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Adrenal gland

The adrenal (suprarenal) glands lie anteromedial to the kidneys. They are a paired part of the endocrine system but are quite asymmetrical in shape. 

Gross anatomy

Each gland is enclosed in the perirenal fascia and each have a body and two limbs -medial and lateral.  However, the right adrenal gland is pyramidal in shape while the left adrenal gland is crescenteric 7

The adrenal gland weighs on average 4-6g and measures 4-6cm long and 2-3cm wide 6. Each limb normally measures <5mm in width and the body should measure <10mm in width 1-4. Proportionately, the adrenal size is larger in neonates and infants, being almost one-third of the size of the kidney 2-4

The adrenal gland has a thick outer cortex and a thin inner medulla surrounded by a fibrous capsule. The medulla produces catecholamines (adrenaline, noradrenaline) as well as dopamine. The cortex is subdivided into three zones (from outer to inner) 5, 7:

  1. zona glomerulosa
  2. zona fasciculata
  3. zona reticularis
Relations
Right adrenal gland 3, 6, 7
  • medial -  right crus of the diaphragm, right inferior phrenic nerve
  • lateral - right lobe (bare area) of the liver
  • anterior - IVC
  • posterior - right kidney
Left adrenal gland 3, 6, 7
  • medial - left crus of the diaphragm, left inferior phrenic nerve
  • anteromedial - diaphragm
  • anterior - less sac, stomach, splenic artery, pancreas
  • posterior - left kidney

Blood supply

  • arterial supply 5
    • superior suprarenal artery (from inferior phrenic artery)
    • middle suprarenal artery (from abdominal aorta)
    • inferior suprarenal artery (from renal artery)
  • venous drainage 5
    • suprarenal veins drain emerge from the hilum and drain to
      • left renal vein (left adrenal gland)
      • IVC (right adrenal gland)

Nerve supply

  • splanchnic nerves via the aortic and renal plexuses 7

Lymphatic drainage

  • para-aortic nodes 7

Variant anatomy

  • horseshoe adrenal gland
  • pancake adrenal gland 8
    • takes on a flattened appearance
    • often in the presence of a pelvic kidney or renal agenesis
  • adrenal gland hypoplasia or agenesis
  • congenital adrenal gland hyperplasia 8

Radiological appearance

Cross-sectional imaging (CT/MRI)
Right adrenal gland
  • located superior and anteromedial to the upper pole of the right kidney
  • appears as a linear, V-shape or comma-shape 1
Left adrenal gland
  • located anteromedial to the upper pole of the left kidney
  • appears as a triangular or Y-shape 1
Ultrasound
  • anterior transverse scanning is the best approach but the adrenal glands are not always seen 6:
    • left adrenal gland seen ~40% at least once during scan
    • right adrenal gland seen ~80% at least once during scan
  • left adrenal gland is more difficult to visualise than the right because it is often posterior to the stomach and is obscured by gas; this can be overcome by 6
    • intercostal scanning in the posterior axillary line
    • scanning through the spleen and left kidney with the left side of the patient elevated

Related pathology


Related articles

Abdominal and pelvic anatomy

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