Source / episode info
- **Episode:**240
- **Title:**Divine Intervention Episode 240 – USMLE Step 2CK Rapid Review Series 38 (Ortho and OBGYN).
- **Published:**2020-06-05
- Source:Episode page
One-liner
This episode provides a rapid review of critical OBGYN prenatal screening timing (e.g., Nuchal Translucency vs. Quad Screen) and detailed orthopedic/neurological anatomy, focusing on the specific nerve deficits associated with different phases of shoulder abduction and humerus fractures.
High-yield summary
- First Prenatal Visit: Must screen for asymptomatic STIs (Chlamydia and Gonorrhea) via urine culture/sensitivity; treatment is mandatory in pregnancy to prevent preterm labor. Also check HIV, VDRL/RPR, and Hepatitis status.
- Prenatal Screening Timing: Nuchal Translucency (NT) screening occurs optimally between 11–14 weeks. The Quad Screen (Maternal serum AFP, hCG, estriol, Inhibin A) is performed later, typically around 15–20 weeks (often 18-20 weeks).
- Shoulder Abduction Mechanics: Shoulder abduction must be analyzed in phases: 0-15° involves the supraspinatus (suprascapular nerve); 15-90° involves the deltoid/teres minor (axillary nerve); >90° involves the serratus anterior and trapezius (Long Thoracic Nerve / Spinal Accessory Nerve).
- Humerus Fracture Nerves: The nerves are mapped sequentially: Surgical neck fracture affects the Axillary nerve; Mid-shaft fracture affects the Radial nerve; Supercondylar fracture affects the Median nerve.
- Rh Status Management: If the mother is Rh negative, an Indirect Coombs test must be performed. RhoGAM should be given at 28 weeks and postpartum within 72 hours based on degree of blood mixing.
Learning objectives
- Identify key components and timing for routine prenatal screening (STI testing, NT scan, Quad screen).
- Differentiate between the functional deficits caused by injuries to the suprascapular, axillary, and long thoracic nerves.
- Recall the anatomical relationship between major peripheral nerves and specific fracture sites on the humerus.
- Understand the mechanism of Rhogam administration based on maternal/fetal blood mixing risk.
- Recognize the clinical presentation of congenital torticollis (fibrosis of sternocleidomastoid).
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