This composite educational graphic illustrates the normal anatomy of the brachial plexus through anatomical diagrams and Magnetic Resonance Imaging (MRI). Panel A is an anatomical diagram depicting the plexus architecture from roots (C5-T1) to terminal branches, labeled with musculoskeletal landmarks like the scalene muscles and coracoid process. Panel B (axial) and Panel C (sagittal) are T1-weighted MRI scans demonstrating the interscalene triangle, defined by the anterior scalene (sa) and middle scalene (sm) muscles. These muscles serve as primary radiological landmarks for identifying the neural roots and trunks (indicated by arrows). Panel D provides an oblique coronal T1-weighted MRI view, tracing the sequential segments of the right brachial plexus: roots (R), trunks (T), divisions (D), and cords (C). This resource is designed for medical education in radiology and neurology to assist in the localization of neural structures and the diagnostic evaluation of conditions like brachial plexopathy, neurogenic tumors, or Pancoast tumors.

This composite educational material consists of a schematic diagram and a corresponding intraoperative clinical photograph illustrating the anatomical segments of the brachial plexus. The schematic on the left delineates the progression from spinal nerve roots (C6, C7, C8, and T1) through trunks, divisions, and chords to terminal nerves, using distinct grayscale patterns for each segment. It highlights the convergence of roots into upper, middle, and lower trunks and the subsequent formation of the medial and lateral cords through ventral divisions. The intraoperative photograph on the right provides clinical correlation in a neonatal model, with white arrows and horizontal lines demarcating the supraclavicular root/trunk region, the infraclavicular chord region, and the distal nerve branches. This comparison is used to facilitate identification of nerve bifurcations—such as the 'M' shape of the terminal branches—and to define anatomical boundaries for biomechanical or surgical study. The content is designed for intermediate to advanced medical education in peripheral nerve anatomy and neurosurgery.

This composite educational graphic details the anatomy of the human brachial plexus (BP) through cadaveric dissections and a schematic diagram. (A) Cadaveric dissection of the cervical spine and axilla with the anterior scalene muscle removed, exposing the C5-T1 nerve roots emerging laterally to the middle scalene muscle (MS). (B) A structured schematic diagram illustrating the hierarchical organization of the BP from roots (C5-T1), trunks (Superior, Middle, Inferior), divisions (Anterior, Posterior), and cords (Lateral, Posterior, Medial) to terminal branches. (C) Dissection showing the roots in situ within the scalene triangle, formed between the anterior (AS) and middle scalene muscles, alongside major vessels including the subclavian artery (SCA) and internal jugular vein (IJV). The phrenic nerve (yellow arrowhead) is seen traversing the anterior scalene. (D) Detailed view of the infraclavicular and axillary regions showing terminal branches (1-8: suprascapular, musculocutaneous, axillary, radial, medial brachial cutaneous, median, ulnar, and intercostobrachial nerves) in relationship to the pectoralis minor (Pmi), pectoralis major (Pma), and subclavian vessels. This content provides essential topographical and clinical anatomy for understanding thoracic outlet syndrome and regional anesthesia.

Educational anatomical resource illustrating the brachial plexus through cadaveric dissections (Panels A, C, D) and a schematic diagram (Panel B). Panel A shows the overview of the plexus and middle scalene muscle (MS) relative to the spinal cord. Panel B provides a detailed schematic of the classical brachial plexus organization: roots (C5-T1), superior (ST), middle (MT), and inferior (IT) trunks, anterior and posterior divisions, cords (lateral, medial, posterior), and terminal branches. Panel C displays a deep neck dissection highlighting the relationship between roots C4-T1 and the anterior scalene (AS), subclavian artery (SCA), internal jugular vein (IJV), and vagus nerve (X). A yellow arrowhead identifies the phrenic nerve. Panel D focuses on the infraclavicular and axillary regions, showing terminal branches: 1 (suprascapular), 2 (musculocutaneous), 3 (axillary), 4 (radial), 6 (median), and 7 (ulnar) nerves. Vascular landmarks include the common carotid artery (CCA) and subclavian vein (SV), alongside the pectoralis major (Pma) and minor (Pmi) muscles, providing clinical context for regional anesthesia and surgical approaches.

This diagnostic ultrasound image demonstrates the sonoanatomy of an Erector Spinae Plane (ESP) block at the level of the T7 thoracic vertebra. The image is presented in a sagittal view with cranial and caudal orientation markers. Key anatomical structures identified include the T7 transverse process (T7 TP), which appears as a hyperechoic, bony landmark with posterior acoustic shadowing, and the superficial erector spinae muscle (ESM), characterized by its striated echo texture. A hyperechoic needle (N) is visualized being advanced in a cranio-caudal direction through the ESM. In the post-injection frame, local anesthetic (LA) is seen as a hypoechoic (dark) fluid collection accumulating in the fascial plane deep to the ESM and superficial to the transverse process. The image illustrates the objective of the ESP block: the hydrodissection of the plane between the musculature and the bony processes to facilitate the cranial and caudal spread of anesthesia along the thoracic paravertebral space. This material is suitable for training in regional anesthesia, pain management, and ultrasound-guided procedural techniques.

This diagnostic ultrasound image demonstrates the sonoanatomy required for an Erector Spinae Plane (ESP) block. The image shows a longitudinal view of the thoracic or lumbar paraspinal region. Key anatomical structures include the erector spinae muscle group, visible as superficial, parallel, hypoechoic layers, and the underlying transverse process of the vertebra, characterized by a highly echogenic (hyperechoic) curvilinear bony surface with posterior acoustic shadowing. An anesthetic needle is visualized using an in-plane technique, appearing as a linear hyperechoic structure. The needle tip is correctly positioned at the fascial plane between the deep aspect of the erector spinae muscle and the apex of the transverse process. This view is typical for regional anesthesia, illustrating the target site for local anesthetic deposition to achieve multisegmental analgesia. The image serves as an educational guide for ultrasound-guided interventional pain management and regional anesthesia protocols.

This diagnostic ultrasound image demonstrates the sonoanatomy of the thoracic paravertebral region in a sagittal plane, specifically used for the Erector Spinae Plane Block (ESPB). The image shows the erector spinae muscle (ESM) appearing as a thick, relatively hypoechoic tissue layer situated superficial to the bony structures. Deep to the ESM, the transverse process of the eighth thoracic vertebra (T8) is identified as a distinct, hyperechoic (bright) linear interface with characteristic posterior acoustic shadowing, typical of mineralized bone. The fascial plane between the deep surface of the ESM and the superficial aspect of the T8 transverse process is the target injection site for regional anesthesia. This visualization is essential for pain management procedures in anesthesiology and palliative care, allowing for real-time needle guidance and ensuring local anesthetic deposition deep to the erector spinae fascia to achieve multisegmental sensory blockade.

This composite image illustrates the clinical application and diagnostic visualization of an ultrasound-guided thoracic paravertebral block (PVB). Figure (a) is a clinical photograph showing the procedural setup, where a linear ultrasound probe is positioned on a patient's back between the fourth and fifth ribs. Figure (b) provides the corresponding ultrasound imaging of the thoracic anatomy. Key landmarks identified include the erector spinae muscle (visualized as a hypoechoic region superiorly), the hyperechoic curved surface of the transverse process, and the internal intercostal membrane (i.i.m.). The pleura is visible as a deeper, hyperechoic linear structure. An echogenic needle is shown in an in-plane approach, penetrating the internal intercostal membrane toward the paravertebral space. This visualization is critical for regional anesthesia in thoracic or breast surgery to ensure accurate local anesthetic deposition while avoiding pleural puncture. The educational focus is on the ultrasonographic identification of thoracic musculature and skeletal landmarks necessary for safe needle guidance.

This procedural photograph demonstrates a thoracic paravertebral block technique under ultrasound guidance. A clinician, wearing white sterile medical gloves, uses a high-frequency linear ultrasound transducer covered with a protective sheath to visualize the underlying paraspinal anatomy. A generous amount of conductive ultrasound gel is applied to the skin of the thoracic region, which shows several benign-appearing nevi. A 16G Tuohy needle is being advanced using a craniocaudal in-plane technique, where the needle is oriented parallel to the long axis of the transducer beam to allow for continuous visualization of the needle shaft and tip. The needle features a clear plastic hub attached to extension tubing for local anesthetic delivery. This image illustrates the standard clinical setup for regional anesthesia, highlighting the spatial relationship between the transducer and the needle entry point to ensure precise localization within the paravertebral space.

This diagnostic ultrasound comparison demonstrates the thoracic paravertebral space (TPVS) before and after the administration of a thoracic paravertebral block. Both images utilize a transverse scanning plane. Image A (pre-block) shows the baseline anatomy: the Transverse Process (TP) appears as a hypoechoic structure with acoustic shadowing; the Superior Costo-transverse Ligament (CTL) is a hyperechoic band; and the Parietal Pleura (PP) is identified as a deep, bright hyperechoic line. In Image A, the potential space between the CTL and PP is narrow. Image B (post-block) reveals the clinical significance of the procedure: the TPVS is significantly expanded by the injection of local anesthetic, visualized as a large wedge-shaped hypoechoic area. This expansion results in the downward displacement of the Parietal Pleura (PP) away from the Superior Costo-transverse Ligament (CTL). This comparison serves as an educational tool for identifying key sonoanatomy and confirming successful anesthetic spread during regional anesthesia in anesthesiology and pain management.

Diagnostic ultrasound images illustrating a serratus plane block (SPB) for regional anesthesia. The visuals demonstrate the layered musculoskeletal anatomy of the lateral chest wall. In both panels, the latissimus dorsi muscle (LDM) is the most superficial muscle layer, followed by the deeper serratus anterior muscle (SAM), which lies directly above the ribs. The ribs are identified by their characteristic curved hyperechoic margins with posterior acoustic shadowing. Image A shows a deep serratus plane block, where the local anesthetic (LA)—visible as an anechoic/hypoechoic fluid collection—is injected between the SAM and the underlying rib. Image B illustrates a dual-plane or superficial block, showing LA distribution both superficial to the SAM (between the LDM and SAM) and deep to the SAM. A Tuohy needle (indicated by white arrows) is visible using the in-plane technique, tracking through the muscle layers to the target fascia. This content is used to teach ultrasound-guided regional anesthesia techniques for pain management in thoracic and chest wall surgeries.

This educational graphic illustrates the ultrasound-guided serratus plane block technique through two side-by-side panels. Panel (a) is a simplified anatomical diagram showing the spatial relationship between thoracic muscles and ribs. The latissimus dorsi is depicted superficially over the serratus anterior muscle, which rests atop the 3rd, 4th, and 5th ribs. Panel (b) is a corresponding ultrasound image in the transverse plane at the axillary region. It identifies key landmarks including the latissimus dorsi, serratus anterior, and the hyperechoic surface of the fifth rib with an acoustic shadow below it. Yellow arrows in both panels indicate the primary targets for local anesthetic infiltration: the interfascial plane between the latissimus dorsi and serratus anterior, and the space deep to the serratus anterior muscle. The visual is designed to teach regional anesthesia residents and clinicians the correct needle placement for blocking the intercostobrachial and lateral intercostal nerves (T3-T9) for thoracic wall analgesia.

This diagnostic image displays dual-pane fluoroscopic views (anteroposterior [AP] and lateral) of a neurolytic celiac plexus block procedure. Two 22-gauge spinal needles are visible, positioned for bilateral approach at the level of the L1 vertebral body. In the left AP view, iodinated contrast agent is distributed bilaterally, appearing as irregular, globular opacities lateral to the mid-vertebral column. In the right lateral view, the needle tips are confirmed at the anterior border of the L1 vertebral body, with a localized, well-defined contrast collection situated anterior to the ventral surface of the vertebra. This pattern demonstrates appropriate needle placement within the retroperitoneal space and confirms the absence of vascular uptake or epidural spread before the administration of neurolytic agents. The image serves as an educational example of fluoroscopy-guided interventional pain management for chronic visceral epigastric pain associated with abdominal malignancy.

This diagnostic fluoroscopy series illustrates a celiac plexus block (CPB) procedure performed on a patient with resistant hypertension. The image set consists of four panels showcasing a bilateral paravertebral posterior approach. Panels (a) and (c) are anteroposterior (AP) views showing the needle tip positioned adjacent to the L1 vertebral body. In these views, radiopaque contrast material is visualized spreading in a characteristic diffuse, cloud-like pattern prevertebrally, confirming correct needle placement for the injection of botulinum toxin. Panels (b) and (d) provide lateral views, demonstrating the needle's depth and its position relative to the anterior aspect of the vertebral column. The contrast distribution in the lateral views appears as a hazy opacification anterior to the lumbar vertebrae. These images demonstrate a pain management and interventional radiology technique used to target the sympathetic nervous system for the treatment of essential hypertension that is refractory to pharmacological and renal denervation therapies.

This composite of three fluoroscopy images demonstrates interventional radiology procedures in a patient with biliary obstruction. Images A and B show a celiac plexus block (CPB) using a posterior retrocrural approach at the T12-L1 level. The anteroposterior view (A) shows a bent tip needle positioned lateral to the vertebral column, while the lateral view (B) confirms the needle's trajectory and depth toward the retrocrural space, posterior to the diaphragmatic crus. Image C is a posteroanterior fluoroscopic view of a percutaneous transhepatic biliary drainage (PTBD) and tract dilatation procedure. Contrast media opacifies the intrahepatic and extrahepatic biliary tree, revealing a clear filling defect (indicated by an arrow) in the common bile duct (CBD). This defect represents a 1-cm CBD stone causing proximal obstruction. The images illustrate the combined use of anesthetic nerve blocks to manage pain during invasive hepatobiliary interventions for acute cholecystitis and choledocholithiasis.

This diagnostic fluoroscopic image in an anteroposterior (AP) view captures a right-sided stellate ganglion block procedure in the lower cervical spine region. The bony anatomy visible includes the base of the skull, the mandible, and the cervical vertebrae from C1 down to the cervicothoracic junction. A radiopaque linear needle or catheter (indicated by a pink arrow) is seen approaching from a lateral-to-medial direction, with its tip positioned at the level of the C6-C7 vertebral interface. Adjacent to the tip of the needle, a localized collection of radiopaque contrast medium (indicated by a yellow arrow) is visible, appearing as an irregular, elongated vertical density lateral to the vertebral bodies. This contrast pattern confirms the appropriate needle tip placement within the prevertebral fascia for the sympathetic block. The image serves as an educational example of interventional pain management techniques, specifically demonstrating fluoroscopic guidance and contrast confirmation during a cervical sympathetic nerve block for conditions such as complex regional pain syndrome (CRPS).

This longitudinal diagnostic ultrasound image illustrates the anatomy of the cervical sympathetic chain, specifically focusing on the stellate ganglion (SG). The stellate ganglion is highlighted by a dashed white outline, demonstrating a characteristic oval shape. Visually, the ganglion exhibits marked hyperechogenicity relative to the adjacent musculature. Anatomical landmarks are labeled for spatial orientation: the Common Carotid Artery (CCA) appears as an anechoic (black) lumen situated anterior to the ganglion, while the Longus Colli Muscle (LCM) is positioned immediately posterior to the ganglion. The image serves as an educational reference for identifying sympathetic nervous system structures in the neck, emphasizing the relationship between vascular and muscular planes in regional anesthesia or pain management procedures. The hyperechoic appearance and ill-defined margins are key sonographic features for identifying the SG within the prevertebral fascia.

**Imaging Modality:** Ultrasound (B-mode ultrasonography) **Anatomical Region:** Cervical spine region (C6–C7 level), transverse view. **Key Landmarks and Findings:** The image displays the anatomical landmarks relevant for a stellate ganglion nerve block. Key vascular structures include the anechoic, pulsatile common carotid artery (CA) and the partially compressible internal jugular vein (JV). Deep to the prevertebral fascia, the longus colli muscle (CL) is visible as a hypoechoic structure situated anterior to the transverse process. The stellate ganglion (cervicothoracic ganglion) is identified as a small, oval, hypoechoic neural structure, marked with a red star, located medial to the carotid artery and superficial to the longus colli muscle. The image demonstrates the relationship between the sympathetic chain and the overlying prevertebral fascia, providing a target for ultrasound-guided regional anesthesia. **Clinical Context:** This ultrasonogram is utilized for procedural guidance in a nerve block, specifically to ensure precise needle placement and to avoid accidental puncture of adjacent vascular structures such as the carotid artery or vertebral artery.