Comparison of the median and intermediate approaches to the ultrasound-guided sacral erector spinae plane block: a cadaveric and radiologic study.

BACKGROUND: Erector spinae plane block (ESPB) is a well-established method for managing postoperative and chronic pain. ESPB applications for the sacral area procedures are called sacral ESPBs (SESPBs). This cadaveric study aimed to determine the distribution of local anesthesia using the median and intermediate approaches to the SESPB. METHODS: Four cadavers were categorized into the median and intermediate approach groups. Ultrasound-guided SESPBs were performed using a mixture of radiopaque agents and dye. Following confirmation of the solution distribution through computed tomography (CT), the cadavers were dissected to observe the solution distribution. RESULTS: CT images of the median group demonstrated subcutaneous pooling of the radiopaque solution between the S1 and S5 horizontal planes. Radiopaque solution also passed from the sacral foramina to the anterior sacrum via the spinal nerves between S2 and S5. In the intermediate group, the solution distribution was observed along the bilateral erector spinae muscle between the L2 and S3 horizontal planes; no anterior transition was detected. Dissection in the median group revealed blue solution distribution in subcutaneous tissue between horizontal planes S1 and S5, but no distribution in superficial fascia or muscle. In the intermediate group, red solution was detected in the erector spinae muscle between the L2 and S3 intervertebral levels. CONCLUSIONS: Radiologic and anatomic findings revealed the presence of radiopaque dye in the superficial and erector spinae compartments in both the median and intermediate groups. However, anterior transition of the radiopaque dye was detected only in the median group.

An anatomical study of the pharyngeal plexus: Application to avoiding postoperative dysphagia following anterior approaches to the cervical spine.

We aimed to localize the pharyngeal branches of the pharyngeal plexus to preclude postoperative complications such as dysphagia resulting from injury to those branches. Cranial nerves IX and X and the sympathetic trunk were dissected on 10 sides in the necks of embalmed adult cadavers of European descent to identify the pharyngeal branches so that anatomical landmarks could be identified and injury thereby avoided. In all sides, the pharyngeal branches originated from the glossopharyngeal and vagus nerves and the superior cervical ganglion and entered the posterior pharyngeal wall at the C2-C4 levels within 10 mm medial to the greater horn of the hyoid bone. All pharyngeal branches were anterior to the alar fascia. Based on our anatomical study, vagus nerve branches to the pharyngeal muscles enter at the C3/C4 vertebral levels. Such knowledge might help decrease or allow surgeons to predict which patients are more likely to develop dysphagia after cervical spine surgery.

Morphological characteristics of the posterior neck muscles and anatomical landmarks for botulinum toxin injections.

PURPOSE: Cervical dystonia is a common movement disorder for which botulinum toxin (BoNT) is the first choice treatment. Injecting the specific neck muscles can be challenging because of their thin morphology and deep locations. We, therefore, designed a study to investigate the locations of the posterior neck muscles to help the physician predict the locations of the targeted neck muscles and to protect the vertebral vessels from injury during deep injections. METHODS: The posterior neck region was divided into four quadrants by imaginary lines passing vertically and transversely through the spinous process of C2 vertebra (C2sp). The thicknesses and depth of the posterior neck muscles were measured in ten formaldehyde-fixed adult male cadavers. These muscles were located and a projection of them was drawn on the neck. Using the measurements, colored latex in place of BoNT was injected into them in one cadaver. The cadaver was dissected to investigate whether the muscles were colored. RESULTS: 2 cm above the C2sp, trapezius, splenius capitis (SPC) and semispinalis capitis (SSC) were colored at depths of 10.70 mm, 11.88 mm and 15.91 mm, respectively. 2 cm below the C2sp, the trapezius, SPC and SSC were colored at depths of 20.89 mm, 23.25 mm and 27.63 mm, respectively. The posterior neck muscles were had taken up their assigned colors when they were injected according to the results obtained in this study. The vertebral vessels were not colored. CONCLUSIONS: Although BoNT injection into the posterior neck muscles is challenging, we think that it can be practically and safely applied using the measurements obtained in this study.

Lower cranial nerve syndromes: a review.

The purpose of this paper is to provide a comprehensive review encompassing the syndromes associated with the lower cranial nerves (LCNs). We will discuss the anatomy of some of these syndromes and the historical contributors after whom they were named. The LCNs can be affected individually or in combination, since the cranial nerves at this level share their courses through the jugular foramen and hypoglossal canal and the extracranial spaces. Numerous alterations affecting them have been described in the literature, but much remains to be discovered on this topic. This paper will highlight some of the subtle differences among these syndromes. Symptoms and signs that have localization value for LCN lesions include impaired speech, deglutition, sensory functions, alterations in taste, autonomic dysfunction, neuralgic pain, dysphagia, head or neck pain, cardiac or gastrointestinal compromise, and weakness of the tongue, trapezius, or sternocleidomastoid muscles. To assess the manifestations of LCN lesions correctly, precise knowledge of the anatomy and physiology of the area is required. Treatments currently used for these conditions will also be addressed here. Effective treatments are available in several such cases, but a precondition for complete recovery is a correct and swift diagnosis.

The falciform ligament: Anatomical study with microsurgical implications.

OBJECTIVES: The current study aims to increase awareness of the falciform ligament and its anatomical and surgical relationships, for the benefit of the neurosurgeon. PATINENTS AND METHODS: Twenty-four sides from twelve Caucasian cadaveric heads (all fresh-frozen) were used in this study. The length and thickness of the falciform ligament were recorded. The relationship of the falciform ligament to the optic nerve was also observed and documented. Finally, the force needed to avulse the falciform ligament was recorded. RESULTS: In all specimens, the ligament was identified as a continuation of the outer dural layer, forming a roof at the entrance of the optic canal. The mean medial-to-lateral length, anteroposterior length, and thickness of the falciform ligament were 7.97 mm, 2.12 mm, and 0.26 mm, respectively. The mean distance from the medial attachment of the ligament to the midline was 5.54 mm. For the undersurface of the falciform ligament, the optic nerve occupied the middle third in 50.0 %, the lateral third in 44.4 %, and the medial third in 5.6 % of sides. The mean optic nerve diameter at the entrance of the optic canal was 4.20 mm. The mean failure force was 2.47 N. CONCLUSION: The anatomical measurements and relationships provided in this description of the falciform ligament serve as a tool for surgery selection and planning, as well as an aid to improving microsurgical techniques, with the final goal being better patient outcomes.

Anatomic Analysis of the Internal and External Aspects of the Pterion.

OBJECTIVE: The pterion is an H-shaped suture complex. This study's goal was to determine the location of its external and internal surfaces and extension and emphasize and discuss its surgical importance. METHODS: Fifty dried adult human skulls were obtained from the Department of Anatomy. A 2-mm drill bit was placed externally over the pterion, and the pterion was drilled through the bone perpendicular to the skull's surface. RESULTS: The midpoint of the H shape in the pterion area was not at the same level on the skull's external and internal pterion surfaces. According to these measurements, the external pterion lay above the internal pterion when the skull was viewed externally. Furthermore, the internal pterion was on average longer than the external pterion. The internal and external pterions were schematized such that the skull was viewed from the outside. These areas were divided into 4 quadrants (anterior-superior, anterior-inferior, posterior-superior, and posterior-inferior) by a vertical and horizontal line. In 30 cases (60%), sulci of the middle meningeal artery's parietal branches entered the posterior-superior quadrant on the bone, whereas the artery's frontal branches were located in the anterior-superior and anterior-inferior quadrants, and the Sylvian fissure's origin was in the posterior-inferior quadrant. CONCLUSIONS: By using a subdivision into 4 quadrants, and considering our anatomic findings, we determined the way surgical procedures can be performed more easily and reliably. Even with modern localization technologies, anatomic landmarks can be useful to the neurosurgeon.

The segmentation of the posterior cerebral artery: a microsurgical anatomic study.

There are still different descriptions of the segmentation of the posterior cerebral artery, although there is a radiological and anatomical consensus on the segmentation of the anterior and the middle cerebral artery. This study aims to define the most appropriate localization for origin and end points of the segments through reviewing the segmentation of the posterior cerebral artery. The segments and the cortical branches originating from those segments of the 40 posterior cerebral arteries of 20 cadaver brains were examined under operating microscope. In this research, the P1, P2, P3, P4, and P5 classification of the segmentation of the posterior cerebral artery is redefined. This redefinition was made to overcome the complexities of previous definitions. The P1 segment in this research takes its origin from the basilar tip and ends at the junction with the posterior communicating artery. The average diameter of this segment at the origin was 2.21 mm (0.9-3.3), and the average length was 6.8 mm (3-12). The P2 segment extends from the junction with the posterior communicating artery to the origin of the lateral temporal trunk. This point usually situates on one level of posterior of the cerebral peduncle. The average diameter of this segment at the origin was 2.32 mm (1.3-3.1), and the average length was 20.1 mm (11-26). The P3 segment extends from the origin of the lateral temporal trunk to the colliculus where both the posterior cerebral arteries are the nearest to each other (quadrigeminal point) and is located at the anterior-inferior of the splenium. The average diameter of this segment at the origin was 1.85 mm (1.2-2.7), and the average length was 16.39 mm (9-28). The P4 begins at the quadrigeminal point and ends at the top of the cuneus. The average diameter of this segment at the origin was 1.55 mm (1.1-2.2). While the P5 segment is named as the terminal branches of the major terminal branches of the posterior cerebral artery, no definite border was found between the P4 and the P5 segments. In this study, the segmentation of the posterior cerebral artery, developed by Krayenbühl and Yasargil, was redefined to be more appropriate for radiological and anatomical purposes.

The Anatomy of Circulus Arteriosus Cerebri (Circle of Willis): A Study in Turkish Population.

AIM: The function of the circle of Willis, an arterial polygon, is to protect the brain from ischemia. The aim of this study is to define the structural characteristics of the circle of Willis within the Turkish adult population, along with variations and arteries involved in the measurement of diameters and lengths on cadavers. MATERIAL AND METHODS: The circle of Willis was evaluated in 100 fresh adult cadavers. Structures of the circle of Willis were evaluated as being typical or atypical images and according to the diameter of AComP. All arteries forming the circle's length and diameters were measured. RESULTS: All arteries forming the circle of Willis as 91% were anatomically observed. The typical structure in which hypoplasia arteries is not involved was obtained as 8%. The atypical circle of Willis with aplasia was seen as 9%. 87% of adult, 9% fetal, and 4% transitional configuration in the samples were detected. The variations of the circle of Willis were more common in the posterior portion. Hypoplasia was found to be the most common variation and noted as a maximum in AComP (85%). Aplasia was noted as the second most common variation after hypoplasia and again the most common in AComP (5%). CONCLUSION: Advances in radiological methods which provide images of cerebral vessels and the development of cerebrovascular surgery have increased the importance of the circle of Willis in neurosurgery and neurology. The structure of the circle of Willis is of great importance in occlusive cerebrovascular diseases and cerebrovascular surgery.

Assessment of the Circle of Willis with Cranial Tomography Angiography.

BACKGROUND: The circle of Willis is a major collateral pathway important in ischemic conditions. The aim of our study was to assess the structural characteristics of the circle of Willis within the Turkish adult population, along with variations and arteries involved in the measurement of diameters and lengths on cranial computed tomography angiography (CTA). MATERIAL AND METHODS: One hundred adult patients who underwent CTA images were evaluated retrospectively. RESULTS: Results of the study revealed 82% adult, 17% fetal, and 1% transitional configurations. A complete polygonal structure was observed in 28% of cases. Variations of the circle of Willis were more common in the posterior portion. Hypoplasia was found to be the most common variation and was observed as a maximum in the posterior communicating artery (AComP). CONCLUSIONS: The patency and size of arteries in the circle of Willis are important in occlusive cerebrovascular diseases and cerebrovascular surgery. Although CTA is an easily accessible non-invasive clinical method for demonstrating the vascular structure, CTA should be evaluated taking into account image resolution quality and difficulties in the identification of small vessels.

Tendon interposition and ligament reconstruction with ECRL tendon in the late stages of Kienböck's disease: a cadaver study.

BACKGROUND: The optimal surgical treatment for Kienböck's disease with stages IIIB and IV remains controversial. A cadaver study was carried out to evaluate the use of coiled extensor carpi radialis longus tendon for tendon interposition and a strip obtained from the same tendon for ligament reconstruction in the late stages of Kienböck's disease. METHODS: Coiled extensor carpi radialis longus tendon was used to fill the cavity of the excised lunate, and a strip obtained from this tendon was sutured onto itself after passing through the scaphoid and the triquetrum acting as a ligament to preserve proximal row integrity. Biomechanical tests were carried out in order to evaluate this new ligamentous reconstruction. RESULTS: It was biomechanically confirmed that the procedure was effective against axial compression and distributed the upcoming mechanical stress to the distal row. CONCLUSION: Extensor carpi radialis longus tendon has not been used for tendon interposition and ligament reconstruction in the treatment of this disease before. In view of the biomechanical data, the procedure seems to be effective for the stabilization of scaphoid and carpal bones.

Quantitative evaluation of the anatomical parameters for subaxial cervical spondylectomy: an anatomical study.

OBJECT: The object of this investigation was to conduct a morphometric study in cadavers to determine anatomical structures, their relationships, and their morphometry for subaxial cervical spondylectomy. METHODS: Forty sides of 20 cadavers were used for this study. Dissections were performed in 2 stages (anteriorly and posteriorly). Twenty-one morphometric measurements were performed for both sides of the C3-6 vertebrae. Data were analyzed statistically. RESULTS: Morphometry of the laminas, tuberculum posterius, pedicle, corpus, foramen transversarium, and processus costalis were measured. CONCLUSIONS: Detailed quantitative anatomical knowledge for operations requiring wide dissection and resection, such as cervical spondylectomy, lowers the morbidity rate.

Investigation of recurrence risk in laryngeal cancer following laser surgery.

BACKGROUND: The general prognostic factors in larynx tumors are believed to be tumor stage, anatomical location, histological differentiation and the presence of neck metastasis. Effects of tumor invasion to sub-regions of larynx (anterior commissure, ventricle, subglottic space) and over-expression of p53, c-erb-B2 and Ki67 detected immunohistochemically on development of recurrence in patients were investigated in this study. METHODS: Twenty patients (Group 1) in whom recurrence had developed and 20 others (Group 2) without recurrence during follow-up were included in this study. RESULTS: Both the anterior commissure and ventricle involvements were found to be more frequent in patients with recurrence. But statistically significant difference was detected with only ventricular involvement (p=0.025). After Immunohistochemical evaluation none of the 3 immunohistochemical parameters were found to be higher in the recurrence group and not any of them showed a statistically significant difference between two groups. CONCLUSION: Only ventricle involvement may be a predictor factor for recurrence.

Does the sphenoid angle effect the operation strategy? Anatomical and radiological investigation.

AIM: The aim of our study is to suggest the sphenoid wing-lesser wing angulation (SWA) importance during surgeries directed to this region. MATERIAL AND METHODS: SWA on 40 skulls were measured bilaterally (n=80). The depth of the middle cranial fossa (DMCF) at the level of the SWA was determined. The same measurements were done on 40 randomly selected computerized tomography (CT) scans bilaterally (n=80). RESULTS: The specimens were classified into 3 groups according the degree of SWA; Group-A, SWA was more than 130° (27%), Group-B, SWA was 110-130° (43%) and Group-C, SWA was less than 110° (28%). MCF was measured (mean) as 10.1 mm in Group-A, 6.4 mm in Group-B and 4.6 mm in Group-C. MCF was increasing with the increase in SWA. CT scans were classified into same procedure. Group-A was 26%, Group-B was 42% and Group-C was 31% fitting in the relevant groups. The superior orbital fissure (SOF) was evaluated according to the Sharma's classification. CONCLUSION: We suggest that by the preoperative evaluation of CT scans measurements the SWA, it is possible to estimate the MCF and the type of SOF. This knowledge may be important for all surgeries requiring removal of the sphenoid wing and these region pathologies.

Anatomic basis of percutaneous Kirschner wire insertion in zygoma fractures.

The combination of Gillies elevation with 1-point percutaneous Kirschner wire fixation of isolated simple zygoma fractures was found to be effective in restoring preinjury appearance and function and avoiding soft tissue morbidity. The proximity of the infraorbital nerve, inferior orbital rim, and dental roots warrants care in the placement of the wire. The need for precise anatomic guidelines becomes apparent when considering these relationships. Eighteen adult skulls (36 sides) were examined, and specific points were determined that could be important while inserting Kirschner wire for zygoma fractures, and the distances between those points were measured with a digital caliper. Then, by using these points, the wire was inserted into the zygoma through the medial wall of the maxillary sinus, and the insertion point of the wire on the lateral wall of the maxilla and the angle of the wire were determined. The mean lengths of the wires of the right and left sides of each skull were counted, and for 18 skulls, the mean length of the wire was measured as 45.12 mm. Direction of the insertion during drilling zygoma, conversely to the location of the insertion, nearly determines the course of the wire and the point of insertion on the lateral wall of the maxilla. Obtaining precise information concerning the installation angle and length of the wire before surgery should contribute to safer and smoother surgical procedures.

A novel approach for anterior sciatic nerve block: cadaveric feasibility study.

BACKGROUND: Sciatic nerve block is a commonly used technique for providing anesthesia and analgesia to the lower extremity. It is classically performed through posterior or lateral approaches. However, an anterior approach should be considered in certain conditions where patient positioning would be complicated. The success rate of the sciatic nerve block with previously defined approaches has been reported to be low, however, the complication rate with such approaches has been found to be high. Therefore, we aimed to conduct an anatomical study defining a new anterior approach to block the sciatic nerve and also to examine if the femoral nerve can be blocked via the same approach. METHODS: Initially, various landmarks and practical measurements were examined on 11 lower extremities. Eight of the lower extremities were used for defining the best approach to the sciatic nerve anteriorly. Once defined, Indian ink was injected into two cadaveric extremities with an anesthetic needle through such an approach. The route of the needle was evaluated via dissection and we observed whether the ink stained the sciatic nerve or injured regional neurovascular structures. The remaining extremity was cut axially to observe the route of the needle after injection. RESULTS: The ideal site of needle insertion was found to be 4-5 cm distal to the inguinal crease and 1-2 cm lateral to the femoral artery. On average, this point corresponded to a point located 8.0 ± 0.7 cm distal to a perpendicular line drawn midway through the straight line connecting the anterior superior iliac spine (ASIS) and the pubic tubercle (PT). The distance of this point to the straight line drawn between the ASIS and PT was approximately equal to half the distance of this line. CONCLUSION: The technique described herein appears anatomically safe with a lower risk of damage to major neurovascular structures. Additionally, the femoral nerve can be blocked simultaneously to obtain a larger area of anesthesia of the lower limb.

Regional anatomic structures of the elbow that may potentially compress the ulnar nerve.

HYPOTHESIS: Traumatic injuries to the ulnar nerve at the elbow are a frequent problem as it is vulnerable to stretching and compression with motion of the upper limb. The aim of the present study was to explore the course of the ulnar nerve at the elbow and forearm and to determine possible anatomical structures that may cause compression of this structure. MATERIALS AND METHODS: We examined 12 upper limbs from cadavers. The length of any fibrous bands, and if present, their distance to the medial epicondyle was recorded. RESULTS: On 5 sides a fibrous band originating from the medial intermuscular septum was observed to cross over the ulnar nerve. The average length of the fibrous band was 5.7 cm, and it attached to the medial epicondyle. The mean length of the ulnar nerve as it coursed in the cubital tunnel was 3.8 cm. In 4 of the cases, the ulnar nerve was covered by muscle fibers originating from the flexor digitorum superficialis and extending to the flexor carpi ulnaris. On 5 sides we observed fibrous thickenings, and on 8 sides vascular structures were found crossing over the ulnar nerve. DISCUSSION: The cubital tunnel is the most common site of compression of the ulnar nerve. Numerous surgical procedures are recommended for cubital tunnel syndrome. Simple decompression is used most commonly. Although surgical procedures are reported to provide efficient pain relief and functional recovery, residual or recurrent symptoms have been reported. Reasons for such recurrences may be more proximal or distal compression of the ulnar nerve as seen in our study. CONCLUSION: Knowledge of possible compression sites of the ulnar nerve is important to the surgeon so that complications are avoided and postoperative recurrence is decreased. LEVEL OF EVIDENCE: Basic science study.

Anatomy of the lateral intermuscular septum of the arm and its relationships to the radial nerve and its proximal branches. Laboratory investigation.

OBJECT: Other than very simple descriptions of the existence of the lateral intermuscular septum (LIS), the literature offers almost nothing about its detailed anatomy, relationships to the radial nerve, and proximal branches. To further elucidate its morphological characteristics, the present cadaveric study was performed. METHODS: The lateral arm was bilaterally dissected from 25 adult fixed cadavers (50 sides). Specifically, a detailed evaluation of the LIS was made, and this structure's attachments and relationships to the radial nerve were analyzed and measured. RESULTS: In addition to the previously described muscles arising from the LIS, the authors identified the extensor carpi radialis brevis muscles as partially arising from this structure. The deep and posterior portion of the deltoid tendon was confluent with the superior aspect of the LIS. The mean thickness of the LIS was 1.0 mm. Distally, the LIS attached strongly to the lateral epicondyle of the humerus and became confluent with the annular ligament encircling the head of the radius. The distal attachment of the LIS was confluent with the capsule of the elbow joint. All radial nerves traveled through a defect (mean diameter 1 cm) in the LIS. With traction on the nerve from proximal and distal to this defect, there was free excursion. In 85% of the specimens, however, the posterior antebrachial cutaneous nerve traveled through a tunnel within the LIS and pierced the septum at a mean of 5 cm proximal to the lateral epicondyle. The lower lateral brachial cutaneous nerve proximally pierced the LIS near its origin, occurring a mean of 3.2 cm distal to the LIS's origin from the humerus. CONCLUSIONS: To the authors' knowledge, the details regarding the LIS and its relationships to the radial nerve have not been reported. Such information may be of use to surgeons who operate in this region, for example, during neural repair or entrapment procedures.

The clinical anatomy of the ligament of Barkow at the proximal tibiofibular joint.

INTRODUCTION: Mention of the ligament of Barkow at the proximal tibiofibular joint is rarely found in the literature and it is not represented in most anatomical atlases. To our knowledge, quantitation of this structure has not been performed. As injury to the knee region is so common, a comprehensive knowledge of this regional anatomy is important to the clinician and surgeon alike. MATERIALS AND METHODS: Forty lower limbs from embalmed cadavers underwent dissection of the proximal leg with special attention toward the presence or absence of ligament of Barkow. When identified, measurements of this structure were made. RESULTS: The ligament of Barkow was identified in 95% of specimens. For right sides, the mean width was 1.5 cm and the mean length was 1.2 cm. For left sides, the mean width of this ligament was 1.2 cm and the mean length was 1.5 cm. The mean thickness of ligament of Barkow was 1.2 mm (range 0.9-1.4 mm). The upper edge of this ligament was on average 3 cm inferior to the inferior most aspect of the proximal tibiofibular joint. The lower edge of ligament of Barkow was a mean distance of 7 mm from the anterior tibial artery at its entrance into the anterior compartment of the leg. One ligament was found to be fully ossified; thereby, creating a bony bar superior to the anterior tibial vessels. CONCLUSIONS: Our hopes are these data will help further elucidate the ligament of Barkow. Imaging studies are now necessary to further elucidate functional and pathological involvement of this structure.

The phrenico-esophageal ligament: an anatomical study.

The phrenico-esophageal ligament (PEL), which is claimed by some to be an important anti-reflux barrier, has been accepted as an important structure by some surgeons dealing with the surgical treatment of hiatal hernias. However, the characteristics of its anatomical structure and the physiological importance of this ligament is still a subject of discussion. The aim of this study was to define this anatomic structure and to point out the clinical importance of the PEL. This study has been carried out on samples taken from 2 fresh and 12 fixed cadavers. The PEL was observed to be derived from the transversalis and endothoracic fascia attaching the esophagus to the diaphragmatic crura at the region of the esophageal hiatus. While the transversalis fascia covered the inferior surface of the diaphragm, it was observed to divide into upper and lower leaflets when it approached the esophageal hiatus. The endothoracic fascia turned superiorly at the level of esophageal hiatus and attached on to the esophagus by uniting with the upper leaflet of the transversalis fascia in 11 of the specimens. In three of the specimens, it attached on the esophagus at a higher level than the transversalis fascia. The histologic sections of our study revealed that the PEL is formed by collagen and elastic fibers composed of fibroblasts and blood vessels. Since the PEL is a strong structure that firmly attached to the esophageal wall and surrounded the upper part of the distal esophagus like a skirt, it is reasonable that it may play an important role in the gastroesophageal sphincteric mechanism. Histological evidence for decrease in collagen fibers with age and the loose arrangement of the elastic fibers due to this decrement might decrease the resistance and the elasticity of the PEL. This situation may explain the predisposition to hiatal hernias seen with increased in age.

Does an anatomical sphincter exist in the distal esophagus?

The presence or absence of a lower esophageal sphincter (LES) has been a matter of debate. The aim of the present study was to revisit the gastro-esophageal region in an attempt to elucidate further the presence or absence of such a structure. The distal part of the esophagus was investigated in 12 fixed and 2 fresh cadavers with the aid of a dissecting microscope. Our findings demonstrated a clear thickening of the circular muscle layer of the gastro-esophageal region in all specimens. The mean length of this muscular thickening was measured to be 3.1 cm. The thickest part of this segment was at its midsection. This midpart had a mean thickness of 5.4 mm. The thickness of the esophagus immediately superior to the sphincter had a mean of 2.7 mm. We believe that the findings of the present study strongly suggest the presence of an internal esophageal sphincter in the distal esophagus. Physiologic experimentation would now be necessary to verify our morphological findings.