A review of the anatomy and a step-by-step visual guide to performing an ultrasound-guided supraclavicular brachial plexus block

Background: The aim of this description is to provide step-by-step guidelines for performing an ultrasound-guided supraclavicularbrachial plexus nerve block. Methods: The brachial plexus in the supraclavicular fossa of sixty healthy volunteers was scanned in the horizontal/transverse plane. The relevant regional anatomy was studied to identify the muscular and vascular structures seen on the ultrasound screen. Results: The entire process was documented and a standard, step-by-step guide to performing ultrasound-guided supraclavicular brachial plexus blocks was developed. Conclusion: This description serves as a comprehensive guide to a technique for performing ultrasound-guided supraclavicular brachial plexus blocks safely and successfully. It also aims to provide the reader with the background knowledge of the technique and the surrounding regional anatomy

The thoracic surface anatomy of adult black South Africans: A reappraisal from CT scans.

Surface landmarks or planes taught in anatomy curricula derive from standard anatomical textbooks. Although many surface landmarks are valid, clear age, sex, and population differences exist. We reappraise the thoracic surface anatomy of black South Africans. We analyzed 76 (female = 42; male = 34) thoracoabdominal CT-scans. Patients were placed in a supine position with arms abducted. We analyzed the surface anatomy of the sternal angle, tracheal, and pulmonary trunk bifurcation, azygos vein termination, central veins, heart apex, diaphragm, xiphisternal joint, and subcostal plane using standardized definitions. Surface anatomy landmarks were mostly within the normal variation limits described in previous studies. Variation was observed where the esophagus (T9) and inferior vena cava (IVC) (T8/T9/T10) passed through the diaphragm. The bifurcations of the trachea and pulmonary trunk were inferior to the sternal angle. The subcostal plane level was positioned at L1/L2. The origin of inferior mesenteric artery was mostly inferior to the subcostal plane. Sex differences were noted for the plane of the xiphisternal joint (P = 0.0082), with males (36%) intersecting at T10 and females (36%) intersecting at T9. We provide further evidence for population variations in surface anatomy. The clinical relevance of surface anatomical landmarks depends on descriptions of normal variation. Accurate descriptions of population, sex, age, and body type differences are essential. Clin. Anat. 29:1018-1024, 2016. © 2016 Wiley Periodicals, Inc.

Retromolar foramen: an anatomical study with clinical considerations.

The retromolar canal and foramen, an anatomical variation in the mandibular retromolar area, houses and transmits neurovascular elements that may innervate the mandibular third molar and associated tissues. These structures have been implicated in local anaesthetic failure, loss of sensation in the normal distribution of the buccal nerve, and local haemorrhage during surgery. Examination of 885 dry mandibles showed that 70 had a retromolar foramen (8%). There were no significant differences between groups according to age, sex, or ancestry. The mean (SD) distance from molar to retromolar foramen was 16.8 (5.6) mm for the mandibular second molar and 10.5 (3.8) mm for the mandibular third molar. The link between these structures and failure of local anaesthesia seems tenuous at best. Bleeding may not represent a serious complication. Although there may be a possibility of perineural spread of infective and invasive pathology, we know of no reported cases. The only clear evidence of complications associated with a confirmed retromolar foramen seems to be loss of sensation in the normal distribution of the buccal nerve. Even though the retromolar foramen does not seem to be of great clinical importance, it could be a source of anxiety for the inexperienced practitioner.

Degenerative trends of the palmaris longus muscle in a South African population.

The literature reports that the palmaris longus muscle (PL) is only found in mammals in which the forelimbs are weight-bearing extremities. It is suggested that the function of this muscle has been taken over by the other flexors in the forearm. Terms used in the literature to describe the diminishing of this muscle include retrogressive or phylogenetic degenerative trends. The aims of this study were to determine the prevalence of PL in a South African population and whether a phylogenetic degenerative trend for the PL exists. To determine the prevalence of the PL, five groups, representing different age intervals (Years 0-20, 21-40, 41-60, 61-80, and 81-99) were used. A sample of 706 participants of various ages was randomly selected. Statistical analysis included comparisons of the prevalence of the muscle between males and females and left and right sides, using a student t-test. A Chi-squared test was used to determine a possible phylogenetic degenerative trend of PL within the five groups. The sample yielded a bilateral absence of the PL in 11.9% of the cases. The muscle was unilaterally absent on the left side in 7.65% and 6.94% on the right side. The Chi-squared tests revealed a P-value of 0.27 for the left arm and 0.39 for the right arm. No obvious trend could be established for the phylogenetic degeneration of the PL in this study. It would appear that the PL muscle should not be considered as a phylogenetically degenerating muscle in a South African population.

The value of Tuffier's line for neonatal neuraxial procedures.

The spine of L4 usually lies on a line drawn between the highest points of the iliac crests (Tuffier's line) in adults. Although its accuracy has been questioned, it is still commonly used to identify the spinous process of the 4th lumbar vertebra before performing lumbar neuraxial procedures. In children, this line is said to cross the midline at the level of L5. A literature search revealed that the description this surface anatomical line is vague in neonates. The aims of this study were to determine the vertebral level of Tuffier's line, as well as its distance from the apex of the sacrococcygeal membrane (ASM), in 39 neonatal cadavers in both a prone and flexed position. It was found that when flexed, Tuffier's line shifted from the level of L4/L5 (prone position) to the upper third of L5. The mean distance from the ASM to Tuffier's line was 23.64mm when prone and 25.47 mm when flexed, constituting a statistically significant increase in the distance (P=0.0061). Therefore, in the absence of advanced imaging modalities, Tuffier's line provides practitioners with a simple method of determining a level caudal to the termination of the spinal cord, at approximately the L4/L5 in a prone neonate and the upper margins of L5 when flexed.

Central venous catheterization--an anatomical review of a clinical skill. Part 2. Internal jugular vein via the supraclavicular approach.

The safe and successful performance of a central venous catheterization (CVC) requires a specific knowledge of anatomy in addition to a working knowledge. Misunderstanding the anatomy may result in failure or complications. This review aims to aid understanding of the anatomical framework, pitfalls, and complications of CVC of the internal jugular veins. CVC is common practice amongst surgeons, anesthesiologists, and emergency room physicians during the preparations for major surgical procedures such as open-heart surgery, as well as for intensive care monitoring and rapid restoration of blood volume. Associated with this technique are certain anatomical pitfalls and complications that can be successfully avoided if one possesses a thorough knowledge of the contraindications, regional anatomy, and rationale of the technique.

Bony landmarks as an aid for intraoperative facial nerve identification.

Identification of the facial nerve trunk is essential during surgery of the parotid gland. Numerous landmarks have been researched and used. The relation between the facial nerve to two constant bony landmarks, the tip of the mastoid process and the central point of the transverse process of the atlas was investigated. Forty cadavers were dissected. A preauricular incision exposed the nerve trunk. Bony landmarks were identified and marked. The distance from the nerve trunk to the mastoid process and the atlas was measured. The mean distance between the mastoid process and nerve for the left was 9.18 +/- 2.05 mm and for the right, 9.35 +/- 1.67 mm. The mean distance between the atlas and the nerve for the left was 14.31 +/- 3.59 mm and for the right, 13.76 +/- 4.65 mm. Confidence intervals were determined. The importance of the aforementioned data revolves around minimizing the chance of injury to the facial nerve during surgery. The applicability of these landmarks needs to be studied in the clinical setting.

Central venous catheterization -- an anatomical review of a clinical skill -- Part 1: subclavian vein via the infraclavicular approach.

The safe and successful performance of a central venous catheterization (CVC) requires a specific knowledge of anatomy in addition to a working knowledge. Misunderstanding the anatomy may result in failure or complications. This review aims to aid understanding of the anatomical framework, pitfalls, and complications of CVC of the subclavian (SCV). CVC is common practice amongst surgeons, anesthesiologists, and emergency room physicians during the preparations for major surgical procedures such as open-heart surgery, as well as, for intensive care monitoring and rapid restoration of blood volume. Associated with this technique are certain anatomical pitfalls and complications that can be successfully avoided if one possesses a thorough knowledge of the contraindications, regional anatomy, and rationale of the technique.

Relation of the external branch of the superior laryngeal nerve to the superior pole of the thyroid gland: an anatomical study.

The external branch of the superior laryngeal nerve (ELN) is intimately associated with the superior thyroid artery (STA) in relation to the superior pole of the thyroid gland, rendering it vulnerable to injury during the ligation of this vessel during thyroidectomy. Although most texts acknowledge the fact that the nerve is in close relation to the STA, there has not been an anatomical study to relate the position of the ELN to the superior pole of the thyroid gland. The aim of this study was to determine the shortest distance, from the most superior point of the thyroid gland, to the ELN. Bilateral micro-dissection on 43 adult cadavers, excluding those with thyroid pathology and previous thyroidectomies, was undertaken. The most superior point of the superior pole of the thyroid gland was identified and the shortest distance to the ELN was measured with a digital calliper (accuracy 0.01 mm). The metric study indicated a mean distance from the ELN to the superior pole of a normal sized thyroid gland of 5.76 mm (range: 2.00-11.26) on the right, and 6.17 mm (range: 2.78-13.48) on the left. From the literature, it is clear that the ELN may even be closer to the superior pole of an enlarged thyroid gland. The recommendation to stay on the substance of the superior pole of the thyroid gland when ligating the STA remains valid, as the nerve is extremely close in relation to the superior pole of the normal thyroid gland.

Anatomical considerations on Sudeck's critical point and its relevance to colorectal surgery.

Sudeck's critical point at the rectosigmoid junction is described as the point of origin of the last sigmoid arterial branch, originating from the inferior mesenteric artery (IMA). There is controversy on the importance of Sudeck's point, and the frequency in which the anastomosis is found. Furthermore, the diameter of the anastomosis, if present, may also impact on the viability of the caudal stump. This study aimed to determine the frequency in which a macroscopic anastomosis occurs, between the superior rectal artery and the last sigmoidal branch, in a cadaver population; the diameter of this anastomosis and the distance from the origin of the IMA to Sudeck's point. Sixty-four cadavers were included in the study, excluding those with previous surgery to the rectosigmoid junction. Sudeck's point was carefully identified and dissected to establish the presence of an anastomosis. Subsequent measurements were performed using a digital caliper (accuracy = 0.01 mm). A macroscopic anatomosis was absent in three cases (4.7%). The mean diameter of the anastomosis when present was 1.9 mm (SD: 0.5 mm), and the distance from the origin of the IMA to Sudeck's point was 55.5 mm (SD: 14.6 mm). Although an anastomosis is present in the majority of cases, the vessel is very small in diameter, and may not be sufficient to meet the demands of the caudal stump. The distance from the origin of the IMA to Sudeck's point is sufficient enough to allow for ligation of the IMA proximal to Sudeck's point.

Superficial radial nerve injury during standard K-wire fixation of uncomplicated distal radial fractures.

This study determines the incidence of superficial radial nerve injury after Kirchner wire insertion. An experienced orthopedic surgeon inserted the K-wires into the radii of 92 adult cadavers. Subsequent dissection of the area exposed the superficial radial nerve and any observed nerve injury was documented. It is clear from the results that nerve injury may still occur as a result of K-wire insertion; however, the current method of K-wire insertion still proves to be a reliable and safe procedure for fixation of distal radial fractures.

Anatomical considerations of the anterior approach for central venous catheter placement.

Central venous catheterization (CVC) entails the catheterization of the superior vena cava via either the subclavian or the internal jugular vein (IJV). This study looked at the frequency in which a needle was inserted into the IJV using the anterior CVC approach, which entails inserting the needle into the apex of Sedillot's triangle, formed by the sternal and clavicular heads of sternocleidomastoid (SCM). The ipsilateral distances from the apex of Sedillot's triangle to the superior aspect of the sternoclavicular joint and the diameter of the IJV were also measured. A needle was inserted into the apex of Sedillot's triangle in 36 adult cadavers with mean age of 62 +/- 19 years (mean +/- SD), mean height of 1.6 +/- 0.18 m, and a mean weight of 55 +/- 16 kg. Subsequent dissections of this area revealed the relation of the needle to the IJV. Results indicate that on the right, the needle was inserted into the IJV in 97.14% of the cases. On the left, the needle entered the IJV in 78.79% of the cases. From the sternoclavicular joint, the apex of Sedillot's triangle was found to be 40.87 +/- 1.62 mm and 38.73 +/- 6.34 mm on the right and left, respectively. The IJV diameter was 17.29 +/- 1.07 mm on the right and 15.30 +/- 0.25 mm on the left. We conclude that the anterior CVC approach is an anatomically accurate technique. It is furthermore important to realize that when performing any invasive procedure, a sound anatomical knowledge of the region is extremely important, as complications are often due to lack of understanding or misunderstanding of the relevant anatomy.

Anatomical considerations of the pediatric ilioinguinal/iliohypogastric nerve block.

BACKGROUND: The ilioinguinal/iliohypogastric nerve block is safe, effective and easy to perform in order to provide analgesia for a variety of inguinal surgical procedures in pediatric patients. A relatively high failure rate of 10-25% has been reported, even in experienced hands. The aim of this study was to determine the exact anatomical position of the ilioinguinal and iliohypogastric nerves in relation to an easily identifiable constant bony landmark, the anterior superior iliac spine (ASIS) in neonates and infants. The current ilioinguinal/iliohypogastric nerve block techniques were also evaluated from an anatomical perspective. METHOD: Dissections were performed on a sample of 25 infant and neonatal cadavers (mean weight = 2.2 kg; mean height = 45.6 cm). The distance from the ASIS to both the ilioinguinal and iliohypogastric nerves, on a line connecting the ASIS to the umbilicus was carefully measured using a digital caliper. Three techniques, commonly used in clinical practice, were simulated on the anatomical specimens. RESULT: The left and right ilioinguinal nerves were closer to the ASIS than previously described, i.e. 1.9 +/- 0.9 mm (mean +/- sd) and 2.0 +/- 0.7 mm, respectively. The mean distance from the left and right iliohypogastric nerves to the ASIS are 3.3 +/- 0.8 mm and 3.9 +/- 1.0 mm, respectively. CONCLUSIONS: We suggest that the high failure rate of the ilioinguinal/iliohypogastric nerve block in this age group could be due to lack of specific spatial knowledge of the anatomy of these nerves in infants and neonates. This cadaver-based study suggests an insertion point closer to the ASIS, approximately 2.5 mm (range: 1.0-4.9) from the ASIS on a line drawn between the ipsilateral ASIS and the umbilicus.

Recovery of Burkholderia cenocepacia strain PHDC from cystic fibrosis patients in Europe.

BACKGROUND: Burkholderia cenocepacia can cause life threatening respiratory tract infections in patients with cystic fibrosis (CF) and has a significant impact on survival. There is extensive evidence for patient to patient spread and nosocomial transmission of this organism, and several widespread B cenocepacia strains have been described including the transatlantic ET12 clone. A study was performed to compare B cenocepacia isolates recovered from CF patients receiving care in several European countries and strains isolated from other clinical samples and the environment, with reference isolates from the epidemic B cenocepacia strain PHDC which has so far only been recovered from CF patients and soil in the USA. METHODS: A large collection of B cenocepacia isolates, including a large number recovered from CF patients receiving care in several European countries, Canada and the USA, were genotyped by means of randomly amplified polymorphic DNA typing (RAPD) and rep-PCR using the BOX-A1R primer (BOX-PCR). RESULTS: Nineteen Burkholderia cenocepacia isolates cultured from clinical samples in Europe (18 recently recovered from CF patients in France and Italy and one recovered in 1964 from urine in the UK) showed RAPD fingerprinting patterns that were similar to patterns obtained from isolates of B cenocepacia strain PHDC. Subsequent analysis of these isolates using BOX-PCR confirmed that the European isolates and strain PHDC represent the same clone. CONCLUSION: Strain PHDC represents a second transatlantic B cenocepacia clone capable of colonising patients with CF.