Adrenal gland

The adrenal (suprarenal) glands lie anteromedial to the kidneys. They are paired organs of the endocrine system but are quite asymmetric 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 more crescentic 7

The adrenal gland weighs on average 4-6 g and measures 4-6 cm long and 2-3 cm wide 6. Each limb normally measures ≤5 mm in width and the body should measure ≤8-10 mm 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
Right adrenal gland
Left adrenal gland
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)
  • splanchnic nerves via the aortic and renal plexuses 7
Lymphatic drainage
  • lymphatics are contained within the capsule and drain to the para-aortic nodes 7, 9

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 8
  • accessory adrenal nests
    • often near adrenal glands but may be found anywhere in the abdomen, pelvis or scrotum 9

Radiographic appearance

Cross-sectional imaging (CT/MRI)

The adrenal glands enhance after contrast administration to approximately 50-60 HU. Hyperenhancement of the adrenal gland is concerning for hypovolaemic shock.

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
  • body should measure ≤8 mm and limbs ≤5 mm 9
Left adrenal gland
  • located anteromedial to the upper pole of the left kidney
  • appears as a triangular or Y-shape 1
  • body should measure ≤10 mm and limbs ≤5 mm 9
  • 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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