Search results
Results from the WOW.Com Content Network
Meckel's cartilage arises from the first pharyngeal arch. The dorsal end of each cartilage is connected with the ear-capsule and is ossified to form the malleus ; the ventral ends meet each other in the region of the mandibular symphysis , and are usually regarded as undergoing ossification to form that portion of the mandible which contains ...
The face and neck development of the human embryo refers to the development of the structures from the third to eighth week that give rise to the future head and neck.They consist of three layers, the ectoderm, mesoderm and endoderm, which form the mesenchyme (derived form the lateral plate mesoderm and paraxial mesoderm), neural crest and neural placodes (from the ectoderm). [1]
Premaxilla, maxilla, mandible (only as a model for mandible not actual formation of mandible), zygomatic bone, part of the temporal bone, [19] the incus, and the malleus of the middle ear, also Meckel's cartilage and the sphenomandibular ligament. Trigeminal nerve (part of V2 [20] and V3) Maxillary artery, external carotid artery, Vidian artery
The theory of recapitulation, also called the biogenetic law or embryological parallelism—often expressed using Ernst Haeckel's phrase "ontogeny recapitulates phylogeny"—is a historical hypothesis that the development of the embryo of an animal, from fertilization to gestation or hatching (), goes through stages resembling or representing successive adult stages in the evolution of the ...
The number of vertebrae in a region can vary but overall the number remains the same. In a human spinal column, there are normally 33 vertebrae. [3] The upper 24 pre-sacral vertebrae are articulating and separated from each other by intervertebral discs, and the lower nine are fused in adults, five in the sacrum and four in the coccyx, or tailbone.
Help; Learn to edit; Community portal; Recent changes; Upload file; Special pages
The spinal cord is an extension of the brain. The spinal cord and the brain stem are joined at the base of the cranium at the foramen magnum. Most of the functions of the head and neck are directly influenced by the brain and transmitted to the PNS via the cranial nerves and spinal nerves of the cervical portion of the spine.
After formation of the tube, the brain forms into three sections; the hindbrain, the midbrain, and the forebrain. The types of neuroectoderm include: Neural crest. pigment cells in the skin; ganglia of the autonomic nervous system; dorsal root ganglia. facial cartilage; aorticopulmonary septum of the developing heart and lungs; ciliary body of ...