This medical illustration depicts an anatomical diagram of the human forearm and hand with a superimposed wearable surface electromyography (sEMG) device. The underlying anatomy displays the radius and ulna bones, the carpal and metacarpal structures, and the phalanges in white. The musculature of the posterior (extensor) compartment is rendered in red, with tendons highlighted in white crossing the wrist joint beneath the extensor retinaculum. A segmented black armband containing eight dry electrodes is shown positioned on the proximal third of the forearm, approximately one finger-width distal to the elbow joint. The electrodes are numbered, with electrode '1' aligned dorsally with the middle finger, while electrodes '2' and '8' are visible laterally. This visual serves as a technical and anatomical protocol for sensor placement in gesture recognition research, emphasizing the relationship between electrode orientation and underlying superficial muscles and tendons.

This clinical anatomical photograph displays a cadaveric gross dissection of the human dorsal forearm, highlighting the muscular and nervous anatomy. The image focuses on the extensor compartment, with several muscles clearly labeled: the extensor digitorum communis (EDC), extensor digiti minimi (EDM), abductor pollicis longus (APL), extensor carpi ulnaris (ECU), extensor pollicis brevis (EPB), extensor pollicis longus (EPL), and extensor indicis proprius (EIP). Centrally, the posterior interosseous nerve (PIN) is visible as it exits the arcade of Frohse (indicated by a black arrow). A specific terminal branch of the PIN is shown extending towards the EPL muscle (highlighted by a white arrow). Surgical forceps are positioned to retract tissue, providing a clear view of the neurovascular relationship and the distal innervation pattern of the deep extensor muscles. This visual serves as a critical educational resource for understanding Zone IX forearm anatomy, particularly for neurovascular preservation during surgical procedures or trauma management.

Anatomical dissection of a human cadaver forearm, focusing on the distal third of the posterior compartment. The image demonstrates the surgical anatomy relevant for raising a posterior interosseous artery (PIA) flap. The dissection reveals the Extensor Carpi Ulnaris (ECU) and Extensor Digiti Minimi (EDM) muscles, with a retracted skin and fasciocutaneous paddle reflected ulnarly. Key features include three distinct fasciocutaneous perforators of the PIA, marked with asterisks, emerging through the intermuscular septum between the EDM and ECU. These vessels are highlighted in red to show their branching pattern as they supply the overlying subcutaneous tissue and skin. Directional markers indicate Distal, Proximal, Ulnar, and Radial orientations. This visual is intended for educational purposes regarding reconstructive surgery, specifically illustrating the vascular landmarks and pivot points required for antegrade or retrograde forearm flaps used in hand or elbow defect coverage.

This diagnostic image and anatomical diagram comparison shows a cross-sectional MRI slice of the human forearm (left) alongside its corresponding segmented anatomical map (right). The MRI is a T1-weighted axial scan displaying cortical bone as low-signal (black) voids and muscle bundles as intermediate-signal structures. The segmented diagram identifies key anatomical structures using a color-coding system: the radius and ulna bones are in gray, the interosseous membrane is a black line connecting them, and individual muscles are uniquely colored (e.g., FCR, FDS, FDP, ECU, and ED). The interosseous membrane serves as a landmark dividing the anterior (flexor) and posterior (extensor) muscle compartments. The diagram also illustrates the superficial integumentary layers, with the skin represented in pink and the underlying subcutaneous fat layer in brown. This visual serves as an educational tool for musculoskeletal anatomy, demonstrating the spatial relationships between forearm skeletal structures, deep and superficial muscle groups, and their respective fascial boundaries.

This clinical anatomical photograph displays a cadaveric gross dissection of the human dorsal forearm, highlighting the muscular and nervous anatomy. The image focuses on the extensor compartment, with several muscles clearly labeled: the extensor digitorum communis (EDC), extensor digiti minimi (EDM), abductor pollicis longus (APL), extensor carpi ulnaris (ECU), extensor pollicis brevis (EPB), extensor pollicis longus (EPL), and extensor indicis proprius (EIP). Centrally, the posterior interosseous nerve (PIN) is visible as it exits the arcade of Frohse (indicated by a black arrow). A specific terminal branch of the PIN is shown extending towards the EPL muscle (highlighted by a white arrow). Surgical forceps are positioned to retract tissue, providing a clear view of the neurovascular relationship and the distal innervation pattern of the deep extensor muscles. This visual serves as a critical educational resource for understanding Zone IX forearm anatomy, particularly for neurovascular preservation during surgical procedures or trauma management.

This clinical photograph displays a cadaveric gross dissection of the dorsal forearm, demonstrating a simulated Zone IX laceration injury. The image focuses on the deep muscle layer and neurovascular structures of the posterior compartment. Key anatomical landmarks identified by text labels include the Extensor Pollicis Brevis (EPB) and the Extensor Pollicis Longus (EPL). Two white arrows specifically indicate the severed ends of a motor branch of the posterior interosseous nerve (PIN) as it enters the EPL muscle. Surgical forceps are visible, retracting tissue to provide a clear view of the nerve gap and the surrounding damaged musculotendinous units. This visual emphasizes the clinical significance of identifying nerve involvement in dorsal forearm lacerations, particularly where distal extensor function (thumb and finger extension) is compromised despite intact superficial tendons.

This clinical photograph displays a surgical dissection of the human forearm, focusing on the peripheral nervous system anatomy of the radial nerve. The primary structure shown is the Posterior Interosseous Nerve (PIN) as it courses distally through the extensor compartment. The image highlights a complex branching pattern: the main PIN trunk bifurcates into the Deep Branch (DBPIN) and the Superficial Branch (SBPIN). Further distal arborization is visible, including the lateral branches (LBPIN) and the specific branch to the extensor digitorum communis (BEDC). The nerves are meticulously isolated and placed over blue background material for visual contrast against the red muscular and soft tissue. Surgical retractors are in situ, maintaining exposure of the deep forearm musculature. This anatomical specimen demonstrates the terminal motor innervation of the wrist and finger extensors, critical for understanding PIN palsy, nerve entrapment syndromes, and reconstructive nerve transfer procedures such as AIN-to-PIN transfers.