Ileum

The ileum is the final part of the small intestine, following the duodenum and jejunum.

Terminology

The ileum is not to be confused with the ilium - the associated plural/adjectival forms are ilea/ileal and ilia/ilial respectively.

Gross anatomy

The ileum is 2-4 m in length and is separated from the cecum by the ileocecal valve (ICV). While there is no discrete line demarcating the jejunum from the ileum, there are a few differences between the two:

• ileal mesentery contains more fat than jejunal mesentery
• ileum tends to be smaller caliber than jejunum
• ileum tends to be lighter in color than the jejunum
• ileum contains abundant Peyer patches
  • Peyer patches are unencapsulated lymphoid nodules that contain large amounts of lymphocytes and other cells of the immune system
  • Peyer patches are only found on the antimesenteric border

Arterial supply

• ileal branches of the superior mesenteric artery

Venous drainage

• correspond to arteries and drain into the superior mesenteric vein

Lymphatic drainage

• drain to superior mesenteric lymph nodes

Innervation

• via superior mesenteric plexus
  • sympathetic supply from lateral horn cells of the T9-T10 spinal cord
  • parasympathetic supply from vagus nerves

Variant anatomy

• Meckel diverticulum

Related pathology

• ileal atresia

Siehe auch:

• Duodenum
• Mesenterium
• Jejunum
• Zökum
• Ileumatresie
• Ileum und Ilium

und weiter:

• Rektum
• Normvarianten der Pankreasgänge
• Dünndarm
• Heterotopie des Pankreas
• small bowel mesentery
• Arteria mesenterica superior
• Colon ascendens