bones of the skull.

There are 20 total skull bones. The skull is comprised of cranial and facial bones:

8 cranial bones. Note the key landmarks on each bone.

Frontal bone (1)
supraorbital foramen: passageway for blood vessels and nerves
frontal sinus: opens into the nasal cavity

Occipital bone (1)
foramen magnum: hole through which the spinal cord passes
occipital condyles: articulate with the top cervical vertebra
external occipital protuberance: muscle attachment site for posterior neck muscles

Ethmoid bone (1)
crista galli: anchor point for membrane stabilizing brain cribriform plate: olfactory foramina (holes) extend though it
palatine process: forms anterior part of hard palate
(middle & superior) nasal conchae: plates in the nasal cavity
perpendicular plate: meets the vomer and helps form the nasal septum
ethmoidal sinus / ethmoid air cells: opens into the nasal cavity

Sphenoid bone (1)
optic canal / optic foramen: optic nerve passes through on way to brain
sella turcica / hypophyseal fossa: the pituitary gland rests here
superior orbital fissure: nerves that control eye movement pass through
sphenoidal sinus: opens into the nasal cavity

Parietal bone (2)

Temporal bone (2)
external auditory meatus: opening carries sound vibration on its way to the ear drum
mastoid process: bump behind your ear, sternocleidomastoid muscle attachment site
styloid process: pointed inferior process muscles connect to hyoid and tongue mandibular fossa: articulates with mandibular condyle of the mandible, part of TMJ
petrous portion: contains middle and inner ear
jugular foramen: internal jugular vein and 3 cranial nerves (IX, X, XI) pass through it
carotid canal: just anterior to jugular foramen, passage of internal carotid to brain 
 
14 facial bones. Note the key landmarks.

Mandible (1)
mental foramen: carry branch of trigeminal nerve which innervates teeth mandibular foramen: nerves and blood vessels that supply lower teeth mandibular condyle: articulates with mandibular fossa of temporal bone 
body: forms the chin

Vomer bone (1): meets perpendicular plate of ethmoid to form bony part of nasal septum

Maxilla (maxillary bone) (2)
palatine process: forms anterior part of hard palate
  maxillary sinus: opens into the nasal cavity

Palatine bone (2): forms posterior part of hard palate

Zygomatic bone (2)
Zygomatic arch: “cheek bone”, connects zygomatic with temporal bone, comprised of both bones

Nasal bone (2): bridge of the nose

Lacrimal bone (2)
Lacrimal fossa / lacrimal canal – drains tears into nasal cavity

Inferior nasal concha (2): inside the nasal cavity


Sutures of the skull:
sagittal suture: between the two parietal bones
coronal suture: between the frontal bone and the parietal bones 
lambdoidal suture: between the temporal bones and the occiput 
squamosal suture: between the temporal bone and the parietal bone

 
Non-skull bones: 
Hyoid bone:  Between mandible and larynx; tongue muscle attachment site


Vertebral Column

Cervical vertebrae (7)
C1 is also called the atlas: The atlas is the top cervical vertebrae and supports the skull.
C2 is also called the axis and has a unique structure called the dens for rotation of the atlas and head.