Iliocostalis muscles in three mammals (dolphin, goat and human): Their identification, structure and innervation

Fetal development and growth of the human erector spinae with special reference to attachments on the surface aponeurosis

PURPOSE

The longissimus (LO) and iliocostalis (IC) of adults consist of myofibers extending from the superolateral to the inferomedial side of the back and, because of the same course, they are fused in the thoracolumbar region. The LO also has a medial attachment to the long myofibers of the transversospinalis (TS) showing a course from the superomedial to the inferolateral side. However, there is apparently no information regarding when and how these similar longitudinal muscles differentiate from a cluster of dorsomedial myotome cells.

METHODS

We examined sagittal and horizontal sections of the trunks of 39 human embryos and fetuses (18-330 mm crown-rump length).

RESULTS

At 6-7 weeks gestational age (GA), the surface aponeurosis appeared prior to and independent of the thoracolumbar fascia. At 6-9 weeks GA, the LO myofibers had a postero-inferior course, from the transverse process to the initial aponeurosis, whereas the TS myofibers had a postero-superior course, from a lateral extension of the intertransverse ligament to the aponeurosis. However, the IC consisted of supracostal longitudinal myofibers and was distant from the LO until 12 weeks GA. Because of the lack of ligamentous attachments and ribs, myofibers of the TS, LO, and IC took a similar inferior course in the lumbar region. When the early TS was represented by the transverso-aponeurotic muscle, consequently, the LO corresponded to the aponeuro-transversal muscle and was independent from the IC.

CONCLUSION

The classical model of TS and LO development does not recognize the essential role of the aponeurosis identified here.

The Analgesic Efficacy of Erector Spinae Plane Blocks in Patients Undergoing Posterior Lumbar Spinal Surgery for Lumbar Fracture

OBJECTIVE

To investigate the postoperative analgesic efficacy of ultrasound-guided lumbar erector spinae plane (ESP) blocks in patients undergoing posterior lumbar spinal surgery for lumbar spinal fractures.

METHODS

A total of 80 patients who were scheduled for posterior internal fixation for lumbar spinal fractures were divided into a patient-controlled analgesia (PCA) group or a combined ESP-PCA group. Numeric rating scale at rest and during movement, postoperative sufentanil consumption, and accumulative and effective bolus presses of PCA were recorded at 6, 12, 24, and 48 hours postoperatively. Numeric rating scale at rest and during movement was the primary outcome. Incidence of postoperative nausea and vomiting during the first 24-48 hours, pruritus and chronic postoperative pain, and dose of pethidine for rescue analgesia were also recorded.

RESULTS

Numeric rating scale at rest and during movement at 6, 12, and 24 hours was lower in the ESP-PCA group (P < 0.001, P < 0.001, P = 0.0016 at rest; all P < 0.001 during movement). Lumbar ESP blocks diminished accumulative bolus presses and effective bolus presses of PCA at 6, 12, 24, and 48 hours postoperatively. Besides, patients in the ESP-PCA group had fewer demands for sufentanil and pethidine. The incidence of postoperative nausea and vomiting in the ESP-PCA group was lower than that in PCA group.

CONCLUSIONS

PCA combined with lumbar ESP blocks provided superior postoperative analgesia for patients with lumbar spinal fractures treated with posterior internal fixation. Lumbar ESP blocks decreased postoperative opioid consumption and incidence of postoperative nausea and vomiting, thereby enhancing postoperative recovery.

Comparative histology of muscle in free ranging cetaceans: shallow versus deep diving species

Different marine mammal species exhibit a wide range of diving behaviour based on their breath-hold diving capabilities. They are classically categorized as long duration, deep-diving and short duration, shallow-diving species. These abilities are likely to be related to the muscle characteristics of each species. Despite the increasing number of publications on muscle profile in different cetacean species, very little information is currently available concerning the characteristics of other muscle components in these species. In this study, we examined skeletal muscle fiber type, fiber size (cross sectional area and lesser diameter), intramuscular substrates, and perimysium-related structures, by retrospective study in 146 stranded cetaceans involving 15 different species. Additionally, we investigated diving profile-specific histological features. Our results suggest that deep diving species have higher amount of intramyocyte lipid droplets, and evidence higher percentage of intramuscular adipose tissue, and larger fibre sizes in this group of animals.

Anatomy of the human thoracolumbar Rami dorsales nervi spinalis

Medial, lateral, and intermedial ramifications have been described for the dorsal branch of the human spinal nerve (R. dorsalis n. spinalis, (RDNS)). Further branching has not been described. We report a ventral approach for dissecting the nerves around the thoracolumbar vertebral column to visualise the spreading of the nerves within the dorsal muscles and towards the skin. We defined three compartments of the deep back muscles in the thoracolumbar region: (A) the origin from the (1) transverse, (2) accessory, and (3) mammillary processes in the lumbar segments, (B) from the (1) ribs, (2)transverse and, (3) articular processes in the thoracolumbar segments. Each compartment was supplied by a ramification of the RDNS. The medial muscle compartment was reached by the descending medial branch of the RDNS. The lateral iliocostal compartment was innervated by an ascending lateral branch of the RDNS, and also by the descending distal branches of an intermedial branch of RDNS. This is a long nerve of the intermedial branch of the RDNS extended to the dorsal-caudal area, where the lateral and the intermedial nerve connected. This nerve, termed as the dorsal intermedial branch of the RDNS, innervated the skin in a more caudal region. Such nerve divided the lateral and the intermediate compartments. A short intermedial branch entered the intermediate segmental compartment from the ventral side. This is a ventral intermedial branch of the RDNS. The dorsal branches were often connected by a connecting branch of the RDNS. The lateral compartment represented the Iliocostalis. The medial and intermediate compartments comprised the Longissimus, part of the Iliocostalis, and additional dorsal muscles.