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Year : 2020  |  Volume : 64  |  Issue : 9  |  Page : 804-805  

Paediatric lumbar paravertebral sonoanatomy: More like a “Dragon fly” than a “Shamrock”

1 Department of Anaesthesia, Ruby Hall Clinic, Pune, Maharashtra, India
2 Department of Anaesthesia, Sancheti Hospital, Pune, Maharashtra, India

Date of Submission05-Jun-2020
Date of Decision21-Jun-2020
Date of Acceptance28-Jun-2020
Date of Web Publication01-Sep-2020

Correspondence Address:
Dr. Nita J Dsouza
A-102, Hibiscus Garden Enclave, 30+32, Uday Baug, Ghorpuri, Pune - 411 013, Maharashtra
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ija.IJA_670_20

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How to cite this article:
Dsouza NJ, Mara KP, Patil P, Diwan S. Paediatric lumbar paravertebral sonoanatomy: More like a “Dragon fly” than a “Shamrock”. Indian J Anaesth 2020;64:804-5

How to cite this URL:
Dsouza NJ, Mara KP, Patil P, Diwan S. Paediatric lumbar paravertebral sonoanatomy: More like a “Dragon fly” than a “Shamrock”. Indian J Anaesth [serial online] 2020 [cited 2020 Sep 27];64:804-5. Available from: http://www.ijaweb.org/text.asp?2020/64/9/804/294076

Paediatric regional anesthesia with ultrasound guidance is emerging as a safe, effective means to provide analgesia.[1] In comparison to adults, many anatomical and physiological differences are noted in paediatric patients.[1] Owing to differential muscle mass, paediatric ultrasound images of the paravertebral sonoanatomy are likely to appear differently. The classical “Shamrock sign” is described on ultrasound-guided lumbar plexus scanning in adults, however this may not be easily visualised in the elderly and obese.[2],[3] In adults, the ultrasound image of the muscles around the lumbar plexus resembles a “Shamrock” comprising of the three leaves: representing three muscles of the erector spinae (spinalis, longissimus, iliocostalis), the QL, the psoas and the stem being the transverse process of the lumbar vertebra.[2],[4] The images also have been previously described as thumbs -up sign, an orca's silhouette or have focussed on the bulging edge of the body of the lumbar vertebra.[5] The success of the QL muscle identification lies in noting its relationships to the abdominal wall muscles, the psoas and the transverse process of the lumbar vertebra. The sonoanatomy of the lumbar paravertebral muscles in adults is almost always achieved with a curvilinear low frequency (5–8 Hz) transducer considering the wide field of view and facilitation of tissue penetration to a deeper muscle. The lumbar plexus in paediatric patients was noted to be relatively superficial, requiring less tissue penetration and a high frequency linear probe for better spatial resolution.[6]

We share the ultrasound imaging of the lumbar paravertebral sonoanatomy of four children (age 1.8 years, 10 years, 7 years, and 3 years- [Figure 1]a, [Figure 1]b, [Figure 1]c, [Figure 1]d, respectively) who underwent upper and lower abdominal surgeries and were administered an anterior QL block. A written informed consent from the parents of these children was obtained. The ultrasound scanning for the children was done in the lateral position using a high frequency linear probe (Hitachi- Aloka arrieta S60) placed in a transverse orientation along the mid/posterior axillary line just cephalad to the iliac crest. A real time scan was performed from the anterior abdomen to the posterior, to confirm the image of the QL muscle. Viewing the psoas and the QL muscle is essential for performing the anterior QL block. The image attained better clarity with a caudad angulation into the pelvis to visualise the QL relative to the transverse process. We observed lack of resemblance of the various ultrasonographic images obtained on scanning paediatric patients to a “Shamrock.”
Figure 1: Ultrasound scans of lumbar paravertebral sonoanatomy in a- 1.8years, b- 10 years, c- 7 years, d- 3 years (superimposed image of dragonfly) paediatric patients with anterior and posterior orientation. (QL-quadratus lumborum, TP - Transverse process lumbar vertebra, ESP - Erector spinae group of muscles, psoas- psoas muscle)

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The ultrasound image on scanning for the QL block appeared more like the outline of the wings of a dragonfly rather than a shamrock [Figure 1]. The upper and lower wings on the left are the QL and the psoas muscle respectively and on the right being the erector spinae muscles. The scans with a linear probe revealed the QL muscle attached to the lumbar transverse process which appeared smaller, less bulky and flattened toward the abdominal muscles lying adjacent to the psoas in contrast to adults where it is bulkier and forms one of the petals of the shamrock. We have not come across any musculoskeletal ultrasound of paediatric patients in literature that describes the age at which the muscles around the lumbar plexus achieve the bulk of an adult. A study to quantitatively evaluate the QL in fetuses and its growth dynamics concluded a logarithmic increase in the length, width and cross-sectional area proportionate to age and can explain differences in paediatric musculoskeletal ultrasonography.[7] We suggest that in children a “dragonfly sign” may be more appropriate than the “Shamrock sign.”

Further studies are needed to validate this observation but are noteworthy that every block's ultrasound image in children may not be similar to that in adults. Knowledge about the varied sonoanatomy in adults and paediatrics (attributable to age, weight, muscle mass) is essential with special reference to musculoskeletal ultrasound in paediatric regional anaesthesia literature.


Our Pediatric surgeon Dr. Balwant Ratta for trusting the children in our care to do what is best possible and for the constant encouragement.

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Conflicts of interest

There are no conflicts of interest.

   References Top

Ponde V. Recent trends in paediatric regional anaesthesia. Indian J Anaesth 2019;63:746-53.  Back to cited text no. 1
[PUBMED]  [Full text]  
Sauter AR, Ullensvang K, Bendtsen TF, Børglum J. The 'Shamrock Method' - A new and promising technique for ultrasound guided lumbar plexus blocks. Br J Anaesth 2013:111(e-letter). doi: 10.1093/bja/el_9814.  Back to cited text no. 2
Coyne J, Mc Donnell JG, Karmakar MK. Abdominal wall nerve blocks Part II: The Quadratus Lumbourm block. In: Karmakar MK, editor. Musculoskeletal Ultrasound for Regional Anaesthesia and Pain Medicine. 2nd ed. Hong Kong: Chinese University of Hong Kong. 2016. Ch. 33, p. 395-401.  Back to cited text no. 3
Elsharkawy H, El-Boghdadly K, Barrington M. Quadratus lumborum block: Anatomical concepts, mechanisms and techniques. Anesthesiology 2019;130:322-35.  Back to cited text no. 4
Nielsen MV, Nielsen TD, Bendtsen TF, Børglum J. The Shamrock sign: Comprehending the trefoil may refine block execution. Minerva Anestesiol 2018;84:1423-5.  Back to cited text no. 5
Kirchmair L, Enna B, Mitterschiffthaler G, Moriggl B, Greher M, Marhofer P, et al. Lumbar plexus in children: A sonographic study and its relevance to pediatric regional anesthesia. Anesthesiology 2004;101:445-50.  Back to cited text no. 6
Grzonkowska M, Baumgart M, Badura M, Dombek M, Wiśniewski M, Paruszewska-Achtel M, et al. Quantitative anatomy of the growing quadratus lumborum in the human foetus. Surg Radiol Anat 2018;40:91-8.  Back to cited text no. 7


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