Question | Answer |
Adult derivative of the 1st pharyngeal pouch | Inner portion of ear and Euctacian tube. (1st pharyngeal membrane becomes the tympanic membrane). |
Adult derivative of the 2nd pharyngeal pouch | BED for the palatine tonsil (immune tissue will migrate here). |
Adult derivative of the 3rd pharyngeal pouch | Dorsal expansion: inferior parathyroid gland.
Ventral expansion: Thymus |
Adult derivative of the 4th pharyngeal pouch | Dorsal expansion: Superior parathyroid gland.
Ventral expansion: Ultimopharyngeal body (C-cells)
**These very important in calcium regulation |
Adult derivative of the 1st pharyngeal groove | External auditory meatus and ear. |
Adult derivative of the 2nd-4th pharyngeal grooves | Cervical sinus. If it fails to obliterate during development it can result in a brachial sinus, cyst, or fistula. |
Brachial Sinus | failure of the cervical sinus to obliterate. Forms a blind sac that can either be external or internal (if internal Palatosis can occur due to food entrapment and rotting) |
Brachial Cyst | Form if cervical sinus fails to obliterate. They are isolated, fluid-filled sacs that do not open to either skin or pharynx |
Brachial Fistula | forms if cervical sinus fails to obliterate. connects the skin to the pharynx. Both sides are open and pt will present with discharge |
Foramen cecum | Origin of the Thyroid glad. located between the anterior 2/3 and posterior 1/3 of the tongue. Descends downward through the thyroglossal duct. |
Pyramidal lobe of the Thyroid | Central lobe extending from the isthmus that is a vestigal remnant of the thyroids migration down the thyroglossal duct. |
Adult derivative of the Truncus Arteriosus | Proximal aorta and pulmonary trunk |
Adult derivative of the Aortic sac | Ascending Aorta and R Brachiocephalic trunk |
Adult derivative of the 1st and 2nd Aortic Arches | Who Cares! GET UM OUTA HERE |
Adult derivative of the 3rd Aortic Arch | L and R common carotid A and internal carotid A |
Adult derivative of the 4th aortic arch | Right side: R subclavian Artery.
Left side: part of aortic arch. |
Adult derivative of the 5th aortic arch | Not in humans, GET UM OUTA HERE |
Adult derivative of the 6th aortic arch | Right: Right pulmonary artery.
Left: Left pulmonary artery and ductus arteriosus (ligamentum arteriosum) |
Adult derivative of the Dorsal Aorta | Right: becomes part of the R subclavian A.
Left: Becomes the aortic arch and descending aorta. |
6th Aortic arch and Dorsal Aorta's developmental effect on the Recurrent Laryngeal N. | The recurrent Lary. Ns wrap aroudn dorsal aorta on both sides. Since the dorsal aorta diminishes on the right side while the left grows into the aortic arch and descending aorta, the R recurrent Larygeal loops around the next arch above: 4th |
What is the most common VASCULAR abnormality | Patent Ductus Arteriosus (PDA). allows oxygen rich blood to flow from high pressured aortic arch to the pulmonary trunk.
**Due to a 6th Arch defect |
Pre-ductal coarctation | Ductus arteriosus remains patent b/c it is the only blood supply to the lower body. The coarctation occurs prox to the ductus arteriosus, just dist to L subclav. Pt will have bounding upper ext. pulses w/ redness. Absent lower extremity pulses w/ cyanosis |
Post-ductal coarctation | Occurs distal to L subclav and ductus arteriosus. Int thoracic A (off the subclav) and the Ant/post intercostal arteries reroute blood so it can reach the lower extremity. Pt will have similar pulses as pre-ductal but there will be not cyanosis. |
Bilateral Dorsal Aortae obliteration | The R and L common Carotids will receive oxygenated Blood while the Descending aorta will receieve unoxygentaed blood from the pulmonary trunk.**ductus arteriosus remains patent to connect the Pul trunk to desc aorta. |
Double Aortic Arch | If the R dorsal aorta doesnt stop at the 7th intersegmental artery, it will migrate left to join the descending aorta.
**this will cause problems wiwth tracheal and esophageal development. |
Bones and Musculature of the 1st Pharyngeal Arch | All the muscles innervated by CN V3:
1.temporalis.
2.Masseter.
3.Medial pterygoid.
4.Lateral pterygoid.
5.tensor veli palatini.
6.tensor tempani.
7.Mylohyoid.
8.Ant belly of digastric.
Bones(from Meckle's cart): Maxilla, malleus, incus |
Bones and Musculature of the 2 Pharyngeal Arch | All the muscles innervated by CN VII:
1.Muscles of facial expression.
2.stapedius.
3.stylohyoid.
4.Post belly of digastric.
Bones: stapes, styloid |
Bones and Musculature of the 3rd Pharyngeal Arch | Innervated by CN IX: Stylopharyngeus.
Bones: Body and greater horn of hyoid bone. |
Bones and Musculature of the 4th Pharyngeal Arch | Innervated by CN X: Muscles of the pharynx and soft palate.
**Laryngeal cartilage |
Bones and Musculature of the 6th Pharyngeal Arch | Innervated by CN X recurrent fibers: Muscles of speech.
**Laryngeal cartilage |
Stomodeum | Facial orifice during development |
Nasal Placodes | Form nostrils |
Frontonasal pominence and mandibular prominence fusion | Necessray to completely form the mouth and palate. Both medial and lateral nasal prominence must fuse with the maxillary prominenece |
Intermaxillary segment | Formed by fusion of the medial nasal prominence and maxillary prominence.
**Failure leads to unilateral cleft lip |
Nasolacrimal groove | Formed by fusion of the lateral nasal prominence and maxillary prominence. |
Holoprosencephaly | Frontonasal prominence was unable to descend, so it protrudes above the eyes. |
Frontonasal prominence forms: | Forehead, lateral and medial nasal prominences |
Philtrum of the lip | Formed by the fusion of the R & L medial nasal prominences. **this fusion also gives rise to the incisors and anterior hard palate |
Auricles | Form from 6 auricular hillocks of the 1st and 2nd pharyngeal arches (3 and 3). |