Obturator nodes !
The obturator nodes are lymph nodes on the pelvic side wall; they filter lymph from the cervix, uterus and bladder and are checked when such cancers are staged.
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What it is
Lymph nodes on the side wall of the pelvis, next to the obturator nerve.
What it does
Filter lymph from the cervix, uterus and bladder; among the first checked when a gynaecological cancer is staged.
Key facts
- Where
- Lateral pelvic wall along the obturator nerve and vessels, below the external iliac vein
- Drains
- Cervix, uterine body, upper vagina, bladder
- Into
- External and common iliac nodes
Relations
- Above
- External iliac vein
- Lateral
- Obturator internus and the pelvic side wall
- Medial
- Urinary bladder and the medial umbilical ligament (obliterated umbilical artery)
- Below
- Obturator nerve, artery and vein on their way to the obturator canal
How to find it
In surgery they are reached by lifting the external iliac vein and drawing the bladder medially; the obturator nerve is identified in the fat before the nodes are removed.
On imaging
On CT, MRI or PET-CT they lie in the fat of the obturator fossa below the external iliac vein, against the pelvic side wall. A short-axis diameter over 10 mm, a round shape, irregular margins or central necrosis suggest metastasis, and PET-CT adds uptake. Normal-sized nodes can still hold tumour, which is why sentinel node mapping is used in early cervical cancer.
Clinical notes
- Obturator nerve injury during dissection weakens hip adduction and numbs the inner thigh
- Sentinel node mapping injects a dye, a radiotracer or a fluorescent agent into the cervix and follows it to the first pelvic node, often in this group
- A corona mortis (a vascular link between the obturator and external iliac or inferior epigastric vessels behind the pubis) can bleed during dissection
Anatomical variants
- Classifications differ: some texts count them as part of the external iliac chain, others with the internal iliac nodes
Related conditions
Test yourself
Think of the answer, then tap the question to see it.
Where do the obturator nodes lie, and which nerve runs through the same fat?
In the obturator fossa below the external iliac vein against the side wall; the obturator nerve.
Which cancers spread early to the obturator nodes?
Cervical cancer (a common sentinel node site), and prostate and bladder cancer.
What deficit follows obturator nerve injury during obturator node dissection?
Weak hip adduction and numbness of the inner thigh.
Educational information, not medical advice. For any symptom, see a health professional.
Its names
- Official Latin (TA2)
- nodi obturatorii TA2 5333
- Official Spanish (DeCS)
- Nódulos linfáticos obturadores DeCS D008198
- English (TA2)
- Obturator nodes
Sources: Terminologia Anatomica (TA2); DeCS; Anatomy, Abdomen and Pelvis: Female Pelvic Cavity; Anatomy, Abdomen and Pelvis: Lymphatic Drainage.
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Representative model, for educational purposes only.
