Paranasal sinuses

Nasal cavity

The air-filled space inside the nose is divided into two passageways by the nasal septum. They contain turbinates. The opening between this structure and the nasopharynx is a nasal choana

Nasal conchae

Bony scrolls covered by the nasal mucosa that warm, humidify and cleanse the air and that also regulate airflow. Are also referred to as turbinates.

Sinus

A cavity within a bone or other tissue

Conchal sinuses

Air-filled cavities within the dorsal, middle, and ventral nasal chonchae in ungulates

Paranasal sinuses

Air-filled extensions of the nasal cavities that invade some of the facial bones

Paranasal sinuses (canine)

• Frontal sinuses only

• Have a maxillary recess (lateral nasal gland)

• No chonchal sinuses

• The two halves of the head do not communicate

Which species have chonchal sinuses

Bovine and Equine

Equine paranasal sinuses

• Maxillary is the largest

  • Divided into rostral and caudal

• Frontal sinus

• Sphenopalatine sinus (sphenoid and palatine sinus)

Conchofrontal sinus

• Only in equine

• Combined frontal sinus and dorsal conchal sinus

Equine sinus communications

• Conchofrontal sinus (frontal and dorsal conchal sinus), middle concha, and sphenopalatine sinuses COMMUNICATES with the caudal maxillary sinus via the frontomaxillary opening

• The two compartments (caudal and rostral) of the maxillary sinus DO NOT communicate

• Rostral maxillary sinus and ventral conchal sinus COMMUNICATE

Equine middle nasal meatus

All sinuses communicate either directly or indirectly with the middle nasal meatus via the nasomaxillary opening/aperture

Bovine paranasal sinuses

• Frontal sinuses (Rostral and caudal)

• Maxillary sinus (not subdivided into compartments)

• Palatine sinus

Bovine sinus communications

• Rostral and Caudal frontal sinus DO NOT communicate

• Palatine COMMUNICATES with the maxillary sinus

• Maxillary COMMUNICATES with middle nasal meatus through the nasomaxillary opening

Lacrimal bulla

A delicate, thin-walled caudal extension of the maxillary sinus in ruminants

The 3 diverticula of the bovine caudal frontal sinus

• Nuchal

• Postorbital

• Cornual

Equine guttural pouches

• Dilations of the internal auditory tubes

• Two pouches, bilaterally positioned, separated by a thin septum (pouches do not communicate)

• Normally air filled

• Each pouch subdivided into medial and lateral compartments by the stylohyoid bone, which indents the pouches ventrally

• Accessed via pharyngeal opening of the auditory tube, which is in the nasopharynx

• Susceptible to infection