Neurovascular foramina of the human clavicle and their clinical significance

The human clavicle's nutrient foramen's prevalence, number, location, and direction: A systematic review and meta-analysis

INTRODUCTION

The clavicle's nutrient foramen is a surrogate marker for its nutrient artery. Knowing its location may be useful for interpreting fractures and to avoid iatrogenic lesions. The aim of this review was to determine the prevalence, number, location, and direction of the nutrient foramen.

METHODS

Embase, Medline, PubMed, Scopus, and Web of Science were searched and supplemented by Google Scholar, hand-searching major anatomical journals, and the reference list of included studies (updated March 08, 2022). Titles and abstracts were screened for eligibility, and observational studies with quantitative data were included based on full text evaluation. Internal validity was assessed using the anatomical quality assessment tool. Pooled prevalence proportions were derived using a random effects DerSimonian-Laird model using the Freeman-Tukey double arcsine transformation with Miller's inverse back-transformation.

RESULTS

From 18,889 unique reports, 33 studies with 3760 clavicles and 3358 foramina were included. All studies suffered from untransparent reporting. The prevalence of the nutrient foramen was 97.75%, 95% confidence interval 94.70%-99.60%. It was mainly found as a single foramen on the middle third segment's posterior surface with acromial (lateral) obliquity. Results were stable over time, robust to sensitivity analyses, albeit limited by unexplained heterogeneity and asymmetry.

CONCLUSION

This review may aid in interpreting fractures passing through a high-risk area (mean foraminal index range 36.31-61.03%) for lesions to the nutrient artery. Practical implications are a need to update current inaccurate textbook descriptions and further advocate evidence-based anatomy to improve conduct and reporting of anatomical research.

3D Mapping of Bone Channel of Blood Supply to Femoral Head in Proximal Femur

Background

A detailed depiction of nutrient foramina is useful for defining guidelines and minimising iatrogenic damage during hip surgery. Therefore, this study aimed to define the location and frequency of nutrient foramina in the proximal femur using mapping techniques.

Methods

One hundred dry human cadaveric proximal femurs, comprising 56 left and 44 right femurs, were scanned using a three-dimensional scanner, with scanning distance 200 mm, precision 0.01 mm, and measuring point 0.04 mm. The image resolution of 1,310,000 pixels was obtained. Digital imaging models were acquired from the proximal femur surface. All the nutrient foramina in each model were identified and marked. The nutrient foramina models were superimposed on one another and oriented to fit a standard template of the femur’s proximal aspect. Three-dimensional mapping in the proximal femur’s nutrient foramina was performed.

Results

The nutrient foramina’s location and dense zones were identified. The dense zones were distributed along the vascular course and gaps between the muscle attachment sites. Eighteen dense zones were identified and found to be location-dependent. They were located in the central part of the fovea capitis femoris, subcapital and basicervical areas of the femoral neck, and muscle attachment gaps of the femoral trochanter.

Conclusions

The terminal branch of the nutrient vessels entering the nutrient foramina is at risk for iatrogenic damage during hip surgeries, especially in cases of close bone exposures. There are 18 dense zones that need to be considered for a safer approach to the proximal femur. To minimise iatrogenic damage to the nutrient vessels entering the nutrient foramina, the dense areas should be avoided when technically possible.

Morphometric analyses of clavicle's nutrient foramen

PURPOSE

Fractures of the clavicle, which has an important location and function in the upper extremity and shoulder joint, compose 10% of all fracture cases. During the osteosynthesis of clavicle fractures and in the post-operative period of patients, considering the detailed morphometric and topographic properties of the nutrient foramen of clavicle is important to avoid the disruption of arterial nutrition of the clavicle and prevent unexpected injuries. The aim of this study was to investigate the morphometric properties of the nutrient foramen of clavicle in more detail using computedtomography images.

METHODS

Computed tomography images of 116 healthy individuals (56 women/60 men) who had no pathology history were included in the presented study. Computed tomography images were reconstructed three-dimensionally using free-licensed Horos v3.3.3 software. Then, distances from clavicle's nutrient foramen to sternal end, anterior and posterior edges of the clavicle were measured. Statistical analyses were completed using SPSS v21 software.

RESULTS

Our results demonstrated that the nutrient foramen of clavicle was located closer to the sternal end of the clavicle. The shortest distance to the sternal edge of clavicle was measured as 3.3 cm. Analyses of gender differences indicated that statistically significant differences were in favor of men. However, topographic properties of the clavicle's nutrient foramen were not affected by age.

CONCLUSION

Nutrient foramen is mostly located closer to the sternal end of clavicle. Especially during osteosynthesis of clavicle fractures at the sternal end, maintaining the arterial supply of clavicle is of great importance for increasing the post-operative life quality of patients.

Number and distribution of nutrient foramina within the femoral neck and their relationship to the retinacula of Weitbrecht: an anatomical study

Precise knowledge of the vascular supply of the femoral head is critical when contemplating surgery around the femoral head and neck junction. To determine the blood supply to the femoral neck, 2417 nutrient foramina from 76 cadaveric specimens were analyzed based on size, number, and distribution. Within the subcapital, transcervical, and basicervical regions of the femoral neck, the largest numbers of nutrient foramina were found on the superior (lateral) surface, followed by the anterior and posterior surfaces, and then the inferior (medial) surface (all p < 0.001). The diameters of most of the nutrient foramina were less than 1 mm. For the posterior and superior surfaces, the nutrient foramina in the basicervical region were significantly larger than those within the transcervical or subcapital regions (nutrient foramina >2 mm posteriorly: 23.6, 12.7, and 9.0 % in the basicervical, transcervical, and subcapital regions, respectively; superiorly: 23.7 vs. 15.4 vs. 16.8 %, respectively). In conclusion, neither the anterior nor the inferior surfaces in the basicervical, transcervical, and subcapital regions showed any significant differences in nutrient foraminal size. The areas containing densely distributed nutrient foramina were consistent with the regions covered by the retinacula of Weitbrecht.

Anatomical study of the clavicle: endomedullary morphology

BACKGROUND

The treatment of clavicle fractures remains controversial. The objective of this study was to investigate the possibility of clavicular intramedullary fixation by nailing through an anatomic study combined with CT scan studies.

METHODS

For the anatomic study, 20 clavicles of donated bodies to science (10 men, 10 women, 10 right, 10 left) were used. We measured the length of the clavicle, lateral epiphysis diameter, mean diaphysis diameter, medial epiphysis diameter, lateral width, lateral radius of curvature, medial width and medial radius of curvature. Intramedullary cavity diameter (anteroposterior and superoinferior) and calibration were measured by CT scan study on 20 clavicles.

RESULTS

Average length was 152 mm for men and 140 mm for women. The anteroposterior curvature was most pronounced. The medullary canal had a gradually decreasing size from the distal portion to the middle segment, but never disappeared.

CONCLUSION

Evaluation of morphological data can clarify the specifications of an intramedullary nail: flexibility of the nail to match clavicle curvature and a locking system to ensure primary stability. Intramedullary fixation by nailing in displaced fractures of the middle portion of the clavicle is a minimally invasive surgical technique, with excellent functional and cosmetic results.

Functional aspects of the coracoclavicular space

BACKGROUND

The coracoclavicular joint has been described as an articulation found inconstantly between the coracoid process and clavicle. We often observe a small space bordered by the fascia which covers the anterior surface of the subclavius muscle and the coracoclavicular ligament. The aim of this study was to observe the space in detail and to discuss the functional role of the coracoclavicular joint.

MATERIALS AND METHODS

Sixteen shoulder girdles from eight Japanese cadavers were used in this study. The scapula, clavicle, and anterior half of the first rib were extracted en bloc together with the subclavius muscle and the surrounding fascia. After observing the motion of the scapula and clavicle, we investigated macroscopically the attachments of the coracoclavicular ligaments and the subclavius muscle, and the extension of the fascia.

RESULTS

The fascia divided laterally into two sheets: the anterior sheet attached to the trapezoid ligament and the posterior to the conoid ligament. Among the two sheets, the coracoclavicular ligaments, coracoid process, and clavicle, a small space was observed. This small space can be recognized as a part of the coracoclavicular joint. When manually moving the inferior angle of the scapula with the sternal end of the clavicle fixed, we observed that the clavicle collided with the trapezoid ligament on the superior surface of the coracoid process within the space and that the scapular motion was restricted by this collision.

CONCLUSION

The coracoclavicular joint could be much more recognizable than in previous papers and play an important role in the normal function of the shoulder joint.

LEVEL OF EVIDENCE

Basic science study.