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Objective: Superior cluneal nerve (SCN) entrapment neuropathy can result in low back pain and thus be confused with other pathologies (e.g., lumbar disk disease). Therefore we performed cadaveric dissection of the SCN to better understand its anatomy and segmental origin., Methods: Twenty sides from 10 Caucasian fresh frozen cadavers (6 females and 4 males) were used in this study. The diameter of the SCN, distance between the exit point of the SCN from the thoracolumbar fascia and midline, and distance between the exit point of the SCN from the thoracolumbar fascia and the posterior superior iliac spine to the medial and lateral SCN were measured. The segmental origins of the SCNs were verified., Results: Seventy-five percent of the dorsal rami of L1, 90% of L2, 95% of L3, 45% of L4, and 10% of L5 contributed to the SCN. The SCN was formed by 3 vertebral levels in 55% and by 4 vertebral levels in 30%. Three SCNs pierced the thoracolumbar fascia in 45%., Conclusions: The origin of the SCN, which has been described in the textbook and literature for a long time, should be reconsidered on the basis of our study results., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Objective: Superior cluneal nerve entrapment neuropathy is one cause of low back pain often referred to as "pseudo sciatica." Studies have found that the superior cluneal nerve can arise variably from T11 to L5. The osteofibrous tunnels formed by a groove on the iliac crest might compress the superior cluneal nerve. Therefore, the purpose of this study was to investigate the origin of the superior cluneal nerve and its course through such bony grooves., Methods: Twenty sides from 10 fresh frozen Caucasian cadavers were used in this study. Once both the superior cluneal nerve and its groove were identified, the distance from the groove to the posterior superior iliac spine and midline was measured., Results: A total of 12 grooves were identified in 11 of 20 sides (55%). On 10 sides, the nerve running on the groove was the medial branch of the superior cluneal nerve. The mean distance from the bony groove to the posterior superior iliac spine and midline was 45.2 ± 11.2 mm and 65.3 ± 8.2 mm, respectively., Conclusions: These results could help identify such bony grooves and better understand low back pain and its related anatomy., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Objective: The aim of this study was to investigate the anatomy of the superior cluneal nerves more proximal to the posterior layer of the thoracolumbar fascia., Methods: Twelve sides of 6 fresh-frozen cadavers were used. The age at death ranged from 54 to 88 years. After a transverse skin incision 10 mm above the iliac crest, the superior cluneal nerves were detected by blunt dissection and traced back to the dorsal root ganglia. The diameter of the nerves from L1 to L3 was measured. Also, the relationship to the erector spinae muscle and dorsal ramus was recorded., Results: The mean diameters of the origin of the L1, L2, and L3 were 1.71 ± 0.29 mm, 1.73 ± 0.40 mm, and 1.52 ± 0.55 mm, respectively. On 7 sides (58.3%) for L1, seven sides (58.3%) for L2, and 10 sides (83.3%) for L3, the nerves pierced the iliocostalis muscle. One side (8.3%) for L2 and one (8.3%) for L3 had no cutaneous branch., Conclusions: The results of this study could help to elucidate the anatomy of the superior cluneal nerves and help avoid complications during surgical approaches to the lumbar spine., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Objective: Pedicle screws placed into C2 necessitate a thorough understanding of this bone's unique anatomy. Although multiple landmarks and measurements have been used by surgeons, these are often varied in the literature with no consensus. Herein, we studied one recently proposed landmark using the nutrient foramina of the posterior aspect of C2 for pedicle screw placement., Methods: On 19 (38 sides) C2 dry bone specimens, the presence, size, location, and distance from the midline of the nutrient foramina found at the junction between the isthmus and lamina were documented and measured. In addition, to discern the source of the artery entering such foramina, an injected adult cadaver was dissected., Results: The number of foramina ranged from 0-5 with a mean of 1.84. On 3 sides, no foramina were identified. The mean diameter of the foramina was 0.57 mm. The location of the foramina was at position 1 on 9.5% of sides, position 2 on 66.4% of sides, and position 3 on 24.1% of sides. The mean horizontal distance from the midline of the spinous process of C2 to the foramina was 25.17 mm. In the cadaveric specimen, the source of the artery entering these C2 nutrient foramina was found to be distal branches of the deep cervical artery., Conclusions: We found the nutrient foramina of the C2 laminae are useful for pedicle screw placement. However, there are minor variations of the number and position of these structures. Lastly, on the basis of our study, 7.9% (n = 3) of sides will not have such foramina., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Pseudoaneurysms are less common than true aneurysms. Herein, we present a rare case of a mass of the right posterior ascending artery., Case Description: This was identified during routine dissection of an adult female cadaver. Histology demonstrated that the mass was a pseudoaneurysm. The mass was located posterior to the right alar ligament superior to the right portion of the transverse ligament and measured 7.37 mm and 2.97 mm., Conclusions: To our knowledge, such a case has not previously been reported. Epidural masses anterior to the cervical dura mater at the craniocervical junction should consider such a pathology in the differential diagnosis., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Objective: Anatomy of the posterior ascending artery (PAA) has been well documented. The PAA forms an apical arcade, which supplies the small branches to the tip of the dens. However, morphometrics of this artery such as diameter and distance from the midline, which could be applied to the diagnosis and surgical procedure, are scant. We aimed to investigate the anatomy of the PAA in order to apply our findings to surgical procedures such as C2 pedicle screw placement., Methods: Ten sides from 5 Caucasian cadaveric heads in which red latex was injected were used. The origin of the PAA, diameter of the PAA and apical arcade, and the distance from midline were recorded., Results: Diameters of the PAA and apical arcade were approximately 1 mm and 0.7 mm, respectively. Distance from the midline to the PAA was approximately 7 mm. In 1 specimen, the os odontoideum was observed on top of the dens., Conclusions: The result of this study could provide anatomic knowledge, which is important for C2 pedicle screw placement to the spine surgeon., (Copyright © 2018 Elsevier Inc. All rights reserved.)