Morphological Spectra of Adult Human Stellate Ganglia: Implications for Thoracic Sympathetic Denervation.

Cardiac sympathetic denervation (CSD) to treat ventricular arrhythmias (VAs) requires transection at the middle or lower third of stellate (cervicothoracic) ganglia (SG). However, the morphological appearance of the adult SG and distribution of neuronal somata within it are not well described. To determine the morphology of left and right SG (LSG and RSG) and the distribution of somata within. LSG and RSG (n = 28) from 14 embalmed adult cadavers were dissected intact. Weight, volume, height, morphologic appearance, relationship between C8 and T1 ganglia (which form the SG) were determined, along with histology. Demographics, history of cardiac disease, and cause of death were also reviewed. Mean age of the subjects was 76 ± 13 years, and 5/14 were male. Three distinct morphologies of SG were identified: fusiform-rounded; fusiform-elongated; and bilobed. RSG and LSG did not differ in weight or volume. RSG were longer than LSG (2.05 ± 0.28 cm vs. 1.66 ± 0.47 cm, P = 0.024). Bilobed morphology was most common in RSGs (8/14), while fused, elongated was most common in LSG (8/14). RSGs lacked fused, rounded appearance, while 28.6% of LSG appeared as such. Histologically, one focus of somata was seen in fused rounded ganglia, while fused elongated SG had somata distributed throughout. Bilobed SG demonstrated two foci of somata, with the interconnecting stalk containing sparse somata. SG appears in three major forms and contains varying distributions of somata. Larger studies are warranted to define the relationship between gross anatomy and distribution of neuronal somata to improve the efficacy of CSD in treating VAs. Anat Rec, 301:1244-1250, 2018. © 2018 Wiley Periodicals, Inc.

Locating the sural nerve during calcaneal (Achilles) tendon repair with confidence: a cadaveric study with clinical applications.

The sural nerve is at risk of iatrogenic injury even during minimally invasive operative procedures to repair the calcaneal (Achilles) tendon. Through 107 cadaveric leg dissections, the data derived from the present study was used to develop a regression equation that will enable surgeons to estimate the intersection point at which the sural nerve crosses the lateral border of the Achilles tendon, an important surgical landmark. In most cases, the sural nerve crossed the lateral border of the Achilles tendon 8 to 10 cm proximal to the superior border of the calcaneal tuberosity. By simply measuring the leg length of the patient (from the base of the heel to the flexor crease of the popliteal fossa), surgeons can approximate the location of this intersection point with an interval length of 0.68 to 1.80 cm, with 90% confidence, or 0.82 to 2.15 cm, with 95% confidence. For example, for a patient with a lower leg length of 47.0 cm, the mean measurement in the present study, a surgeon can be 90% confident that the sural nerve will cross the lateral border of the Achilles tendon 8.28 to 8.96 cm (interval width of 0.68 cm) proximal to the calcaneal tuberosity. Currently, ultrasound and clinical techniques have been implemented to approximate the location of the sural nerve. The results of the present study offer surgeons another method, that is less intensive, to locate reliably and subsequently avoid damage to the sural nerve during calcaneal (Achilles) tendon repair and other procedures of the posterolateral leg and ankle.

Clinical implications of novel variants of the fibularis (peroneus) quartus muscle inserting onto the cuboid bone: peroneocuboideus and peroneocalcaneocuboideus.

Two variants of the fibularis (peroneus) quartus muscle were identified and photographed in the legs of a 70-year-old white male cadaver. A rare peroneocuboideus (fibulocuboideus) muscle (as described by Chudzinski) and a novel peroneocalcaneocuboideus (fibulocalcaneocuboideus) muscle was found in the right and left leg, respectively. The latter muscle has not been previously reported and was termed "peroneocalcaneocuboideus" on the basis of its origin and insertions. Also, the distal attachment of both muscles inserted onto the distal lip of the peroneal sulcus of the cuboid bone, which differs from the historical data. The insertion of the peroneocuboideus muscle was previously described as being at the tuberosity of the cuboid bone or, simply, the lateral surface of the cuboid. Therefore, the present case study provides the first gross anatomic photographs of these variant leg muscles along their entire length, identifies a novel fibularis quartus variant, and describes a new insertion site for the peroneocuboideus muscle. Throughout our report, the historical data are reviewed to list the prevalence and describe the clinical implications of the fibularis quartus muscle and its variants. The presence of variant fibularis quartus muscles has been known to cause lateral ankle pain and stenosis, ankle instability, fibular tenosynovitis, subluxation of the fibular (peroneal) tendons, and longitudinal splitting of the fibularis brevis tendon in radiologic and case studies. Therefore, surgeons, radiologists, and clinicians should be aware of these variant muscles when considering various diagnoses, interpreting radiographs, and pursuing surgical intervention to relieve lateral ankle pathologic features.

The fibulocalcaneus (peroneocalcaneus) internus muscle of MacAlister: Clinical and surgical implications.

A fibulocalcaneus (peroneocalcaneus) internus (PCI) muscle (of MacAlister) was identified and photographed in the left leg of a 78-year-old Caucasian female cadaver. This case study provides the first gross anatomical photo of this anomalous leg muscle and represents the first gross anatomical dissection of this muscle since 1914. The PCI muscle arose from the distal third of the fibula, posterior intermuscular septum of the leg, and flexor hallucis longus muscle. The PCI muscle inserted into the inferior surface of the medial calcaneus distal to the coronoid fossa, a small depression between the anterior tuberosity and the anterior apex of the sustentaculum tali. This insertion point differs from the historical literature, which commonly refers to the muscle inserting into the inferior surface of the sustentaculum tali of the calcaneus or simply distal to the sustentaculum tali into the medial aspect of the calcaneus. The PCI muscle is one of the least common muscular variants associated with the ankle joint, and it has been implicated in posterior ankle pain and impingement, as well as involvement in tarsal tunnel syndrome. This muscle is often confused with the flexor digitorum accessorius longus (FDAL) muscle. Additionally, this study describes ways to differentiate between the PCI and FDAL muscles in the lower leg. Radiologists and clinicians should be aware of this anomalous muscle when considering various diagnoses, interpreting radiographs, and pursuing surgical intervention to relieve posterior ankle symptoms.