Original Research

Anatomical evaluation of the greater occipital nerve block using embalmed neonatal cadavers

Lané Prigge, Amelia Ayres, Adrian T. Bosenberg, Albert N. van Schoor

Received: 18 Feb. 2026; Accepted: 19 May 2026; Published: 27 June 2026

Copyright: © 2026. The Author(s). Licensee: AOSIS.
This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license (https://creativecommons.org/licenses/by/4.0/).

Abstract

Background: The greater occipital nerve block is indicated for pain relief in children undergoing, among others, posterior fossa craniotomies. This nerve, which arises from the C2 spinal nerve, travels alongside the occipital artery and provides sensation to the posterior scalp.

Aim: The aim of this study was to anatomically determine the location of the greater occipital nerve and accompanying occipital artery, as it travels through the hiatus in the trapezius muscle aponeurosis, in the occipital region, in embalmed neonatal cadavers.

Setting: Study was conducted at the Department of Anatomy, University of Pretoria, South Africa.

Methods: Following ethical approval, the greater occipital nerve and occipital artery were bilaterally dissected and exposed in 35 embalmed neonatal cadavers from the Department of Anatomy at the University of Pretoria. The distance between the external occipital protuberance, the rudimentary mastoid process and the greater occipital nerve was measured, while the relationship between the neurovascular structures was observed.

Results: The greater occipital nerves were found to be on average 19.85 mm ± 4.70 mm from the external occipital protuberance in neonates, while the external occipital protuberance and rudimentary mastoid process are 42.55 mm ± 8.46 mm apart. In 77.3% of the specimens, the greater occipital nerve was located medial to the occipital artery, while in the remaining cases, the artery lies between the cutaneous branches of the greater occipital nerve at the trapezius muscle hiatus.

Conclusion: In this neonatal sample, the greater occipital nerve is located at the approximate mid-point of the line between the external occipital protuberance and rudimentary mastoid process.

Contribution: Careful aspiration is recommended, because the greater occipital nerve is not always located medial to the occipital artery.

Keywords: child pain; neonatal anatomy; paediatric; regional anaesthesia; occipital artery.

Introduction

Knowledge of anatomy is a cornerstone of successful regional anaesthesia.¹ Historically, anatomy has been based on dissections performed on adult cadavers; however, anatomical landmarks change as a child grows. The application of anatomy based on dissections of neonatal cadavers is more appropriate for regional anaesthesia in neonates and infants.²

Regional anaesthesia, when used for perioperative pain management in neonates and infants, has many advantages, such as elimination of the respiratory depression associated with opiate analgesia.³ Head and neck surgery is not common in neonates and infants; however, nerve blocks have been used for intraoperative and postoperative pain control.^4,5 The choice of a regional nerve block is dependent on the skill of the practitioner, their knowledge of anatomy and the safety of the specific patient.¹

The aim of this study was to provide a detailed description of the location of the greater occipital nerve as it travels within the occipital area of the neonate’s head, in relation to the occipital artery and easily palpable landmarks, in embalmed neonatal cadavers. This article expands on a previous pilot study, which included only five infant cadavers.⁶

Anatomy – Current understanding

Our current knowledge of anatomy is predominantly based on adult specimens. The greater occipital nerve originates as a medial branch of the posterior ramus of the spinal nerve C2, after which it emerges between the axis (C2) and obliquus inferior capitis muscle. It then ascends across the roof of the suboccipital triangle and pierces the semispinalis capitis and splenius capitis muscles, and lastly the trapezius muscle aponeurosis.⁷ This nerve is responsible for the cutaneous innervation to the posterior region of the scalp and is accompanied by the occipital artery.^7,8 When administering a block, it is crucial to carefully determine the precise injection site for the local anaesthetic, given the close location of the greater occipital nerve and the occipital artery. To date, there are few anatomical studies of neonatal cadavers^9,10 evaluating head and neck blocks in general or the greater occipital nerve in particular.

Research methods and design

The whole-body donors were embalmed using a standard submersion technique with an ethanol-formalin solution (< 20% formalin). All dissections were conducted in the Department of Anatomy in conformity with the Declaration of Helsinki (1964) and its subsequent revisions, and in line with the provisions outlined in the South African National Health Act (Act 61 of 2003).

The occipital region of 35 purposefully selected embalmed neonatal cadavers (0–28 days; mean age 2.66 days) of very low to normal birthweight was dissected bilaterally to visualise the path of the greater occipital nerve and to measure the related landmarks. With the cadavers in a prone position, the skin was reflected laterally to expose the greater occipital nerve and occipital artery in the posterior neck and occipital region, using standard microdissection, without the aid of optical magnification tools. The distance between the neurovascular structures and easily identifiable, palpable bony landmarks such as the external occipital protuberance and the rudimentary mastoid process was measured. The relationship and distance between the greater occipital nerve and the occipital artery, at the point of emergence from the trapezius aponeurosis, as seen in Figure 1, were determined using a sliding digital Vernier calliper (accuracy 0.01 mm).

FIGURE 1: Dissection of the left occipital region of a neonatal cadaver, exposing the greater occipital nerve and occipital artery, highlighted in yellow and red, respectively.

Statistical methods

Descriptive statistics, which include the mean of each measurement, standard deviation (s.d.), as well as a 95% confidence interval (CI) to establish the true population value, were determined using SAS® version 9.3 for Windows. Intraclass correlation coefficients (ICCs) of 0.981 and 0.986 for intra- and inter-rater reliability, respectively, were obtained, indicating the reliability of the collected data. To evaluate the statistical significance of differences between the left and right values, a Wilcoxon signed-rank test was performed.

Ethical considerations

Ethical approval to complete dissections on a sample of neonatal cadavers, donated to and stored at the Department of Anatomy, University of Pretoria, was obtained from the Faculty of Health Sciences Research Ethics Committee of the University of Pretoria UP:77/2014.

Results

The measurements taken from the cadavers showed no statistically significant difference between the left and right sides (p > 0.5; Wilcoxon signed-rank test). The samples from the right and left sides were thus combined, yielding a total of 70 measurements (Table 1).

Table 1 displays the distances between the external occipital protuberance and the neurovascular bundle, and between the external occipital protuberance and the rudimentary mastoid process. From this sample, it was ascertained that the mean distance between the bony landmarks, the external occipital protuberance and the rudimentary mastoid process was 42.55 mm ± 8.46 mm, (95% CI: 1.98 mm), while the span from the external occipital protuberance to the greater occipital nerve was recorded at 19.85 mm ± 4.70 mm (95% CI: 1.10 mm).

The relationship between the greater occipital nerve and the occipital artery could not be quantified in two neonatal cadavers because the occipital artery was accidentally removed during preliminary dissections. These were excluded from this analysis, and thus the relationship between the two structures, at their point of emergence from the trapezius aponeurosis, was examined bilaterally in 33 specimens.

Discussion

The greater occipital block has been used in children to provide pain relief for occipital neuralgia,^4,11 an occipital incision,¹² treatment of migraines^13,14 and headaches.^13,15 It has also been used for postoperative analgesia in an 18-day-old critically ill neonate who required an Ommaya reservoir placement for hydrocephalus.¹⁶ The greater occipital nerve block may also be used in conjunction with other nerve blocks, such as the supra-orbital and supratrochlear nerve blocks, to provide analgesia for various craniotomies.^17,18,19

When locating the greater occipital nerve in a neonatal patient, a similar approach is used as in adult patients, with bony landmarks palpated or ultrasound used. In adults, this is done by using a point two-thirds of the distance on a line drawn between the mastoid process and the external occipital protuberance.²⁰ Prigge and colleagues⁶ found that following anatomical dissections of infants, the greater occipital nerve can be found approximately three-finger’s breadth (of the infant) lateral to the external occipital protuberance, medial to the occipital artery.

Furthermore, the greater occipital nerve can be identified by palpating the laterally located occipital artery.^11,20 Although using the technique of ‘blindly’ injecting medial to the palpated artery is easy to perform, increased quantities of the anaesthetic solution could result in complications.²¹

When a greater occipital nerve block is indicated for neonates and infants, the rudimentary mastoid process and external occipital protuberance are commonly used landmarks. In Table 1, we showed that the mean distance between the external occipital protuberance and the rudimentary mastoid process was 42.55 mm ± 8.46 mm (95% CI: 1.98 mm). In this study, the distance between the external occipital protuberance and the greater occipital nerve was measured at 19.85 mm ± 4.70 mm (95% CI: 1.10 mm).

The proportion of the distance from the external occipital protuberance to the greater occipital nerve compared to the distance from the external occipital protuberance to the rudimentary mastoid process can be represented as a percentage. Specifically, the distance to the greater occipital nerve is 46.65% of the distance to the rudimentary mastoid process. According to the findings of this study, the greater occipital nerve emerges from the trapezius muscle aponeurosis roughly halfway along the line connecting the external occipital protuberance and the rudimentary mastoid process. This supports the literature that suggests that the greater occipital nerve can be blocked midway between the rudimentary mastoid process and external occipital protuberance.²²

It is interesting how the location of the greater occipital nerve differs as the skull matures. In adults, the point is approximately 33% (one-third) on the line between the external occipital protuberance and the mastoid process.^20,23 It was found in a 2-year-old cadaver that the nerve is located at 36%, whereas in infants, it is located 44% along the line from the external protuberance towards the mastoid process.⁶ This study now confirms that this point is almost 47%, indicating that the distance between the greater occipital nerve and the external occipital protuberance is greater, the smaller the patient.

According to the literature, the greater occipital nerve is accompanied by the occipital artery.^7,8 Table 2 indicates the relationship between the two neurovascular structures at their point of emergence at the trapezius aponeurosis in 33 neonatal cadavers. In 77.3% (n = 51/66) of the instances, the occipital artery was positioned laterally to the greater occipital nerve. Conversely, in 22.7% (n = 15/66) of the cases, the artery was located between the nerve’s branches, as illustrated in Figure 2.

FIGURE 2: Dissection of the left occipital region of a neonatal cadaver, exposing the occipital artery emerging between branches of the greater occipital nerve, highlighted in red and yellow, respectively.

Two separate studies, including 25 adult cadavers, examined the relationship between the greater occipital nerve and the occipital artery.^24,25 In the first,²⁴ the compression points of the greater occipital nerve were evaluated. They concluded that the occipital artery could intertwine, cross or compress the greater occipital nerve. In the second study, the occipital artery and the greater occipital nerve were closely related in 54% of cases, either as a single interaction (29.6%) or a twisting and spiral relationship (70.4%).²⁵

Even though the exact relationship between these neurovascular structures was not evaluated in our study, the close proximity and small distances (0.82 mm) between them are consistent with the results reported by Janis and co-authors.^24,25 The proximity of the greater occipital nerve to the occipital artery underscores the significance of understanding anatomical variations. It is important to note that the occipital artery is not consistently positioned laterally to the greater occipital nerve, underscoring the need for careful aspiration before administering a local anaesthetic.

Study limitations and strengths

Possible disfigurement and distortion of anatomical structures during the embalming process of the neonatal cadavers with formalin could potentially affect the obtained data. However, the bony landmarks used for the greater occipital nerve block are not likely to be altered. Moreover, the study was limited by a small sample size due to the scarcity of donated specimens, which affects the generalisability of the results. Gestational age data were unavailable for the neonatal cadavers, and therefore, the potential influence of prematurity on the anatomical findings could not be assessed. Furthermore, the data on sex and body weight of the cadavers were not analysed in relation to the obtained measurements. Even though these parameters were recorded, the quantities were insufficient to allow meaningful subgroup analyses. Lastly, a small number of specimens were excluded from specific measurements due to inadvertent damage to anatomical structures during dissection. However, the data obtained provide useful clinical information that could assist practitioners in performing greater occipital nerve blocks in neonates and infants.

Conclusion

This research study employed anatomical dissections as a primary method, indicating that the greater occipital nerve can be blocked medial to the occipital artery, midway between the external occipital protuberance and the rudimentary mastoid process, in neonates.

The position of the greater occipital nerve varies with age, with a greater distance from the external occipital protuberance observed in younger cadavers compared to adults, where the nerve is closer to the midline and external occipital protuberance.

Acknowledgements

The authors express their heartfelt gratitude for the generous contribution of whole-body donors (cadaveric specimens), which enabled this research and facilitated advancements in science and medicine. Dr Louw and Ms Jordaan of the Department of Statistics, University of Pretoria, are acknowledged for their assistance with the statistical analysis. While their contribution was important, it did not meet the criteria for authorship.

This article includes content that overlaps with research originally conducted as part of Lané Prigge’s doctoral thesis titled ‘An Anatomical Study of the Nerves Targeted for Sensory Blocks of the Head and Neck in Neonates and Infants’, submitted to the School of Medicine, University of Pretoria in 2018. The thesis was supervised by Albert N. van Schoor and Adrian T. Bosenberg. Portions of the data, analysis and discussion have been revised, updated and adapted for publication as a journal article. The original thesis is publicly available at: https://www.proquest.com/docview/2890698901?fromopenview=true&pq-origsite=gscholar&sourcetype=Dissertations%20&%20Theses. The authors affirm that this article complies with ethical standards for secondary publication, and appropriate acknowledgement has been made of the original work.

This article is based on data from a larger study. Related articles have been published: (1) ‘Anatomy of the greater occipital nerve block in infants’ focusing on the anatomical location and morphometry of the greater occipital nerve in relation to landmarks used for occipital nerve blocks in infants (1-24 months), published in Pediatric Anesthesia, 29, pp. 945–949 (https://doi.org/10.1111/pan.13693); (2) ‘External jugular vein pierced by supraclavicular branches in a neonatal cadaver: a case report’ focusing on a rare anatomical variation involving the relationship between the external jugular vein and supraclavicular branches of the superficial cervical plexus in a neonate, published in Anatomical Science International, 96, pp. 564–567 (https://doi.org/10.1007/s12565-020-00596-2); and (3) ‘Anatomical study of the superficial cervical plexus targeted for sensory nerve blocks in neonates’ focusing on the branching patterns, anatomical relationships, and surface landmarks of the superficial cervical plexus relevant to sensory nerve block procedures in neonates, published in Regional Anesthesia & Pain Medicine (https://doi.org/10.1136/rapm-2025-106997). The present article addresses a distinct research question, focusing on the anatomy of the greater occipital nerve block, based on a larger neonatal (0-28 days) sample.

In preparing this article, the authors used Grammarly, a language model, to assist with minor editorial refinements and grammatical enhancements. No generative artificial intelligence (AI) was employed in the data analysis or the development of this article.

The authors declare that they have no financial or personal relationships that may have inappropriately influenced them in writing this article.

Lané Prigge: Conceptualisation, Investigation, Methodology, Writing – original draft, Writing – review & editing. Amelia Ayres: Writing – review & editing. Adrian T. Bosenberg: Supervision, Writing – review & editing. Albert N. Van Schoor: Supervision, Writing – review & editing. All authors reviewed the article, contributed to the discussion of results, approved the final version for submission and publication and take responsibility for the integrity of its findings.

This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors.

The data that support the findings of this study are available from the corresponding author, Lané Prigge, upon reasonable request.

The views and opinions expressed in this article are those of the authors and are the product of professional research. They do not necessarily reflect the official policy or position of any affiliated institution, funder, agency or that of the publisher. The authors are responsible for this article’s results, findings and content.

References