Flashcards in Embryology of Head Deck (15)
What bones form the neurocranium? How are they formed?
Frontal, parietal, squamous portion of temporal, interparietal portion of occipital
What bones form the viscerocranium? How are they formed?
Facial bones: intramembranous ossification
Ossicles, hyoid: endochondral ossification
What bones form the cranial base? How are they formed?
Ethmoid, sphenoid, petrous portion of temporal, occipital
What is the spheno-occipital synchondrosis and when does it close?
A fibrous joint between the sella turcica part of the sphenoid and the occipital bone. Allows longitudinal growth. Fuses around 15-17 years.
What is the cranial base angle and how does it affect face shape?
The angle between sphenoid and occipital bones.
Predicts the position of the mandible:
large angle associated wtih square jaws and overbites
small angle associated with wide angled mandibles and mandibular protrusion
What type of cells converge in the pharyngeal arches?
Mesenchyme and neural crest cells
What types of tissues do the cells in the pharyngeal arches produce?
Cartilage that may remain cartilage or ossify
Artery (aortic arch)
What are the key nerve, muscle, and bony/cartilage structures associated with the mandibular arch?
Mandible, maxilla, zygoma, malleus, incus, squamous temporal
Muscles of mastication, anterior digastric, tensors tympani and palati
What are the main pharyngeal arches?
Mandibular, hyoid, third, and fourth
What are the key nerve, muscle, and bony/cartilage structures associated with the hyoid arch?
Styloid process, hyoid, stapes
Muscles of facial expression, posterior digastric, stylohyoid, stapedius
What are the key nerve, muscle, and bony/cartilage structures associated with the third arch?
What are the key nerve, muscle, and bony/cartilage structures associated with the fourth arch?
Describe the structures that arise from the pharyngeal grooves and pouches, including any migrations.
1: external auditory meatus
1: tympanic cavity & auditory tube
2: palatine tonsil
3: thymus and parathyroid glands, migrate down into the neck
4: parathyroid and C cells of thyroid, migrate down into the neck
Describe the development and migration of the thyroid gland
Descends from the base of the tongue through foramen cecum and thyroglossal duct, around the front of the hyoid to its final position anterior to the larynx.