Thorax & Abdomen NATS2004 MRD: Abdomino-Pelvic Wall Lecture

Instructor Information

• Instructor: Dr. Manisha Dayal
• Contact: [email protected], (02) 4620-3493
• Campus: Campbelltown Campus, Western Sydney University

Learning Outcomes

By the end of this lecture, you should be able to:

• Name and identify the abdominal planes and regions.
• Describe the anterolateral abdominal walls and their muscle anatomy.
• Explain the rectus sheath.
• Understand the development and anatomy of the inguinal canal.
• Describe different types of inguinal hernias.
• Describe the posterior abdominal walls including the muscle anatomy.
• Identify the muscles of the pelvic diaphragm.

Case Study

• Patient: 65-year-old male with a 3cm soft mass in the right scrotum.
• Diagnosis: Right indirect inguinal hernia.

Inguinal Hernia

• Anatomy and development of the inguinal canal.
• Description of inguinal hernias.

Pelvic Girdle and Bone

• Pelvic Girdle: Formed by the sacrum.
• Pelvic Bone: Known as the innominate or hip bone, consists of three parts including the acetabulum.

Ilium Anatomy

• Ala, iliac crest, iliac tuberosity, various iliac spines, greater sciatic notch, iliac fossa, auricular surface.

Ischium Anatomy

• Components include the body, ramus, obturator foramen, ischial spine, sciatic notches, ischial tuberosity.

Pubis Anatomy

• Consists of the body and ramus along with the symphyseal face, pubic symphysis, crest, and tubercles.

Abdominal Planes and Regions

• Planes: Two sagittal and two transverse planes.
• Regions: Nine regions including hypochondrium, epigastric, lumbar, umbilical, iliac, and hypogastric.

Anterolateral Abdominal Wall

• Extends from the thoracic cage to the pelvis.
• Bounded by rib cartilages, xiphoid process, inguinal ligament, and pelvic girdle.
• Layers: Skin, subcutaneous tissue, muscles, fascia, fat, peritoneum.
• Fascia: Camper fascia (superficial), Scarpa fascia (deep).

Muscles of Anterolateral Abdominal Wall

• Five muscles: Three flat (external oblique, internal oblique, transversus abdominis) and two vertical (rectus abdominis, pyramidalis).
• External Oblique: Originates from 5th-12th ribs, inserts at linea alba, pubic tubercle, iliac crest.
• Internal Oblique: Originates from thoracolumbar fascia, iliac crest, inserts at ribs, linea alba.
• Transversus Abdominis: Originates from costal cartilages, iliac crest, inserts at linea alba.
• Rectus Abdominis: Originates from pubic symphysis, inserts at xiphoid process, costal cartilages.
• Pyramidalis: Tenses linea alba.

Rectus Sheath

• Encloses rectus abdominis and pyramidalis.
• Formed by the aponeuroses of flat muscles.
• Features arcuate line.

Innervation and Vasculature

• Nerves: Thoracoabdominal, subcostal, iliohypogastric, ilioinguinal.
• Vasculature: Superior and inferior epigastric vessels, circumflex iliac vessels, posterior intercostal.

Inguinal Region

• Groin region, site of herniation risks.
• Inguinal Canal: 4cm passage, involves spermatic cord (males) or round ligament (females).
• Inguinal Ligament: From ASIS to pubic tubercle.

Development of Inguinal Canal

• Males: Testis descends via the gubernaculum, processus vaginalis.
• Females: Ovaries relocate; round ligament passes through the canal.

Posterior Abdominal Wall

• Includes lumbar vertebrae, diaphragm, lumbar plexus, fascia.
• Muscles: Psoas major, psoas minor, iliacus, quadratus lumborum.

Pelvic Cavity

• Bordered by pubic bones, hip bones, ligaments, muscles.
• Muscles: Obturator internus, piriformis, levator ani, coccygeus.

Summary

• Key focus on abdominal and pelvic anatomical structures, their development, clinical implications, and common conditions like hernias.