What Is Another Name for the Cranium? Exploring the Skull’s Anatomy and Terminology 🧠

Introduction to the Cranium and Skull
Cranial Bones Overview
Calvaria (Cranial Vault)
Cranial Base (Skull Base)
Key Foramina & Canals
Lateral & Frontal Views
Internal Cranial Features
Epicranium (Scalp Layers)
Clinical Correlates
Cranial Development & Variations
Conclusion
FAQs

1. Introduction to the Cranium and Skull

1.1 Definition of Cranium vs Skull

Cranium, or calvaria, refers to the neurocranium—the bony “braincase” encasing the brain.
Skull = cranium + viscerocranium (facial bones supporting sensory organs and airway).

1.2 Neurocranium vs Viscerocranium

Neurocranium (8 bones) protects the brain.
Viscerocranium (14 bones) shapes face, supports eyes, mouth, and nasal cavities.

1.3 Function: Protection, Support, Entrances for Structures

Shields brain and sensory organs.
Anchors muscles for chewing and facial expression.
Forms foramina for cranial nerves and blood vessels.

2. Cranial Bones Overview

2.1 Paired vs Unpaired Bones

Unpaired: frontal, occipital, sphenoid, ethmoid
Paired: parietal, temporal

2.2 Flat Bones and Diploë

These bones have an outer and inner table with diploë—a spongy, marrow‑rich middle layer.

2.3 Fontanelles: Neonates vs Adults

Fontanelles are soft spots where bones haven’t fused—allowing skull growth and passage in birth.
Neonates: anterior fontanelle closes ~18 mo; posterior by ~2 mo.
We’ll expand on this in Section 9.

3. Calvaria (Cranial Vault)

3.1 Superior Aspect: Frontal, Parietal, Occipital

These roof‑forming bones meet along the vertex (top of skull).

3.2 Landmarks: Vertex, Bregma, Lambda

Bregma: intersection of sagittal and coronal sutures.
Lambda: intersection of sagittal and lambdoid sutures.

3.3 Sutures: Sagittal, Coronal, Lambdoid

Sagittal: between parietals
Coronal: between frontal & parietals
Lambdoid: between parietals & occipital

4. Cranial Base (Skull Base)

4.1 Anterior Cranial Fossa

Holds the frontal lobes; includes cribriform plate (olfactory foramina).

4.2 Middle Cranial Fossa & Sella Turcica

Houses temporal lobes; sella turcica holds the pituitary gland.

4.3 Posterior Cranial Fossa

Contains cerebellum, brainstem, and includes foramen magnum.

5. Key Foramina & Canals

5.1 Foramen Magnum

Largest opening—spinal cord, vertebral arteries pass here.

5.2 Hypoglossal Canal

Transmits cranial nerve XII.

5.3 Jugular Foramen

Cranial nerves IX, X, XI and internal jugular vein pass through.

5.4 Foramen Lacerum & Optic Canal

Lacerum: filled with cartilage in life
Optic canal: transmits optic nerve and ophthalmic artery.

5.5 Olfactory Foramina (Cribriform Plate)

Tiny holes in the ethmoid bone for olfactory nerve fibers.

6. Lateral & Frontal Views

6.1 Lateral Aspect: Temporal Fossa, Zygomatic Arch, Pterion

Temporal fossa: houses temporalis muscle.
Zygomatic arch: cheekbone prominence.
Pterion: thin skull junction (greatest risk of epidural hematoma).

6.2 Frontal Aspect: Orbit, Nasal Bones, Maxilla, Mandible

Frontal view reveals facial structure and sensory openings.

6.3 Features: Glabella, Supraorbital Foramen, Mental Protuberance

Glabella: smooth area above nose.
Supraorbital foramen: nerve/artery exit above the orbit.
Mental protuberance: chin’s prominence.

7. Internal Cranial Features

7.1 Grooves: Middle Meningeal, Venous Sinuses

Meningeal grooves mark the middle meningeal arteries.
Venous sinuses (e.g., superior sagittal sinus) drain blood from brain.

7.2 Depressions: Pacchionian Bodies

Small pits along sinuses—arachnoid granulation sites for CSF absorption.

8. Epicranium (Scalp Layers)

8.1 Layers: Scalp, Aponeurosis, Muscle

Composed of five layers: Skin, Connective tissue, Epicranial aponeurosis, Loose connective tissue, Pericranium (S‑C‑A‑L‑P).

8.2 Clinical relevance in neurosurgery

Understanding scalp layers is vital for safe neurosurgical incisions.

9. Clinical Correlates

9.1 Pediatric Fontanelle Closure Ages

Anterior: usually by 18–24 months
Posterior: by 2–3 months
Delays can signal hydrocephalus; early closure may cause craniosynostosis.

9.2 Pterion: Weak Spot & Epidural Hematoma

A blow to pterion can rupture the middle meningeal artery → epidural hematoma—a neurosurgical emergency.

9.3 Internal Surface Injuries: Subdural/Extradural Hematoma

Extradural (epidural): arterial bleed between skull and dura.
Subdural: venous tear under dural layers.
Anatomical bone landmarks guide neurosurgical relief.

10. Cranial Development & Variations

10.1 Embryological Origin (Ectoderm vs Mesoderm)

Frontal, zygomatic: from neural crest (ectoderm)
Parietal, occipital: mesoderm
Insights tie into syndromes involving cranial bone development.

10.2 Sex Dimorphism in Cranial Shape

Men’s skulls usually exhibit more prominent muscle attachments, heavier brow ridges, larger mastoid processes—a key forensic tool.

10.3 Anthropological Modifications

Skull shape differs across populations based on climate, diet, genetics. Terms like dolichocephalic and brachycephalic describe head forms.

11. Conclusion

We’ve covered the many names for the cranium—calvaria, cranial vault, braincase—and explored its anatomy, clinical quirks, growth timeline, and forensic significance. This guide intentionally integrates strategic keywords like “fontanelle closure timeline” and “pterion clinical importance” while linking to key anatomy references.

FAQs (Schema‑ready)

Q1: What are other names for the cranium?
A: The cranium is also called the calvaria, braincase, or cranial vault—specifically covering the neurocranium, excluding facial bones.

Q2: When do skull fontanelles close?
A: The posterior fontanelle typically closes by 2–3 months; the anterior fontanelle by 18–24 months in most infants.

Q3: What makes the pterion clinically important?
A: It’s the thinnest point on the skull roof—trauma here can quickly lead to an epidural hemorrhage by damaging the middle meningeal artery.

Q4: How many bones are in the neurocranium vs viscerocranium?
A: Neurocranium: 8 bones; Viscerocranium: 14 facial bones making up the skull’s supporting structure.

Q5: What are the major cranial sutures?
A: Key sutures include sagittal, coronal, and lambdoid on the calvaria; squamous suture lies on the lateral aspect.

🔗 Internal & External Linking

Internal link to your privacy post: What Is Another Name for the Cranium?
External resources for authority:
- Wikipedia’s “Human skull” for deep anatomical background
- Forbes Health or similar neurology sources to link clinical topics like head trauma