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.

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.

Morphometric and morphological evaluation of the nasolacrimal groove in 150 dry bones in the Anatolian population.

PUPOSE: In this study, we aimed to evaluate the anatomical features of the nasolacrimal groove in detail by providing a morphological classification based on morphometric evaluations of the nasolacrimal groove. METHODS: A total of 150 sagittal dry bones in the Department of Anatomy, Faculty of Medicine, Istanbul University were evaluated. The length and the width at different points of the nasolacrimal canal were calculated. According to the widths of the nasolacrimal canal ten different morphological types were revealed. RESULTS: The length of the canal was found as mean 13.62 ± 2.42 mm on the right and 12.44 ± 2.68 mm on the left side. The entrance, the base, the upper and the lower thirds of nasolacrimal canal were 6.22 ± 1.19 mm, 7.95 ± 1.85 mm, 5.85 ± 1.06 mm, 6.60 ± 1.54 mm, on the right and 6.08 ± 1.16 mm, 7.24 ± 1.64 mm, 5.45 ± 1.29 mm, 6.23 ± 1.48 mm, on the left side, respectively. The width of the entrance of the nasolacrimal canal was the narrowest width compared to the base, upper and lower thirds in 7/10 types of 71/150 cranial bones. CONCLUSION: This comprehensive morphological classification of the nasolacrimal groove sheds new light on its complex variations. We support that the finding of this study has the potential to improve the precision of diagnostic assessments and guide specific therapeutic interventions for patients with lacrimal drainage disorders.

Anatomical evaluation of P1 segment of posterior cerebral artery and posterior communicanting artery in 340 human hemispheres: a proposal for morphological classification.

PURPOSE: The aim of our study is to examine the morphometry of the P1 segment of the posterior cerebral artery (P1) and the posterior communicating artery (PcomA) and to present a descriptive classification according to morphometric findings. METHODS: 340 hemispheres from 170 cadavers were included. The outer diameters of P1 and PcomA were measured with ImageJ software. Then, the configurations of the posterior cerebral artery were revealed as fetal, adult and transitional. The findings were correlated with the demographic information of the cadavers such as gender, body mass index (BMI), age. RESULTS: According to the morphometric findings, 83.75%, 13.85% and 2.40% of the posterior cerebral arteries were found to be adult, fetal and transitional, respectively. The fetal type was more common in cadavers aged 60 years and older (13.73%) compared to the 18-39 and 40-59 age groups. In addition, P1 and PcomA diameters also increased with age. Fetal and transtional types showed a similar low distribution in people with low (< 18.5), normal (18.5-24.9), overweight (25-29.9) and obese (> 30) BMI, whereas adult type was found in cadavers with a normal BMI of 140/303. CONCLUSION: We believe that the findings of our study will contribute to the planning of neurointerventional procedures, the development of endovascular devices, the success of invasive procedures and the reduction of complications.

Anatomical variations of the zygomaticofacial foramen and its related canal through the zygomatico-orbital and zygomaticotemporal foramina in dry human skulls.

PURPOSE: The aim of this study is to reveal the location of the zygomaticofacial foramina, the variations of their numbers, and their connections between the zygomatico-orbital and zygomaticotemporal foramina. METHODS: Ethics committee approval of our study was received by the Istanbul Medical Faculty Clinical Research Ethics Committee (date:30.07.2021, number:358356). 171 zygomatic bones of unknown gender from the Department of Anatomy, Istanbul University, were included in this study. The number of zygomaticofacial foramina and their connections with the zygomatico-orbital foramen and the zygomaticotemporal foramina were examined. Also, the morphometric distances between the zygomaticofacial foramen were calculated. Evaluation of the data was done with SPPS v.21. RESULTS: The number of zygomaticofacial foramina was found as 299. It was found single, double, three, four, five and six foramina, in 52 (30.4%), 52 (30.4%), 24 (14.03%), 10 (5.85%), 5 (2.93%), 1 (0.58%) zygomatic bone, respectively. Zygomaticofacial foramen was absent in 27 (15.8%) bones. Of these 299 foramina, 129 were found to be connected with zygomatico-orbital foramen and 23 with zygomaticotemporal foramen. It was noted that 147 zygomaticofacial foramina had no connection with any foramina. The distances between the zygomaticofacial foramen and the frontozygomatic suture, temporal process, maxillary process, the lowest point of the zygomatic bone, and orbital rim were found as 25.30 ± 2.81mm, 18.74 ± 3.56mm, 21.56 ± 4.16mm, 18.72 ± 2.57mm, 6.67 ± 3.27mm, respectively. CONCLUSION: Consequently, the location and variations of ZFF are of great importance for maxillofacial surgery and regional block anesthesia. Knowing its location and variations will help prevent complications during any surgical intervention in this region.

The life of the prince of anatomists Jean Riolan, Jr. (the Younger) (1577-1657).

For the first time in the history of anatomy, the important French anatomist Jean Riolan, Jr., clarifies several conditions that anatomy adepts should accomplish during their preparation in his work Anthropographia. Anatomists should be physically, mentally, culturally, and ethically ready for their work. The anatomy teacher should consider three rules: have experience in anatomical dissection, have the essential knowledge and approach to dissection, and use a suitable teaching method.

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.

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.

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.

Anatomical Landmarks of the Beard Region.

BACKGROUND: With recent advancements in hair restoration techniques, hair can be transplanted into nonscalp areas, such as the beard region, and the result looks natural. Although scalp zones and landmarks have been available for planning and designing the hairline, landmarks that will determine the beard lines are yet to be presented and made known for clinical practice. OBJECTIVE: This study aimed to determine and analyze the beard lines and anatomical boundaries of the beard area to provide a more natural restoration/reconstruction appearance. MATERIALS AND METHODS: The soft-tissue landmarks of the face that will enable physicians to create natural-looking beard lines were determined. Based on these important points, beard lines were analyzed with anthropometric methods by using the photographs of 32 male volunteers. RESULTS: The ideal upper and lower beard lines and the anatomical boundaries of the beard area were determined using these landmarks. CONCLUSION: These lines ensure that beard restoration/reconstruction provides a more natural appearance.

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.

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.

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 relationship of the superficial radial nerve and its branch to the thumb to the first extensor compartment.

PURPOSE: The superficial radial nerve and its branches are vulnerable during surgery for de Quervain tenovaginitis. We studied the proximity of the nerve branches to the first extensor compartment. METHODS: We dissected 20 forearms of 11 cadavers and measured the branching point of the superficial radial nerve relative to the radial styloid. We defined the midline of the first extensor compartment and measured distances of nerves adjacent to it. RESULTS: The superficial radial nerve gave the lateral dorsal digital branch to the thumb at 50 ± 13 mm (minimum, 26 mm; maximum, 72 mm) proximal to the radial styloid. Average distances of the lateral dorsal digital branch to the thumb to the midline of first extensor compartment from proximal to distal were 2, 2, and 2 mm, respectively. In 8 forearms, the lateral dorsal digital branch to the thumb passed directly over the first extensor compartment along its entire length. We found that as the superficial radial nerve diverged from the first extensor compartment, its lateral dorsal digital branch to the thumb coursed parallel and in close relation to it. CONCLUSIONS: Anatomic knowledge of the course of the superficial radial nerve and its branches is important during open release for avoiding nerve injury. CLINICAL RELEVANCE: The close relation of the superficial radial nerve and its lateral dorsal digital branch to the thumb with the first extensor compartment may guide surgeons during surgery for de Quervain tenovaginitis.

Anatomical and morphometrical evaluation of the jugular tubercle.

BACKGROUND: The jugular tubercle (JT) is an important part of the craniovertebral junction. The removal of the JT in the far-lateral approach provides a significant increase in the operative space. The purpose of this morphometrical study was to define the anatomical variations of the JT. METHODS: Thirty-eight dry skulls were included in this study. Seven anatomical parameters were defined and analyzed. The JT, hypoglossal canal (HC), jugular bulb, condylar fossa, occipital condyle (OC), internal jugular foramen, and condylar canal were selected as landmarks. The measurements were made separately for the right and the left sides. RESULTS: Significant morphological variations in the JT were noted. A protuberance was apparent on the JT and classified according to its shape, size, and number. Morphological differences of protuberance of JT were described and classified into seven different types as follows: flat (Type I), sharp (Type II), circular (Type III), pin-point (Type IV), large (Type V), double (Type VI), and unclassified (Type VII). The HC was observed in all specimens. To define the relationship between the JT and the intracranial orifice of the HC, four localizations were identified. To define the relationship between the JT and the intracranial orifice of the HC. CONCLUSIONS: Variations of the JT and the relationship of the JT to the neighboring bone and neural structures are important for modifications of the far-lateral approach. This study presents a detailed anatomical analysis of the shape, size, and orientation of the JT with a new description of protuberance of JT classified into seven types.