The viscerocranium (splanchnocranium or facial skeleton) is the anterior-inferior region of the human
skull that forms the structural framework of the face. Composed of 14 distinct bones—paired
maxillae, zygomatic, nasal, lacrimal, palatine, and inferior nasal conchae, along with unpaired vomer
and mandible—its primary functions are to house and protect the sensory organs of vision, smell, and
taste, form the entryways for the respiratory and digestive systems, provide muscle attachment for
facial expression and mastication, and support dentition. Surrounding anatomical regions
include the Neurocranium, Orbital Cavities, Nasal and Oral Cavities, Anterior Cranial Fossa, and
Cervical Spine.
Anatomical Terminology · Structural Review
Term Spotlight: Viscerocranium
An essential fundamental term in human gross anatomy, oral-maxillofacial surgery, and clinical
health assessment. Master the osteological breakdown of the 14 facial bones, spatial
positioning, functional mechanics, and surrounding anatomical borders.
In human skull anatomy, the skeletal framework is divided into two primary functional
components: the neurocranium (which encapsulates the brain) and the
viscerocranium (also termed the splanchnocranium or facial skeleton).
The viscerocranium forms the anterior and inferior portion of the skull, sculpting the
individual contours of the human face and encircling the proximal entries of both the
respiratory tract and digestive system.
The human viscerocranium is constructed from 14 individual bones (6 paired bones and
2 unpaired median bones) that interlock via rigid, immovable sutures, with the notable
exception of the lower jaw:
Maxillae (2): Paired central upper jawbones that join at the intermaxillary
suture. They form the upper dental arch, the hard palate floor of the nasal cavity,
and the floor of the orbits.
Zygomatic Bones (2): Paired cheekbones that form the prominent lateral contours
of the face, contributing significantly to the lateral walls and floors of the
orbital cavities and forming the zygomatic arches alongside the temporal bones.
Nasal Bones (2): Small oblong bones that meet at the midline to form the bridge
of the nose, supporting the nasal cartilages inferiorly.
Lacrimal Bones (2): The smallest bones of the face, situated in the anterior
medial wall of each orbit, featuring the lacrimal groove for tear drainage.
Palatine Bones (2): L-shaped bones positioned posteriorly that form the back
segment of the hard palate and contribute to the floor of the orbit and lateral
nasal cavity walls.
Inferior Nasal Conchae (2): Paired curved horizontal scroll-like bones extending
along the lateral walls of the nasal cavity to increase mucosal surface area for air
filtration and warming.
Vomer (1): A single thin, plow-shaped median bone that forms the inferior and
posterior portion of the bony nasal septum.
Mandible (1): The largest, strongest, and only mobile bone of the
viscerocranium. It forms the lower jaw, holds the inferior teeth, and
articulates with the temporal bones.
Embryologically, the viscerocranium derives primarily from neural crest cells associated
with the first and second pharyngeal arches, developing through intramembranous
ossification (except for small endochondral portions like the mandibular condyles)
.
2. Anatomical Position & Spatial
Relationships
Using standard anatomical position terminology, the viscerocranium occupies the
anterior and inferior portion of the skull. It is positioned directly
beneath the anterior part of the neurocranium.
Relative to surrounding structures, the viscerocranium lies:
Inferior and Anterior to: The frontal bone and anterior cranial fossa of the
neurocranium.
Anterior to: The sphenoid bone, temporal bones, basilar occipital bone, and
middle/posterior cranial fossae.
Superior to: The hyoid bone, larynx, and anterior cervical soft tissues.
3. Primary Physiological & Mechanical
Functions
The viscerocranium fulfills essential sensory, respiratory, digestive, and mechanical
roles:
1. Sensory Housing
Constructs protective bony vaults (orbits, nasal chambers, oral cavity) for the
visual, olfactory, and gustatory organs.
2. Airway & GI Entryways
Sustains patent anatomical conduits for air intake (nasal passages) and food
ingestion (oral cavity).
3. Mastication & Speech
Provides alveolar sockets for upper and lower dentition and anchoring points for
muscles of mastication (masseter, temporalis, pterygoids) and facial
expression.
4. Facial Identity & Contour
Establishes the individual structural geometry of human facial appearance,
aesthetic projection, and interpersonal identity.
Anatomical
Boundaries
5 Bordering Areas Surrounding the
Viscerocranium
Understanding the viscerocranium requires examining the five adjacent anatomical regions
that border its structural boundaries:
Positioned superiorly and posteriorly, meeting the facial skeleton at the
frontonasal, frontomaxillary, and zygomaticofrontal sutures.
2. Orbital Cavities
Embedded within the upper viscerocranium, created by contributions from both facial
bones (maxilla, zygomatic, lacrimal, palatine) and neurocranial bones (frontal,
sphenoid, ethmoid).
3. Anterior Cranial Fossa
Located directly superior-posterior to the nasal and orbital components of the
viscerocranium, housing the brain's frontal lobes.
4. Infratemporal & Pterygopalatine Fossae
Deep spaces situated immediately behind the maxilla and zygomatic bone, containing
key neurovascular structures and masticatory muscles.
5. Anterior Cervical Region (Craniocervical
Transition)
The inferior boundary comprising the submandibular region, hyoid bone, and upper
neck soft tissue structures beneath the mandibular base.
Nursing &
Medical Relevance
Clinical Assessment & Trauma Relevance
For healthcare professionals, emergency clinicians, and nursing staff, physical evaluation
of the viscerocranium is vital during facial trauma triage. High-impact injuries to
the facial skeleton are classified using the Le Fort fracture classification system (Le
Fort I, II, and III), which describes predictable lines of traumatic separation across the
maxillae, pterygoid plates, and midface structures. Assessment requires monitoring
airway patency, as displaced midface or mandibular fractures can compromise the pharyngeal
airway.
Frequently Asked
Questions
Viscerocranium Anatomy FAQ
What is the difference between the
neurocranium and the viscerocranium?
The neurocranium forms the protective braincase enclosing the brain, while the
viscerocranium forms the facial skeleton supporting the face, jaw, eyes, nose, and
mouth.
Which bone of the viscerocranium forms
the hard palate?
The hard palate is formed anteriorly by the palatine processes of the maxillae
(anterior 3/4) and posteriorly by the horizontal plates of the palatine bones
(posterior 1/4).
