"A comprehensive study of the potential compression points of the third occipital nerve and its possible clinical interests".

BACKGROUND: The anatomical features of the third occipital nerve (TON) are the least studied among the occipital nerves. This study aimed to analyze the anatomical features and potential compression points of the TON. METHODS: The posterior neck and scalp of 39 cadavers were dissected. The TON was carefully followed from the emerging point from C2-C3 vertebrae distally. Its muscular investments were detected. The determined points were marked superficially and measured according to external occipital protuberance with the Image J Software program. RESULTS: The TON revealed 4 different potential entrapment points along its course. The most proximal point was between the C2-C3 vertebrae. The second and third points were at their piercing points of semispinalis capitis and splenius capitis muscles, respectively. The final point was at its penetrating point of the trapezius muscle. Additionally, TON did not pierce the semispinalis capitis muscle on 6 sides and pierced this muscle from 3 different points by splitting into 3 branches on 1 side. Moreover, on 5 sides, the TON split into two branches and perforated the splenius capitis muscle from two different points. CONCLUSION: There were 4 potential compression points regarding the TON. These entrapment points and variations of TON in this study may play a significant role in understanding the reason for TON-related headaches and the treatment of headaches caused by TON.

The triangular area between the greater, lesser, and third occipital nerves and its possible clinical significance.

PURPOSE: Occipital Neuralgia (ON) is defined as a unilateral or bilateral pain in the posterior area of the scalp occurring in the distribution area or areas of the greater occipital nerve (GON), lesser occipital nerve (LON), and/or third occipital nerve (TON). In the present study, the purpose was to show the possible importance of the triangular area (TA) in nerve block applied in ON by measuring the TA between GON, TON, and LON. METHODS: A total of 24 cadavers (14 males, 10 females) were used in the present study. The suboccipital region was dissected, revealing the points where the GON and TON pierced the trapezius muscle and superficial area, and the point where the LON left the sternocleidomastoid muscle from its posterior edge and was photographed. The area of the triangle between the superficial points of these three nerves and the center of gravity of the triangle (CGT) were determined by using the Image J Software and the results were analyzed statistically. RESULTS: The mean TA values were 952.82 ± 313.36 mm2 and 667.55 ± 273.82 mm2, respectively in male and female cadavers. Although no statistically significant differences were detected between the sides (p > 0.05), a statistically significant difference was detected between the genders (p < 0.05). The mean CGT value was located approximately 5 cm below and 3-3.5 cm laterally from the external occipital protuberance in both genders and sides. CONCLUSION: In ON that has more than one occipital nerve involvement, all occipital nerves can be blocked by targeting TA with a single occipital nerve block, and thus, the side effects that may arise from additional blocks can be reduced. The fact that there was a statistically significant difference according to the genders in the TA suggests that different block amounts can be applied according to gender.

Anatomical Features of Posterior Cerebral Arteries and Basilar Artery in 170 Anatolian Fresh Cadavers: Implications for Surgical Planning and Intervention.

BACKGROUND: The posterior cerebral arteries (PCAs) are terminal branches of the basilar artery (BA) and are responsible for the primary supply of the occipital lobe. Saccular aneurysm is most commonly seen close to the bifurcation of the BA. Various surgical interventions are performed for aneurysms. Therefore, the anatomy and localization of the BA and PCA are crucial. The aim of this study was to determine the characteristics of these arteries in a large Anatolian population. METHODS: The study included 170 Anatolian fresh cadavers. The diameters of the BA and PCA were measured. Correlations according to sex and age groups were analyzed. The Q1, Q2, and Q3 angles between the right and left PCA, between the right PCA and BA, and between the left PCA and BA, respectively, were measured. The location of the PCA relative to the sulcus pontocruralis (pontocrural groove) was also evaluated. RESULTS: The diameter of the artery increased with age and was higher in males than in females. Q1 and Q2 diameters were larger in males, while the Q3 diameter was larger in females. The Q1 angle between the right and left PCAs was found to be higher in age range 40-59 years with a mean of 87.33 ± 17.91 mm. Finally, the bifurcation point of the PCA was most frequently located above the sulcus pontocruralis (pontocrural groove) and least frequently located on the sulcus pontocruralis (pontocrural groove). CONCLUSIONS: The findings of our study will contribute to the planning of surgical approaches, the development of endovascular devices, the success of invasive procedures, and the reduction of complications.

Morphological features of the greater occipital nerve and its possible importance for interventional procedures.

Being one of the most prevalent neurological symptoms, headaches are burdensome and costly. Blocks and decompression surgeries of the greater occipital nerve (GON) have been frequently used for migraine, cervicogenic headache, and occipital neuralgia which are classified under headache by International Headache Society. Knowledge of complex anatomy of GON is crucial for its decompression surgery and block. This study was performed to elucidate anatomical features of this nerve in detail. Forty-one cadavers were dissected bilaterally. According to its morphological features, GON was classified into four main types that included 18 subtypes. Moreover, potential compression points of the nerve were defined. The number of branches of the GON up to semispinalis capitis muscle and the number of its branches that were sent to this muscle were recorded. The most common variant was that the GON pierced the aponeurosis of the trapezius muscle, curved around the lower edge of the obliquus capitis inferior muscle, and was loosely attached to the obliquus capitis inferior muscle (Type 2; 61 sides, 74.4%). In the subtypes, the most common form was Type 2-A (44 sides, 53.6%), in which the GON pierced the aponeurosis of each of the trapezius muscle and fibers of semispinalis muscle at one point and there was a single crossing of the GON and occipital artery. Six potential compression points of the GON were detected. The first point was where the nerve crossed the lower border of the obliquus capitis inferior muscle. The second and third points were at its piercing of the semispinalis capitis muscle and the muscle fibers/aponeurosis of the trapezius, respectively. Fourth, fifth, and sixth compression points of GON were located where the GON and occipital artery crossed each other for the first, second, and third times, respectively. On 69 sides, 1-4 branches of the GON up to the semispinalis capitis muscle were observed (median = 1), while 1-4 branches of GON were sent to the semispinalis capitis muscle on 67 sides (median = 1). The novel anatomical findings described in this study may play a significant role in increasing the success rate of invasive interventions related with the GON.

Accessory Muscles Associated With the Levator Palpebrae Superioris Muscle in 100 Cadavers.

PURPOSE: This study aimed to determine the variations of the levator palpebrae superioris muscle and to reveal its morphological features. METHODS: This study conducted on 100 adult orbit cadavers in the Department of Anatomy, Istanbul University, used an exploratory, descriptive research design. The anatomical and morphological variations of the levator palpebrae superioris muscle and its relationship with the superior ophthalmic vein were evaluated. RESULTS: Variations of levator palpebrae superioris muscle were discovered in 11 of 100 orbits. Single (9%), double (1%), and triple (1%) accessory muscle slips were observed. The origin of accessory muscle slips showed variation as the accessory muscle slips originated either from the proximal or distal half of the levator palpebrae superioris muscle. Also, the insertions of accessory muscle slips were variable, as they were inserted into levator aponeurosis, trochlea, lacrimal gland, lateral orbital wall, or the fascia of the superior ophthalmic vein. CONCLUSIONS: Accessory muscles associated with levator aponeurosis were found in a significant proportion of cadavers. These muscles may cause confusion in orbital surgery and should be taken into account during surgical planning and orientation in the superior orbit.

Topographic and morphometric anatomy of the proximal part of the dorsal scapular nerve.

The dorsal scapular nerve (DSN) entrapment neuropathy has recently been recognized as a common cause of circumscapular pain and cases of winged scapula. Course of the nerve is important because the middle scalene muscle is frequently accessed for surgical treatments. Studies in the literature have not focused on the morphometric relationship of the DSN with the scalene muscles and its relationship with the long thoracic nerve (LTN). The neck regions of 13 adult cadavers were dissected bilaterally. The relationship of DSN with scalene muscles and LTN was evaluated. Cervical spinal nerves involved in the formation of the DSN were identified. Three types of DSN were observed based on the cervical spinal nerves from which it originates, five types of DSN from its relationship with the scalene muscles, and two types of DSN from its relationship with the LTN. The distance from where the nerve pierces the scalene muscle to the mastoid process was found to be greater in DSNs originating from C4 and C5 (93.85 ± 4.11 mm, p = 0.033). In DSNs not connected with LTN, the distance from where the nerve pierces the scalene muscle to the superior trunk/C5 (12.74 ± 7.73 mm, p = 0.008) and the length of the nerve within the scalene muscle (14.94 ± 5.5 mm, p = 0.029) were found to be statistically significantly greater. The topographic and morphometric anatomy of the proximal part of the DSN is important, especially for scalene muscles-focused surgical treatments and interscalene nerve blocks. We believe our results may guide clinical approaches and surgery.

Frequency Morphologic and Morphometric Properties and Osseous Relationships of Whitnall's Tubercle.

Whitnall tubercle (WT) of the zygomatic bone is used as an anatomical landmark in some surgical approaches to the orbit. The authors aimed to determine the localization of WT by using some palpable bony landmarks and to reveal its morphological and morphometric features. Three hundred twenty-two zygomatic bones (167 right and 155 left) belonging to adults of unknown sex, were examined. An acetate prepared by drawing a clock with a dial on it was used to determine the localization of WT according to marginal tubercle and zygomatic arch. Distances between WT and frontozygomatic suture and lateral margin of the orbital rim were measured with digital calipers. One zygomatic bone had double tubercles, thus 321 bones were taken into consideration. Whitnall tubercle was determined in 284 of 321 zygomatic bones. 181 were classified as small, 10 as medium, and 93 as large. The position of the WT according to the marginal tubercle was at the 8, 9, and 10 o'clock positions on the left, and at 2, 3, and 4 o'clock on the right. The position of the WT according to the zygomatic arch was at the 9,10 and 11 o'clock positions on the left, and at the 1 and 2 o'clock positions on the right. Distances between the WT and lateral margin of the orbital rim and the frontozygomatic suture were measured meanly as 1.94±0.31 mm and 8.17±5.82 mm, respectively. The authors believe that the data obtained regarding WT will contribute to anatomy and surgical procedures of the related region.

Pre-operative measurement of the morphometry and angles of the anterior clinoid process (ACP) for aneurysm surgery / Medición preoperatoria de la morfometría y los ángulos del proceso clinoide anterior (PCA) para la cirugía de aneurisma

The anterior clinoid process (ACP) is proximal to vital structures, such as the optic nerve, internal carotid artery and ophthalmic artery; therefore, study of its anatomy is important in guiding and defining surgery. We studied the anatomical structure of the ACP, including the angle formed by the apex of the ACP triangle, and its orientation, to provide information for easier and safer surgery. The measurement was performed on the axial planes of 242 cranial computerized tomography (CT) scans and 27 adult Turkish skulls of both sexes. The length of the ACP, width of the ACP at its base, the angle formed by the apical angle of the ACP triangle and the orientation of the ACP defined according to the sagittal midline were examined. In the Turkish skulls, the length and width of the ACP were similar to previous studies. Our study was the first to measure the angle and orientation of the ACP. The mean angle was 39.67±12.64 (16.6-89.5) and 135 posterior (55 %) and 107 medial (45 %) orientations. Surgical complications can be avoided by pre-operative radiological planning using axial CT scans and by determining whether the morphology is Type 2 (long, narrow, acute-angled), which requires total resection.

El proceso clinoide anterior (PCA) está próximo a estructuras vitales, como el nervio óptico, la arteria carótida interna y la arteria oftálmica, por tanto el estudio de su anatomía es importante en la orientación y la definición de la cirugía de base de cráneo. Se estudió la estructura anatómica de la PCA, incluyendo el ángulo formado por el vértice del triángulo PCA, y su orientación, para proporcionar información para una cirugía más fácil y más segura. La medición se realizó en los planos axiales de 242 exploraciones craneales de tomografía computarizada (TC) y 27 cráneos de individuos adultos turcos de ambos sexos. Se examinó la longitud del PCA, el ancho del PCA en su base, el ángulo formado por el ángulo apical del triángulo PCA y la orientación del PCA definido de acuerdo con la línea mediana sagital. En cráneos turcos, la longitud y el ancho del PCA fueron similares a estudios anteriores. Nuestro estudio fue el primero en medir el ángulo y la orientación del PCA. El ángulo promedio fue de 39,67 ± 12,64 (16,6 a 89,5) y, la orientación fue posterior en 135 cráneos (55 %) y medial en 107 cráneos (45 %). Las complicaciones quirúrgicas pueden evitarse mediante la planificación radiológica preoperatoria através de cortes axiales de tomografía computarizada y determinando si la morfología del PCA es de tipo 2 (larga, estrecha y aguda en ángulo recto), lo que requiere la resección total.

The amount of information provided in articles published in clinical anatomy and surgical and radiologic anatomy regarding human cadaveric materials and trends in acknowledging donors/cadavers.

AIM: Appreciating the contribution of donor-cadavers to medical education is a well observed practice among anatomists. However, the appreciation of their contribution in research and scientific articles remains dubious. We aimed to evaluate how much data anatomists provide about specimens they have used and how frequently anatomists acknowledge their cadavers in published articles. MATERIALS AND METHODS: We evaluated all articles performed on human cadaveric specimens that were published in Clinical Anatomy and Surgical and Radiologic Anatomy between January 2011 and December 2015. We evaluated how much data on the demographics, preservation method(s), source, and ethical/legal permissions regarding cadavers were provided. We also evaluated the number of articles that acknowledged donor-cadavers. RESULTS: The majority of articles provided demographic data (age and sex) and preservation method used in the article. The source of the specimens was not mentioned in 45.6 % of the articles. Only 26.2 % of the articles provided a degree of consent and only 32.4 % of the articles reported some form of ethical approval for the study. The cadavers and their families were acknowledged in 17.7 % of the articles. We observed that no standard method for reporting data has been established. CONCLUSIONS: Anatomists should collaborate to create awareness among the scientific community for providing adequate information regarding donor-cadavers, including source and consent. Acknowledging donor-cadavers and/or their families should also be promoted. Scientific articles should be used to create a transparent relationship of trust between anatomists and their society.

A new anatomic trait for identifying the mendosal suture in young children: the mendosal-lambdoidal angle.

PURPOSE: Radiologic diagnosis of skull fractures in young children is difficult due to numerous accessory sutures. This is especially true around the occipital bone because it has more than one ossification center. Normal anatomic variants, such as the mendosal suture, may be misinterpreted as a skull fracture. We investigated the anatomic traits of the mendosal suture in young children. METHODS: We retrospectively evaluated 52 children, aged between 1 month and 4 years, who had undergone head computed tomography with three-dimensional reconstructions. We evaluated the presence or absence of the mendosal suture. If present, then we measured the length of the suture and the angle between the lambdoidal and mendosal suture lines. RESULTS: The presence of the mendosal suture was bilateral in 12 children and unilateral in 5 children. The mendosal suture had a mean length of 13.9 ± 3.4 mm on the right side and 11.2 ± 4 mm on the left side. The angle between the mendosal and lambdoidal sutures had a mean value of 54.2° ± 11° for the right side and 53.6° ± 13.9° for the left side. The 95 % confidence interval for the mean value of the angle had a lower and upper bounds of 48° and 60° on the right side and 46° and 61° on the left side, respectively. CONCLUSIONS: The angle between mendosal and lambdoidal suture lines may help radiologists to identify the mendosal suture.

A mixed-type intermesenteric trunk as a major contributor to the ascending, transverse, and descending colons: a case report.

PURPOSE: We present a case in which a mixed-type intermesenteric trunk was the major arterial supply for the ascending, transverse, and descending colons. METHODS: We dissected a cadaver of a man aged 74 years that was used for a routine abdominal dissection course of 2nd year medical students. RESULTS: We observed that a mixed-type intermesenteric trunk supplied the majority of the colon, originating from the inferior mesenteric artery. The vessel was non-tortuous and had a counter clockwise course. It gave branches that supply the marginal artery at the splenic and hepatic flexures and at the transverse colon and finally it anastomosed with the ileocolic artery at the ileocecal junction. Through the intermesenteric trunk, the inferior mesenteric artery supplied the descending, transverse, and ascending colons with contributions from the sigmoidal and ileocolic arteries. CONCLUSIONS: The intermesenteric trunk is an important central connection between the superior and inferior mesenteric arteries. It probably is an embryologic remnant that constituted a longitudinal anastomosis between both mesenteric arteries.

Anatomical relations between anterior coracoscapular ligament and suprascapular neurovascular structures and a proposal for classification.

OBJECTIVE: Although suprascapular nerve entrapment is rare, the most common site of compression is the suprascapular notch. The anterior coracoscapular ligament (ACSL), which lies inferior to the superior transverse scapular ligament (STSL), may also be a cause of entrapment. We aimed to investigate the presence of ACSL and its relations to the suprascapular nerve and vessels. METHODS: We dissected 50 shoulders of 26 cadavers. We excluded 2 shoulders due to previous shoulder surgery. We observed the course of the suprascapular nerve, artery, and vein(s), and examined whether they passed between STSL and ACSL or under ACSL. We classified the anatomical relations between neurovascular structures, STSL, and ACSL. In Type I, the suprascapular nerve passed between STSL and ACSL; in Type Iia, the suprascapular nerve and a single suprascapular vein passed between STSL and ACSL; in Type Iib, a suprascapular vein passed under ACSL and the suprascapular nerve passed between STSL and ACSL; in Type III, the suprascapular artery, vein, and nerve passed between STSL and ACSL. RESULTS: ACSL was present in 16 shoulders (32%). The suprascapular nerve passed between STSL and ACSL in all cases. We observed Type I, Type Iia, Type Iib, and Type III anatomical relations in 14%, 12%, 2%, and 4% of cases, respectively. CONCLUSION: Vascular structures that pass under STSL may cause suprascapular nerve entrapment. Presence of ACSL with vessel(s) passing under it and/or between it and STSL may increase the risk of nerve entrapment.

Inferior Phrenic Arteries and Their Branches, Their Anatomy and Possible Clinical Importance: An Experimental Cadaver Study.

BACKGROUND: Transcatheter arterial chemoembolization is a common treatment for patients with inoperable hepatocellular carcinoma. If the carcinoma is advanced or the main arterial supply, the hepatic artery, is occluded, extrahepatic collateral arteries may develop. Both, right and left inferior phrenic arteries (RIPA and LIPA) are the most frequent and important among these collaterals. However, the topographic anatomy of these arteries has not been described in detail in anatomy textbooks, atlases and most previous reports. AIMS: To investigate the anatomy and branching patterns of RIPA and LIPA on cadavers and compare our results with the literature. STUDY DESIGN: Descriptive study. METHODS: We bilaterally dissected 24 male and 2 female cadavers aged between 49 and 88 years for this study. RESULTS: The RIPA and LIPA originated as a common trunk in 5 cadavers. The RIPA originated from the abdominal aorta in 13 sides, the renal artery in 2 sides, the coeliac trunk in 1 side and the left gastric artery in 1 side. The LIPA originated from the abdominal aorta in 9 sides and the coeliac trunk in 6 sides. In 6 cadavers, the ascending and posterior branches of the LIPA had different sources of origin. CONCLUSION: As both the RIPA and LIPA represent the half of all extrahepatic arterial collaterals to hepatocellular carcinomas, their anatomy gains importance not only for anatomists but interventional radiologists as well.

The anatomy of the fibrous and osseous components of the first extensor compartment of the wrist: a cadaveric study.

PURPOSE: De Quervain disease is the stenosing tenosynovitis of the first extensor compartment of the wrist. It is diagnosed with a history of pain at the radial aspect of the wrist and a positive Finkelstein test. Although anatomic variations, such as a septum within the compartment, are considered as risk factors, bony anatomy of distal radius and its correlation with the septa are studied scarcely in the literature. METHODS: We dissected 50 wrists of 26 cadavers. Presence and location of a septum within the compartment was evaluated. We also observed the grooves at distal radius and their relation to the first extensor compartment and its content. RESULTS: The septum was absent in 23 wrists (46%). A septum was present in 27 (54%) wrists (15 incomplete 30%, 12 complete 24%). At the distal radius, we classified three radial groove types as Type 1 on 28 (56%), Type 2 on 14 (28%), and as Type 3 on 8 (16%) wrists. There was a statistically significant relation between complete type of septa and Type 1 grooves (p = 0.002). CONCLUSION: We investigated the bony structures of the compartment along with its content and we believe our results might guide clinicians who diagnose and treat de Quervain tenosynovitis.

The localization and morphology of pterion in adult West Anatolian skulls.

The pterion is an important skull landmark because it is located where the frontal, the great wing of sphenoid, parietal, and squamous parts of the temporal bone junction. The objectives of this study were to determine the localization and the shape of pterion on skulls and to find out the distances between the pterion and some certain anatomic landmarks on neighboring structures. The study was performed on the skulls of 128 (256 sides) adult West Anatolian people. All of the morphometric measurements of the distances between the pterion and the anatomic landmarks were performed using a Vernier caliper with an accuracy of 0.1 mm. The pterion was classified into 4 types: the sphenoparietal, frontotemporal, stellate, or epipteric types. The incidences of types of pterion in the skulls were also found as the sphenoparietal type (85.2%), the epipteric type (8.2%), the stellate type (5.5%), and the frontotemporal type (1.1%). The mean (SD) distances from the center of the pterion to the zygomatic arch were measured as 40.02 (4.06) mm and 39.88 (4.01) mm; to the frontozygomatic suture, 31.80 (4.51) mm and 31.44 (4.73) mm; to the zygomatic angle, 41.54 (4.95) mm and 41.35 (5.14) mm; to the mastoid process, 82.48 (5.45) mm and 81.81 (5.50) mm; and to the external acoustic meatus, 53.29 (4.55) mm and 56.22 (4.60) mm, on the right and left sides, respectively. The mean (SD) distances between the foremost point of pterion and the anterior edge of the lateral wall of the orbit were 31.02 (5.78) mm and 32.31 (5.79) mm on the right and left sides, respectively. The localization and the shape of pterion are of importance because it is an anatomic landmark and should be of use in surgical approaches and interventions via the pterion.