Posterior Abdominal Wall Question And Answers

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Posterior Abdominal Wall Question And Answers

Question 1. What is thoracolumbar fascia? What are its attachments?
Answer:

Thoracolumbar Fascia

Posterior Abdominal Wall Vertebral Attachments Of Posterior, Middle And Anterior Layers Of Lumbar Fascia

  • It is the deep fascia covering the deep muscles on the posterior aspect of the trunk
  • It attaches erector spinae to the posterolateral surface of vertebral bodies
  • Thoracolumbar Fascia Can Be Divided Into Two Parts:
    1. Lumbar Part
    2. Thoracic Part.

Read And Learn More: Abdomen And Pelvis

1. Thoracolumbar Fascia Lumbar Part

  • Made Up Of 3 Strong Layers Of Deep Fascia, Namely:
    • Anterior Layer: The layer
    • Middle And Posterior Layers: Thick and strong layers
  • Between the anterior and middle layers lies the quadratus lumborum muscle
  • Between the middle and posterior layers lies the erector spinal muscle and transversal spinal muscle
  • Laterally the 3 layers fuse to form an aponeurotic sheet
  • Internal oblique and transversus abdominis muscles gets there origin from this aponeurotic sheet.

Thoracolumbar Fascia Attachments

  • Anterior Layer
    • Superiorly: Forms the lateral arcuate ligament
    • Inferiorly: Iliac crest
    • Medially: Transverse process of lumbar vertebrae
  • Middle Layer
    • Superiorly: Lower border of 12th rib
    • Inferiorly: Iliac crest
    • Medially: Tips of the transverse process of lumbar vertebrae, intertransverse ligaments
  • Posterior Layer
    • Superiorly: Thracic part of the thoracolumbar fascia
    • Inferiorly: Iliac crest
    • Medially: Spinous process of lumbar vertebrae.

2. Thoracolumbar Fascia Thoracic Part

Thoracolumbar Fascia Attachments

  • Superiorly: Continuous with the superficial lamina of investing layer of cervical fascia
  • Laterally: Angles of ribs
  • Medially: Spinous process of thoracic vertebrae.

Question 2. Write a note on psoas major.
Answer:

Psoas Major

Posterior Abdominal Wall Attachments Of Illiopsoas

  • The Psoas major is one of the important muscles in the posterior abdominal wall
  • Other Muscles Are Psoas minor, iliacus, and quadratus lumborum.

Psoas Major Origin

  • Psoas arises from 14 fleshy Slips:
    • Five Slips: Each slip arises from bodies and intervertebral discs between two adjacent vertebrae, from T12 – L5
    • Five Slips: Each slip arises from the anterior surface and lower borders of the transverse process of five lumbar vertebrae (L1 – L5)
    • Four Slips: Each slip arises from tendinous arches connecting the constricted parts of the lumbar vertebrae.

Psoas Major Insertion

  • Psoas major descends along the pelvic brim
  • Passes anterior to the inguinal ligament and anterior to the hip joint
  • Enter the thigh
  • And ends on the medial side of a tendon (the lateral side of this tendon receives fiers of iliacus)
  • This tendon is inserted into the anterior surface of tip of the lesser trochanter
  • Since psoas major and iliacus have a common insertion and action they are together called Iliopsoas.

Psoas Major Nerve Supply: Ventral rami of L2, L3, and L4 spinal nerves.

Psoas Major Actions

  • Chief flexor of thigh
  • Maintain stability at hip
  • Lateral flexion of the trunk on same side.

Psoas Major Relations:

  • At Abdomen
    • Anterolaterally
      • Kidney
      • Ureter
      • Renal vessels
      • Gonadal vessels
      • Psoas fascia
      • Medial arcuate ligament
      • Psoas minor
    • Medially
      • Lumbar vertebral bodies and vessels
    • Posteriorly
      • Lumbar plexus
      • Transverse process of lumbar vertebrae
  • At Thigh
    • Anteriorly
      • Femoral artery
      • Fascia lata
    • Posteriorly
      • Synovial bursa separating capsule of the hip joint from the muscle
    • Medially
      • Femoral vein
      • Pectineus muscle
    • Laterally
      • Iliacus muscle
      • Femoral nerve

Question 3. What is psoas sheath?
Answer:

Psoas Sheath

  • Psoas Sheath is a fascial sheath enclosing the psoas major muscle
  • Psoas Sheath is derived from psoas fascia.

Question 4. Write a note on cisterna chyli.
Answer:

Cisterna Chyli

  • Elongated lymphatic sac
  • Length: 5–7 cm
  • Breadth: 4 mm
  • Vertebral level: L1 – L2
  • Location: Between aorta and azygos vein, in front of L1 and L2
  • It is overlapped by right crus of the diaphragm
  • Formed by union of right and left lumbar lymph trunks
  • It continues superiorly as the thoracic duct

Psoas Sheath Tributaries:

  • Two lymph vessels from lower intercostal lymph nodes (open superiorly).
  • Right and left intestinal lymph trunks (opens in the middle)—arising from preaortic lymph nodes.
  • Right and left lumbar lymph trunks (opens inferiorly)—arising from lateral aortic lymph nodes.

Posterior Abdominal Wall Multiple Choice Questions

Question 1. Thoracolumbar fascia:

  1. Is also known as lumbar ventral fascia
  2. Encloses all the intrinsic muscles of the back
  3. Encloses the trapezius, rhomboids, and serratus anterior muscles
  4. Terminates at the first rib

Answer: 2. Encloses all the intrinsic muscles of the back

Question 2. Which is not true about the psoas major?

  1. It arises from the lower border of T12–L5 vertebrae and intervertebral discs between them
  2. It crosses the pelvic brim and passing deep to the inguinal ligament, gets attached to the lesser trochanter of the femur
  3. It is supplied by L1, L2, L3
  4. It causes flexion and lateral rotation movements at hip joint

Answer: 4. It causes flexion and lateral rotation movements at hip joint

Question 3. The cisterna chyli lies adjacent to the:

  1. T12 vertebral body on the right side, posterior to the aorta
  2. T12 vertebral body on the left side, anterior to the aorta
  3. L1 vertebral body on the left side, anterior to the aorta
  4. L1 vertebral body on the right side, posterior to the aorta

Answer: 4. L1 vertebral body on the right side, posterior to the aorta

 

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