The lateral cutaneous branches of the dorsal rami of the thoraco-lumbar junction

Summary Thirty-seven dissections have shown that the skin of the low back is innervated by the lateral branches of the dorsal rami of T12 and L1 in 22 cases (60%) or T12 L1 and L2, in 10 cases (27%) or T12 L1 and L2 receiving an anastomosis from L3 in 5 cases (13%). The most medial nerve crossed the iliac crest through a rigid osseo-aponeurotic orifice located 7–8 cm from the midline which was seen compressing the nerve in 2 instances. This pattern of distribution may sometimes explain unilateral low back pain.

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Les branches cutanées latérales des n. rachidiens de la charnière thoraco-lombaire. Une étude anatomique sur 37 coupes

Résumé Trente-sept dissections ont montré que les téguments lombaires bas sont innervés par les branches latérales des rameaux dorsaux de T12 et L1 dans 22 cas (60 %) ou T12, L1 et L2 dans 10 cas (27 %) ou T12, L1 et L2 recevant une anastomose de L3 dans 5 cas (13 %). Le nerf le plus médial croise la crête iliaque en passant à travers un orifice ostéoaponévrotique inextensible, situé à 7, 8 cm de la ligne des épineuses. Cet orifice comprimait nettement le nerf dans 2 cas. Ce mode de distribution pourrait expliquer certaines douleurs lombaires unilatérales.

     

Upper thoracic dorsal rami: anatomic study of their medial cutaneous branches

Summary The authors describe the distribution of the medial branches of the upper thoracic dorsal rami (T1 to T5 levels). At each level, after travelling through the erector spinae, they become superficial, and reach the apex of the spinous process of the corresponding vertebra. They then spread out laterally, innervating the skin. They can occasionally be compressed by paravertebral tendons, and this possibly contributes to certain forms of dorsal pain. Anastomosis of the dorsal cutaneous branch of the second thoracic nerve (T2) with the descending lateral branch of the accessory nerve has been observed. Its presence could explain the occasional clinical situations where there is no resultant paralysis from accidental surgical section of the latter nerve.

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Rameaux dorsaux thoraciques supérieurs. Etude anatomique de leur branche médiale cutanée

Résumé Les auteurs décrivent le trajet des branches médiales des rameaux dorsaux thoraciques supérieurs (niveaux T1 et T5). A chaque niveau, après avoir cheminé au sein des muscles érecteurs du rachis, ces nerfs deviennent superficiels lorsqu'ils atteignent le sommet du processus épineux de la vertèbre correspondante. Ils se dirigent alors latéralement pour se distribuer à la peau. Ils peuvent parfois être comprimés par les formations tendineuses para-vertébrales ce qui pourrait expliquer certaines douleurs dorsales. Une anastomose de la branche cutanée dorsale du 2e nerf thoracique avec la branche latérale descendante du nerf accessoire a été observée. Sa présence pourrait rendre compte de l'absence occasionnelle de paralysie après section chirurgicale accidentelle de ce dernier.

     

经皮穿刺冷冻腰神经后支治疗腰痛的应用解剖

在15具成人尸体和6套成人骨架上,观测了腰神经后支。结合冷冻腰神经后支止痛术式,按本文提供的表面投影数据,垂直刺入4～5cm,即能贴近各腰神经的后支。对 L_5神经后支的穿刺,应在骶骨上关节突下内或 L_5神经横突占内下方1.5cm 处进针。     

Cutaneous branches from the dorsal rami of the cervical nerves, with emphasis on their positional relations to the semispinalis cervicis

The courses of the cutaneous branches arising from the dorsal rami of the cervical and the upper thoracic nerves were examined on 61 sides in 31 human adults, and their positional relations to the semispinalis cervicis muscle were particularly noted. Absence of the cutaneous branch from the dorsal rami of the lower cervical nerves was observed in 60 of the 61 cases; and in the one remaining case, all the cervical nerves except C1 gave off a cutaneous branch. A difference in course of the cutaneous branches was clearly observed between those from the upper cervical and the upper thoracic segments. That is, those of the former passed superficial to the semispinalis cervicis, whereas those of the latter were situated deep to it. The absence of cutaneous branches of the lower cervical segments could be classified into two types: continuous absence and alternate absence. In the former, which was observed in 53 cases (87%), cutaneous branches were absent in continuous segments. In the latter, which was observed in 7 cases (11%), they were absent in alternate segments. Dermatome problems are discussed on the basis of the present results. Keegan-Garrett's chart could be supported in the one exceptional case only.     

Danger of damaging the medial branches of the posterior rami of spinal nerves during a dorsomedian approach to the spine

Postoperative atrophy of the deep back muscles may be caused by denervation during a dorsomedian approach to the thoracolumbar spine; ensuing instability of the spine with poor clinical results, perhaps due to such muscle loss, has been observed in 11.7% of cases (Sihvonen et al., 1993, Spine 18:575--581). More specifically, this complication may be caused by damaging the medial branches of the posterior rami of the spinal nerves during lateral retraction of the muscles. To investigate the anatomic topography of the medial branches of the posterior rami of the spinal nerves, 18 carbol-formol-fixed specimens were dissected using an operation microscope; also, 3 fresh cadavers were cut in horizontal and vertical planes with a rotary cryotome to confirm the anatomic topography observed in the fixed specimens. In the thoracolumbar spine the medial branch of the posterior ramus of the spinal nerve is subject to ligamentous fixation by the strong fibers of the mammillo-accessory ligament, which extends between the mammillary process and accessory process infero lateral to the superior articular process. When the dorsomedian approach to the thoracolumbar spine is enlarged laterally to the articular processes by retracting the paraspinous muscles, the medial branches of the posterior rami of the spinal nerves are endangered. This may cause postoperative pain as well as dynamic instability beyond the corresponding segments. The results of our anatomic study suggest that the posterior surgical midline approach to the thoracolumbar spine should not be enlarged laterally to the articular processes to prevent injury to the medial branches of the posterior rami of the spinal nerves.     

Fiber arrangements of cutaneous and muscular rami in cervical nerves of the rat--regarding conception of the spinal nerve stratum-structure

Fluorescence tracers DiO and DiI were applied to compare fiber arrangements of cutaneous and muscular rami in the proximal region of anterior and posterior branches of cervical nerves. Results show that a ventrodorsal relationship of cervical nerves is observed in gross level; however, fiber arrangements of cutaneous and muscular rami differ in anterior branches according to distance from the anterior root and dorsal root ganglia. That is, the fibers have a scattering course (no ventrodorsal relationship) in distal regions. Moreover, just before entering anterior roots, the motor fibers of muscular ramus run through the ventral part and sensory fibers of muscles and fibers of cutaneous ramus run through the dorsal part and intersect with motor fibers of the posterior muscular ramus. In contrast with the anterior one, in posterior branches of cervical nerves, cutaneous and muscular rami fibers are very regularly arranged in the distal and proximal region. Based on these results, the ventrodorsal relationship of fiber arrangements could exist in posterior branches and proximal region of anterior branches. Present results differ with those of the spinal nerve stratum-structure; therefore, they are insufficient to elucidate the relationship of peripheral nerves by conception of spinal nerve stratum-structure.     

On the rami intermedii of the spinal nerves and their equivalent offshoots

Summary Distribution patterns of the nerves of supply to the intertransversarii posteriores cervicis, levatores costarum breves and intertransversarii laterales lumborum were carefully studied in nine body-halves of male human cadavers. Any of these muscles lie wegded in between the commencements of the dorsal and ventral primary rami of the spinal nerves. In the great majority of the cases the levatores costarum breves derived their nerve supply in the upper segments from both primary rami of the corresponding spinal nerves and in the lowest segments as the rami intermedii from the bifurcation of each spinal nerve into its primary rami. Both patterns of the nerve supply to the levatores costarum breves were turned into one another in the intervening segments. The intertransversarii posteriores cervicis of similar location to the levatores costarum breves in the thoracic region were regarded as the upper serial homologues of these muscles, because they were supplied by both primary rami of the spinal nerves, similarly the intertransversarii laterales lumborum, principally supplied by the rami intermedii of the spinal nerves, as the lower serial homologues of the same muscles.In view of location as well as mode of innervation it was proposed that the intertransversarii posteriores cervicis, levatores costarum breves and intertransversarii laterales lumborum should be grouped into the musculi intervertebrales laterales (abbrev. l) as the serially homologous muscles deriving innervation of an ambiguous character from both primary rami of the spinal nerves and therefore as the third muscle system more or less distinct from the musculi trunci dorsales (abbrev. D, Nishi) and ventrales (abbrev. V, Nishi) which are supplied alternatively by either of the primary rami of the spinal nerves.     

第二和第三掌背动脉皮支皮瓣的应用解剖

目的为掌背动脉远段皮支皮瓣的设计提供解剖学依据。方法在10侧成人手标本动脉乳胶灌注后,解剖观测第2、3掌背动脉走行,皮支的起始部位、走行、外径和吻合方式,模拟掌背动脉皮支皮瓣的切取方法。结果第2、3掌背动脉位置恒定,其皮支发出部位主要集中在远1/3段,直径大于0.2mm者占15%,小于0.2mm占85%,可解剖长度大于20mm;在指蹼处指蹼动脉1～3支,大于0.3mm者为1支,可解剖长度超过10mm。结论以掌背动脉远段皮支为蒂可设计顺行或逆行皮支皮瓣,修复近、中手指皮肤缺损。以指蹼动脉为蒂的顺行皮瓣可修复近、中节手指掌侧皮肤缺损。皮瓣面积以不超过20mm×40mm为宜。     

基于Sihler’s技术的踝和足背皮神经的整体分布模式研究

目的 揭示踝及足背皮神经的整体分布模式,为皮瓣移植感觉重建提供形态学指导。 方法 成年尸体24具,紧贴肌表面摘取含皮下脂肪的踝及足背皮肤,用改良的Sihler’s染色法显示并观察皮神经整体分布模式。 结果 在Sihler’s染色的标本中,肉眼可见隐神经支配踝前区（40.01±7.6）%、踝后区（30±6.7）%、以及部分足背内侧缘。腓浅神经支配踝前区（60.03±6.8）%,其足背内侧皮神经支配足背内侧区、第1、2趾背及第3趾背内侧半;95.83%的足背中间皮神经分布到第3趾背外侧半、第4、5趾背。腓肠神经支配踝后区（70±5.3）%,其足背外侧皮神经支配足背外侧缘皮肤。腓深神经分布到第1、2趾背相对面。初级神经支密度以踝前区最高,次级及以下神经支密度和总的神经支密度均以足背内侧区最高。 结论 在踝或足背的皮瓣移植中,建议把踝前区或足背内侧区设计为利于感觉重建的首选供区或感觉需求较高的受区。     

Effect of embryonal nerve tissue transplantation on regeneration of dorsal roots of the rat spinal nerves

Using cobalt salts axonal ionophoresis posttraumatic regeneration of TXII dorsal roots nerve fibres in the zone of hemisection in conditions of 14 wks embryo spinal cord transplantation into the zone of trauma of spinal cord. Regro Invasion of dorsal roots nerve fibres into recipients posterior cords and Lissawers tract through the transitional zone "spinal cord--dorsal roots" was observed on posttransplantation d 14-120. It was show that afferent axons predominantly spread in substantia alba and substantia grisea caudal to the level of spinal cord transection with only individual fibres invading rostrad through the neuronal plate. In the transplants neurons were encountered up to d 120 of the observation although transplant neuropil was limited from recipient tissue brain by a glial and connective tissue scar. The influence of embryonal nervous tissue transplantation on intraspinal regeneration of dorsal roots afferents was discussed.     

On the connections between the rami communicantes of the sympathicus and the rami posteriores of the loin nerves (author's transl)]

The existence of anastomoses between the Rami communicantes of the Truncus sympathicus and the Rami posteriores of the loin nerve in man has been confirmed macroscopically and microscopically in 50% of the cases. This is followed by a discussion of the causality of pains in the loin region.     

Anterior retroperitoneal rami: Until now unnamed direct branches of the abdominal aorta

The aim of the study was to gain a thorough knowledge of the topography and distribution of until now officially unnamed minute direct branches from abdominal aorta, stemming from its ventral and lateral aspects, supplying surrounding tissue, and to comprise it to the existing studies. The study was performed in fixed cadaverous material collected from India ink injections of abdominal aorta samples with large surrounding retroperitoneal tissue. The 25 samples were dissected under magnifying binocular glass, followed by graphic reconstruction; statistical analysis, and the study was preceded with detailed review of branches from abdominal aorta. For systematization of the segmental anatomy of the abdominal aorta and infrarenal segment of inferior vena cava, we defined three levels in this area. The retroperitoneal branches were most frequently situated simultaneously within all three predefined levels according to renal and inferior mesenteric arteries origin. There were 18% of retroperitoneal branches within Level 1, 39% within Level 2 and 43% within Level 3. They were branches not only from the abdominal aorta, but also from the testicular/ovarian artery, common iliac artery and in one case from the right accessory renal artery. Paired arrangement was recorded mainly cranially to the origin of inferior mesenteric artery, unpaired branches were more frequently found caudally. In conclusion, due to the terminological disunity of these arteries in the clinical literature and total absence in the anatomical literature, we propose to denominate them as anterior retroperitoneal branches of abdominal aorta (rami retroperitoneales anteriores aortae abdominalis). Clin. Anat. 27:894–899, 2014. © 2014 Wiley Periodicals, Inc.     

Segmental hypermobility in lumbar spine and entrapment of dorsal rami

Low back pain patients (N = 18) having segmental hypermobility in one lumbar segment and healthy controls (N = 13) were chosen for this study. Patients had no other structural spinal pathology except displacement of one vertebra to another in lateral X-ray bending pictures. Kinetic intramuscular EMG-activity from paraspinal muscles was studied off-line during back flexion and reextension. Routine needle EMG study of paraspinal muscles was also performed in addition to measurements of the tibial nerve H-reflexes and peroneal F-responses. Results showed that the number of MUAPs in erector spinae muscle on voluntary efforts was rarefied at hypermobile levels, and spontaneous activity, positive sharp waves and high frequency discharges were found in more than half of the patients in paraspinal muscles, usually at hypermobile levels only. No signs of proximal nerve root compression were found. This indicates neuropathy of dorsal rami at the instable level.     

Anatomy of the ilioinguinal and iliohypogastric nerves with observations of their spinal nerve contributions

Proper anesthesia and knowledge of the anatomical location of the iliohypogastric and ilioinguinal nerves is important during hernia repair and other surgical procedures. Surgical complications have also implicated these nerves, emphasizing the importance of the development of a clear topographical map for use in their identification. The aim of this study was to explore anatomical variations in the iliohypogastric and ilioinguinal nerves and relate this information to clinical situations. One hundred adult formalin fixed cadavers were dissected resulting in 200 iliohypogastric and ilioinguinal nerve specimens. Each nerve was analyzed for spinal nerve contribution and classified accordingly. All nerves were documented where they entered the abdominal wall with this point being measured in relation to the anterior superior iliac spine (ASIS). The linear course of each nerve was followed, and its lateral distance from the midline at termination was measured. The ilioinguinal nerve originated from L1 in 130 specimens (65%), from T12 and L1 in 28 (14%), from L1 and L2 in 22 (11%), and from L2 and L3 in 20 (10%). The nerve entered the abdominal wall 2.8 ± 1.1 cm medial and 4 ± 1.2 cm inferior to the ASIS and terminated 3 ± 0.5 cm lateral to the midline. The iliohypogastric nerve originated from T12 on 14 sides (7%), from T12 and L1 in 28 (14%), from L1 in 20 (10%), and from T11 and T12 in 12 (6%). The nerve entered the abdominal wall 2.8 ± 1.3 cm medial and 1.4 ± 1.2 cm inferior to the ASIS and terminated 4 ± 1.3 cm lateral to the midline. For both nerves, the distance between the ASIS and the midline was 12.2 ± 1.1 cm. To reduce nerve damage and provide sufficient anesthetic for nerve block during surgical procedures, the precise anatomical location and spinal nerve contributions of the iliohypogastric and ilioinguinal nerves need to be considered.