Grzegorz Wysiadecki

The abducens nerve: its topography and anatomical variations in intracranial course with clinical commentary.

BACKGROUND The sixth cranial nerve (CN VI) - or the abducens nerve - in humans supplies only the lateral rectus muscle. Due to its topographic conditions, including angulations and fixation points along its course from the brainstem to the lateral rectus muscle, the CN VI is vulnerable to injury. Every case of CN VI palsy requires precise diagnostics, which is facilitated by an understanding of the anatomy. The present articles aims include a detailed study of the intracranial course of the CN VI, determination of occurrence of its particular anatomical variations, as well as presentation of some essential anatomical conditions which may conduce to CN VI palsy. Special emphasis was put on the correlation between craniometric measurements and a particular variation of the CN VI, which complements the data that can be found in literature. MATERIALS AND METHODS Twenty randomly selected specimens of cadaveric heads fixed in a 10% formalin solution were studied. The study used 40 specimens of the CN VI in order to examine its course variations within the section between the pontomedullary sulcus and the superior orbital fissure. RESULTS Detailed analysis of the CN VI topography and anatomy in its intracranial course revealed 3 anatomical variations of the nerve in the studied specimens. Variation I, found in 70% of cases, covers those cases in which the CN VI was found to be a single trunk. Those cases in which there was a branching of the CN VI exclusively inside the cavernous sinus were classified as variation II, occurring in 20% of cases. Cases of duplication of the CN VI were classified as variation III, found in 10% of the specimens. In 75% of cases of CN VI duplication one of the nerve trunks ran upwards from the petrosphenoidal ligament, outside Dorellos canal. CONCLUSIONS The CN VI throughout its intracranial course usually runs as a single trunk, however, common variations include also branching of the nerve in the cavernous sinus or duplication. Topographic relations of the CN VI with adjacent structures account for the risk of injuries which may be caused to the nerve as a result of a disease or surgical procedures.

The report on the co-occurrence of two different rare anatomic variations of the plantaris muscle tendon on both sides of an individual.

The plantaris muscle usually begins with a short and small muscle belly on the popliteal surface of the femur and on the knee joint capsule. It continues distally to form a long and thin tendon typically fixed to the calcaneal tuberosity. However, the course and the insertion of the plantaris muscle is variable, which may influence the development of Achilles tendinopathy. The plantaris tendon may also be used for reconstruction of tendons and ligaments, such as talofibular and calcaneofibular ligament. In literature review no data concerning the co-occurrence of anatomic variations of the plantaris muscle tendon in different individuals has been found. This report presents a rare variant of the plantaris muscle insertion into the deep crural fascia on the left leg and absence of the plantaris muscle on the right leg of the same individual.

Accessory (multiple) renal arteries – Differences in frequency according to population, visualizing techniques and stage of morphological development

The aim of this paper is to comprehensively analyze the literature focused on frequency of the presence of the accessory renal arteries in the human body. A systematic analysis of papers has been made. With regard to ethnicity, the incidence of accessory renal arteries fluctuates from 4% in a Malaysian population to 61.5% in a Brazilian population. The frequency is lowest in eastern and southern Asia (from 4% to 18.4%). In some, not ethnically homogenous populations, wide span of occurrence of accessory renal arteries is described (e.g. American – averaging from 18% to 28.8%). A higher frequency of accessory renal arteries was observed in fetuses compared to adults. Moreover, differences in the presence and number of accessory renal arteries reported in different papers are a consequence of type of visualizing technique used in research – especially when computed tomography and anatomical dissection were compared. The increasing number of surgical interventions, especially where laparoscopic methods are concerned, underlines the importance of such knowledge especially to surgeons, interventional radiologists, nephrologists, and vascular surgeons.

An unusual variant of the abducens nerve duplication with two nerve trunks merging within the orbit: a case report with comments on developmental background

This study reports the first case of abducens nerve duplication along its entire intracranial course, ending within the orbit. A distinct abducens nerve duplication reaching the common tendinous ring (annulus of Zinn), as well as another split within the intraconal segment of the nerve have been revealed. Additionally, two groups (superior and inferior) of abducens nerve sub-branches to the lateral rectus muscle were visualised using Sihler’s stain. The analysed anatomical variation has never been reported before and it seems to be in the middle of the spectrum between the cases of duplication occurring only within the intracranial segments of the abducens nerve found in the literature and those continuing throughout the whole course of the nerve. Abducens nerve duplication may be treated as a relic of early stages of ontogenesis. Such a variant might result from alternative developmental pathways in which axons of the abducens nerve, specific for a given segment of the lateral rectus muscle, run separately at some stage, instead of forming a single stem.

Persistent jugulocephalic vein: case report including commentaries on distribution of valves, blood flow direction and embryology

This paper is a detailed case study of the persistent anastomotic channel between the cephalic vein and the external jugular vein, running anterior to the clavicle, corresponding to the jugulocephalic vein present at early stages of the ontogenesis in humans. This connection is not only a relic of early foetal development seldom occurring in adults, but it may also be of clinical significance, increasing the risk of complications during the cephalic vein catheterisation, clavicular fractures or head and neck surgery. The novelty in this paper was to determine the presence and distribution of valves within the persistent jugulocephalic vein. Three bicuspid venous valves were found that allowed the blood to flow only in one direction - from the cephalic vein to the external jugular vein. The anastomosis between the persistent jugulocephalic vein and the thoracoacromial veins was additionally present. Due to lack of similar data in the literature, further research should be performed on the presence and distribution of the venous valves in various types of the persistent jugulocephalic vein in humans.

Morphological variations of intra-testicular arterial vasculature in bovine testis - a corrosion casting study

BackgroundProper blood supply is necessary for the physiological function of every internal organ. The article offers the first classification of the bovine intra-testicular arteries. A corrosive study focused on the intra-testicular arterial vasculature was performed on 40 bovine testes. The vessels were analyzed accurately using MultiScanBase v.18.02 software.MethodsA corrosive study focused on the intra-testicular arteries was performed on 40 bovine testes. The vessels were analyzed accurately using MultiScanBase v.18.02 software.ResultIn bulls, the centripetal arteries tended to run straight to the mediastinal region, where they form knot-like vascular structures. Those structures are the origin for centrifugal recurrent branches, running peripherally. However, three basic types of intra-testicular arterial vasculature were noted. Type I had centrifugal, recurrent branches, running peripherally towards the surface of the testis but did not reach the tunica albuginea. Type II exhibited centrifugal, recurrent branches running more horizontally than type I. Type III is the most heterogeneous type, composed of other variform types of arteries not classified as type I or type II. Type II was most commonly observed as a vascular conglomerate of intra-testicular arteries within the arterial network of the mediastinum testis. In type III, artery diameter was significantly smaller than observed in types I and II (p < 0.01). Types I and II did not differ between each other regarding artery diameter (p > 0.05).ConclusionVariations of the intra-testicular arterial vasculature in bovine testis may suggest that particular types of vessels play different physiological roles. The most common type of intra-testicular artery comprising the arterial network of the mediastinum testis was type II.

What Each Clinical Anatomist Has to Know about Left Renal Vein Entrapment Syndrome (Nutcracker Syndrome): A Review of the Most Important Findings

Nutcracker syndrome (NCS) is the most common term for compression of the left renal vein between the superior mesenteric artery and the abdominal aorta. The development of NCS is associated with the formation of the left renal vein (LRV) from the aortic collar during the sixth to eighth week of gestation and abnormal angulation of the superior mesenteric artery from the aorta. Collateralization of venous circulation is the most significant effect of NCS. It includes mainly the left gonadal vein and the communicating lumbar vein. Undiagnosed NCS may affect retroperitoneal surgery and other radiological and vascular procedures. The clinical symptoms of NCS may generally be described as renal presentation when symptoms like haematuria, left flank pain, and proteinuria occur, but urologic presentation is also possible. Radiological methods of confirming NCS include Doppler ultrasonography as a primary test, retrograde venography, which can measure the renocaval pressure gradient, computed tomography angiography, which is faster and less traumatic, intravascular ultrasound, and magnetic resonance angiography. Treatment can be conservative or surgical, depending on the severity of symptoms and degree of LRV occlusion. Nutcracker syndrome is worth considering especially in differential diagnosis of haematuria of unknown origin.

The Epidemiological, Morphological, and Clinical Aspects of the Cervical Ribs in Humans.

A familiarity with the anatomy of some types of bone anomalies is necessary for clinicians involved in many medical areas. The aim of this paper is to review the newest literature concerning the morphology, embryology, clinical image, and therapeutic methods of the cervical ribs in the humans. The incidence of cervical ribs has been found to vary from 0.58% in Malaysian population to 6.2% in Turkish population. Cervical ribs have clinical implications that are generally divided into neurological or vascular. This study is of particular importance for clinicians, as early identification of cervical ribs may prevent life-threatening complications.

Types of coeliac trunk branching including accessory hepatic arteries: a new point of view based on cadaveric study

The coeliac trunk is major visceral branch of the abdominal aorta. Familiarity with anatomic variations of the coeliac trunk is relevant for planning radiological and surgical procedures. The aim of our research was determining variations of the coeliac trunk, including the occurrence of accessory hepatic arteries. 40 cadavers were studied. Six patterns of coeliac trunk branching were observed in this study. Accessory hepatic arteries were observed in seven specimens (17.5%). The most prevalent variation was normal trifurcation, accounting for 62.5% of cases. The rarest variation was absence of the coeliac trunk, with an incidence of 2.5%. In this variant the left gastric artery, the common hepatic artery, and the splenic artery branched directly off the abdominal aorta. The study material allowed to distinguish two coeliac tunk branching patterns which, to the best of our knowledge, have not been reported before. It was a type with four branches originating from the coeliac trunk: the left gastric artery, the common hepatic artery, the splenic artery, and right accessory hepatic artery. The other previously unreported pattern variant was also a coeliac trunk which gave off the coeliac trunk gave off three branches: the common hepatic artery, the splenic artery and right accessory hepatic artery. The average distance between the aortic hiatus and the coeliac trunk calculated for all the cadavers amounted to 54 mm (SD = 11.85 mm). The average distance between the coeliac trunk and the superior mesenteric artery was 11.1 mm (SD = 7.7 mm).

Anterior Coracoscapular Ligament as a Factor Predisposing to or Protective for Suprascapular Neuropathy

Suprascapular neuropathy is a pathology caused by injury or compression of the suprascapular nerve. As the nerve runs from the anterior to posterior side of the scapula, the hot point where it is most susceptible to both injury and compression is the suprascapular notch. A literature search reveals several potential predisposing morphological factors in this area. However the most recent reports indicate that the structures at the suprascapular notch region may also prevent nerve injury and compression. The role of the anterior coracoscapular ligament (ACSL) remains unclear. While some studies indicate that it may predispose to suprascapular neuropathy, the newest study proposes a protective function. The aim of the article was to review the function of the anterior coracoscapular ligament in the light of the most recent studies. An understanding of the role of the ligament is essential for arthroscopic and other surgical procedures of this area in order to avoid iatrogenic injury of the suprascapular nerve.