Pathogenesis

1. Due to a defect in the linea alba adjacent to umbilicus
   • usually due to obesity stretching the fibres
   • Pregnancy
   • Ascities
   • Ovarian cysts / fibroids
   • Bowel distension
2. Uncommon before age 40
3. Can grow to enormous size
4. Neck of sac often tight and held with fibrous band - increase rate of strangulation and infarction of contained bowel; occasionally spontanoeus discharge of contents (as enterocutaneous fistula) can occur 

Umbilical hernia in children

1. Minor defect in neonates (usually self-repair spontaneously)
2. Most cases resolve before puberty and should only be repaired if symptomatic 

Approach

• Expose patient and begin to examine the hands

1. Inspect
   1. Overweight?
   2. Ask patient to lift head off bed, then cough - observe bulge
   3. Note any associated ulceration or skin damage
   4. Note presence of overlying scar indicated recurrent hernia
   5. Point out presence of lumb underlying umbilicus, pushing umbilicus out from abdominal wall
2. Palpate
   1. Determine size of defect
   2. If there is lump - ask patent to reduce
   3. Ask patient to cough - demonstrate expansile cough impulse
3. Percuss
4. Auscultate

Completion

1. Examine rest of abdominal system

Repair of Umbilical herniae

1. Treat pre-disposing medical problems
2. Surgery: Mayo "vest over pants" operation
   • Horizontal ellipse of skin excisied
   • Deepen incision to rectus sheath, identify fibrous band
   • Sac opened near neck, return protruding bowel to abdomen
   • Whole sac removed
   • Lower edge of rectus sutured behind upper edge
   • Mesh used to reinforce larger defect