Reappraisal of the classical abdominal anatomical landmarks using in vivo computerized tomography imaging

Surface anatomical landmarks for spine surgery: A CT-based study of the sternal notch and sternal angle in 1,035 patients

BACKGROUND

Understanding the location of surface anatomical landmarks in relation to the cervical and thoracic spine is important for a wide array of clinical applications. The objective of this study was to investigate the influence of patient demographic and anthropometric characteristics on the locations of the sternal notch and sternal angle in relation to the spine using computed tomography (CT) of a large cohort of young adult patients without spinal pathology.

METHODS

Vertebral levels corresponding to the sternal notch and sternal angle were analyzed using CT of 1,035 patients. Influences of patient height, weight, body mass index (BMI), sex, and ethnicity were assessed.

RESULTS

567 male and 468 female patients were included in this study. Mean patient height, weight, BMI, and age were 1.68 ± 0.11 m, 81.94 ± 24.39 kg, 27.79 ± 7.9 kg/m2, and 25.9 ± 5.9 years. Of the 1,035 patients, 495 were Hispanic or Latino, 321 were Caucasian, 130 were African American, 68 were Asian, 5 were identified as "other," and 16 did not have racial or ethnic data available. The location of the sternal notch in relation to the thoracic spine demonstrated a bimodal distribution pattern clustered at the T2 and T3 vertebral bodies. The location of the sternal angle in relation to the thoracic spine demonstrated a bimodal distribution pattern clustered at the T4 and T5 vertebral bodies. Moderate, negative correlations were observed between patient weight and location of the sternal notch (r = -0.447; p <.001) and sternal angle (r = -0.499; p <.001), respectively. Zero significant correlations were observed between patient height and location of the sternal notch (r = -0.045; p =.377) or sternal angle (r = -0.080; p =.229). A weak, negative correlation was observed between patient BMI and location of the sternal notch (r = -0.378; p <.001). A moderate, negative correlation was observed between patient BMI and location of the sternal angle (r = -0.445; p <.001). The locations of the sternal landmarks did not differ based on patient sex, race or ethnicity.

CONCLUSIONS

The location of the sternal notch most frequently corresponds to the T2 or T3 vertebral body, while the sternal angle is most frequently located at the T4 or T5 vertebral body. Increased patient weight is associated with relatively cephalad sternal landmarks. Patient height, sex, and ethnicity are not associated with either sternal landmark.

Surface anatomy and lumbar lordosis angle

Awareness of the anatomical variations in abdominal surface anatomy with emphasis on relation to the abdominal planes may facilitate anatomical education and physical examination and inconvenience surgical intervention by giving surgeons more insight in surgical planning and training. This study was designed to verify whether the anatomical planes promote to the comprehension of surface anatomy and how the lumbar lordosis angle affects the vertebral level of the bifurcation of great vessels. This retrospective study was performed using computed tomography angiography images of 155 patients ranging from 18 up to 82 years. The vertebral levels of the celiac truncus, superior mesenteric artery, portal vein confluence, right and left renal arteries were within the transpyloric plane in 60%, 70%, 56.1% and 48.3-36.2% of patients, respectively. The inferior mesenteric artery was below the subcostal plane in 58% of patients. The aortic bifurcation (AB) was mostly corresponded to the level of L4 and was located within the umbilical plane in 73.1% of patients. The level of the inferior vena cava (IVC) confluence was within the supracristal plane in 54% of patients. We measured the mean value of the AB, IVC and lumbar lordosis angles as 39.54°, 58.05° and 54.26°, respectively. The AB and IVC levels showed a downward shift with decreasing lumbar lordosis angle. Precise knowledge of these relationships is crucial in clinical practice and surgical approaches to the anterior lumbosacral spine for safer and effective surgery.

Variation in the vertebral levels of the origins of the abdominal aorta branches: a retrospective imaging study

Our aim was to investigate the variation in the vertebral levels of the origins of the celiac artery, superior and inferior mesenteric arteries, paired renal arteries, and common iliac arteries. We conducted a retrospective imaging study in a large public secondary hospital on a nonrandom sample of 227 participants. We consecutively included adult patients who had undergone computed tomography angiography of the abdomen and excluded patients with a history of any vertebral abnormality or whose images revealed evidence of a vertebral abnormality or a congenital anomaly of any of the branches of the abdominal aorta. The primary outcome was the frequency distribution of the vertebral levels of the landmarks. The secondary outcomes were the intercorrelations of the vertebral levels of the landmarks and their relationships with age, sex, weight, height, and body mass index. The celiac artery originated at T11/T12–L1/L2, followed by the superior mesenteric artery at T12–L2, the paired renal arteries at T12/L1–L2/L3, the inferior mesenteric artery at L2–L4, and the common iliac arteries at L3–L5. The vertebral levels of the landmarks were positively intercorrelated and stronger between proximate pairs. In addition, the vertebral levels of the landmarks were related to age, but not sex, weight, height, or body mass index. The intercorrelations suggest that a considerable proportion of the variation is accounted for by ‘trickle-down’ variation; variation in the vertebral level of a proximal landmark results in variation in the vertebral level of the immediate distal landmark. The overarching parameter remains unidentified.