Case Report of a Pelvic Crossed Fused Renal Ectopic Kidney.

Herein we present a case of a horseshoe kidney with crossed fused renal ectopia. Both of these pathologies are congenital anomalies; however, to date, there are few cases that present with both. In this case, discovered during routine dissection, the fused kidney was mostly left-sided and very low in the pelvis. No renal artery arose from the right wall of the abdominal aorta, and the right renal vein drained into the lower part of the inferior vena cava (IVC) where the right and left common iliac veins joined. It is essential for clinicians and surgeons to understand these types of congenital anomalies, as they could impact patient care.

Anatomic Study of Superior Cluneal Nerves: Revisiting the Contribution of Lumbar Spinal Nerves.

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.

Anatomic Study of the Superior Cluneal Nerve and Its Related Groove on the Iliac Crest.

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.

Anatomical and Biomechanical Study of the Lumbar Interspinous Ligament.

OBJECTIVE: The lumbar interspinous ligaments (ISLs) are thin and short fibers connecting adjacent spinous processes. However, their morphology is variably described and their biomechanics are not well understood. Therefore, the purpose of this study was to assess the anatomy and biomechanics of the lumbar ISL. MATERIALS AND METHODS: Five fresh frozen cadaveric specimens were dissected posteriorly to reveal and study the lumbar ISL. Measurements of the ligaments included the anterior vertical height (length A), the posterior vertical height (length P), and the length (length H) at each lumbar level. Next, 17 lumbar vertebral levels from 6 cadaveric specimens were used for tensile strength testing. The ISLs were subjected to vertically controlled increasing manual tension. The force necessary to disrupt the ISL was recorded. RESULTS: All the ISLs ran horizontally in an anterior-posterior direction with a slight curve. The average of length A, length P, and length H on the right sides was 9.82, 9.57, and 20.12 mm, respectively. The average of length A, length P, and length H on the left sides was 11.56, 12.01, and 21.42 mm, respectively. The mean tensile strength of the ISL was 162.33 (N) at L1/2, 85.67 (N) at L2/3, and 79 (N) at L3/4. There was a significant difference in the tensile force between L1/2 and L2/3 and L1/2 and L3/4 (P < 0.05). The ligaments became weaker with a descent along the lumbar levels. CONCLUSION: The results of this study might help surgeons understand pathology/trauma of the lumbar vertebral region.

Revisiting the genital and femoral branches of the genitofemoral nerve: Suggestion for a more accurate terminology.

The genitofemoral nerve is a branch of the lumbar plexus originating from the ventral rami of the first and second lumbar spinal nerves. During routine dissections of this nerve, we have occasionally observed that the genital branch of the genitofemoral nerve gave rise to the femoral branch, and the femoral branch of the genitofemoral nerve gave rise to the genital branch. Therefore, this study aimed to investigate the aforementioned distributions of the genitofemoral nerve in a large number of cadaveric specimens. Twenty-four sides from fourteen fresh-frozen cadavers derived from nine males and five females were used in this study. For proximal branches of the genitofemoral nerve, that is, as they first arise from the genitofemoral nerve, the terms "medial branch" and "lateral branch" were used. For the final distribution, the terms "genital branch" and "femoral branch" were used. On eight sides (33.3%) with nine branches, one or two branch(s) from either the medial or lateral branch became coursed as the femoral or genital branches (five became femoral and four became genital branches). Our study revealed that the distribution of the genitofemoral nerve is more complicated than previously described. The "medial branch" and "lateral branch" that we have used in the present study for describing the proximal branches of the genitofemoral nerve are more practical terms to describe the genitofemoral nerve. Clin. Anat. 32:458-463, 2019. © 2019 Wiley Periodicals, Inc.

The majority of piriformis muscles are innervated by the superior gluteal nerve.

The piriformis muscle is clinically implicated in pain disorders, posterior approaches for total hip arthroplasty, and iatrogenic injury to the muscle and the surrounding nerves. The piriformis muscle has been said to receive innervation from L5 to S3 ventral rami with most sources using S1 and S2 ventral rami as the most common innervation this muscle. However, descriptions of the nerve in the literature are vague. Therefore, the aim of this study was to clarify the anatomy of the nerve supply to the piriformis muscle. Twenty sides from ten fresh-frozen cadavers were studied. Specifically, via anterior dissection of the sacral plexus, branches to the piriformis were identified. Once identified, the nerves to the piriformis muscle were traced proximally to clarify their origin. Nerves supplying the piriformis muscle existed on all sides. On 80% of sides, the piriformis was innervated by two to three nerves. The origin of these nerves was from the superior gluteal nerve on 14 sides (70%), inferior gluteal nerve on one side (5%), L5 ventral ramus on one side (5%), S1 ventral ramus on 17 sides (85%), and S2 ventral ramus on 14 sides (70%), respectively. The most common nerve branches to the piriformis are from the superior gluteal nerve, and the ventral rami of S1 and S2. Based on our study, a single "nerve to piriformis" does not exist in the majority of specimens thus this term should be abandoned. Clin. Anat. 32:282-286, 2019. © 2018 Wiley Periodicals, Inc.

Paramastoid Process: Literature Review of Its Anatomy and Clinical Implications.

The paramastoid process is a rare variation found on the occipital bone as an extension of its jugular process. In the literature, this process has been called many names including the paraoccipital, paracondylar, or parajugular process. The paramastoid process can articulate with the lateral aspect of the transverse process of the atlas creating clinical consequences and potentially resulting in diminished range of motion of the head. Herein, we describe the anatomy, embryology, prevalence, imaging, and clinical consequences of the paramastoid process in order to improve our understanding of this rare anatomic variation.

Treatment of Gunshot Wounds to Spine During Late 19th Century.

BACKGROUND: The demand for neurosurgical procedures increased drastically in the late 19th century owing to advances in ballistics during the American Civil War and Crimean War. METHODS AND RESULTS: Surgical care for a gunshot wound to the spine relied on skilled identification and removal of the fractured bone. Hemorrhage control and infection prevention were also imperative for improving survival rates. CONCLUSIONS: Although new techniques were implemented, the mortality rate from spinal injuries during this period was staggering. Nevertheless, those 19th century procedural methods provided the basis for present-day treatment for spinal injury patients.

Mechanical relationship of filum terminale externum and filum terminale internum: is it possible to detether the spinal cord extradurally?

INTRODUCTION: Intradural transection of the filum terminale (FTI) is often used to treat tethered cord syndrome. Recently, some have proposed that the extradural part of the filum terminale (FTE) can be sectioned with equal results but with fewer complications. Therefore, the present cadaveric study aimed to evaluate the anatomical foundation of such procedures. METHODS: A posterior lumbosacral approach was performed on five fresh-frozen cadaveric specimens to expose both the FTI and FTE. Tension was then applied to the FTE and observations and measurements made of any movement of the FTI. Other morphological measurements (e.g., length, diameter) of the FTI and FTE were also made. RESULTS: Although very minimal movement of the FTI was seen in the majority of specimens following tension on the FTE, no specimen was found to have more cranial movement of the conus medullaris or cauda equina. The mean length and diameter of the FTI was 52.2 and 0.38 mm, respectively. The mean length and diameter of the FTE was 77 and 0.60 mm, respectively. The force necessary to move the FTI with tension applied to the FTE had a mean of 0.03 N. The average distance that the FTI moved with distal FTE tension was 1.33 mm. All specimens had a thecal sac that terminated at the S2 vertebral level. And no specimen had a low-lying conus medullaris, cutaneous stigmata of occult spinal dysraphism, or grossly visible adipose tissue in either the FTI or FTE. CONCLUSIONS: Based on our studies, tension placed on the FTE has very little effect on the FTI and no obvious effect on the conus medullaris or cauda equina. Therefore, isolated transection of the FTE for a patient with tethered cord syndrome is unlikely to have significant effect. To our knowledge, this is the first study to quantitate the distal forces needed on the FTE to move the FTI.