A. Elhan

A clinico-anatomic study of the auricular branch of the vagus nerve and arnold's ear-cough reflex

The results of a clinico-anatomic study of the auricular branch of the vagus nerve (ABVN) and Arnold’s ear-cough reflex are presented. The frequency of the ear-cough reflex was found to be 2.3% (12 out of 514 patients). It was bilateral in 3 cases (0.6%). The reflex was elicited by palpation of the postero-inferior wall of the external acoustic meatus (EAM) in 11 patients, and by palpation of the antero-inferior wall in one patient (0.2%). The reflex was frequently noticed to occur after a short latent period. The course of the ABVN inside the jugular foramen (JF), and distribution of the terminal branches of the ABVN in the external acoustic meatus were determined in 8 male cadavers (16 sides). In addition, the length of the mastoid canaliculus (MC) and the relationships of the ABVN with the facial nerve and stylomastoid foramen (SMF) were studied in both cadavers and 25 dry skulls (50 sides). High-resolution computed tomography (HRCT) scanning was also performed in all cadavers prior to microdissections. The ABVN emerged from the superior ganglion of the vagus nerve in all the cadavers. It ran between the internal jugular vein (IJV) and the bony wall of the jugular foramen. The ABVN was encased in a partial bony canal during its course from the jugular foramen to mastoid canaliculus in 18% of all specimens. The average length of the mastoid canaliculus was 5.6 mm (4.2–6.5), and it ran transversely towards the tympanomastoid suture 4.5 mm (4–5.1) above the stylomastoid foramen. The mastoid canaliculus was well demonstrated in all the HRCT scans.

Endoscopic Anatomy of Sphenoid Sinus for Pituitary Surgery

Endoscopic endonasal transsphenoidal approach to the sellar region yields an alternative to classical microsurgical approaches. Endoscopes provide images that differ from microscopic view. This study aimed to highlight surgical landmarks and their anatomical relationships for pituitary surgery through endoscopic perspective. Ten sides of five adult cadaveric heads with red‐colored latex injected arteries were evaluated. Endoscopic dissections were performed and measurements were done in the sphenoid sinuses before and after the removal of bony structures in all the aspects. Endoscopic vision of the sellar region enabled a wide panoramic perspective and detailed inspection. The measurements, in general, indicated the variations in the bony structures and soft tissues. The width of the pituitary, which is the distance between the medial margins of the carotid prominences, was measured as 21 ± 2.5 mm and the distance between the medial margin of the carotid prominences at the lower margin of the pituitary was 18 ± 3.1 mm. After the bony structures were removed, further measurements were done. The width of the pituitary, which is the distance between the medial margins of the anterior curvature of the ICA, was measured as 23.2 ± 3 mm, while the distance between the posterior curvature of the ICA was 19.7 ± 4.9 mm. Endoscopic view provided superior detailed visualization of the close relationships between pituitary gland, internal carotid arteries, and optic nerves. This facilitated exact evaluation for variations, which could result in more effective and safe surgery. However, these variations again emphasize the necessity of preoperative radiological evaluation in each case. Clin. Anat. 21:627–632, 2008.

Callosal branches of the anterior cerebral artery: An anatomical report

Although the morphology of the corpus callosum is well defined, the arterial supply of this structure has not been comprehensively studied. To elucidate this further, 40 cerebral hemispheres from 30 adult cadaveric brains were obtained. The anterior cerebral arteries were cannulated and injected with red latex. The following were observed and documented: (1) the number, diameter, and course of the arteries supplying the corpus callosum; (2) the territories vascularized by these arteries; (3) any variations of the callosal arteries. Short callosal arteries were present in 58 hemispheres (96.6%) and supplied the superficial surface of the corpus callosum along its midline and were a primary arterial source to this structure. Long callosal arteries were found in 28 hemispheres (46.6%) and contributed to the pial plexus. The cingulocallosal arteries were present in all hemispheres and supplied the corpus callosum, cingulate gyrus, and also contributed to the pericallosal pial plexus. The recurrent cingulocallosal arteries were present in 17 hemispheres (28.3%) and also contributed to the pericallosal pial plexus. The median callosal artery, an anatomical variation, was present in 10 brains (33.3%). This vessel supplied the corpus callosum and the cingulate gyrus. The aim of the present study was to provide a detailed description of the arteries supplying the corpus callosum for those who encounter these vessels radiologically or surgically. Clin. Anat. 21:383–388, 2008.

Fossa navicularis: Anatomic variation at the skull base

The fossa navicularis is a relatively rare anatomic variation of the skull base. Awareness of its existence will avoid misinterpretations of radiological images and unnecessary investigations. This study describes the appearance of the fossa navicularis, and investigates its incidence and whether it is related to pathology at the basiocciput. We studied 492 dry human skulls and 525 computer tomography (CT) images of patients. Dry skulls showing a fossa navicularis were investigated by CT scan, whereas patients identified as having a fossa navicularis were further examined with magnetic resonance imaging (MRI). To document the position of the fossa more precisely, measurements were made between the fossa navicularis and certain anatomic landmarks such as the foramen ovale, the pharyngeal tubercle, the posterior border of the vomer, the foramen lacerum, the carotid canal, and the occipital condyle. Upon examination, 26 of 492 skulls (5.3%) were found to have a fossa navicularis. Twelve were <2 mm in depth and the other 14 had a depth of ≥2 mm. Of the 525 patients, 16 (3.0%) were identified as having a fossa navicularis in CT images. Evaluation of MRIs showed no soft tissue lesions in any of these patients. Comprehensive anatomic details of the fossa navicularis have not been reported in the literature. The results of this study may be useful to radiologists, anatomists, and surgeons interested in the skull base. Clin. Anat. 17:118–122, 2004.

The marginal mandibular branch of the facial nerve

The peripheral, extraparotid course and localisation of the marginal mandibular branch of the facial n. is described, with variations, based on the dissection of 40 cadaver half heads. Its anatomical relationships with the ramus of mandible and facial a. are studied and morphometric features are reported. Knowledge of the accurate course and relationship of the marginal mandibular branch should help to protect this nerve from surgical injury.

Nerve root to lumbar disc relationships at the intervertebral foramen from a surgical viewpoint: An anatomical study

The objective of this study was to analyze relationship of the intervertebral disc to the nerve root in the intervertebral foramen. Fourteen formalin‐fixed cadavers were studied and measurements were performed. At the medial line of the neural foramen, the disc‐root distance gradually increased from L1‐L2 to L5‐S1. The shortest distance between the disc to nerve root was L1‐L2 (mean, 8.2 mm) and the greatest distance was found at L3‐L4 (mean, 10.5 mm). In the mid‐foramen, the disc‐root distance decreased from L1‐2 to L5‐S1. The shortest distance from the disc to nerve root was found at L5‐S1 (mean, 0.4 mm); and the greatest distance, at L1‐L2 (mean, 3.8 mm). For the lateral line, the distance between an intersection point between the medial edge of the nerve root and the superior edge of the disc and lateral line of the foramen consistently increased from L1‐L2 to L5‐S1. The shortest distance from nerve root to the lateral border of the foramen, at the point where the nerve root crosses disc was at level L1‐L2 (mean, 2.6 mm), the greatest distance, L5‐S1 (mean, 8.8 mm). The width of the foramina progressively increased in a craniocaudal direction (mean, 8.3–17.8 mm from L1‐2 to L5‐S1, respectively). The mean height of the foramina was more or less the same for disc levels (range, 19.3–21.5). The results showed that nerve roots at lower levels traveled closer to the midline of the foramen. This morphometric information may be helpful in minimizing the incidence of injury to the lumbar nerve root during foraminal and extraforaminal approaches. Clin. Anat. 25:218–223, 2012.

Accurate course and relationships of the transverse facial artery in human cadavers

Both the course and localization of the transverse facial artery are described, based upon the bilateral dissection of heads from 20 human cadavers. Its anatomical relationships with the mandibular fossa, the articular tubercle, the zygomatic arch, the parotid duct and the maxillary artery are studied and morphometric features are calculated. Furthermore, the transverse facial territory was examined. This territory was supplied by a single perforating branch in 28 cases, by two perforating branches in 10 and by three perforating branches in 2. Knowledge of the course and relationships of the transverse facial artery should help to protect this artery from the risk for transection. However, the variable course of the transverse facial artery must always be taken into consideration by the clinicians during surgical procedures.

Motor nerve lengths of twenty-seven muscles in upper extremity

The purpose of this study is to determine the lengths of motor nerves in the upper extremity. Motor nerves of 27 muscles in 10 cadavers (16 extremities) were dissected from their roots at the level of intervertebral foramen to the entry point of the nerves to the corresponding muscles. Distance between acromion and the lateral epicondyle of the humerus was also measured in all cadavers. Nerve length of the coracobrachialis muscle was the shortest (18.26 ± 1.64 cm), while the longest was the nerve of the extensor indicis (59.51 ± 4.80 cm). The biceps brachii, the extensor digitorum communis, and the brachialis muscles showed highest coefficient of variation that makes these nerve lengths of muscles inconsistent about their lengths. This study also offers quotients using division of the lengths of each nerve to acromion—the lateral epicondyle distance. Knowledge of the nerve lengths in the upper extremity may provide a better understanding the reinnervation sequence and the recovery time in the multilevel injuries such as brachial plexus lesions. Quotients may be used to estimate average lengths of nerves of upper extremity in infants and children. Moreover, reliability of the biceps brachii as a determinant factor for surgery in obstetrical brachial plexus lesions should be reconsidered due to its highest variation coefficient. Clin. Anat. 25:373–378, 2012.

361 DOES THE PRESENCE OF ACCESORY OBTURATOR NERVE EFFECT THE SUCCESS OF OBTURATOR NERVE BLOCKADE

L.B. Couto2,3, C.M.R. Ferreira1, D.H. Elias-Filho1, C.A. Parada1, I.R. Pelá2, N.C. Coimbra1 °. 1Laboratory of Neuroanatomy & Neuropsychobiology, Department of Pharmacology, School of Medicine of Ribeirão Preto of the University of São Paulo-USP, Ribeirão Preto (SP), Ribeirão Preto (SP), 2Laboratory of Pharmacology, School of Pharmaceutical Sciences of Ribeirão Preto; University of São Paulo, Ribeirão Preto (SP), 3Medicine and Odontology Course, University of Ribeirão Preto (UNAERP), Ribeirão Preto (SP), Brazil