Diaphragm & Abdominal Muscles

Question 1

What are the openings of the Diaphragm? Location?
What goes through?

Answer 1

T8 (Central Tendon) - IVC, Right phrenic nerve

T10 (Right crus) Oesophagus, Vagus nerves

T12 (Behind median arcuate ligament) Aorta, Azygous vein, Thoracic duct

Question 2

What are the attachments of the Diaphragm?

Answer 2

• Origin:
  
  • Sternal part: Xiphoid process of the sternum
  • Costal part: Inner surface of the lower six costal cartilages
  • Vertebral part (crura and arcuate ligaments):
    
    • Right crus (L1, L2, L3)
    • Left crus (L1, L2)
    • Median arcuate ligament (between the 2 crura)
    • Medial arcuate ligament (extends from the side of the body of L1 to the tip of the transverse process of L2)
    • Lateral arcuate ligament (extends from the tip of the transverse process of L1 and is inserted into the lower border of the 12th rib)
• Insertion: Central aponeurotic tendon
• Actions: Inspiration and forced expiration

Question 3

What is the Blood supply and nerve supply of the Diaphragm?

Answer 3

• Innervation: Phrenic nerve (C3, C4, C5) – “3, 4, 5, keeps the diaphragm alive”
• Blood Supply: Inferior Phrenic artery

Question 4

What do you know about the External Oblique Muscle?

Answer 4

• Origin: Outer surfaces of the lowest eight ribs
• Insertion:
  
  • iliac crest
  • ASIS
  • Pubic crest
  • Pubic tubercle
  • Linea alba
• Nerve supply: Lower six thoracic nerves (T7 – T12)
• Direction of fibers: Downwards, forwards and medially
• Actions:
  
  • Raise intra-abdominal pressure.
  • Moves trunk to one side.

Question 5

What do you know about the Internal Oblique Muscle?

Answer 5

• Origin:
  
  • Thoracolumbar fascia
  • Anterior 2/3 of the iliac crest
  • Lateral 2/3 of the inguinal ligament
• Insertion:
  
  • Cartilages of the lower 3 ribs
  • Conjoint tendon
  • Pubic crest
  • Linea alba
• Nerve supply:
  
  • Lower six thoracic nerves (T7 – T12)
  • Iliohypogastric and ilioinguinal nerves

Question 6

What do you know about Inguinal rings?

Answer 6

• Deep (internal) ring:
  
  • Found above the midpoint of the inguinal ligament (lateral to the epigastric vessels).
  • The ring is created by the transversalis fascia
• Superficial (external) ring:
  
  • Lies just superior to the pubic tubercle.
  • Formed by the invagination of the external oblique

Question 7

What are the boundaries of the inguinal canal?

Answer 7

• Anterior wall– aponeurosis of the external oblique, reinforced by the internal oblique muscle laterally.
• Posterior wall– transversalis fascia.
• Roof– transversalis fascia, internal oblique, and transversus abdominis.
• Floor– inguinal ligament (a ‘rolled up’ portion of the external oblique aponeurosis), thickened medially by the lacunar ligament.

Question 8

What is the content of the inguinal canal?

Answer 8

• Spermatic cord(biological males only)
• Round ligament(biological females only)
• Ilioinguinal nerve– contributes towards the sensory innervation of the genitalia
• Genital branch of the genitofemoral nerve–supplies the cremaster muscle and anterior scrotal skin in males, and the skin of the mons pubis and labia majora in females.

Question 9

What is the nerve most at risk of damage during an inguinal hernia repair?

Answer 9

Ilioinguinal nervetravels throughpartof the inguinal canal, exiting via the superficial inguinal ring (it does not pass through the deep inguinal ring)

Question 10

Describe the inguinal canal

Answer 10