This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nerves of Abdomen, Subject name: Anatomy
[{'content': 'Lumbar plexus is situated in \nSelect and explain. \nA. Anterior portion of psoas, B. Posterior portion of psoas, C. Anterior portion of quadratus lumborum, D. Posterior portion of quadratus lumborum', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. b (Posterior portion of psoas) (Ref. BDC anatomy Vol. II 3rd ed., 278)LUMBAR PLEXUS# The lumbar plexus lies in the posterior part of the substance of the PSOAS MAJOR muscle.# It is formed by the ventral rami of the upper 4 lumbar nerves.Its branches include:- Ilioinguinal nerve (L1)- Lateral cutaneous nerve of the thigh (L2, L3 dorsal divisions)- Lumbosacral trunk (L4, 5; ventral trunk)- Genitofemoral nerve (L1, L2, ventral divisions)- Obturator nerve (L2, 3, 4; dorsal divisions)- Femoral nerve (L2, 3, 4; dorsal divisions)- Iliohypogastric nerve (L1)Branches of the lumbar plexusNerveSegmentMuscleMotionSensationIliohypogastricT12 -L1# Inter oblique# External oblique# Transversus abdominusAnterior abdominal wall# Inferior abdominal wall# Upper lateral quadrant of buttockIlioinguinalL1Internal obliqueAnterior abdominal wall# Internal medial inguinal ligament# GenitaliaGenitofemoralL1-L2CremasterTesticular# Inferior medial inguinal ligament# Spermatic cordLateral femoral cutaneousL2-L3 # Anterior, lateral and posterior aspect of thighFemoral Nerve1. Anterior division L2-L4# Sartorius,# Pectineus# Medial aspect of lower thigh# Adduction of thigh# Anterior medial skin of thigh2. Posterior division Quadriceps# Knee extension# Patellar movement# Anterior thigh hip and kneeObturator nerve1. Anterior division L2-L4# Gracilis# Adductor longus# Adductor brevis# PectineusThigh adduction# Posterior medial thigh# Medial knee# Hip2. Posterior division # Adductor magnus# Obturator externusThigh adduction with lateral hip rotationKnee', 'role': 'assistant'}]