Overview
Structure
4 zones from dentin-pulp junction inward: Odontoblast → Cell-free → Cell-rich → Pulp core
1. Odontoblast Zone
Location
Peripheral; adjacent to predentin
Function
Secretes Type I Collagen (predentin matrix) → mineralizes to dentin. Rate reduces with age.
Process
Extends from cell body to DEJ (dentinoenamel junction) in dentinal tubule, with lateral processes
2. Cell-Free Zone of Weil
Width
~40 µm; prominent in coronal pulp; may be absent in radicular pulp
Traversed by
Blood vessels, unmyelinated nerves, fibroblast cytoplasmic processes
3. Cell-Rich Zone
Contents
Fibroblasts (high density), undifferentiated mesenchymal cells, macrophages, lymphocytes, capillaries, nerves
4. Pulp Core (Pulp Proper)
Contents
Fibroblasts (most abundant), larger vessels, nerves, undifferentiated cells, collagen bundles
Defense cells
Macrophages in perivascular areas
Parts of Lateral Wall
Vestibule
Anterior depressed area · lined by modified skin with vibrissae (short curved hairs)
Atrium
Middle part, known as atrium of the middle meatus
Conchae region
Posterior part containing 3 conchae; spaces between them = meatuses
Formation of Lateral Wall
Bony part (7 bones)
Nasal · Frontal process of maxilla · Lacrimal · Labyrinth of ethmoid (sup & mid conchae) · Inferior nasal concha · Perpendicular plate of palatine bone · Medial pterygoid plate
Cartilaginous part
Superior nasal cartilage · Inferior nasal cartilage · 3–4 small ala cartilages
Cuticular lower part
Fibrofatty tissue covered with skin
Nasal Conchae
Inferior concha
Independent bone (not ethmoid)
Middle concha
Projection from medial surface of ethmoidal labyrinth
Superior concha
Smallest · projection from medial ethmoidal labyrinth · above posterior part of middle concha
Meatuses
Inferior meatus
Largest · nasolacrimal duct opens here
Middle meatus
Contains: ethmoidal bulla (mid ethmoid opens at upper margin) · hiatus semilunaris (deep semicircular sulcus below bulla) · infundibulum (short passage at anterior end of hiatus). Opens: frontal sinus (ant hiatus) · ant ethmoidal sinus · maxillary sinus (post hiatus semilunaris)
Superior meatus
Shortest and shallowest · receives posterior ethmoidal air sinuses
Sphenoethmoidal recess
Triangular fossa above superior concha · receives opening of sphenoidal air sinus
Arterial Supply (4 Quadrants)
Anterosuperior
Anterior ethmoidal artery (+ posterior ethmoidal assists)
Anteroinferior
Facial artery branches
Posterosuperior
Sphenopalatine artery branches
Posteroinferior
Greater palatine artery → pierces perpendicular plate of palatine → up through incisive fossa
Venous Drainage
Drainage
Plexus → anteriorly to facial vein · posteriorly to pharyngeal plexus · middle part to pterygoid plexus
Nerve Supply (4 Quadrants)
Anterosuperior
Anterior ethmoidal nerve (branch of ophthalmic CN V1)
Anteroinferior
Anterior superior alveolar nerve (branch of infraorbital → continuation of maxillary nerve CN V2)
Posterosuperior
Lateral posterior superior nasal branches from pterygopalatine ganglion
Posteroinferior
Anterior palatine branch from pterygopalatine ganglion
Special sensory
Olfactory nerves → upper lateral wall below cribriform plate up to superior concha
Lymphatic Drainage
Anterior half
→ Submandibular nodes
Posterior half
→ Retropharyngeal and upper deep cervical nodes