Adrenal gland

The adrenal (suprarenal) glands are paired organs of the endocrine system, often asymmetric in shape. 

Each gland is enclosed in the perirenal fascia and each has a body and two limbs: a medial limb and a lateral limb. However, the right adrenal gland is usually more pyramidal in shape while the left adrenal gland is more crescentic 7

The right adrenal gland has a maximum width of 6.1 mm and the left adrenal gland has a maximum width of 7.9 mm 6. 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 consists of two portions: an outer cortex and an inner medulla. The gland is covered by a collagenous capsule.

The cortex is subdivided into three zones (from outer to inner) 5, 7:

  1. zona glomerulosa
  2. zona fasciculata
  3. zona reticularis

The medulla produces catecholamines (adrenaline, noradrenaline) as well as dopamine. 

Locations

The adrenal glands lie superior and anteromedial to the kidneys.

Relations
Right adrenal gland
Left adrenal gland
  • lymphatics are contained within the capsule and drain to the para-aortic nodes 7, 9
  • splanchnic nerves via the aortic and renal plexuses 7
  • 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 rests
    • often near adrenal glands but may be found anywhere in the abdomen, pelvis or scrotum 9
  • horseshoe adrenal gland
Ultrasound
  • anterior transverse scanning is the best approach but the adrenal glands are often difficult to see 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 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
CT and 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
Left adrenal gland
  • located superior and anteromedial to the upper pole of the left kidney
  • appears as a triangular or Y-shape 1
Abdominal and pelvic anatomy
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Article information

rID: 16568
System: Urogenital
Section: Anatomy
Synonyms or Alternate Spellings:
  • Adrenal glands
  • Suprarenal gland
  • Suprarenal glands
  • Adrenal gland anatomy

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Cases and figures

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    Figure 1
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    Figure 2: adrenal glands highlighted in yellow
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    Case 1: normal CT anatomy
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    Renal Ultrasound
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    Case 2: pancake adrenal gland
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