Embryology Key Concepts

• Radiation to the oral roof requires a differential diagnosis.
• Arterial blood supply and nuclei are visible on arteriograms and diffusion tensor imaging (DTI).

Embryology

• A baby with bluish discoloration due to tricuspid atresia has issues stemming from the right endocardial cushion's failure to properly form the atria.
• Abnormal development of the prosencephalon results in a single large ventricle and fused single thalamus.
• The metencephalon forms the cerebellum.
• During development, radial glial processes facilitate neuroblast migration into specified areas.
• Failure of the urethral folds to fuse results in urine exiting from under the penis' surface.
• A coloboma indicates incomplete fusion of the choroid of the retina.
• Fetal alcohol syndrome has recognizable facial features.
• SHH is essential for signaling in the Zone of Polarizing Activity (ZPA).
• Failure of the physiological herniation to return results in omphalocele.
• Bowel loops are covered with amnion, not peritoneum.
• Muscles derived from the epimere include the erector spinae.
• Myelomeningocele is associated with Spina Bifida, due to failure of the spinal cord to close
• The 4th pharyngeal pouch forms the superior parathyroid gland.
• Ductus arteriosus becomes the ligamentum arteriosum.
• Pyloric stenosis presents with a palpable knot at the gastric margin.
• The diencephalon gives rise to the retina.
• Rubella exposure during weeks 3-8 of pregnancy (organogenesis) leads to complications like cataracts.
• Gastroschisis is a lateral fold defect.

Anatomy

• Pelvic splanchnic nerves are necessary for pelvic vasodilation and are required for erection.

• Chordae tendineae prevent regurgitation of the mitral valve.

• Vessels are contained within the suspensory ligament of the ovary.

• The ureter is inferior to the uterine artery in proximity.

• The pelvic diaphragm consists of the coccygeus and levator ani muscles.

• The zone most affected by prostate cancer is the peripheral zone.

• Testicular cancer spreads to the para-aortic lymph nodes.

• Normal, quiet respiration requires the diaphragm.

• A murmur in the right 2nd intercostal space (ICS) is due to the aortic semilunar valve.

• Pneumonia in the midaxillary line within the 4th ICS involves the medial lobe.

• Pneumonia in the 5th ICS to the side involves the mitral valve.

• The inferior epigastric vessels form the lateral border of Hesselbach's triangle.

• The ilioinguinal nerve passes through the roof of the superficial inguinal ring.

• The ligamentum venosum and IVC are boundaries of the caudate lobe.

• The splenic artery is posterior to the stomach.

• Compression of the common bile duct results in obstructive jaundice.

• It can be caused by the major duodenal papilla/the head of the pancreas.

• The layers of the vessels from superficial to deep are skin, superficial fascia, external intercostal muscle, internal intercostal muscle.

• Morrison's pouch is the hepatorenal recess.

• Damage to the radial nerve causes inability to extend the wrist.

• The "dangerous area of the face" is near the ophthalmic nerve

• Damage to posterior rami paralyzes the erector spinae.

• Frey's syndrome involves the auriculotemporal nerve.

• Winged scapula results from damage to the thoracodorsal nerve, which innervates the serratus anterior muscle.

• Nodes in the 11 o'clock position are among the first to receive lymphatic drainage from the breast.

• Difficulty supinating the arm results from biceps brachii damage.

• The superior thyroid artery runs with the external laryngeal nerve.

• The internal laryngeal nerve passes through the piriform fossa.

• Located in the anterior inferior nasal septum, Kiesselbach's plexus is a common site of nosebleeds.

• The great auricular nerve innervates the ear lobe.

• Tibial nerve provides innervation to the plantar surface of the foot.

• The 1st lumbrical is innervated by the medial plantar nerve

• The 2nd-4th lumbricals are innervated by the lateral plantar nerve.

• Lateral cricoarytenoid closes the rima glottidis by adducting the vocal cords.

• Whispering uses the thyroarytenoid muscle.

• The posterior cricoarytenoid (PCA) abducts the vocal cords.

• Damage to the external branch of the superior laryngeal nerve impairs the ability to sing high pitched notes.

• Eversion of the foot involves the superficial fibular/peroneal nerve and fibularis/peroneus brevis and longus muscles.

• Temporalis is an elevator and retractor of the mandible.

• The glossopharyngeal nerve is responsible for taste and general sensation on the posterior third of the tongue.

• The nerve to the medial pterygoid innervates the tensor veli palatini, which tenses the palatine aponeurosis.

• Sublingual medication administration occurs under the tongue.

• The posterior part of the genioglossus muscle is responsible for tongue protrusion.

• The styloglossus, superior longitudinal, and inferior longitudinal muscles curl the sides of the tongue.

• Superior oblique and superior rectus are muscles used when looking up.

• Inferior, middle, and superior constrictors are superior to the stylopharyngeus muscle.

• The retropharyngeal space is located posterior to the constrictors .

• The temporomandibular ligament provides stability to the temporomandibular joint (TMJ).

• Tracheostomy is performed at tracheal rings 2-3.

• Superior laryngeal artery runs with the internal laryngeal nerve

• Prevertebral and buccopharyngeal fascia are located posterior and inferior to the constrictors