Lower Limb BRS questions

The rectus femoris muscle develops from which of the following? A) Posterior condensation B) Anterior condensation C) Lateral plate mesoderm D) Extraembryonic mesoderm E) Sclerotome mesoderm

A. Somite mesoderm migrates into the limb bud and forms two condensations. The posterior condensation of the lower limb gives rise to the extensors of the lower limb, which attain an anterior location in the adult because of the medial rotation of 90*.

During week 6-8, the lower limb bud will rotate A) Medially 90* B) Laterally 90* C) medially 180* D) Laterally 180* E) no rotation

A. The lower limb bud will rotate medially 90* so that the knee points anteriorly.

The femur develops from which of the following? A) Somite mesoderm B) Lateral plate mesoderm C) Intermediate mesoderm D) Extraembryonic mesoderm E) Sclerotome mesoderm

B. All bones of the lower limb form from lateral plate mesoderm that condenses along the central axis of the lower limb bud

Which of the following arteries gives rise to the axis artery of the lower limb? A) External iliac artery B) Femoral artery C) Profound femoral artery D) Umbilical artery E) Inferior gluteal artery

D. Early in development, the umbilical artery gives rise to the axis artery.

Which of the following muscles will the posterior divisions of the lumbosacral plexus innervate? A) Semitendinosus B) Semimembranosus C) Long head of biceps femoris D) Rectus femoris E) Gastrocnemius

D. One of the nerves that forms from the posterior divisions of the lumbosacral plexus is the femoral nerve. Posterior divisions of the lumbrsacral plexus will innervate muscles dervied from the posterior condensation (extensors). The rectus femoris muscle is an extensor at the knee joint.