Adrenals | pacs

Lovely

adrenal glands. Another view of the lovely adrenal.

Kidneys •

Kidney and adrenal gland anatomy (Gray's illustration) - Ganzer Fall bei Radiopaedia

Illustrations G, Kidney and adrenal gland anatomy (Gray's illustration). Case study, Radiopaedia.org (Accessed on 06 Jan 2023) https://doi.org/10.53347/rID-26448 • CC by-nc-sa 3.0 (modified)

Adrenal gland

• Adrenal glands: Gray's anatomy illustration - Ganzer Fall bei Radiopaedia

Illustrations G, Adrenal glands: Gray's anatomy illustration. Case study, Radiopaedia.org (Accessed on 06 Jan 2023) https://doi.org/10.53347/rID-26449 • CC by-nc-sa 3.0 (modified)

Adrenal gland

• Adrenal glands (normal CT anatomy) - Ganzer Fall bei Radiopaedia

Bashir O, Adrenal glands (normal CT anatomy). Case study, Radiopaedia.org (Accessed on 06 Jan 2023) https://doi.org/10.53347/rID-16570 • CC by-nc-sa 3.0 (modified)

Adrenal gland

• Pancake adrenal gland in patient with a right pelvic kidney - Ganzer Fall bei Radiopaedia

Slater L, Pancake adrenal gland in patient with a right pelvic kidney. Case study, Radiopaedia.org (Accessed on 06 Jan 2023) https://doi.org/10.53347/rID-11140 • CC by-nc-sa 3.0 (modified)

Radiopaedia • CC-by-nc-sa 3.0 • de

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

Gross anatomy

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 .

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 . Proportionately, the adrenal size is larger in neonates and infants, being almost one-third of the size of the kidney .

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) :

zona glomerulosa

zona fasciculata

zona reticularis

The medulla (chromaffin cells) produces catecholamines (epinephrine, norepinephrine) as well as dopamine.

Locations

The adrenal glands lie superior and anteromedial to the kidneys.

Relations

Right adrenal gland

medial: right crus of the diaphragm, right inferior phrenic artery
lateral: right lobe (bare area) of the liver
anterior: inferior vena cava (IVC)
posterior: right kidney

Left adrenal gland

medial: left crus of the diaphragm, left inferior phrenic artery
anterior: lesser sac, stomach, splenic artery, pancreas
lateral: spleen
posterior: left kidney

Arterial supply

arterial supply is via three adrenal arteries
- superior adrenal artery (from inferior phrenic artery)
  - usually a group of 6-8 arteries arise
middle adrenal artery (from abdominal aorta)
inferior adrenal artery (from renal artery)

Venous drainage

venous drainage
- adrenal veins emerge from the hilum and drain to different veins depending on the side:
  - left adrenal vein drains to the left renal vein
    - may join with the left inferior phrenic vein before entering the left renal vein
  - right adrenal gland drains to the IVC

Lymphatic drainage

lymphatics are contained within the capsule and drain to the para-aortic nodes

Innervation

presynaptic sympathetic fibers, from thoracic splanchnic nerves synapse directly with chromaffin cells
post synaptic fibers from celiac, aorticorenal, and renal ganglia innervate surrounding vessels

Variant anatomy

lying down adrenal sign
- takes on a flattened appearance
- often in the presence of a pelvic kidney or renal agenesis
adrenal gland hypoplasia or agenesis
accessory adrenal rests
- often near adrenal glands but may be found anywhere in the abdomen, pelvis or scrotum
horseshoe adrenal gland

Radiographic features

Ultrasound

anterior transverse scanning is the best approach but the adrenal glands are often difficult to see :
- 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 visualize than the right because it is often posterior to the stomach and obscured by gas; this can be overcome by
- 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 hypovolemic shock.