Anatomia, Volume 3, Issue 3 (September 2024) – 7 articles

Several terminologies exist for a vestigial muscle connecting the clavicle to the cervical vertebrae; however, “levator claviculae muscle” and “cleidocervical muscle” are commonly found in the contemporary literature. The term “levator claviculae” does not determine the location of the superior insertion point, but rather describes a single function of the muscle. However, similar to the sternocleidomastoid muscle, the bilateral presence of this muscle could result not only in increased strength for elevating the clavicle, but also in enhanced neck flexion and greater neck stability. To provide anatomical precision, the muscle could be more accurately termed the cleidocervical muscle. This literature review was performed using “PubMed” as the search engine. Mesh terms such as levator AND claviculae, cleidocervicalis, cleidocervical, cleidoatlanticus, and cleidotrachelian were used. Our proposal for a precise methodology in addressing the terminology would be as follows: [Position 1: cleidocervical muscle] [Position 2: vertebra levels]. In this opinion paper, we advocate for the anatomical community to discontinue the use of the term “levator claviculae” and instead adopt the more appropriate “cleidocervical muscle” in academic discourse. Full article

During anatomical dissection of a female body donor at the Howard University College of Medicine, a rare renal anomaly was discovered. Detailed anatomical and histological analyses on this anomaly were compared to a normal kidney from another donor and previously published reports from a comprehensive literature review. Anatomical assessment confirmed the condition of pancake kidney, a rare form of completely fused, ectopic kidneys without an isthmus. Due to the lack of symptoms in patients with this condition and the limited number of published case reports, very little information is available regarding the anatomy, development, and histology of pancake kidneys, making it difficult to determine an accurate estimate of the number of individuals who are affected. In the case presented here, a single kidney was located in the pelvis, below the bifurcation of the abdominal aorta into the common iliac arteries. The histological analysis of the pancake kidney revealed focal segmental glomerulosclerosis, dilated renal tubules, and increased interstitial fluid, all common characteristics of renal disease and not present in the normal kidney of the other donor. Future studies are needed to compare the histology of pancake kidneys and typical kidneys in order to help determine potential pathologies. Full article

Limited reports have evaluated the utility of the popliteal vein (PV) specific to cannulation. The objective of this study was to characterize the diameter and length of the PV to evaluate this area as a potential cannulation site. The popliteal region in 23 formalin-embalmed, prosected donors was dissected, and the PV was exposed from the adductor hiatus (AH) superiorly to the small saphenous vein (SSV) inferiorly. The diameter of the popliteal vein was measured at the AH, SSV, and half of the distance from the AH to the SSV (MID) using a brass plumb bob. The length of the PV was measured to the AH, SSV, MID, and femoral condyles (FCs). Overall, the mean diameters and mean lengths for the combined population were calculated, as well as individual limbs (right, left) and anatomical sex. Univariate analysis used to evaluate differences in mean diameter and length measurements based on anatomical sex revealed significant differences (p < 0.05) for both diameter and length at all the landmarks evaluated. Multivariate analysis of PV diameter at the AH and SSV landmarks was statistically significant (p < 0.05) when laterally and anatomical comparing sex. These data provide full characterization of the PV in support of its utility in vascular access. Full article

Variations of the sciatic nerve and piriformis muscle (SN-PM) relationship must be considered when discussing orthopedic procedures within the region as they may cause increased risk of SN injuries. Thirty-one formalin-embalmed, prosected donors were evaluated using the Beaton and Anson (B&A) classification system (1939). Major landmarks of the SN-PM relationship were identified, including the posterior superior iliac spine (PSIS), ischial tuberosity (IT), greater trochanter (GT), and the middle of the SN as it exits under the PM (S1). Distances measured included: PSIS-IT, PSIS-GT, IT-GT, PSIS-S1, IT-S1, GT-S1, S1-Q (distance of perpendicular line connecting S1 to PSIS-IT), and S1-R (distance of perpendicular line connecting S1 to PSIS-GT). Measurements from 49 lower extremities were evaluated using a two-tailed t-test to compare by sex and laterality; a one-tailed t-test was utilized to compare groups based on anatomical sex. Six donors displayed asymmetric B&A classifications, demonstrating gross anatomical differences within a single individual; however, no measurements were significant when comparing extremities. Seven measurements were statistically significant (p < 0.05) between sexes, indicating notable sex-based differences. These data highlight sex-based differences in the SN-PM relationship, as well as consistencies within measurements among extremities, which can be utilized by clinicians when treating male and female patients needing unilateral or bilateral orthopedic procedures or injections within the gluteal region. Full article

The rhesus monkey (Macaca mulatta) is one of the most frequently used primate species in biomedical research. As a common animal model used to study human disease, the validation of the obtained research data depends on a solid understanding of rhesus monkey anatomy. Unfortunately, the number of anatomical studies on the rhesus monkey is low. Moreover, the available anatomical books and atlases are outdated. For example, no color photographs—only line drawings—are presented. Luckily, renewed interest in rhesus monkey anatomy has been observed. The present study builds upon a recently published manuscript on the topographical anatomy of the thoracic limb of the rhesus monkey. More specifically, the musculature of the rhesus monkey hand is described using full-color anatomical photographs taken during dissections of the hands of three rhesus monkeys. The structures that are visible in the different layers, from the superficial to the deepest layer, are described using veterinary anatomical nomenclature. As expected, the anatomy of the rhesus monkey hand largely parallels human anatomy, which supports the value of the rhesus monkey as animal model. However, some remarkable differences have been identified as well. The present publication could therefore be useful when modeling the human hand (e.g., surgical protocols) using the rhesus monkey. Full article

Congenital Adrenal Hyperplasia (CAH) has been reported to involve structural alterations in some brain regions. However, it remains to be established whether there is also an impact on the size of the brain as a whole. Here, we compiled the largest CAH sample to date (n = 53), matched pair-wise to a control group (n = 53) on sex, age, and verbal intelligence. Using T1-weighted brain scans, we calculated intracranial volume (ICV) as well as total brain volume (TBV), which are both common estimates for brain size. The statistical analysis was performed using a general linear model assessing the effects of CAH (CAH vs. controls), sex (women vs. men), and any CAH-by-sex interaction. The outcomes were comparable for ICV and TBV, i.e., there was no significant main effect of CAH and no significant CAH-by-sex interaction. However, there was a significant main effect of sex, with larger ICVs and TBVs in men than in women. Our findings contribute to an understudied field of research exploring brain anatomy in CAH. In contrast to some existing studies suggesting a smaller brain size in CAH, we did not observe such an effect. In other words, ICV and TBV in women and men with CAH did not differ significantly from those in controls. Notwithstanding, we observed the well-known sex difference in brain size (12.69% for ICV and 12.50% for TBV), with larger volumes in men than in women, which is in agreement with the existing literature. Full article

Veins of the lower extremity can be categorized into three hierarchically ordered groups: the epifascial, the interfascial, and the deep ones. In the past, the interfascial veins, e.g., the great saphenous vein, were categorized as superficial veins. But nowadays, experts recommend regarding these veins as a separate group because of their unique topography and clinical relevance. In order to better understand the venous anatomy of the lower limbs, which is highly variable, one should also comprehend their embryological development. Venous embryogenesis in the lower limb consists of three stages. During the first stage the primitive fibular vein is the main vein of the extremity. During the second stage it is replaced by the axial vein and finally by the femoral vein. In some adult individuals this embryonic or fetal venous anatomy is still present. Unfortunately, current anatomical textbooks and atlases, as well as traditional cadaver dissections, are not very useful regarding these issues. Therefore, undergraduate teaching of anatomy can be challenging. New educational tools, such as ultrasonography, seem indispensable to teach the anatomy of these veins properly. Full article