Flexor Digitorum Profundus: Function & 3D Anatomy

Educational draft · anatomical review pendingSources checked 19 October 2026. Prepared with AI assistance; not yet reviewed by a qualified anatomist. Not for diagnosis or treatment.

Region: Deep anterior forearm
Digits: Index to little finger
Distal attachment: Distal phalanges
Abbreviation: FDP

A forearm muscle reaching the fingers

Flexor digitorum profundus acts on digits 2–5: index, middle, ring and little fingers. It is distinct from the superficial finger flexor, flexor digitorum superficialis.

Here FDP is one selectable source mesh. Individual digital portions are not separate buttons, and selecting gold does not identify a separately activated finger muscle.

Sources: Anatomy tables

From the ulna toward the distal phalanges

Its origin includes proximal anterior and medial ulnar surfaces and the interosseous membrane. Distally, its tendons reach the distal phalanges of the four fingers.

The ulna is available in this scene, but the membrane and phalanges are absent. Trace the surface beyond the wrist region without interpreting its end as a complete insertion footprint.

The superficial flexor’s middle-phalangeal destination is different. That muscle is not yet assembled in this scene, so this is not a complete comparison of the two tendon systems.

Sources: Loyola anatomy · Anatomy tables

Flexion at the distal finger joints

FDP flexes the distal interphalangeal joints and also contributes to flexion at more proximal finger joints and the wrist.

The source pose is fixed. Camera rotation does not bend the fingers or thumb, and the model does not simulate tendon gliding, grip or muscle contraction. Muscle and tendon are not separately selectable tissues.

A geometric section can expose the loaded surface, but cannot reveal fascicles, individual motor units or a functional grip pattern.

Sources: Loyola anatomy

Two named nerve contributions

The usual teaching pattern assigns the index- and middle-finger portion to the anterior interosseous branch of the median nerve, and the ring- and little-finger portion to the ulnar nerve.

This is not a patient-specific nerve map. The source mesh is not divided into nerve territories, and neither nerve is visible here.

Sources: Anatomy tables

Read the model

Explore flexor digitorum profundus in 3D

Follow the whole mesh. Start with Front, then Oblique. Focus selection fits the complete source surface, including its distal extensions, into the view.
Find the ulnar context. Choose Show context and Fade others. Alternate Ulna and Flexor digitorum profundus in the list; the hand remains without bone context.
Compare the thumb flexor. Select Flexor pollicis longus and open its selected title. Its related link returns to this guide.
Inspect a geometric cut. Use the regional forearm page for Section. The cut is a model intersection, not medical imaging; the added tendons change the scene bounds and relative cut positions. Open forearm study →

What this model can—and cannot—show

BodyParts3D provides this right-sided surface model, not every anatomical variant. Colors distinguish structures; they are not tissue textures.

This forearm subset includes radius, ulna and the two deep digital flexors, but not the hand bones, interosseous membrane, flexor retinaculum, tendon sheaths, nerves or vessels. Flexor digitorum superficialis is not loaded. Distal mesh ends extend into a hand region without its bones; they must not be read as attachments to the forearm bones.

FDP is represented as one reduced-resolution mesh, not four independently movable tendons. The arm and elbow subsets do not include it. Fine tendon splits, pulleys and internal tissue organization are not reconstructed.

The experimental Section tool is available in the regional forearm study, not on this isolated-structure page. Its flat cut surfaces are geometric aids, not CT images or tissue sections.

Sources and editorial status

This guide uses independently written explanations with links to the evidence behind them. Source checking and specialist anatomical review are separate steps; the latter is still pending.

Loyola University Chicago — LUMEN, Flexor digitorum profundus
Ulnar and membrane origin, distal phalangeal attachments and flexion actions. No illustrations reproduced.
Texas Tech University Health Sciences Center El Paso — Forearm & Wrist anatomy tables
FDP, FDS and nerve rows: digital destinations and usual anterior-interosseous/ulnar innervation pattern.

3D geometry and its separate license are credited beneath the viewer. References do not imply endorsement of this site.

Flexor digitorum profundus