Lumbricals (Hand) - Podcast Version 0:00 / 0:00 1x 0.25x 0.5x 0.75x 1x 1.25x 1.5x 1.75x 2x The lumbricals are intrinsic muscles of the hand. There are four lumbricals – each associated with a digit. Attachments: Originates from the tendon of the flexor digitorum profundus. Inserts onto the radial aspect of the extensor hood of each digit. Actions: Flexion at the metacarpophalangeal joint and extension at the interphalangeal (IP) joints. Innervation: Lateral two lumbricals (of the index and middle fingers) are innervated by the median nerve. Medial two lumbricals (of the little and ring fingers) are innervated by the ulnar nerve. Blood supply: Superficial and deep palmar arches By TeachMeSeries Ltd (2026) Figure 1The lumbricals of the hand. Note the differing unipennate and bipennate structure. Pro Feature - 3D Model You've Discovered a Pro Feature Access our 3D Model Library Explore, cut, dissect, annotate and manipulate our 3D models to visualise anatomy in a dynamic, interactive way. Learn More Pro Feature - Dissection Atlas Prosection of the superficial muscles and tendons of the hand. The tendons of the flexor digitorum superficialis can be seen as they pass through the carpal tunnel to insert onto each digit. Prosection of the superficial muscles and tendons of the hand. The tendons of the flexor digitorum superficialis can be seen as they pass through the carpal tunnel to insert onto each digit. You've Discovered a Pro Feature Access our Dissection Image Library Enhance your understanding with high-resolution dissection images showcasing real-life anatomy. Learn More Frequent questions What are the lumbricals in the hand? The lumbricals are intrinsic muscles of the hand, with four muscles corresponding to each digit. They play a crucial role in finger movements. What are the attachments of the lumbricals? The lumbricals originate from the tendon of the flexor digitorum profundus and insert onto the radial side of the extensor hood of each digit. This unique attachment allows them to facilitate finger movements effectively. What actions do the lumbricals perform? The primary actions of the lumbricals include flexion at the metacarpophalangeal joint and extension at the interphalangeal joints. This dual action is essential for coordinated finger function. How are the lumbricals innervated? The lateral two lumbricals, associated with the index and middle fingers, are innervated by the median nerve, while the medial two lumbricals, linked to the little and ring fingers, receive innervation from the ulnar nerve. This differential innervation is crucial for hand dexterity. What is the blood supply to the lumbricals? The blood supply to the lumbricals comes from the superficial and deep palmar arches. This vascularisation is vital for their function and health. Rate This Article