Blocks of Nerves of the Sacral Plexus Supplying the Lower Extremities
Bernard J. Dalens, Jean-Pierre Monnet, Yves Harmand in Pediatric Regional Anesthesia, 2019
The sacral plexus is formed by the union of the ventral rami from L5, S1, S2, S3, and partly from L4 and S4 spinal nerves.11 L4 and L5 ventral rami unite closely at their emergence from intervertebral foramina, thus constituting the lumbosacral trunk which appears at the medial border of the psoas major muscle (Figure 2.28). The lumbosacral trunk runs over the pelvic brim, towards the sacro-iliac joint where it unites with the ventral ramus of the first sacral nerve (Figure 2.1B). The other sacral rami join the plexus just above the greater sciatic notch, thus constituting (1) a lower small band, plexiform in arrangement and prolonged into the pudendal nerve; and (2) an upper large band prolonged by the sciatic nerve, which passes out of the pelvis at this level.
Neurologic disorders in pregnancy
Hung N. Winn, Frank A. Chervenak, Roberto Romero in Clinical Maternal-Fetal Medicine Online, 2021
Lumbosacral trunk is unprotected as it crosses the pelvic brim to enter the true pelvis and is prone to compression by the fetal head or forceps. Rarely sciatic nerve itself may be compressed. Injury to lumbosacral plexus or sciatic nerve predominantly affects the peroneal nerve component. Foot drop is noted immediately postpartum. There is weakness of dorsiflexion, inversion and eversion of the foot, and sensory impairment corresponding to L5 dermatome. Ankle reflex is preserved with L4–5 trunk lesion but is absent with sciatic nerve injury. Differential diagnosis is from lumbar radiculopathy and peroneal nerve compression at the fibular neck. Electrophysiologic studies help distinguish by findings of denervation in paraspinal muscles in lumbar radiculopathy and focal nerve conduction abnormality at fibular head in peroneal neuropathy. When difficult to distinguish from lumbar radiculopathy, MRI of lumbar spine is warranted.
The Thigh (Anterior and Medial Compartments)
Gene L. Colborn, David B. Lause in Musculoskeletal Anatomy, 2009
Identify the descending limb of the fourth lumbar nerve, the ventral ramus of the fifth lumbar nerve and their junction to form the lumbosacral trunk. The lumbosacral trunk and the ventral rami of the first four sacral nerves take part in the formation of the sacral plexus. Notice that the sciatic nerve arises from lumbar roots L4 and L5 and sacral roots S1, 2 and 3 (Fig. 10:5).
Analysis of magnetic resonance signal intensity changes in the sacrococcygeal region of patients with uterine fibroids treated with high intensity focused ultrasound ablation
Published in International Journal of Hyperthermia, 2020
Dandan Li, Chunmei Gong, Jin Bai, Lian Zhang
In this study, we found a relatively high incidence of MR signal intensity changes in the sacrum and the soft tissue adjacent to the sacrum, but only a small number of patients complained of sacral pain or leg pain after HIFU. To evaluate any relationship between the MR signal intensity changes in the pelvis and the sacral or leg pain, we further reviewed the post-HIFU MR images of the 25 cases of sacrococcygeal pain and the 3 cases of leg pain after HIFU treatment. There was no significant difference in the rate of sacral pain among the patients with signal intensity changes in the sacrum, in the soft tissue adjacent to the sacrum, or in both. However, our results showed that the signal intensity change volume in the soft tissue on T2WI in patients with sacral pain was significantly larger than that in patients without sacral pain (Table 7). Sacral pain is only related to local tissue injury or inflammation without involvement of sacral nerve. In this study, leg pain was only seen in patients with MR signal intensity changes in both the sacrum and the soft tissue adjacent to the sacrum, but we did not find any significant difference in signal intensity change volume between the patients with leg pain and those without. We carefully reviewed the MR images of the patients with leg pain and found the signal intensity change area was located in sacral 1 and sacral 2, and the soft tissue adjacent to the lumbosacral trunk (Figure 3). Therefore, sacral pain is only related to local tissue injury or inflammation without the involvement of the sacral nerve, leg pain was generally caused by sacral nerve irritation after HIFU. It seems that sacral pain or leg pain is more likely related to the location of the signal changed area, not the volume. Sacral pain was relieved within 2 weeks after HIFU treatment when the edema subsided. Leg pain persisted for a longer period of time and treatment for symptoms with Celebrex (200 mg oral once a day) and physical therapy was required. The duration of leg pain was related to the area of MR signal intensity changes and pain was generally relieved 2-6 months after HIFU treatment.
Related Knowledge Centers
- Childbirth
- Fetal Head
- Lumbar Nerves
- Lumbar Plexus
- Obturator Nerve
- Pelvic Brim
- Sacral Plexus
- Sacrum
- Ventral Ramus of Spinal Nerve
- Leg