The inner ear of the sea lamprey was examined by scanning electron microscopy, antibody labeling with tubulin, Myo7a, Spectrin, and Phalloidin stain to elucidate the canal cristae organization and the morphology and polarity of the hair cells. We characterized the hair cell stereocilia bundles and their morphological polarity with respect to the kinocilia. We identified three types of hair cells. In Type 1 hair cells, the kinocilia were slightly longer than the tallest stereocilia. This type was located along the medial bank of the crista and their polarity, based on kinocilia location, was uniformly pointed ampullipetally. Type 2 hair cells that had kinocilia that were much longer than the stereocilia, were most abundant in the central region of the crista. This type of hair cell displayed variable polarity. Type 3 hair cells had extremely long kinocilia (~40–50 μm long) and with extremely short stereocilia. They were mostly located in the lateral zone crista and displayed ampullipetal polarity. Myo7a and tubulin antibodies revealed that hair cells and vestibular afferents are distributed across the canal cristae in the lamprey, covering the area of cruciate eminence; a feature that is absent in more derived vertebrates. Spectrin shows hair cells of varying polarities in the central zone. In this zone, some cells followed the main polarity vector (lateral) like those in medial and lateral zones, whereas other cells displayed polarities that carried up to 40° from the main polarity vector.

Objective: Congenital defects/diseases Background: The configuration of the hepatic arteries is known to vary substantially between individuals. Here, we report a rare retroperitoneal configuration of an accessory hepatic artery existing alongside a left and right hepatic artery branching from the proper hepatic artery. During routine dissection, we discovered an anomalous configuration of the hepatic arteries that does not fit the commonly used categorizations for abnormal hepatic vasculature. We briefly discuss potential implications of this finding. Case Report: The left and right hepatic arteries branch directly from the common hepatic artery and supply the liver. The accessory hepatic artery arises directly from the superior mesenteric artery, travels posterior to the portal triad, and enters the porta hepatis. It was found to travel posterior to the neck of the pancreas, duodenum, and portal triad at the same depth as the inferior vena cava, suggesting that the accessory right hepatic artery was traveling retroperitoneally, posterior to the opening of the lesser sac. The accessory hepatic artery exclusively supplies the cystic arteries. Considering existing classification schemes, our case most closely resembles Michels's type 6 and Hiatt's type 3, but most specifically L & oacute;pez-And & uacute;jar's type 6. To the best of our knowledge, this is one of the first reported cases of a retroperitoneal accessory right hepatic artery. Conclusions: Knowledge of the possible variations of the hepatic arteries is important to reduce the risk of iatrogenic injury and improve patient outcomes in surgery, especially in laparoscopic cases or pancreatoduodectomies where more unique variants may be especially difficult to identify or easier to injure. Future research should explore the frequency of retroperitoneal accessory right hepatic arteries, as their unique course may be easily missed.

The ansa cervicalis (AC) is a neural loop within the carotid triangle of the anterior neck. The loop is traditionally formed by nerve roots C1–C3 of the cervical plexus and extends multiple motor branches. The current case was discovered during a routine dissection as an anatomical variation of the right AC in an 86-year-old Caucasian male cadaver. In this variation, the C1 nerve root did not form the typical loop with the C2 and C3 nerve roots, but instead, remained independent, traveling deep to the superior belly of the omohyoid muscle to supply the sternothyroid muscle. Because no loop was formed, the anatomy of the current case was not an ansa according to the Latin origin of the word, meaning handle or loop. The AC is an important anatomical landmark within the neck and is implicated in laryngeal reinnervation and respiratory nerve stimulation for patients with sleep apnea. The current anatomical variant contributes to a relatively limited catalog of identified anomalies. Knowledge of new AC variations can guide future surgical interventions and further develop the current base of knowledge surrounding the neuromuscular structures of the head and neck.

Translation: The University of Toledo Journal of Medical Sciences is the online journal launched by the University of Toledo. Manuscripts will be considered on the understanding that they report original work and are not under consideration for publication by any other journal. The journal publishes original articles reporting experimental results of basic or clinical research, case reports, and reviews. The journal uses a single blind peer review system and each manuscript, based on the results presented in its original submission, will be evaluated by two student reviewers and one faculty reviewer. This process will provide an opportunity for medical students, graduate students, residents, fellows and faculty to publish research observation in a timely manner.

Background: The brachial plexus is a network of nerves responsible for the motor and sensory innervation of the upper limb. Variations in the formation and course of the brachial plexus are well documented, though combinations of multiple unilateral abnormalities are rare. The complex pathology of this structure nerve may result in clinical consequences. We present a unique set of brachial plexus abnormalities involving the C4–C6 nerve roots, superior and middle trunks, additional communicating branches, and delayed median nerve union. Case Presentation: During the routine dissection of a 70-year-old female cadaver, several unique variations in the brachial plexus anatomy were identified. The C4 root contributed to C5 before the superior trunk formed, resulting in a superior trunk composed of C4–C6. The C5 root was located anterior to the anterior scalene muscle, whereas C6 maintained its usual posterior position. Additionally, an anterior communicating branch from the middle trunk to the posterior cord was observed. A communicating branch between the lateral and medial cords split into two terminal branches: one merged with the ulnar nerve, and the other joined the medial contribution of the median nerve. The median nerve contributions from the lateral and medial cords merged approximately two inches above the elbow. Conclusions: This rare combination of brachial plexus anomalies has not been previously described in the literature and is of significant clinical relevance. The additional anterior communicating branch from the middle trunk may suggest potential flexor muscle innervation by the posterior cord, which typically innervates extensor muscles. Additionally, the delayed convergence of the median nerve may provide a protective mechanism in cases of midshaft humeral fracture. Awareness of these peripheral nerve abnormalities is important for diagnostic imaging, surgery, or peripheral nerve blocks. Knowledge of such variations is critical for clinicians managing upper limb pathologies.

Background: In standard anatomical presentations, the right gonadal vein drains directly into the inferior vena cava, whereas the left gonadal vein empties into the left renal vein. Standard renal blood supply consists of a single renal artery arising from the abdominal aorta for each kidney. While these patterns are typical, clinical variations exist. Case Presentation: During routine cadaveric dissection of a 71-year-old male at a medical institution, a collection of concurrent, unilateral vascular anomalies was discovered. The donor presented with duplicate right testicular veins that converged prior to anomalously draining into the right renal vein rather than the inferior vena cava. Additionally, a co-occurring right inferior polar artery was observed originating directly from the abdominal aorta and traversing to the lower pole of the right kidney. Conclusions: This specific combination of a duplicated, aberrantly draining right testicular vein and a concurrent right inferior polar artery is unrepresented in current anatomical literature. Recognizing such anatomical variations is highly significant for modifying retroperitoneal surgical approaches, optimizing preoperative radiological mapping, and exploring potential clinical correlations with chronic health conditions such as hypertension.