Fosse temporale

Synapsid:

Synapsids evolved from basal amniotes and are one of the two major groups of amniotes, the other being the sauropsids, the group that includes reptiles and birds. The distinctive temporal fenestra developed in the ancestral synapsid about 312 million years ago, during the Late Carboniferous period.

(...) Synapsids evolved a temporal fenestra behind each eye orbit on the lateral surface of the skull. It may have provided new attachment sites for jaw muscles. A similar development took place in the diapsids, which evolved two rather than one opening behind each eye. Originally, the openings in the skull left the inner cranium covered only by the jaw muscles, but in higher therapsids and mammals, the sphenoid bone has expanded to close the opening. This has left the lower margin of the opening as an arch extending from the lower edges of the braincase.


Les fosses temporales, ou fenêtres temporales, sont des ouvertures présentes dans les crânes de certains amniotes. Elles allègent considérablement le crâne et permettent aussi l'insertion de muscles qui actionnent la mandibule (la mâchoire inférieure). La contribution des différents os à la bordure de ces fenêtres varie selon les groupes considérés.

Différents termes servent à classer les crânes d'amniotes, selon le nombre et la position des fenêtres temporales : anapside, synapside, euryapside et diapside. 

(...) Chez certains amniotes, le crâne est percé d'une fenêtre temporale inférieure : il s'agit d'une configuration synapside. 


yes, there is an anatomical homologue of temporal fenestra in humans (and to the best of my knowledge, in all the extant mammals), and no, it's not the zygomatic arch (...) The temporal fenestra in mammals is reduced to a rather small opening (about 1x1 cm in humans) situated close to the fissure between the posterior part of maxilla (tuber maxillae) and lateral parts of the sphenoid bone (processus pterygoideus). The superior end of this "fissure" is actually the lateral opening of the pterygopalatine fossa and this opening is (the remnant of) the synapsid temporal fenestra.


If you take a look at any depiction of a "phylotypic" synapsid skull, you will notice that the temporal fenestra is situated right behind the postorbital (and partially jugal) bone. In humans, the postorbital bone became known as the frontal process of the zygomatic bone, and right behind it you can clearly see the opening of the pterygopalatine fossa, i.e. temporal fossa of the synapsides."




In human anatomy, the pterygopalatine fossa (sphenopalatine fossa) is a fossa in the skull. A human skull contains two pterygopalatine fossae—one on the left side, and another on the right side. Each fossa is a cone-shaped paired depression deep to the infratemporal fossa and posterior to the maxilla on each side of the skull, located between the pterygoid process and the maxillary tuberosity close to the apex of the orbit. It is the indented area medial to the pterygomaxillary fissure leading into the sphenopalatine foramen. It communicates with the nasal and oral cavities, infratemporal fossa, orbit, pharynx, and middle cranial fossa through eight foramina.[

(...) The pterygopalatine fossa contains

-the pterygopalatine ganglion suspended by nerve roots from the maxillary nerve

-the terminal third of the maxillary artery

-the maxillary nerve (CN V2, the second division of the trigeminal nerve), with which is the nerve of the pterygoid canal, a combination of the greater petrosal nerve (preganglionic parasympathetic) and the deep petrosal nerve (postganglionic sympathetic). To obtain block anesthesia of the entire second division of the trigeminal nerve, an intraoral injection can be administered into this area.





Aucun commentaire:

Enregistrer un commentaire