| primitive ridge | One of the paired ridge's on either side of the primitive groove. (05 Mar 2000) |
|---|---|
| primitive streak | An ectodermal ridge in the midline at the caudal end of the embryonic disk from which arises the intraembryonic mesoderm; achieved by inward and then lateral migration of cells; in human embryos, it appears on day 15 and gives a cephalocaudal axis to the developing embryo. Synonym: germinal streak. (05 Mar 2000) |
| secondary palate | The posterior portion of the embryonic palate, which forms from the palatal processes of the embryonic maxilla and develops into the hard palate. (05 Mar 2000) |
| soft palate | The muscular part of the roof of the mouth. The soft palate is directly behind the hard palate. It lacks bone and so is soft. (12 Dec 1998) |
| neuroectodermal tumour, primitive | A malignant brain tumour sharing common features and biologic properties with medulloblastoma. Some pathologists and clinicians use the terms interchangeably: they both can disseminate throughout the nervous system and, in some cases, systemically. most lesions arise from the posterior fossa in children under five years of age. The tumour often produces hydrocephalus and symptoms of increased intracranial pressure. Papilledema is often present. (12 Dec 1998) |
| tensor muscle of soft palate | <anatomy> Tensor muscle of soft palate, musculus tensor palati; musculus palatosalpingeus; musculus sphenosalpingostaphylinus; dilator tubae; origin, scaphoid fossa of sphenoid, cartilaginous and membranous part of auditory (eustachian) tube and spine of sphenoid; insertion, posterior border of hard palate and aponeurosis of soft palate; action, tenses the soft palate; contributes to opening of auditory tube; nerve supply, branches of trigeminal nerve through the otic ganglion. Synonym: musculus tensor veli palatini, dilator tubae, musculus palatosalpingeus, musculus sphenosalpingostaphylinus, musculus tensor palati, palatosalpingeus, tensor muscle of soft palate. (05 Mar 2000) |
| elevator muscle of soft palate | <anatomy, muscle> Origin, apex of petrous portion of temporal bone and lower part of cartilaginous auditory (eustachian) tube; insertion, aponeurosis of soft palate; action, raises soft palate; through the expansion of its fleshy belly during contraction, it helps to "push" open the auditory tube; nerve supply, pharyngeal plexus (cranial root of accessory nerve). Synonym: musculus levator veli palatini, elevator muscle of soft palate, levator palati muscle, musculus levator palati, musculus petrostaphylinus. (05 Mar 2000) |
| falling palate | Relaxation or elongation of the uvula. Synonym: falling palate, staphylodialysis, staphyloptosis, uvulaptosis. Origin: uvulo-+ G. Ptosis, a falling (05 Mar 2000) |