This functionally creates a smaller structure to pass through the maternal pelvis. The greatest rate of descent occurs during the deceleration phase of the first stage and during the second stage of labor.įlexion: While descending through the pelvis, the fetal head flexes so that the fetal chin is touching the fetal chest. Descent of the fetus is not a steady, continuous process. This normally occurs 2-3 weeks before labour in nulliparous women and may occur any time before or after onset of labour in multiparous women.ĭescent: Descent refers to the downward passage of the presenting part through the pelvis. Seven discrete cardinal movements of the fetus occur over the course of labor and delivery: engagement, descent, flexion, internal rotation, extension, external rotation or restitution, and expulsion.Įngagement: Engagement is the descent of the widest part of the fetus through the pelvic inlet. This is required for fetal descent through the birth canal. Since Facial nerve also does some taste it comes closely following the facial nerve.ĬN X or 10: Vagus (the party starts at 10pm in vegas! Vagus is a huge nerve so it does both motor and sensory).ĬN XI or 11: Spinal Accessory: We saw this nerve innervating spinal muscles and its similar to spinal (not cranial) nerves so it must be motor only and lower ranked on the stem.ĬN XII or 12: Hypoglossal: Tongue muscle nerve gets to be the last in the chain! It is just tongue muscles so motor only.To accommodate itself to the maternal pelvic dimensions, the fetus must undergo a series of changes in the attitude of its presenting part. Abducens (we are back in order! “I soT for lArs” second part of this phrase l and r stand for the muscle lateral rectus which the abducens nerve controls)ĬN VII or 7: Facial: (CN 7 lucky number 7 is the nerve that gets to show facial expression of surprise when winning a jackpot! Important nerve does both sensory and motorĬN VIII or 8: Vestibulocochlear (CN 8 travels with 7 so it must come right after in sequence does cochlear = hearing vestibular = balance so only sensoryĬN IX or 9: Glossopharyngeal (DONT MIX UP WITH CN XII HYPOGLOSSAL WHICH IS MOTOR ONLY this tongue nerve (glosso=tongue) does both taste AND motor. Trigeminal (The trigeminal nerve is an exception to the first nerves being only eye nerves but it does all the sensation of your face and has 3 parts CNVa (occipital), CNVb (maxillary), CNVc (mandibular) Part Vb and Vc also do motor so CN5 is BOTH sensory and motor!ĬN VI or 6. Trochlear (“I soT for lArs” Superior oblique eye movement (covered later) by Trochlear SOT is first part of mnemonic so trochlear is CN IV: does ONLY MOVEMENT via superior oblique for EYES motor)ĬN V or 5. Oculomotor (eye muscles are most inward so it is CN III does ONLY MOVEMENT EYES motor)ĬN IV or 4. Optic (eyes stick out second farthest so it is CN II does ONLY VISION sensory)ĬN III or 3. Olfactory (nose sticks out farthest so it is CN I does ONLY SMELL sensory)ĬN II or 2. “Oh Oh Oh To Touch And Feel A Girls Very Soft Hands” or try Trend finding for memorization where you assume that nerves of eyes come first + more important nerves are both sensory and motor (others are just sensory or just motor)ĬN I or 1. Use a mnemonic (it’s not as difficult as they make it out to be the tough part during medical school is memorizing their “route” which is similar to being asked to memorize map quest directions)
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