Pathways and nerve densities in cerebrovascular innervation

It is gradually becoming clear that cerebrovascular nerves contribute to the control of the cerebral circulation although the knowledge of the functional mechanisms is far from complete. However, many aspects of the morphologic substrate have been identified. The basal cerebral arteries receive sympathetic, parasympathetic and sensory innervation, utilizing the superior cervical and stellate, the pterygopalatine and otic, and the trigeminal ganglia, respectively, as the main peripheral sources. Many of the neural pathways to the cerebral arteries have been elucidated. Those to the supratentorial arterial tree are distributed via the cavernous sinus and surrounding regions. Not only the "classical" neurotransmitters, but also many neuropeptides are found in cerebrovascular nerves. This will lead to new insights since the concepts of cotransmission and neuromodulation have been established now. In the arterial wall, a multilayered organization of nerves has been recognized, consisting of paravascular nerve bundles of passage, a superficial plexus and a terminal plexus located at the adventitial-medial border. Human basal cerebral arteries display a topographical heterogeneity of densities of terminal nerve plexuses. Highest nerve densities are found in arterial segments forming the circle of Willis, in the efferent part of the posterior cerebral artery and in the anterior choroidal artery. Nerve density appears to be determined by locality rather than vascular diameter. Furthermore, local decreases in nerve density are observed with ageing and disease in animals and humans.Biomedical Reviews 1995; 4: 35-46

The Legal and Ethical Framework Governing Body Donation in Europe - 2nd update on Current Practice.

BACKGROUND In 2008, members of the TEPARG provided first insights into the legal and ethical framework governing body donation in Europe. In 2012, a first update followed. This paper is now the second update on this topic and tries to extend the available information to many mor European contries. METHODS For this second update, we have asked authors from all European countries to contribute their national perspectives. By this inquiry, we got many contributions compiled in this paper. When we did not get a personal contribution, one of us (EB) searched the internet for relevant information. RESULTS Perspectives on the legal and ethical framework governing body donation in Europe. CONCLUSIONS We still see that a clear and rigorous legal framework is still unavailable in several countries. We found national regulations in 18 out of 39 countries; two others have at least federal laws. Several countries accept not only donated bodies but also utilise unclaimed bodies. These findings can guide policymakers in reviewing and updating existing laws and regulations related to body donation and anatomical studies

The virtual dissecting room : creating highly detailed anatomy models for educational purposes

INTRODUCTION: Virtual 3D models are powerful tools for teaching anatomy. At the present day, there are a lot of different digital anatomy models, most of these commercial applications are based on a 3D model of a human body reconstructed from images with a 1 millimeter intervals. The use of even smaller intervals may result in more details and more realistic appearances of 3D anatomy models. The aim of this study was to create a realistic and highly detailed 3D model of the hand and wrist based on small interval cross-sectional images, suitable for undergraduate and postgraduate teaching purposes with the possibility to perform a virtual dissection in an educational application. METHODS: In 115 transverse cross-sections from a human hand and wrist, segmentation was done by manually delineating 90 different structures. With the use of Amira the segments were imported and a surface model/polygon model was created, followed by smoothening of the surfaces in Mudbox. In 3D Coat software the smoothed polygon models were automatically retopologied into a quadrilaterals formation and a UV map was added. In Mudbox, the textures from 90 structures were depicted in a realistic way by using photos from real tissue and afterwards height maps, gloss and specular maps were created to add more level of detail and realistic lightning on every structure. Unity was used to build a new software program that would support all the extra map features together with a preferred user interface. CONCLUSION: A 3D hand model has been created, containing 100 structures (90 at start and 10 extra structures added along the way). The model can be used interactively by changing the transparency, manipulating single or grouped structures and thereby simulating a virtual dissection. This model can be used for a variety of teaching purposes, ranging from undergraduate medical students to residents of hand surgery. Studying the hand and wrist anatomy using this model is cost-effective and not hampered by the limited access to real dissecting facilities

The virtual dissecting room : creating highly detailed anatomy models for educational purposes

INTRODUCTION: Virtual 3D models are powerful tools for teaching anatomy. At the present day, there are a lot of different digital anatomy models, most of these commercial applications are based on a 3D model of a human body reconstructed from images with a 1 millimeter intervals. The use of even smaller intervals may result in more details and more realistic appearances of 3D anatomy models. The aim of this study was to create a realistic and highly detailed 3D model of the hand and wrist based on small interval cross-sectional images, suitable for undergraduate and postgraduate teaching purposes with the possibility to perform a virtual dissection in an educational application. METHODS: In 115 transverse cross-sections from a human hand and wrist, segmentation was done by manually delineating 90 different structures. With the use of Amira the segments were imported and a surface model/polygon model was created, followed by smoothening of the surfaces in Mudbox. In 3D Coat software the smoothed polygon models were automatically retopologied into a quadrilaterals formation and a UV map was added. In Mudbox, the textures from 90 structures were depicted in a realistic way by using photos from real tissue and afterwards height maps, gloss and specular maps were created to add more level of detail and realistic lightning on every structure. Unity was used to build a new software program that would support all the extra map features together with a preferred user interface. CONCLUSION: A 3D hand model has been created, containing 100 structures (90 at start and 10 extra structures added along the way). The model can be used interactively by changing the transparency, manipulating single or grouped structures and thereby simulating a virtual dissection. This model can be used for a variety of teaching purposes, ranging from undergraduate medical students to residents of hand surgery. Studying the hand and wrist anatomy using this model is cost-effective and not hampered by the limited access to real dissecting facilities

The innervation of the soft palate muscles involved in cleft palate : a review of the literature

OBJECTIVE: Surgical techniques to obtain adequate soft palate repair in cleft palate patients elaborate on the muscle repair; however, there is little available information regarding the innervation of muscles. Improved insights into the innervation of the musculature will likely allow improvements in the repair of the cleft palate and subsequently decrease the incidence of velopharyngeal insufficiency. We performed a literature review focusing on recent advances in the understanding of soft palate muscle innervation. MATERIAL AND METHODS: The Medline and Embase databases were searched for anatomical studies concerning the innervation of the soft palate. RESULTS: Our literature review highlights the lack of accurate information about the innervation of the levator veli palatini and palatopharyngeus muscles. It is probable that the lesser palatine nerve and the pharyngeal plexus dually innervate the levator veli palatini and palatopharyngeus muscles. Nerves of the superior-extravelar part of the levator veli palatini and palatopharyngeus muscles enter the muscle form the lateral side. Subsequently, the lesser palatine nerve enters from the lateral side of the inferior-velar part of the levator veli palatini muscle. This knowledge could aid surgeons during reconstruction of the cleft musculature. The innervation of the tensor veli palatini muscle by a small branch of the mandibular nerve was confirmed in all studies. CONCLUSION: Both the levator veli palatini and palatopharyngeus muscles receive motor fibres from the accessory nerve (through the vagus nerve and the glossopharyngeal nerve) and also the lesser palatine nerve. A small branch of the mandibular nerve innervates the tensor veli palatini muscle. CLINICAL RELEVANCE: Knowledge about these nerves could aid the cleft surgeon to perform a more careful dissection of the lateral side of the musculature

The innervation of the soft palate muscles involved in cleft palate : a review of the literature

OBJECTIVE: Surgical techniques to obtain adequate soft palate repair in cleft palate patients elaborate on the muscle repair; however, there is little available information regarding the innervation of muscles. Improved insights into the innervation of the musculature will likely allow improvements in the repair of the cleft palate and subsequently decrease the incidence of velopharyngeal insufficiency. We performed a literature review focusing on recent advances in the understanding of soft palate muscle innervation. MATERIAL AND METHODS: The Medline and Embase databases were searched for anatomical studies concerning the innervation of the soft palate. RESULTS: Our literature review highlights the lack of accurate information about the innervation of the levator veli palatini and palatopharyngeus muscles. It is probable that the lesser palatine nerve and the pharyngeal plexus dually innervate the levator veli palatini and palatopharyngeus muscles. Nerves of the superior-extravelar part of the levator veli palatini and palatopharyngeus muscles enter the muscle form the lateral side. Subsequently, the lesser palatine nerve enters from the lateral side of the inferior-velar part of the levator veli palatini muscle. This knowledge could aid surgeons during reconstruction of the cleft musculature. The innervation of the tensor veli palatini muscle by a small branch of the mandibular nerve was confirmed in all studies. CONCLUSION: Both the levator veli palatini and palatopharyngeus muscles receive motor fibres from the accessory nerve (through the vagus nerve and the glossopharyngeal nerve) and also the lesser palatine nerve. A small branch of the mandibular nerve innervates the tensor veli palatini muscle. CLINICAL RELEVANCE: Knowledge about these nerves could aid the cleft surgeon to perform a more careful dissection of the lateral side of the musculature

Intraneural or Extraneural Diagnostic Accuracy of Ultrasound Assessment for Localizing Low-Volume Injection

Background and Objectives: When one is performing ultrasound-guided peripheral nerve blocks, it is common to inject a small amount of fluid to confirm correct placement of the needle tip. If an intraneural needle tip position is detected, the needle can then be repositioned to prevent injection of a large amount of local anesthetic into the nerve. However, it is unknown if anesthesiologists can accurately discriminate intraneural and extraneural injection of small volumes. Therefore, this study was conducted to determine the diagnostic accuracy of ultrasound assessment using a criterion standard and to compare experts and novices in ultrasound-guided regional anesthesia. Methods: A total of 32 ultrasound-guided infragluteal sciatic nerve blocks were performed on 21 cadaver legs. The injections were targeted to be intraneural (n = 18) or extraneural (n = 14), and 0.5 mL of methylene blue 1% was injected. Cryosections of the nerve and surrounding tissue were assessed by a blinded investigator as "extraneural" or "intraneural." Ultrasound video clips of the injections were reviewed by 10 blinded observers (5 experts, 5 novices) independently who scored each injection as either "intraneural," "extraneural," or "undetermined." Results: The mean sensitivity of experts and novices was measured to be 0.84 (0.80-0.88) and 0.65 (0.60-0.71), respectively (P = 0.006), whereas mean specificity was 0.97 (0.94-0.98) and 0.98 (0.96-0.99) (P = 0.53). Conclusions: Discrimination of intraneural or extraneural needle tip position based on an injection of 0.5 mL is possible, but even experts missed 1 of 6 intraneural injections. In novices, the sensitivity of assessment was significantly lower, highlighting the need for focused education

Motor innervation of the corrugator supercilii muscle in relation to orbital landmarks : Guidelines for surgical denervation

Precise knowledge of the nerve supply of the corrugator supercilii muscle (CSM) is a prerequisite for performing a selective denervation of the CSM. The authors' goal was to determine the course and variability of the motor nerves of the CSM in relation to fixed orbital landmarks. The facial nerve branches toward the CSM were identified during microscopic dissection of 9 Caucasian formaldehyde-fixed cadaver half-heads. The distances between the branches and defined landmarks were measured. All branches to the transverse head of the CSM ran between 15 and 32mm superior to the lateral orbital margin. Medially the CSM was supplied by a superficial zygomatic, buccal, or bucco-zygomatic branch, which was much smaller than the temporal branches. This branch ran 4 to 7mm medial to the medial canthus. This anatomical knowledge can be applied for surgical denervation of the corrugator supercilii muscle. The authors suggest a surgical procedure for corrugator denervation through a blepharoplasty incision

Venous bypass drainage of the small saphenous vein in the neurovascular pedicle of the sural flap: Anatomical study and clinical implications

Background: Little is known about the necessary dimensions of the neurovascular pedicle of the sural flap for inclusion of the concomitant bypass veins of the small saphenous vein to secure sufficient retrograde venous flow. Therefore, the authors evaluated the anatomical basis for venous outflow of the sural flap and were able to give recommendations as to the necessary pedicle width for the flap to be transferred safely. Methods: The collateral bypass pathway of the small saphenous vein was studied in five formalin-preserved cadaver legs. The authors evaluated the usefulness of duplex sonography to visualize the venous collateral system of the small saphenous vein in five legs of healthy volunteers. Results: The pedicle width necessary to bypass the small saphenous vein ranged from 1.4 to 3.1 cm in the human cadavers and 0.09 to 1.5 cm in the duplex group. In both groups, only one side, medial or lateral to the small saphenous vein, was responsible for a total proximal-to-distal bypass. The opposite side partly bypassed the vein. Ultrasonography alone without Doppler was sufficient to visualize this variable suprafascial venous network. Conclusion: Preoperative evaluation of the venous system through duplex sonography is essential to localize on which side the bypass veins are present, making it possible to decrease the width of the pedicle without interfering with the reliability of the sural flap