Nasal Cavity

27 April 2010

Sagittal section

Auditory tube

· torus tubarius

· salpingopalatal fold

· salpigopharyngeal fold

Adjacent muscles

· Tensor veli palatini

· Levator veli palatini

· Hook of hamulus (process from pterygoid plate of sphenoid bone)

Netter, 2003 pls. 48, 59, 60; Netter, 2006 pls. 52, 63, 64

Bones of Nasal Cavity

nasal septum

· Ethmoid - perpendicular plate

· Nasal

· Septal cartilage

· Vomer

· Palatine

· Maxilla (palatal process)

lateral wall

· Ethmoid (superior & middle nasal conchae)

· Maxilla (frontal process)

· Lacrimal

· Inferior nasal concha (its own bone)

· Palatine

· Sphenoid

Netter, 2003 pls. 34, 35; Netter, 2006 pls. 38, 39

Nasal cavity (lateral wall continued)

· Sup. nasal concha

· Middle nasal concha

· Ager nasi

· Inf. nasal concha

· Nasal meati

· Limen nasi

· Sphenoid sinus

· Ethmoid bulla

· Semilunar hiatus

· Opening of maxillary sinus

· Opening of sphenoidal sinus

· Opening of nasolacrimal duct

Netter, 2003 pl. 33; Netter, 2006 pl. 37

Paranasal Sinuses (coronal section)

· Frontal sinus

· Middle nasal concha

· Inf. Nasal concha

· Ethmoid air cells

· Maxillary sinus

· Nasal septum

· Hard palate

Note relationship of molars to the maxillary sinus. Maxillary sinusitus can cause pain or numbness in molar teeth, or can involve them.

Netter, 2003 pls. 44, 45; Netter, 2006 pls. 48, 49

Branches of Trigeminal nerve (sensory innervation to nasal cavity – primarily by maxillary n)

Semilunar ganglion

· Ophthalmic n.

· Maxillary n.

– Pterygopalatine gang.

– Superior alveolar nn.

– Infraorbital n.

Netter, 2003 pl. 41; Netter, 2006 pl. 45

Parasympathetic Division of Autonomic Nervous system

· Origin

– Brainstem

– Lateral horn of spinal cord segments S2, S3 and S4

· Distribution

– Cranial nerves

– Pelvic splanchnic nerves

· Targets

– Eyes, salivary glands, lacrimal glands, thoracic & abdominal viscera, pelvic viscera & genitalia

See: Moore & Dalley 2006, pp. 62-67 (MD&A 2010, p. 62-65)

Parasympathetics in head are part of CN's III, VII, IX and X

· Synapse in a parasympathetic ganglion

– Ciliary

– Pterygopalatine

– Otic

– Submandibular

· Nothing else synapses in a parasympathtic ganglion

See: Rosse & Gaddum-Rosse 1997, fig. 7-8

Effects of Parasympathetics

· Stimulate secretion of saliva, tears and digestive secretions

· Bronchoconstriction in lungs

· Decrease heart rate

· Increase gastrointestinal motility

Parasympathetic Innervation of Nasal Cavity

Facial nerve (CN VII)

Nerve of pterygoid canal

Pterygopalatine ganglion

Infraorbital nn.

Sup. Alveolar nn.

Greater & Lesser palatine nn

Carotid plexus is the source of sympathetic innervation to head. It reaches the head on the carotid a. from the superior sympathetic ganglion. This innervation is antagonistic to the parasympathtics. Together they control and regulate production of secretions from lacrimal glands, salivary glands and nasal mucosa.

Netter, 2003 pl. 40; Netter, 2006 pl. 44

Innervation of nasal cavity

Olfactory bulb gives off Olfactory nn.

Ant. Ethmoidal n.

Nasal branches of maxillary n.

Pterygopalatine gang.

Greater palatine n.

Lesser palatine n.

Netter, 2003 pl. 39; Netter, 2006 pl. 43

Parasympathetic Innervation of Nasal Cavity

– Facial nerve

– Nerve of pterygoid canal

– Pterygopalatine ganglion

– Infraorbital nn.

– Sup. Alveolar nn.

– Greater & Lesser palatine nn

– Carotid plexus

Netter, 2003 pl. 40; Netter, 2006 pl. 44

Blood supply of nasal cavity supplied primarily by Maxillary a. Blood also comes from anterior and posterior ethmoidal aa., and from the facial a.

The rich blood supply from three different arteries explains why nose-bleeds can be so difficult to control.

· Sphenopalatine a.

· Descending palatine a.

· Greater palatine a.

· Sphenopalatine a.

– lateral nasal br.

– septal br.

· Anterior ethmoidal a.

· Posterior ethmoidal a.

· Branches of Facial a.

Netter, 2003 pl. 36, 37; Netter, 2006 pl. 40, 41