3.3. Sectional Anatomy
The anatomy of the bony nasal cavity was described through transverse, dorsal and sagittal sections of the domestic cat heads (
Figure 4,
Figure 5,
Figure 6,
Figure 7,
Figure 8,
Figure 9,
Figure 10,
Figure 11,
Figure 12,
Figure 13,
Figure 14,
Figure 15,
Figure 16,
Figure 17 and
Figure 18).
In the most rostral view of the transverse sections (
Figure 4,
Figure 5,
Figure 6,
Figure 7,
Figure 8,
Figure 9,
Figure 10 and
Figure 11), the nasal bone can be observed covering the most rostral part of the nasal cavity (
Figure 4A). In this figure, we can also see the cartilages that make up the external nose and maintain and support the nostrils. Thus, we can observe the dorsal lateral cartilage of the nose forming the anatomical base of the dorsum of the openings. The ventral lateral cartilage limits the ventrolateral part of the nose, and the alar fold closes it laterally. The alar groove was described in the ventrolateral area of the opening. Once inside the nasal cavity and in the caudal cross-sectional view (
Figure 4B), the framework of the ectoturbinates was observed in the frontal sinus. The dorsal and middle nasal conchae were seen, and the third endoturbinate can also be observed in a more medial position. The ventral nasal concha could be seen sectioned with one or two conchal crests of the maxilla depending on the section’s symmetry.
Figure 4.
Transverse anatomical sections of the cat’s head at the level of the nasal plane, vestibule and rostral part of the nasal cavity: respiratory part. (A): Rostral view, level section I. (B): Caudal view, level section II. 1. Tip of the nose; 2. Nasal orifice (nares); 3. Subnasal groove or philtrum; 4. Lateral accessory nasal cartilage; 5. Dorsal lateral nasal cartilage; 6. Ventral lateral nasal cartilage; 7. Alar groove; 8. Frontal bone; 9. Frontal sinus: septum; 10. Nasal septum: cartilage; 11. Vomer; 12. Maxilla: palatine process; 13. Canine tooth: root; 14. Maxilla: orbital surface; 15. Ectoturbinates; 16. Dorsal and middle nasal conchae; 17. 3rd endoturbinate; 18. Ventral nasal concha; 19. Conchal crest of the maxilla; 20. Nasal bone.
Figure 4.
Transverse anatomical sections of the cat’s head at the level of the nasal plane, vestibule and rostral part of the nasal cavity: respiratory part. (A): Rostral view, level section I. (B): Caudal view, level section II. 1. Tip of the nose; 2. Nasal orifice (nares); 3. Subnasal groove or philtrum; 4. Lateral accessory nasal cartilage; 5. Dorsal lateral nasal cartilage; 6. Ventral lateral nasal cartilage; 7. Alar groove; 8. Frontal bone; 9. Frontal sinus: septum; 10. Nasal septum: cartilage; 11. Vomer; 12. Maxilla: palatine process; 13. Canine tooth: root; 14. Maxilla: orbital surface; 15. Ectoturbinates; 16. Dorsal and middle nasal conchae; 17. 3rd endoturbinate; 18. Ventral nasal concha; 19. Conchal crest of the maxilla; 20. Nasal bone.
In the next section (
Figure 5), the septum of the frontal sinus is already observed. The dorsal and middle nasal conchae appeared quite narrow and displaced at this level, and the third endoturbinate begins to increase in size. The ventral nasal concha was observed at this level in its maximum development, and the maxillary recess develops on its lateral surface. At this level, the nasal cavernous plexuses reach great development and the vomeronasal organ was well appreciated.
Figure 5.
Transverse anatomical sections of the cat’s head at the level of the rostral part of the nasal cavity: respiratory part. (A) Rostral view, level section III. (B) Caudal view, level section IV. 1. Frontal bone; 2. Frontal sinus: septum; 3. Nasal septum: cartilage; 4. Vomer; 5. Maxilla: palatine process; 6. Canine tooth: root; 7. Maxilla: orbital surface; 8. Ectoturbinates; 9. Dorsal nasal concha; 10. Middle nasal concha; 11. 3rd endoturbinate; 12. Ventral nasal concha; 13. Conchal crest of the maxilla; 14. Vomeronasal organ; 15. Nasal cavernous plexuses; 16. Maxillary recess.
Figure 5.
Transverse anatomical sections of the cat’s head at the level of the rostral part of the nasal cavity: respiratory part. (A) Rostral view, level section III. (B) Caudal view, level section IV. 1. Frontal bone; 2. Frontal sinus: septum; 3. Nasal septum: cartilage; 4. Vomer; 5. Maxilla: palatine process; 6. Canine tooth: root; 7. Maxilla: orbital surface; 8. Ectoturbinates; 9. Dorsal nasal concha; 10. Middle nasal concha; 11. 3rd endoturbinate; 12. Ventral nasal concha; 13. Conchal crest of the maxilla; 14. Vomeronasal organ; 15. Nasal cavernous plexuses; 16. Maxillary recess.
In the following transverse section (
Figure 6), in the medial part of the nasal cavity, the ventral nasal concha was already decreasing in size while the third endoturbinate reaches its greatest development. At this level, the dorsal nasal concha also increases in size. Furthermore, the three ectoturbinates could be clearly identified. From dorsal to ventral, the first, the third and the second ectoturbinates were observed.
Figure 6.
Transverse anatomical sections of the cat’s head at the level of the middle part of the nasal cavity; respiratory part. (A): Rostral view, level section V. (B): Caudal view, level section VI. 1. Frontal bone; 2. Frontal sinus: septum; 3. Nasal septum: cartilage; 4. Vomer; 5. Maxilla: palatine process; 6. 1st premolar tooth: root; 7. Frontal bone: orbital surface; 8. 1st ectoturbinate; 9. 2nd ectoturbinate; 10. 3rd ectoturbinate; 11. Dorsal nasal concha; 12. Middle nasal concha; 13. 3rd endoturbinate; 14. Ventral nasal concha; 15. Conchal crest of the maxilla; 16. Maxillary recess; 17. Vomeronasal organ; 18. Nasal cavernous plexuses; 19. Frontal sinus.
Figure 6.
Transverse anatomical sections of the cat’s head at the level of the middle part of the nasal cavity; respiratory part. (A): Rostral view, level section V. (B): Caudal view, level section VI. 1. Frontal bone; 2. Frontal sinus: septum; 3. Nasal septum: cartilage; 4. Vomer; 5. Maxilla: palatine process; 6. 1st premolar tooth: root; 7. Frontal bone: orbital surface; 8. 1st ectoturbinate; 9. 2nd ectoturbinate; 10. 3rd ectoturbinate; 11. Dorsal nasal concha; 12. Middle nasal concha; 13. 3rd endoturbinate; 14. Ventral nasal concha; 15. Conchal crest of the maxilla; 16. Maxillary recess; 17. Vomeronasal organ; 18. Nasal cavernous plexuses; 19. Frontal sinus.
In the next transverse section (
Figure 7), the end of the ventral nasal concha was seen. At this level a lateral attachment of the third endoturbinate to the frontal bone could also be identified. Ectoturbinates also decrease at this level and the greater size of the frontal sinus was observed. At this stage, the vomeronasal organ reaches its caudal extent.
Figure 7.
Transverse anatomical sections of the cat’s head at the level of the caudal part of the nasal cavity; respiratory part. (A): Rostral view, level section VII. (B): Caudal view, level section VIII. 1. Frontal bone; 2. Frontal sinus: septum; 3. Nasal septum: cartilage; 4. Vomer; 5. Maxilla: palatine process; 6. 2nd premolar tooth: root; 7. Frontal bone: orbital surface; 8. 1st ectoturbinate; 9. 2nd ectoturbinate; 10. 3rd ectoturbinate; 11. Dorsal nasal concha; 12. Middle nasal concha; 13. Conchal crest of the 3rd endoturbinate; 14. 3rd endoturbinate; 15. Conchal crest of the maxilla; 16. Ventral nasal concha; 17. Maxillary recess; 18. Frontal sinus; 19. Vomeronasal organ; 20. Nasal cavernous plexuses.
Figure 7.
Transverse anatomical sections of the cat’s head at the level of the caudal part of the nasal cavity; respiratory part. (A): Rostral view, level section VII. (B): Caudal view, level section VIII. 1. Frontal bone; 2. Frontal sinus: septum; 3. Nasal septum: cartilage; 4. Vomer; 5. Maxilla: palatine process; 6. 2nd premolar tooth: root; 7. Frontal bone: orbital surface; 8. 1st ectoturbinate; 9. 2nd ectoturbinate; 10. 3rd ectoturbinate; 11. Dorsal nasal concha; 12. Middle nasal concha; 13. Conchal crest of the 3rd endoturbinate; 14. 3rd endoturbinate; 15. Conchal crest of the maxilla; 16. Ventral nasal concha; 17. Maxillary recess; 18. Frontal sinus; 19. Vomeronasal organ; 20. Nasal cavernous plexuses.
Figure 8 continues with a caudal section of the nasal cavity where the olfactory bulb was already sectioned. The nasal septum is replaced at this level by the perpendicular plate of the ethmoid bone and the third endoturbinate was no longer observed. The fourth endoturbinate begins to be appreciated and the choana or nasopharyngeal opening was already identified ventrally between the basal plate of the ethmoid bone and palatine process of the maxilla.
Figure 8.
Transverse anatomical sections of the cat’s head at the level of the caudal part of the nasal cavity; olfactory part. (A): Rostral view, level section IX. (B): Caudal view, level section X. 1. Frontal bone; 2. Frontal sinus: septum; 3. Ethmoid bone: perpendicular plate; 4. Vomer; 5. Maxilla: palatine process; 6. 3rd premolar tooth: root; 7. Ethmoid bone: orbital plate; 8. Frontal sinus; 9. 1st ectoturbinate; 10. 2nd ectoturbinate; 11. Dorsal nasal concha; 12. Middle nasal concha; 13. 3rd endoturbinate; 14. 4th endoturbinate; 15. Maxillary recess; 16. Ethmoid bone: basal plate; 17. Choana; 18. Olfactory bulb.
Figure 8.
Transverse anatomical sections of the cat’s head at the level of the caudal part of the nasal cavity; olfactory part. (A): Rostral view, level section IX. (B): Caudal view, level section X. 1. Frontal bone; 2. Frontal sinus: septum; 3. Ethmoid bone: perpendicular plate; 4. Vomer; 5. Maxilla: palatine process; 6. 3rd premolar tooth: root; 7. Ethmoid bone: orbital plate; 8. Frontal sinus; 9. 1st ectoturbinate; 10. 2nd ectoturbinate; 11. Dorsal nasal concha; 12. Middle nasal concha; 13. 3rd endoturbinate; 14. 4th endoturbinate; 15. Maxillary recess; 16. Ethmoid bone: basal plate; 17. Choana; 18. Olfactory bulb.
In
Figure 9, the tectorial plate of the ethmoid bone can be visualized independently as a plate that embraces the ectoturbinates dorsally and ventrally. The fourth endoturbinate is larger in this section.
Figure 9.
Transverse anatomical sections of the cat’s head at the level of the caudal part of the nasal cavity: olfactory part. (A) Rostral view, level section XI. (B) Caudal view, level section XII. 1. Frontal bone; 2. Frontal sinus: septum; 3. Ethmoid bone: tectorial plate; 4. Ethmoid bone: perpendicular plate; 5. Vomer; 6. Ethmoid bone: basal plate; 7. Palatine bone: perpendicular plate; 8. Palatine bone: horizontal plate; 9. Molar tooth: root; 10. Presphenoid wing: orbital surface; 11. Frontal bone: orbital surface; 12. Frontal sinus; 13. 3rd endoturbinate; 14. 4th endoturbinate; 15. Choana; 16. Olfactory bulb.
Figure 9.
Transverse anatomical sections of the cat’s head at the level of the caudal part of the nasal cavity: olfactory part. (A) Rostral view, level section XI. (B) Caudal view, level section XII. 1. Frontal bone; 2. Frontal sinus: septum; 3. Ethmoid bone: tectorial plate; 4. Ethmoid bone: perpendicular plate; 5. Vomer; 6. Ethmoid bone: basal plate; 7. Palatine bone: perpendicular plate; 8. Palatine bone: horizontal plate; 9. Molar tooth: root; 10. Presphenoid wing: orbital surface; 11. Frontal bone: orbital surface; 12. Frontal sinus; 13. 3rd endoturbinate; 14. 4th endoturbinate; 15. Choana; 16. Olfactory bulb.
Figure 10 shows both the external and the internal plates of the frontal bone. At this level, we could also observe the fourth endoturbinate in the sphenoidal sinus, which has a medial septum that divides it into two.
Figure 10.
Transverse anatomical sections of the cat’s head at the level of the paranasal sinuses and nasopharynx (pars nasalis pharyngis). (A): Rostral view, level section XIII. (B): Caudal view, level section XIV. 1. Frontal bone: external plate; 2. Frontal bone: internal plate; 3. Frontal sinus: septum; 4. Frontal bone: orbital surface; 5. Basisphenoid bone: wing (orbital surface); 6. Presphenoid bone: body; 7. Sphenoidal sinus: septum; 8. Basisphenoid bone: pterygoid process; 9. Vomer; 10. Soft palate; 11. Frontal sinus; 12. Sphenoidal sinus; 13. 4th endoturbinate; 14. Sphenoidal sinus: caudal wall; 15. Nasopharynx (pars nasalis pharyngis); 16. Cranial cavity.
Figure 10.
Transverse anatomical sections of the cat’s head at the level of the paranasal sinuses and nasopharynx (pars nasalis pharyngis). (A): Rostral view, level section XIII. (B): Caudal view, level section XIV. 1. Frontal bone: external plate; 2. Frontal bone: internal plate; 3. Frontal sinus: septum; 4. Frontal bone: orbital surface; 5. Basisphenoid bone: wing (orbital surface); 6. Presphenoid bone: body; 7. Sphenoidal sinus: septum; 8. Basisphenoid bone: pterygoid process; 9. Vomer; 10. Soft palate; 11. Frontal sinus; 12. Sphenoidal sinus; 13. 4th endoturbinate; 14. Sphenoidal sinus: caudal wall; 15. Nasopharynx (pars nasalis pharyngis); 16. Cranial cavity.
In this last transverse section (
Figure 11), we observed dorsal to the nasopharynx (pars nasalis pharyngis) the caudal extension of the sphenoidal sinus.
Figure 11.
Transverse anatomical sections of the cat’s head at the level of the paranasal sinuses and nasopharynx (pars nasalis pharyngis). (A): Rostral view, level section XV. (B): Caudal view, level section XVI. 1. Frontal bone; 2. Frontal bone: orbital surface; 3. Cranial cavity; 4. Sphenoidal sinus: septum; 5. Sphenoidal sinus; 6. Presphenoid bone: body; 7. Presphenoid bone: wing; 8. Vomer; 9. Nasopharynx (pars nasalis pharyngis): mucosa; 10. Soft palate; 11. Oropharynx; 12. Tongue.
Figure 11.
Transverse anatomical sections of the cat’s head at the level of the paranasal sinuses and nasopharynx (pars nasalis pharyngis). (A): Rostral view, level section XV. (B): Caudal view, level section XVI. 1. Frontal bone; 2. Frontal bone: orbital surface; 3. Cranial cavity; 4. Sphenoidal sinus: septum; 5. Sphenoidal sinus; 6. Presphenoid bone: body; 7. Presphenoid bone: wing; 8. Vomer; 9. Nasopharynx (pars nasalis pharyngis): mucosa; 10. Soft palate; 11. Oropharynx; 12. Tongue.
The dorsal sections (
Figure 12,
Figure 13,
Figure 14 and
Figure 15) show, in the most dorsal section (
Figure 12A), the external and internal plates of the frontal bone, outlining the frontal sinus and their septum. In the next sections (
Figure 12B,C), the first ectoturbinate was located inside the frontal sinus, and lateral to it is the third ectoturbinate.
Figure 12.
Dorsal anatomical sections of the cat’s head at the level of the (A) frontal sinus, level I and (B,C) frontal sinus and ectoturbinates, levels II and III. Images are oriented so that the rostral part is at the top. All views are dorsal. 1. Frontal bone: external plate; 2. Frontal bone: internal plate; 3. Frontal sinus; 4. Frontal sinus: septum; 5. 1st ectoturbinate; 6. 3rd ectoturbinate; 7. Cranial cavity.
Figure 12.
Dorsal anatomical sections of the cat’s head at the level of the (A) frontal sinus, level I and (B,C) frontal sinus and ectoturbinates, levels II and III. Images are oriented so that the rostral part is at the top. All views are dorsal. 1. Frontal bone: external plate; 2. Frontal bone: internal plate; 3. Frontal sinus; 4. Frontal sinus: septum; 5. 1st ectoturbinate; 6. 3rd ectoturbinate; 7. Cranial cavity.
In the next section, more caudal in position (
Figure 13A,B), the ectoturbinates could be visualized in their maximum development. The first ectoturbinate was within the most dorsal part of and attached to the septum of the frontal sinus. The second ectoturbinate could also be visualized, and the third ectoturbinate appeared to be more developed on the lateral face. In
Figure 13C, the dorsal nasal concha begins to be observed.
Figure 13.
Dorsal anatomical sections of the cat’s head at the level of the (A,B) ectoturbinates, levels IV and V, and (C) endoturbinates, level VI. Images are oriented so that the rostral part is at the top. All views are dorsal. 1. Nasal bone; 2. Maxilla; 3. Frontal sinus: septum; 4. 1st ectoturbinate; 5. 2nd ectoturbinate; 6. 3rd ectoturbinate; 7. Frontal bone: internal plate; 8. Ethmoid bone: tectorial plate; 9. Ethmoid bone: cribriform plate; 10. Frontal sinus; 11. Nasal septum: cartilage; 12. Dorsal nasal concha; 13. Ethmoidal fossa; 14. Cranial cavity.
Figure 13.
Dorsal anatomical sections of the cat’s head at the level of the (A,B) ectoturbinates, levels IV and V, and (C) endoturbinates, level VI. Images are oriented so that the rostral part is at the top. All views are dorsal. 1. Nasal bone; 2. Maxilla; 3. Frontal sinus: septum; 4. 1st ectoturbinate; 5. 2nd ectoturbinate; 6. 3rd ectoturbinate; 7. Frontal bone: internal plate; 8. Ethmoid bone: tectorial plate; 9. Ethmoid bone: cribriform plate; 10. Frontal sinus; 11. Nasal septum: cartilage; 12. Dorsal nasal concha; 13. Ethmoidal fossa; 14. Cranial cavity.
Ventral to this, in
Figure 14A,B, the middle nasal concha and the third endoturbinate can be seen, sections in which the entire extent of the latter can be clearly appreciated. The ventral nasal concha was observed in the most rostral area, lateral to the third endoturbinate. Additionally, in
Figure 14C, the alar fold continues with the ventral nasal concha. In these sections, we could also see the sphenoidal sinus and the fourth endoturbinate.
Figure 14.
Dorsal anatomical sections at the level of cat’s head at the level of the (A,B) endoturbinates, levels VII and VIII, and (C) sphenoidal sinuses, level IX. Images are oriented so that the rostral part is at the top. All views are dorsal. 1. Nose; 2. Nasal septum: cartilage; 3. Ethmoid bone: cribriform plate; 4. Incisive bone: nasal process; 5. Maxilla; 6. Presphenoid bone; 7. Middle nasal concha; 8. 3rd endoturbinate; 9. 4th endoturbinate; 10. Ventral nasal concha; 11. Basal fold; 12. Alar fold; 13. Sphenoidal sinus: septum; 14. Sphenoidal sinus; 15. Dorsal nasal concha.
Figure 14.
Dorsal anatomical sections at the level of cat’s head at the level of the (A,B) endoturbinates, levels VII and VIII, and (C) sphenoidal sinuses, level IX. Images are oriented so that the rostral part is at the top. All views are dorsal. 1. Nose; 2. Nasal septum: cartilage; 3. Ethmoid bone: cribriform plate; 4. Incisive bone: nasal process; 5. Maxilla; 6. Presphenoid bone; 7. Middle nasal concha; 8. 3rd endoturbinate; 9. 4th endoturbinate; 10. Ventral nasal concha; 11. Basal fold; 12. Alar fold; 13. Sphenoidal sinus: septum; 14. Sphenoidal sinus; 15. Dorsal nasal concha.
In the most ventral dorsal section of the nasal cavity (
Figure 15), the ventral nasal concha and the third and fourth endoturbinates were clearly observed. In addition to the palatine bone, the ventral part of the floor of the nasal cavity was represented by the vomer. The nasal cavernous plexuses were seen, but the vomeronasal organ was not observed. The space between the vomer and palatine bone and the soft palate forms the choana or nasopharyngeal opening.
Figure 15.
Dorsal anatomical sections of the cat’s head at the level of the (A) endoturbinates and ventral nasal concha, level X and (B) nasopharynx (pars nasalis pharyngis), level XI. Images are oriented so that the rostral part is at the top. All views are dorsal. 1. Nasal orifice; 2. Canine tooth: root; 3. Vomer; 4. Nasal cavernous plexuses; 5. Presphenoid bone; 6. Choana; 7: Soft palate: dorsal surface; 8. Nasopharynx (pars nasalis pharyngis); 9. 3rd endoturbinate; 10. Ventral nasal concha; 11. 4th endoturbinate.
Figure 15.
Dorsal anatomical sections of the cat’s head at the level of the (A) endoturbinates and ventral nasal concha, level X and (B) nasopharynx (pars nasalis pharyngis), level XI. Images are oriented so that the rostral part is at the top. All views are dorsal. 1. Nasal orifice; 2. Canine tooth: root; 3. Vomer; 4. Nasal cavernous plexuses; 5. Presphenoid bone; 6. Choana; 7: Soft palate: dorsal surface; 8. Nasopharynx (pars nasalis pharyngis); 9. 3rd endoturbinate; 10. Ventral nasal concha; 11. 4th endoturbinate.
In the sagittal sections of the nasal cavity (
Figure 16,
Figure 17 and
Figure 18), the ectoturbinates are observed in the frontal sinus, and the endoturbinates begin to extend from the cribriform plate of the ethmoid bone. In addition, the ventral nasal concha was seen to be continuous rostrally with the alar and basal folds, while the dorsal nasal concha was continuous with the straight fold. The bullas of the dorsal and ventral nasal conchae were not identified (
Figure 16).
Figure 16.
Sagittal anatomical sections of the cat’s head at the level of the (A,B) paranasal sinuses, nasal cavity and nasopharynx (pars nasalis pharyngis), levels I and II, and (C) frontal sinuses and nasal cavity, level III. Images are oriented so that the rostral part is to the left and the dorsal is at the top. All views are left lateral. 1. Nose; 2. Nasal bone; 3. Frontal bone: external plate; 4. Frontal bone: internal plate; 5. Ethmoid bone: tectorial plate; 6. Ethmoid bone: cribriform plate; 7. Basal fold; 8. Alar fold; 9. Straight fold; 10. Ectoturbinates; 11. Dorsal nasal concha; 12. Middle nasal concha; 13. 3rd endoturbinate; 14. 4th endoturbinate; 15. Ventral nasal concha; 16. Sphenoidal sinus; 17. Frontal sinus: septum; 18. Frontal sinus; 19. Choana; 20. Nasopharynx (pars nasalis pharyngis); 21. Maxilla: palatine process; 22. Incisive bone.
Figure 16.
Sagittal anatomical sections of the cat’s head at the level of the (A,B) paranasal sinuses, nasal cavity and nasopharynx (pars nasalis pharyngis), levels I and II, and (C) frontal sinuses and nasal cavity, level III. Images are oriented so that the rostral part is to the left and the dorsal is at the top. All views are left lateral. 1. Nose; 2. Nasal bone; 3. Frontal bone: external plate; 4. Frontal bone: internal plate; 5. Ethmoid bone: tectorial plate; 6. Ethmoid bone: cribriform plate; 7. Basal fold; 8. Alar fold; 9. Straight fold; 10. Ectoturbinates; 11. Dorsal nasal concha; 12. Middle nasal concha; 13. 3rd endoturbinate; 14. 4th endoturbinate; 15. Ventral nasal concha; 16. Sphenoidal sinus; 17. Frontal sinus: septum; 18. Frontal sinus; 19. Choana; 20. Nasopharynx (pars nasalis pharyngis); 21. Maxilla: palatine process; 22. Incisive bone.
In the next anatomical sections shown in
Figure 17, the entire longitudinal path of the conchae can be seen, along with the maximum extent of the third endoturbinate, while the ventral nasal concha was limited only to the cranial half of the nasal cavity (
Figure 17A). In the more sagittal sections (
Figure 17B,C), the fourth endoturbinate close to the sphenoidal sinus could already be identified, but it was not observed in the sagittal section.
Figure 17.
Sagittal anatomical sections of the cat’s head at the level of the (A–C) nasal cavity, paranasal sinuses and nasopharynx (pars nasalis pharyngis), levels IV, V and VI. Images are oriented so that the rostral part is to the left and the dorsal is at the top. All views are left lateral. 1. Nose; 2. Nasal bone; 3. Frontal bone: external plate; 4. Frontal bone: internal plate; 5. Ethmoid bone: tectorial plate; 6. Basal fold; 7. Alar fold; 8. Straight fold; 9. Ectoturbinates; 10. Dorsal nasal concha; 11. Middle nasal concha; 12. 3rd endoturbinate; 13. 4th endoturbinate; 14. Ventral nasal concha; 15. Frontal sinus: septum; 16. Frontal sinus; 17. Sphenoidal sinus; 18. Choana; 19. Maxilla: palatine process; 20. Incisive bone.
Figure 17.
Sagittal anatomical sections of the cat’s head at the level of the (A–C) nasal cavity, paranasal sinuses and nasopharynx (pars nasalis pharyngis), levels IV, V and VI. Images are oriented so that the rostral part is to the left and the dorsal is at the top. All views are left lateral. 1. Nose; 2. Nasal bone; 3. Frontal bone: external plate; 4. Frontal bone: internal plate; 5. Ethmoid bone: tectorial plate; 6. Basal fold; 7. Alar fold; 8. Straight fold; 9. Ectoturbinates; 10. Dorsal nasal concha; 11. Middle nasal concha; 12. 3rd endoturbinate; 13. 4th endoturbinate; 14. Ventral nasal concha; 15. Frontal sinus: septum; 16. Frontal sinus; 17. Sphenoidal sinus; 18. Choana; 19. Maxilla: palatine process; 20. Incisive bone.
Finally,
Figure 18 shows a sagittal section after injection of blue latex to better highlight the vascularization of the respiratory part of the nasal cavity. It is worth noting the extensive blood supply to the respiratory part of the nasal cavity due to the large number of nasal cavernous plexuses that exist at this level and their scarcity in the olfactory part.
Figure 18.
Sagittal anatomical section of the cat’s head at the level of the nasal cavity and paranasal sinuses, level I. The venous plexuses have been injected with blue latex via an external jugular vein. The image is oriented so that the rostral part is to the left and the dorsal is at the top. Left lateral view. 1. Nasal vestibule; 2. Respiratory part; 3. Olfactory part; 4. Nasal cavernous plexuses.
Figure 18.
Sagittal anatomical section of the cat’s head at the level of the nasal cavity and paranasal sinuses, level I. The venous plexuses have been injected with blue latex via an external jugular vein. The image is oriented so that the rostral part is to the left and the dorsal is at the top. Left lateral view. 1. Nasal vestibule; 2. Respiratory part; 3. Olfactory part; 4. Nasal cavernous plexuses.
3.4. Felid Skulls CT
The section levels of each plane are represented in
Figure 19. The CT study of the felid skull allowed for the identification in the three spatial anatomical planes of the bony base that makes up this cavity: transverse, sagittal and dorsal (
Figure 20,
Figure 21,
Figure 22,
Figure 23,
Figure 24,
Figure 25 and
Figure 26). This study has been carried out on the leopard, the lion, the cheetah and the cat.
The nasal bone extends less rostrally in lions than in the other felids. This is seen in
Figure 20, where in a rostral cross-section the nasal bone does not cover the roof of the nasal cavity, and again in
Figure 25, shown in a sagittal view. Ventrally, the vomer, as well as the palatine process of the maxilla could be clearly observed in the four species in this first level of transverse section (
Figure 20). The rostral end of the conchae could not be visualized very well in the leopard or the lion. This fact could also be seen in the sagittal sections (
Figure 25B,C). In the cheetah and the cat, the dorsal ventral nasal conchae could be identified as thin, slightly hyperattenuated lamellae. The frontal sinus begins to be observed in the following more caudal sections.
Figure 20.
Amira representative transverse CT images at level of the rostral portion of the respiratory part, level I. Images are oriented so that the left side of the head is to the right and the dorsal is at the top. All views are rostral. (A): Leopard; (B): Lion; (C): Cheetah and (D): Cat. 1. Nasal bone; 2. Maxilla; 3. Maxilla: palatine process; 4. Canine tooth: root; 5. Vomer; 6. Dorsal nasal concha; 7. Ventral nasal concha.
Figure 20.
Amira representative transverse CT images at level of the rostral portion of the respiratory part, level I. Images are oriented so that the left side of the head is to the right and the dorsal is at the top. All views are rostral. (A): Leopard; (B): Lion; (C): Cheetah and (D): Cat. 1. Nasal bone; 2. Maxilla; 3. Maxilla: palatine process; 4. Canine tooth: root; 5. Vomer; 6. Dorsal nasal concha; 7. Ventral nasal concha.
In a more caudal cross-section, the frontal sinus is visible in the leopard and the cat (
Figure 21A,D), but not in the lion or the cheetah. The development of the middle and ventral nasal conchae could already be seen, as well as the great development of the third endoturbinate. Lateral to the ventral nasal concha, the maxillary recess could be identified. The infraorbital foramen was clearly observed at this level in all four species.
Figure 21.
Amira representative transverse CT images at level of the middle portion of the respiratory part, level II. Images are oriented so that the left side of the head is to the right and the dorsal is at the top. All views are rostral. (A): Leopard; (B): Lion; (C): Cheetah and (D): Cat. 1. Nasal bone; 2. Frontal bone; 3. Maxilla; 4. Zygomatic bone; 5. Infraorbital canal; 6. Ethmoid bone: tectorial plate; 7. Maxilla: palatine process; 8. Nasal septum; 9. Vomer; 10. Dorsal nasal concha; 11. Middle nasal concha; 12. Ventral nasal concha; 13. 3rd endoturbinate; 14. Maxillary recess; 15. Frontal sinus; 16. Dorsal nasal meatus; 17. Common nasal meatus; 18. Ventral nasal meatus.
Figure 21.
Amira representative transverse CT images at level of the middle portion of the respiratory part, level II. Images are oriented so that the left side of the head is to the right and the dorsal is at the top. All views are rostral. (A): Leopard; (B): Lion; (C): Cheetah and (D): Cat. 1. Nasal bone; 2. Frontal bone; 3. Maxilla; 4. Zygomatic bone; 5. Infraorbital canal; 6. Ethmoid bone: tectorial plate; 7. Maxilla: palatine process; 8. Nasal septum; 9. Vomer; 10. Dorsal nasal concha; 11. Middle nasal concha; 12. Ventral nasal concha; 13. 3rd endoturbinate; 14. Maxillary recess; 15. Frontal sinus; 16. Dorsal nasal meatus; 17. Common nasal meatus; 18. Ventral nasal meatus.
Figure 22 shows the greater thickness of the frontal bone and maxillae of the lion compared to the other species studied. At this level, the temporal process of the zygomatic bone is visible in all four species and the third endoturbinate reaches its greatest development. This was observed as a set of hyperattenuated lamellae on the medial part of the nasal cavity. The ventral nasal concha was already very small in all four species. Ectoturbinates were seen at this level only in the domestic cat. The frontal sinus was now apparent in the cheetah, but not yet in the lion. The tectorial plate of the ethmoid bone was seen as a hyperattenuated area at the base of the frontal sinus.
Figure 22.
Amira representative transverse CT images at level of the middle portion of the respiratory part, level III. Images are oriented so that the left side of the head is to the right and the dorsal is at the top. All views are rostral. (A): Leopard; (B): Lion; (C): Cheetah and (D): Cat. 1. Frontal bone; 2. Maxilla; 3. Zygomatic process: body; 4. Zygomatic bone: temporal process; 5. Infraorbital canal; 6. Ethmoid bone: tectorial plate; 7. Maxilla: palatine process; 8. Nasal septum; 9. Vomer; 10. Dorsal nasal concha; 11. Middle nasal concha; 12. 3rd endoturbinate; 13. Ventral nasal concha; 14. Maxillary recess; 15. Frontal sinus; 16. 1st ectoturbinate; 17. 2nd ectoturbinate; 18. 3rd ectoturbinate; 19. Dorsal nasal meatus; 20. Common nasal meatus; 21. Ventral nasal meatus.
Figure 22.
Amira representative transverse CT images at level of the middle portion of the respiratory part, level III. Images are oriented so that the left side of the head is to the right and the dorsal is at the top. All views are rostral. (A): Leopard; (B): Lion; (C): Cheetah and (D): Cat. 1. Frontal bone; 2. Maxilla; 3. Zygomatic process: body; 4. Zygomatic bone: temporal process; 5. Infraorbital canal; 6. Ethmoid bone: tectorial plate; 7. Maxilla: palatine process; 8. Nasal septum; 9. Vomer; 10. Dorsal nasal concha; 11. Middle nasal concha; 12. 3rd endoturbinate; 13. Ventral nasal concha; 14. Maxillary recess; 15. Frontal sinus; 16. 1st ectoturbinate; 17. 2nd ectoturbinate; 18. 3rd ectoturbinate; 19. Dorsal nasal meatus; 20. Common nasal meatus; 21. Ventral nasal meatus.
In the caudal section of the respiratory part of the nasal cavity (
Figure 23), the frontal sinus could be observed in the four species. In it, the three ectoturbinates could also be identified as areas limited by hyperattenuated lines, the first and second being more medial and the third developing lateral to these. At this level, the ventral nasal concha could no longer be visualized. We observed that the body of the presphenoid bone closes the caudal wall of the nasal cavity. The space between it and the horizontal and perpendicular plates of the palatine bone forms the choana or the nasopharyngeal opening. The bony borders of the choanae could be seen in the leopard, while in the other species it was no longer ossified.
Figure 23.
Amira representative transverse CT images at the level of the caudal portion of the respiratory part, level IV. Images are oriented so that the left side of the head is to the right and the dorsal is at the top. All views are rostral. (A): Leopard; (B): Lion; (C): Cheetah and (D): Cat. 1. Frontal bone: external plate; 2. Frontal bone: orbital surface; 3. Frontal sinus; 4. Frontal sinus: septum; 5. 1st ectoturbinate; 6. 2nd ectoturbinate; 7. 3rd ectoturbinate; 8. Dorsal nasal concha; 9. Middle nasal concha; 10; Ethmoid bone: perpendicular plate; 11. 3rd endoturbinate; 12. 4th endoturbinate; 13. Presphenoid bone: wing (orbital surface); 14. Presphenoid bone: body; 15. Vomer; 16. Choana; 17. Palatine bone: horizontal and perpendicular plates.
Figure 23.
Amira representative transverse CT images at the level of the caudal portion of the respiratory part, level IV. Images are oriented so that the left side of the head is to the right and the dorsal is at the top. All views are rostral. (A): Leopard; (B): Lion; (C): Cheetah and (D): Cat. 1. Frontal bone: external plate; 2. Frontal bone: orbital surface; 3. Frontal sinus; 4. Frontal sinus: septum; 5. 1st ectoturbinate; 6. 2nd ectoturbinate; 7. 3rd ectoturbinate; 8. Dorsal nasal concha; 9. Middle nasal concha; 10; Ethmoid bone: perpendicular plate; 11. 3rd endoturbinate; 12. 4th endoturbinate; 13. Presphenoid bone: wing (orbital surface); 14. Presphenoid bone: body; 15. Vomer; 16. Choana; 17. Palatine bone: horizontal and perpendicular plates.
The last transverse section shows the olfactory part of the nasal cavity (
Figure 24). In this section, the ethmoid bone was hyperattenuated, specifically the perpendicular plate, the caudal continuation of the nasal septum. The fourth endoturbinate could now be visualized as a thin hyperattenuated line at this level close to the floor of the nasal cavity.
Figure 24.
Amira representative transverse CT images at the level of the olfactory part of the nasal cavity, level V. Images are oriented so that the left side of the head is to de right and the dorsal is at the top. All views are rostral. (A): Leopard; (B): Lion; (C): Cheetah and (D): Cat. 1. Frontal bone: external plate; 2. Frontal bone: orbital surface; 3. Frontal sinus; 4. Frontal sinus: septum; 5. 1st ectoturbinate; 6. 2nd ectoturbinate; 7. 3rd ectoturbinate; 8. Dorsal nasal concha; 9. Middle nasal concha; 10. Ethmoid bone: perpendicular plate; 11. Basisphenoid bone: wing (orbital surface); 12. 3rd endoturbinate; 13. 4th endoturbinate; 14. Presphenoid bone: wing; 15. Presphenoid bone: body; 16. Vomer; 17. Choana; 18. Palatine bone: horizontal and perpendicular plates.
Figure 24.
Amira representative transverse CT images at the level of the olfactory part of the nasal cavity, level V. Images are oriented so that the left side of the head is to de right and the dorsal is at the top. All views are rostral. (A): Leopard; (B): Lion; (C): Cheetah and (D): Cat. 1. Frontal bone: external plate; 2. Frontal bone: orbital surface; 3. Frontal sinus; 4. Frontal sinus: septum; 5. 1st ectoturbinate; 6. 2nd ectoturbinate; 7. 3rd ectoturbinate; 8. Dorsal nasal concha; 9. Middle nasal concha; 10. Ethmoid bone: perpendicular plate; 11. Basisphenoid bone: wing (orbital surface); 12. 3rd endoturbinate; 13. 4th endoturbinate; 14. Presphenoid bone: wing; 15. Presphenoid bone: body; 16. Vomer; 17. Choana; 18. Palatine bone: horizontal and perpendicular plates.
In the sagittal images of the felid skulls, the bone removal of the ethmoturbinates was clearly observed (
Figure 25). Ectoturbinates were observed as a framework of hyperattenuated lines in the frontal sinus. The bony origin of the dorsal and middle nasal conchae and the third and fourth endoturbinates was located in the cribriform plate of the ethmoid bone, which was observed as a thin hyperattenuated vertical line. The ventral nasal concha was observed in the most rostral part; however, in the lion it was not possible to visualize it due to damage to these structures in the fragile skull of this species. The sphenoidal sinus was seen caudal to the fourth endoturbinate, as a single hypoattenuated area.
Figure 25.
Amira representative sagittal multiplanar reconstruction (MPR) CT images at the the level of the nasal cavity and paranasal sinuses, level I. Images are oriented so that the rostral part is to the right and dorsal is at the top. All views are right lateral. (A): Leopard; (B): Lion; (C): Cheetah and (D): Cat. 1. Nasal bone; 2. Frontal bone: external plate; 3. Frontal bone: internal plate; 4. Ethmoid bone: tectorial plate; 5. Frontal sinus; 6. Ectoturbinates (1st, 2nd and 3rd); 7. Dorsal nasal concha; 8. Middle nasal concha; 9. 3rd endoturbinate; 10. 4th endoturbinate; 11. Ventral nasal concha; 12. Ethmoid bone: cribriform plate; 13. Sphenoidal sinus; 14. Presphenoid bone: body; 15. Basisphenoid bone: body; 16. Occipital bone: basilar part; 17. Choana; 18. Incisive bone: palatine process; 19. Maxilla: palatine process; 20. Palatine bone: horizontal plate; 21. Parietal bone; 22. Occipital bone: squama.
Figure 25.
Amira representative sagittal multiplanar reconstruction (MPR) CT images at the the level of the nasal cavity and paranasal sinuses, level I. Images are oriented so that the rostral part is to the right and dorsal is at the top. All views are right lateral. (A): Leopard; (B): Lion; (C): Cheetah and (D): Cat. 1. Nasal bone; 2. Frontal bone: external plate; 3. Frontal bone: internal plate; 4. Ethmoid bone: tectorial plate; 5. Frontal sinus; 6. Ectoturbinates (1st, 2nd and 3rd); 7. Dorsal nasal concha; 8. Middle nasal concha; 9. 3rd endoturbinate; 10. 4th endoturbinate; 11. Ventral nasal concha; 12. Ethmoid bone: cribriform plate; 13. Sphenoidal sinus; 14. Presphenoid bone: body; 15. Basisphenoid bone: body; 16. Occipital bone: basilar part; 17. Choana; 18. Incisive bone: palatine process; 19. Maxilla: palatine process; 20. Palatine bone: horizontal plate; 21. Parietal bone; 22. Occipital bone: squama.
Finally, in the dorsal section (
Figure 26), the ventral nasal concha was visible in the rostrolateral area of the nasal cavity, which extends only to the middle of the cavity; it could be seen laterally in the lion (
Figure 26B). The third endoturbinate embraces the ventral nasal concha and occupies most of the cavity. In these sections, the nasal septum was very well identified in the most rostral area and its continuation as a perpendicular plate of the ethmoid bone in the most caudal area of the nasal cavity (
Figure 26).
Figure 26.
Amira representative dorsal multiplanar reconstruction (MPR) CT images at level of the 3rd and 4th endoturbinates, level I. Images are oriented so that the rostral part is at the top. All views are dorsal. (A): Leopard; (B): Lion; (C): Cheetah and (D): Cat. 1. Incisive bone; 2. Maxilla; 3. Common nasal meatus; 4. Ventral nasal concha; 5. Nasal septum; 6. Zygomatic bone: body; 7. Zygomatic bone: temporal process; 8. 3rd endoturbinate; 9. 4th endoturbinate; 10. Frontal bone: orbital surface; 11. Mandible: ramus; 12. Presphenoid bone: wing; 13. Ethmoid bone: perpendicular plate; 14. Ethmoid bone: cribriform plate; 15. Frontal sinus.
Figure 26.
Amira representative dorsal multiplanar reconstruction (MPR) CT images at level of the 3rd and 4th endoturbinates, level I. Images are oriented so that the rostral part is at the top. All views are dorsal. (A): Leopard; (B): Lion; (C): Cheetah and (D): Cat. 1. Incisive bone; 2. Maxilla; 3. Common nasal meatus; 4. Ventral nasal concha; 5. Nasal septum; 6. Zygomatic bone: body; 7. Zygomatic bone: temporal process; 8. 3rd endoturbinate; 9. 4th endoturbinate; 10. Frontal bone: orbital surface; 11. Mandible: ramus; 12. Presphenoid bone: wing; 13. Ethmoid bone: perpendicular plate; 14. Ethmoid bone: cribriform plate; 15. Frontal sinus.
Through tomographic studies carried out on the heads of felids, 3D reconstruction models were developed using 3D MIP (
Figure 27,
Figure 28,
Figure 29 and
Figure 30) and VR (
Figure 31,
Figure 32,
Figure 33 and
Figure 34) applications. MIP reconstruction techniques allowed us to clearly visualize the internal dimension of each structure of the nasal cavity and paranasal sinuses. Sagittal, transverse, and dorsal views of the four felids were selected.
Starting with the leopard (
Figure 27), the extension of the frontal sinus was observed in the sagittal and transverse planes. In this sinus, the very limited ectoturbinates could be visualized, especially in the transverse image. The dorsal nasal concha was observed throughout its entire length, reaching its maximum dimension in the middle area of the nasal cavity and becoming thinner as it approached its rostral end. The ventral nasal concha was limited to the rostral half of the nasal cavity. With this technique, the extension of the choana could also be clearly seen.
Figure 27.
OsiriX MIP reconstructed CT images of the leopard’s head. (A) Sagittal image. Left lateral view. (B) Transverse image. Caudal view. (C) Dorsal image. Dorsal view. 1. Incisive bone; 2. Nasal bone; 3. Maxilla; 4. Frontal bone: external plate; 5. Frontal bone: internal plate; 6. Frontal bone: orbital surface; 7. Ethmoid bone: tectorial plate; 8. Ethmoid bone: cribriform plate; 9. Frontal sinus; 10. Frontal sinus: septum; 11. 1st ectoturbinate; 12. 2nd ectoturbinate; 13. 3rd ectoturbinate; 14. Dorsal nasal concha; 15. Middle nasal concha; 16. 3rd endoturbinate; 17. 4th endoturbinate; 18. Ventral nasal concha; 19. Ethmoid bone: perpendicular plate; 20. Nasal septum; cartilage; 21. Vomer; 22. Zygomatic bone: body; 23. Sphenoidal sinus; 24. Choana; 25. Palatine bone: horizontal and perpendicular plate; 26. Presphenoid bone.
Figure 27.
OsiriX MIP reconstructed CT images of the leopard’s head. (A) Sagittal image. Left lateral view. (B) Transverse image. Caudal view. (C) Dorsal image. Dorsal view. 1. Incisive bone; 2. Nasal bone; 3. Maxilla; 4. Frontal bone: external plate; 5. Frontal bone: internal plate; 6. Frontal bone: orbital surface; 7. Ethmoid bone: tectorial plate; 8. Ethmoid bone: cribriform plate; 9. Frontal sinus; 10. Frontal sinus: septum; 11. 1st ectoturbinate; 12. 2nd ectoturbinate; 13. 3rd ectoturbinate; 14. Dorsal nasal concha; 15. Middle nasal concha; 16. 3rd endoturbinate; 17. 4th endoturbinate; 18. Ventral nasal concha; 19. Ethmoid bone: perpendicular plate; 20. Nasal septum; cartilage; 21. Vomer; 22. Zygomatic bone: body; 23. Sphenoidal sinus; 24. Choana; 25. Palatine bone: horizontal and perpendicular plate; 26. Presphenoid bone.
Figure 28 represents the MIP reconstruction of the lion’s head. In the sagittal and dorsal planes, the route and dimensions of the ethmoturbinates were observed. The sphenoidal sinus was perfectly located and limited in the sagittal plane, just as the limits of the frontal sinus could be clearly outlined.
Figure 28.
OsiriX MIP reconstructed CT images of the lion’s head. (A) Sagittal image. Left lateral view. (B) Transverse image. Caudal view. (C). Dorsal image. Dorsal view. 1. Incisive bone; 2. Nasal bone; 3. Maxilla; 4. Frontal bone: external plate; 5. Frontal bone: internal plate; 6. Frontal bone: orbital surface; 7. Ethmoid bone: tectorial plate; 8. Ethmoid bone: cribriform plate; 9. Frontal sinus; 10. Frontal sinus: septum; 11. 1st ectoturbinate; 12. 2nd ectoturbinate; 13. 3rd ectoturbinate; 14. Dorsal nasal concha; 15. Middle nasal concha; 16. 3rd endoturbinate; 17. 4th endoturbinate; 18. Ventral nasal concha; 19. Nasal septum: ethmoid bone (perpendicular plate); 20. Nasal septum; cartilage; 21. Vomer; 22. Zygomatic bone: frontal process; 23. Sphenoidal sinus; 24. Choana; 25. Palatine bone: horizontal and perpendicular plate; 26. Presphenoid bone.
Figure 28.
OsiriX MIP reconstructed CT images of the lion’s head. (A) Sagittal image. Left lateral view. (B) Transverse image. Caudal view. (C). Dorsal image. Dorsal view. 1. Incisive bone; 2. Nasal bone; 3. Maxilla; 4. Frontal bone: external plate; 5. Frontal bone: internal plate; 6. Frontal bone: orbital surface; 7. Ethmoid bone: tectorial plate; 8. Ethmoid bone: cribriform plate; 9. Frontal sinus; 10. Frontal sinus: septum; 11. 1st ectoturbinate; 12. 2nd ectoturbinate; 13. 3rd ectoturbinate; 14. Dorsal nasal concha; 15. Middle nasal concha; 16. 3rd endoturbinate; 17. 4th endoturbinate; 18. Ventral nasal concha; 19. Nasal septum: ethmoid bone (perpendicular plate); 20. Nasal septum; cartilage; 21. Vomer; 22. Zygomatic bone: frontal process; 23. Sphenoidal sinus; 24. Choana; 25. Palatine bone: horizontal and perpendicular plate; 26. Presphenoid bone.
The MIP of the cheetah head is represented in
Figure 29. The frontal sinus is considerably larger in this species, as is the sphenoidal sinus, which is proportionally much larger than in the other species examined.
Figure 29.
OsiriX MIP CT reconstruction images of the cheetah’s head. (A) Sagittal image. Left lateral view. (B) Transverse image. Caudal view. (C) Dorsal image. Dorsal view. 1. Incisive bone; 2. Nasal bone; 3. Maxilla; 4. Frontal bone: external plate; 5. Frontal bone: internal plate; 6. Frontal bone: orbital surface; 7. Ethmoid bone: tectorial plate; 8. Ethmoid bone: cribriform plate; 9. Frontal sinus; 10. Frontal sinus: septum; 11. 1st ectoturbinate. 12. 2nd ectoturbinate; 13. 3rd ectoturbinate; 14. Dorsal nasal concha; 15. Middle nasal concha; 16. 3rd endoturbinate; 17. 4th endoturbinate; 18. Ventral nasal concha; 19. Nasal septum: ethmoid bone (perpendicular plate); 20. Nasal septum; cartilage; 21. Vomer; 22. Zygomatic bone: frontal process; 23. Sphenoidal sinus; 24. Choana; 25. Palatine bone: horizontal and perpendicular plates; 26. Presphenoid bone.
Figure 29.
OsiriX MIP CT reconstruction images of the cheetah’s head. (A) Sagittal image. Left lateral view. (B) Transverse image. Caudal view. (C) Dorsal image. Dorsal view. 1. Incisive bone; 2. Nasal bone; 3. Maxilla; 4. Frontal bone: external plate; 5. Frontal bone: internal plate; 6. Frontal bone: orbital surface; 7. Ethmoid bone: tectorial plate; 8. Ethmoid bone: cribriform plate; 9. Frontal sinus; 10. Frontal sinus: septum; 11. 1st ectoturbinate. 12. 2nd ectoturbinate; 13. 3rd ectoturbinate; 14. Dorsal nasal concha; 15. Middle nasal concha; 16. 3rd endoturbinate; 17. 4th endoturbinate; 18. Ventral nasal concha; 19. Nasal septum: ethmoid bone (perpendicular plate); 20. Nasal septum; cartilage; 21. Vomer; 22. Zygomatic bone: frontal process; 23. Sphenoidal sinus; 24. Choana; 25. Palatine bone: horizontal and perpendicular plates; 26. Presphenoid bone.
Finally, the MIP reconstruction of the domestic cat’s head is shown in
Figure 30. The frontal sinus in this species, also proportionally large, deepens to more ventral levels than in the other felids. The ectoturbinates could also be clearly seen in the sagittal and transverse images. Both the path and the width of the nasopharynx (pars nasalis pharyngis) could also be observed extending caudal from the choana.
Figure 30.
OsiriX MIP reconstruction images of the cat’s head. (A) Sagittal image. Left lateral view. (B) Transverse image. Caudal view. (C) Dorsal image. Dorsal view. 1. Incisive bone; 2. Nasal bone; 3. Maxilla; 4. Frontal bone: external plate; 5. Frontal bone: internal plate; 6. Frontal bone: orbital surface; 7. Ethmoid bone: tectorial plate; 8. Ethmoid bone: cribriform plate; 9. Frontal sinus; 10. Frontal sinus: septum; 11. 1st ectoturbinate. 12. 2nd ectoturbinate; 13. 3rd ectoturbinate; 14. Dorsal nasal concha; 15. Middle nasal concha; 16. 3rd endoturbinate; 17. 4th endoturbinate; 18. Ventral nasal concha; 19. Nasal septum: ethmoid bone (perpendicular plate); 20. Nasal septum: cartilage; 21. Vomer; 22. Zygomatic bone: body; 23. Sphenoidal sinus; 24. Choana; 25. Palatine bone: horizontal and perpendicular plate; 26. Presphenoid bone.
Figure 30.
OsiriX MIP reconstruction images of the cat’s head. (A) Sagittal image. Left lateral view. (B) Transverse image. Caudal view. (C) Dorsal image. Dorsal view. 1. Incisive bone; 2. Nasal bone; 3. Maxilla; 4. Frontal bone: external plate; 5. Frontal bone: internal plate; 6. Frontal bone: orbital surface; 7. Ethmoid bone: tectorial plate; 8. Ethmoid bone: cribriform plate; 9. Frontal sinus; 10. Frontal sinus: septum; 11. 1st ectoturbinate. 12. 2nd ectoturbinate; 13. 3rd ectoturbinate; 14. Dorsal nasal concha; 15. Middle nasal concha; 16. 3rd endoturbinate; 17. 4th endoturbinate; 18. Ventral nasal concha; 19. Nasal septum: ethmoid bone (perpendicular plate); 20. Nasal septum: cartilage; 21. Vomer; 22. Zygomatic bone: body; 23. Sphenoidal sinus; 24. Choana; 25. Palatine bone: horizontal and perpendicular plate; 26. Presphenoid bone.
In addition, four OsiriX surface and deep VR reconstruction CT images of the felid’s heads are presented (
Figure 31,
Figure 32,
Figure 33 and
Figure 34). These VR images allowed for the assessment of the external nose and the integrity and the extensions of the bones, enhancing the anatomical understanding of this region.
Figure 31 shows the reconstructed leopard images. The nasal plane and the bony framework that supports the nasal cavity were clearly observed, as well as the boundaries between these bones. In this way, we visualized the frontal and the nasal bones, laterally the maxilla and ventrally the most rostral side of the incisive bone.
Figure 31.
OsiriX 3D reconstructed CT images of the leopard’s head showing the external nares and nasal plane. (A): VR surface reconstruction. Rostral view. (B): VR deep reconstruction. Rostral view. (C) VR deep reconstruction. Right rostrolateral view. a. Root of the nose; b. Dorsum of the nose; c. Tip of the nose; d. Nasal orifice; 1. Nasal bone; 2. Frontal bone; 3. Maxilla; 4. Incisive bone; 5. Nasal cavity; 6. Turbinates.
Figure 31.
OsiriX 3D reconstructed CT images of the leopard’s head showing the external nares and nasal plane. (A): VR surface reconstruction. Rostral view. (B): VR deep reconstruction. Rostral view. (C) VR deep reconstruction. Right rostrolateral view. a. Root of the nose; b. Dorsum of the nose; c. Tip of the nose; d. Nasal orifice; 1. Nasal bone; 2. Frontal bone; 3. Maxilla; 4. Incisive bone; 5. Nasal cavity; 6. Turbinates.
In the lion CT VR images (
Figure 32), we could also observe the external nose and these bones. However, the morphology of these skulls differed from the rest. The short rostral extension of the nasal bone was observed, as well as the convex morphology that the frontal bone acquires. The bone structure was much more compact than in other felines.
Figure 32.
OsiriX 3D reconstructed CT images of the lion’s head showing the external nares and nasal plane. (A): VR surface reconstruction. Rostral view. (B): VR deep reconstruction. Rostral view. (C) VR deep reconstruction. Right rostrolateral view. a. Root of the nose; b. Dorsum of the nose; c. Tip of the nose; d. Nasal orifice; 1. Nasal bone; 2. Frontal bone; 3. Maxilla; 4. Incisive bone; 5. Nasal cavity; 6. Turbinates.
Figure 32.
OsiriX 3D reconstructed CT images of the lion’s head showing the external nares and nasal plane. (A): VR surface reconstruction. Rostral view. (B): VR deep reconstruction. Rostral view. (C) VR deep reconstruction. Right rostrolateral view. a. Root of the nose; b. Dorsum of the nose; c. Tip of the nose; d. Nasal orifice; 1. Nasal bone; 2. Frontal bone; 3. Maxilla; 4. Incisive bone; 5. Nasal cavity; 6. Turbinates.
In the reconstruction of the cheetah’s head (
Figure 33), the limit between the frontal and nasal bones was not so pronounced. The frontal bone in the cheetah was completely concave, unlike the lion.
Figure 33.
OsiriX 3D reconstructed CT images of the cheetah’s head showing the external nares and nasal plane. (A): VR surface reconstruction. Rostral view. (B): VR deep reconstruction. Rostral view. (C) VR deep reconstruction. Right rostrolateral view. a. Root of the nose; b. Dorsum of the nose; c. Tip of the nose; d. Nasal orifice; 1. Nasal bone; 2. Frontal bone; 3. Maxilla; 4. Incisive bone; 5. Nasal cavity; 6. Turbinates.
Figure 33.
OsiriX 3D reconstructed CT images of the cheetah’s head showing the external nares and nasal plane. (A): VR surface reconstruction. Rostral view. (B): VR deep reconstruction. Rostral view. (C) VR deep reconstruction. Right rostrolateral view. a. Root of the nose; b. Dorsum of the nose; c. Tip of the nose; d. Nasal orifice; 1. Nasal bone; 2. Frontal bone; 3. Maxilla; 4. Incisive bone; 5. Nasal cavity; 6. Turbinates.
Finally, the VR reconstruction of the domestic cat skull (
Figure 34) showed that the bone limits were not as noticeable as in the leopard or cheetah. The frontal bone represents a large extension since its zygomatic process developed very laterally, unlike in big felids.
Figure 34.
OsiriX 3D reconstructed CT images of the cat’s head showing the external nares and nasal plane. (A): VR surface reconstruction. Rostral view. (B): VR deep reconstruction. Rostral view. (C) VR deep reconstruction. Right rostrolateral view. a. Root of the nose; b. Dorsum of the nose; c. Tip of the nose; d. Nasal orifice; 1. Nasal bone; 2. Frontal bone; 3. Maxilla; 4. Incisive bone; 5. Nasal cavity; 6. Turbinates.
Figure 34.
OsiriX 3D reconstructed CT images of the cat’s head showing the external nares and nasal plane. (A): VR surface reconstruction. Rostral view. (B): VR deep reconstruction. Rostral view. (C) VR deep reconstruction. Right rostrolateral view. a. Root of the nose; b. Dorsum of the nose; c. Tip of the nose; d. Nasal orifice; 1. Nasal bone; 2. Frontal bone; 3. Maxilla; 4. Incisive bone; 5. Nasal cavity; 6. Turbinates.
3.5. 3D Prints
The 3D printing of the feline skulls made it possible to create different molds that were very similar to the anatomy of the live animal (
Figure 35,
Figure 36,
Figure 37 and
Figure 38). In this way, we obtained molds of the bony nasal cavity of the leopard, lion, cheetah and domestic cat. These molds were printed with a sagittal section to permit visualization of the entire course of the bone structures in the nasal cavity and a transverse section through the middle of the nasal cavity. The four species studied have different bone densities, and that is why the printed molds of each species had different textures.
Figure 35 shows the 3D printing of the leopard’s nasal cavity. In this mold, we observed the three ectoturbinates in the frontal sinus in the transverse plane. On the sagittal view, the sphenoidal sinus could be seen and only the first and second ectoturbinates could be observed since the third develops more laterally. The endoturbinates could be perfectly visualized along their entire length. Furthermore, the rostral view of the nasal cavity presented in the preparation allowed for the observation of the dorsal nasal concha upon arrival at the nasal vestibule, as well as the ventral nasal concha. This only reached the rostral half of the nasal cavity. Except for the ventral nasal concha (in a rostral position), the rest of the endoturbinates were seen as arising from the ethmoid bone, specifically its cribriform plate. Furthermore, with this mold we could also identify the bones that limit the nasal cavity externally, identifying the zygomatic bone and its temporal and frontal processes as well as the zygomatic process of the frontal bone.
The infraorbital canal was clearly seen.
Figure 35.
OsiriX 3D printing images of the leopard’s head at the level of the nasal cavity and paranasal sinuses. (A) Rostral view so that the dorsal is at the top. (B) Left lateral view so that the rostral part is to the left and the dorsal is at the top. 1. Nasal bone; 2. Frontal bone: external plate; 3. Frontal bone: zygomatic process; 4. Frontal bone: internal plate; 5. Ethmoid bone: cribriform plate; 6. Zygomatic bone: body; 7. Zygomatic bone: temporal process; 8. Zygomatic bone: frontal process; 7. Maxilla; 10. Maxilla: palatine process; 11. Palatine bone: perpendicular and horizontal plates; 12. Presphenoid bone: body; 13. Choana; 14. Frontal sinus; 15. Ethmoid bone: tectorial plate; 16. 1st ectoturbinate; 17. 2nd ectoturbinate; 18. 3rd ectoturbinate; 19. Dorsal nasal concha; 20. Middle nasal concha; 21. 3rd endoturbinate; 22. 4th endoturbinate; 23. Ventral nasal concha; 24. Sphenoidal sinus; 25. Maxillary recess; 26. Vomer; 27. Cerebral fossa; 28. Infraorbital canal.
Figure 35.
OsiriX 3D printing images of the leopard’s head at the level of the nasal cavity and paranasal sinuses. (A) Rostral view so that the dorsal is at the top. (B) Left lateral view so that the rostral part is to the left and the dorsal is at the top. 1. Nasal bone; 2. Frontal bone: external plate; 3. Frontal bone: zygomatic process; 4. Frontal bone: internal plate; 5. Ethmoid bone: cribriform plate; 6. Zygomatic bone: body; 7. Zygomatic bone: temporal process; 8. Zygomatic bone: frontal process; 7. Maxilla; 10. Maxilla: palatine process; 11. Palatine bone: perpendicular and horizontal plates; 12. Presphenoid bone: body; 13. Choana; 14. Frontal sinus; 15. Ethmoid bone: tectorial plate; 16. 1st ectoturbinate; 17. 2nd ectoturbinate; 18. 3rd ectoturbinate; 19. Dorsal nasal concha; 20. Middle nasal concha; 21. 3rd endoturbinate; 22. 4th endoturbinate; 23. Ventral nasal concha; 24. Sphenoidal sinus; 25. Maxillary recess; 26. Vomer; 27. Cerebral fossa; 28. Infraorbital canal.
The 3D printing of the lion’s head (
Figure 36) in the transverse plane allowed for the observation of all the ectoturbinates and endoturbinates. In the sagittal plane, the origin of the ectoturbinates and endoturbinates was seen. In addition, the tentorium of the cerebellum was very well ossified and large in size.
Figure 36.
OsiriX 3D printing images of the lion’s head at the level of the nasal cavity and paranasal sinuses. (A) Rostral view so that the dorsal is at the top. (B) Left lateral view so that the rostral part is to the left and the dorsal is at the top. (C) Right lateral view so that the rostral part is to the right and the dorsal is at the top. 1. Nasal bone; 2. Frontal bone: external plate; 3. Frontal bone: zygomatic process; 4. Frontal bone: internal plate; 5. Frontal bone: orbital surface; 6. Temporal bone: squamous part; 7. Temporal bone: zygomatic process; 8. Mandible: ramus; 9. Mandible: angular process; 10. Parietal bone; 11. Occipital bone: nuchal crest; 12. Occipital bone: external occipital protuberance; 13. Occipital bone: squamous part; 14. Osseous tentorium of the cerebellum; 15: Occipital bone: basilar part; 16. Basisphenoid bone: body; 17. Frontal sinus; 18: Frontal sinus: septum; 19. 1st ectoturbinate; 20. 2nd ectoturbinate; 21. 3rd ectoturbinate; 22. Ethmoid bone: tectorial plate; 23. Nasal septum: cartilage; 24. Dorsal nasal concha; 25. Middle nasal concha; 26. 3rd endoturbinate; 27. 4th endoturbinate; 28. Cerebral fossa; 29. Cerebellar fossa.
Figure 36.
OsiriX 3D printing images of the lion’s head at the level of the nasal cavity and paranasal sinuses. (A) Rostral view so that the dorsal is at the top. (B) Left lateral view so that the rostral part is to the left and the dorsal is at the top. (C) Right lateral view so that the rostral part is to the right and the dorsal is at the top. 1. Nasal bone; 2. Frontal bone: external plate; 3. Frontal bone: zygomatic process; 4. Frontal bone: internal plate; 5. Frontal bone: orbital surface; 6. Temporal bone: squamous part; 7. Temporal bone: zygomatic process; 8. Mandible: ramus; 9. Mandible: angular process; 10. Parietal bone; 11. Occipital bone: nuchal crest; 12. Occipital bone: external occipital protuberance; 13. Occipital bone: squamous part; 14. Osseous tentorium of the cerebellum; 15: Occipital bone: basilar part; 16. Basisphenoid bone: body; 17. Frontal sinus; 18: Frontal sinus: septum; 19. 1st ectoturbinate; 20. 2nd ectoturbinate; 21. 3rd ectoturbinate; 22. Ethmoid bone: tectorial plate; 23. Nasal septum: cartilage; 24. Dorsal nasal concha; 25. Middle nasal concha; 26. 3rd endoturbinate; 27. 4th endoturbinate; 28. Cerebral fossa; 29. Cerebellar fossa.
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The 3D printing of the cheetah’s head (
Figure 37) showed, in the same way as mentioned above, a frontal sinus of large proportions and a clear sphenoidal sinus. Furthermore, between the lateral aspect of the ventral nasal concha and the maxilla, the maxillary recess was observed.
Figure 37.
OsiriX 3D printing of the cheetah’s head at the level of the nasal cavity and paranasal sinuses. (A) Rostral view so that the dorsal is at the top. (B) Left lateral view so that the rostral part is to the left and the dorsal is at the top. (C) Right lateral view so that the rostral part is to the right and the dorsal is at the top. 1. Nasal bone; 2. Frontal bone: external plate; 3. Frontal bone: zygomatic process; 4. Frontal bone: internal plate; 5. Frontal bone: orbital surface; 6. Temporal bone: squamous part; 7. Temporal bone: zygomatic process; 8. Mandible: ramus; 9. Mandible: angular process; 10. Mandible: coronoid process; 11. Parietal bone; 12. Occipital bone: nuchal crest; 13. Occipital bone: external occipital protuberance; 14. Occipital bone: squama; 15. Osseous tentorium of the cerebellum; 16: Occipital bone: basilar part; 17. Basisphenoid bone: body; 18. Frontal sinus; 19: Frontal sinus: septum; 20. 1st ectoturbinate; 21. 2nd ectoturbinate; 22. 3rd ectoturbinate; 23. Ethmoid bone: tectorial plate; 24. Nasal septum: cartilage; 25. Dorsal nasal concha; 26. Middle nasal concha; 27. 3rd endoturbinate; 28. 4th endoturbinate; 29. Ventral nasal concha; 30. Sphenoidal sinus; 31. Maxillary recess; 32. Incisive bone: palatine process; 33. Maxilla: palatine process; 34. Palatine bone: horizontal and perpendicular plates; 35. Cerebral fossa; 36. Cerebellar fossa.
Figure 37.
OsiriX 3D printing of the cheetah’s head at the level of the nasal cavity and paranasal sinuses. (A) Rostral view so that the dorsal is at the top. (B) Left lateral view so that the rostral part is to the left and the dorsal is at the top. (C) Right lateral view so that the rostral part is to the right and the dorsal is at the top. 1. Nasal bone; 2. Frontal bone: external plate; 3. Frontal bone: zygomatic process; 4. Frontal bone: internal plate; 5. Frontal bone: orbital surface; 6. Temporal bone: squamous part; 7. Temporal bone: zygomatic process; 8. Mandible: ramus; 9. Mandible: angular process; 10. Mandible: coronoid process; 11. Parietal bone; 12. Occipital bone: nuchal crest; 13. Occipital bone: external occipital protuberance; 14. Occipital bone: squama; 15. Osseous tentorium of the cerebellum; 16: Occipital bone: basilar part; 17. Basisphenoid bone: body; 18. Frontal sinus; 19: Frontal sinus: septum; 20. 1st ectoturbinate; 21. 2nd ectoturbinate; 22. 3rd ectoturbinate; 23. Ethmoid bone: tectorial plate; 24. Nasal septum: cartilage; 25. Dorsal nasal concha; 26. Middle nasal concha; 27. 3rd endoturbinate; 28. 4th endoturbinate; 29. Ventral nasal concha; 30. Sphenoidal sinus; 31. Maxillary recess; 32. Incisive bone: palatine process; 33. Maxilla: palatine process; 34. Palatine bone: horizontal and perpendicular plates; 35. Cerebral fossa; 36. Cerebellar fossa.
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Finally, in the bony nasal cavity of the cat (
Figure 38), the bony limits of the frontal sinus were very well identified, the roof being represented by the external plate of the frontal bone, the lateral wall by the orbital surface of the frontal bone, the caudal limit by the internal plate of the frontal bone and the floor by the tectorial plate of the ethmoid bone. Both ectoturbinates and endoturbinates could be seen in these molds. It was also observed that the great lateral development of the zygomatic process of the frontal bone, as well as that of the frontal process of the zygomatic bone, were very close to merging, unlike the other species studied. Finally, this 3D printing showed that the ventral nasal concha was embraced medially by the large extension of the third endoturbinate.
Figure 38.
OsiriX 3D printing of the cat’s head at the level of the nasal cavity and paranasal sinuses. (A) Rostral view so that the dorsal is at the top. (B) Left lateral view so that the rostral part is to the left and the dorsal is at the top. (C) Right lateral view so that the rostral part is to the right and the dorsal is at the top. 1. Nasal bone; 2. Frontal bone: external plate; 3. Frontal bone: zygomatic process; 4. Frontal bone: internal plate; 5. Frontal bone: orbital surface; 6. Temporal bone: squamous part; 7. Temporal bone: zygomatic process; 8. Mandible: ramus (sectioned); 9. Parietal bone; 10. Occipital bone: nuchal crest; 11. Occipital bone: external occipital protuberance; 12. Occipital bone: squama; 13. Osseous tentorium of the cerebellum; 14: Occipital bone: basilar part; 15. Basisphenoid bone: body; 16. Presphenoid bone: body; 17. Frontal sinus; 18: Frontal sinus: septum; 19. 1st ectoturbinate; 20. 2nd ectoturbinate; 21. 3rd ectoturbinate; 22. Ethmoid bone: tectorial plate; 23. Nasal septum: cartilage; 24. Dorsal nasal concha; 25. Middle nasal concha; 26. 3rd endoturbinate; 27. 4th endoturbinate; 28. Ventral nasal concha; 29. Sphenoidal sinus; 30. Maxilla: palatine process; 31. Palatine bone: horizontal and perpendicular plates; 32. Cerebral fossa; 33. Cerebellar fossa.
Figure 38.
OsiriX 3D printing of the cat’s head at the level of the nasal cavity and paranasal sinuses. (A) Rostral view so that the dorsal is at the top. (B) Left lateral view so that the rostral part is to the left and the dorsal is at the top. (C) Right lateral view so that the rostral part is to the right and the dorsal is at the top. 1. Nasal bone; 2. Frontal bone: external plate; 3. Frontal bone: zygomatic process; 4. Frontal bone: internal plate; 5. Frontal bone: orbital surface; 6. Temporal bone: squamous part; 7. Temporal bone: zygomatic process; 8. Mandible: ramus (sectioned); 9. Parietal bone; 10. Occipital bone: nuchal crest; 11. Occipital bone: external occipital protuberance; 12. Occipital bone: squama; 13. Osseous tentorium of the cerebellum; 14: Occipital bone: basilar part; 15. Basisphenoid bone: body; 16. Presphenoid bone: body; 17. Frontal sinus; 18: Frontal sinus: septum; 19. 1st ectoturbinate; 20. 2nd ectoturbinate; 21. 3rd ectoturbinate; 22. Ethmoid bone: tectorial plate; 23. Nasal septum: cartilage; 24. Dorsal nasal concha; 25. Middle nasal concha; 26. 3rd endoturbinate; 27. 4th endoturbinate; 28. Ventral nasal concha; 29. Sphenoidal sinus; 30. Maxilla: palatine process; 31. Palatine bone: horizontal and perpendicular plates; 32. Cerebral fossa; 33. Cerebellar fossa.
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