Anatomy of the muscles and nerves of the posterior abdominal wall

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Anatomy of the muscles and nerves of the posterior abdominal wall

Abdomen

Anatomy

Abdominal quadrants, regions and planes

Anatomy of the anterolateral abdominal wall

Anatomy of the abdominal viscera: Blood supply of the foregut, midgut and hindgut

Anatomy of the abdominal viscera: Esophagus and stomach

Anatomy of the abdominal viscera: Small intestine

Anatomy of the abdominal viscera: Large intestine

Anatomy of the abdominal viscera: Pancreas and spleen

Anatomy of the abdominal viscera: Kidneys, ureters and suprarenal glands

Anatomy of the abdominal viscera: Innervation of the abdominal viscera

Anatomy of the abdominal viscera: Liver, biliary ducts and gallbladder

Anatomy of the diaphragm

Anatomy of the inguinal region

Anatomy of the muscles and nerves of the posterior abdominal wall

Anatomy of the peritoneum and peritoneal cavity

Anatomy of the vessels of the posterior abdominal wall

Anatomy clinical correlates

Anatomy clinical correlates: Anterior and posterior abdominal wall

Anatomy clinical correlates: Viscera of the gastrointestinal tract

Anatomy clinical correlates: Peritoneum and diaphragm

Anatomy clinical correlates: Other abdominal organs

Anatomy clinical correlates: Inguinal region

Assessments

Anatomy of the muscles and nerves of the posterior abdominal wall

USMLE® Step 1 questions

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Questions

USMLE® Step 1 style questions USMLE

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Several students are studying the peripheral nervous system in a cadaver. One nerve is identified to originate from the anterior rami of L2 to L4. This nerve then runs along with the psoas muscles. An image of the nerve is shown below:


Which of the following statements regarding this nerve is most accurate? 

Transcript

Contributors

Anca-Elena Stefan, MD

Rachel Yancey

Alaina Mueller

Ursula Florjanczyk, MScBMC

The posterior abdominal wall is a complex area of the body made up of muscles, vessels and nerves that work together to hold abdominal organs in place, adjust our posture, stabilize the hip joint and even flex our thighs on leg day!

The main paired muscles of the posterior abdominal wall include psoas major, iliacus and quadratus lumborum; and naturally, for those muscles to work properly, they receive innervation from various nerves.

Okay, now let’s take a closer look at these muscles! First up is the psoas major, which is a long, thick muscle that lies lateral to the lumbar vertebrae. It originates superiorly on the transverse processes of the bodies, and adjacent intervertebral discs of the T12 through L5 vertebrae.

The psoas major passes inferolaterally, deep to the inguinal ligament in order to insert on the lesser trochanter of the femur. Finally, approximately half the population has a psoas minor muscle that sits on the anterior aspect of each psoas major muscle.

Now, the psoas major muscle is covered by the psoas fascia or the psoas sheath, which is attached medially to the lumbar vertebrae and pelvic brim. The psoas sheath is thickened superiorly forming the medial arcuate ligament.

Sources

  1. "Raj's Practical Management of Pain" Mosby (2007)
  2. "Anatomical Variations of the Lumbar Plexus: A Descriptive Anatomy Study with Proposed Clinical Implications" Journal of Manual & Manipulative Therapy (2009)
  3. "Nerves and Nerve Injuries" Academic Press (2015)
  4. "Caring in Emergencies" Churchill Livingstone (1994)
  5. "Gray's Anatomy" Churchill Livingstone (2007)
  6. "Easy Injections" Elsevier Health Sciences (2006)
  7. "Nerves and Nerve Injuries" Academic Press (2015)
Elsevier

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