Dart Thrower's Motion of the Wrist: Clinical Guide

By Joseph Sharaya, OTD, OTR/L, CHT · Certified Hand Therapist · Updated September 2026

Dart Thrower's Motion is an oblique plane of wrist movement that travels from radial extension to ulnar flexion — the arc the wrist traces when throwing a dart or hammering a nail.

The DTM plane is oblique, and its angle varies widely between people. In 24 healthy adults, the plane ranged from 28 to 57 degrees relative to the flexion-extension axis (Vardakastani et al., 2018). In a simulated hammering task, the path of wrist motion averaged 41 degrees from the sagittal plane (Leventhal et al., 2010).

Two subtypes worth knowing

The 2013 IFSSH Committee report formally distinguishes between two forms of DTM (Moritomo et al., 2014):

Pure DTM

An oblique plane that intercepts the coronal and sagittal planes at the neutral wrist position. In this plane, scaphoid and lunate motion approach zero, and wrist rotation occurs almost exclusively at the midcarpal joint (Moritomo et al., 2014; Crisco et al., 2005).

Functional DTM

The plane used in real tasks such as hammering. It runs almost parallel to the pure plane but is offset toward extension, and it involves more scaphoid and lunate motion (Moritomo et al., 2014). In a CT study of a simulated hammering task, the path passed through a position offset 36 degrees into extension, and scaphoid and lunate rotation still averaged 40 and 41 percent of total wrist motion (Leventhal et al., 2010). This is the DTM most patients actually use.

Why DTM matters — proximal row protection

The landmark Crisco et al. (2005) CT study of both wrists of 28 healthy adults, covering 504 wrist positions, showed that scaphoid and lunate motion is significantly smaller along the DTM path than along any other direction of wrist movement. The DTM path marks the transition point where scaphoid and lunate switch between flexion and extension rotation.

This has clinical consequences. Because the proximal row moves so little during DTM, rehabilitation that constrains motion to the DTM plane can allow functional wrist movement while keeping radiocarpal motion to a minimum. In healthy wrists, the scapholunate joint stays stable and scapholunate ligament elongation is minimal during DTM (Moritomo et al., 2014). Werner et al. (2004) proposed that restricting wrist motion to this path might allow early mobility after surgery on the scaphoid and lunate, and radiocarpal arthrodesis preserves DTM better than midcarpal arthrodesis (Moritomo et al., 2014).

DTM and PNF D2 · the wrist endpoint connection

For clinicians trained in Proprioceptive Neuromuscular Facilitation, the relationship between DTM and PNF D2 is worth understanding explicitly.

PNF D2 is a full upper-extremity diagonal pattern defined primarily at the shoulder. The D2 flexion pattern — often cued as combing hair or reaching overhead — terminates at the wrist with extension and radial deviation. That's the up endpoint of DTM. The D2 extension pattern — sword sheathing — terminates at the wrist with flexion and ulnar deviation. That's the down endpoint of DTM.

In other words, the wrist component of PNF D2 is DTM. The distinction is that DTM is defined at the wrist alone, while D2 integrates the kinetic chain through the shoulder, forearm, and hand.

When to use DTM in rehabilitation

Distal radius fracture

DTM is appropriate. In a pilot randomized controlled trial after open reduction and internal fixation, home exercise in the DTM plane produced outcomes similar to sagittal-plane exercise, with higher patient satisfaction and motivation to self-train (Kaufman-Cohen et al., 2021). A case report describes early controlled DTM mobilization in the conservative management of a distal radius styloid fracture with scapholunate ligament injury (Feehan & Fraser, 2016). Because the wrist follows the DTM plane during many daily tasks (Brigstocke et al., 2014), it is a motion patients need to recover.

Lunotriquetral injury

In lunotriquetral-deficient cadaver wrists, the extensor carpi ulnaris was the only wrist motor able to extend and pronate the collapsed triquetrum, and the authors suggest proprioceptive ECU training while avoiding carpal supination torques (León-López et al., 2013). For lunotriquetral instability, Hagert and Rein (2024) start with ECU exercises in forearm neutral, add combined ECU and FCR activation in the reverse dart-throwing motion (radial flexion to ulnar extension) in later stages, and advise against training the carpal supinators (ECRL, ECRB, APL, FCU). Clinically, DTM itself is generally appropriate for LT injury, ideally with the forearm in neutral.

Triangular fibrocartilage complex injury

In a cadaver model of TFCC injury, loading the extensor carpi ulnaris stabilized the DRUJ and ulnocarpal joint in supination and neutral forearm rotation, with little effect in pronation (Iida et al., 2012). A case report of a staged sensorimotor program that incorporated DTM and PNF for TFCC injury reported improvement on every outcome measure (Chen, 2019). Assess DRUJ stability before progressing to full-range DTM, especially if combined with forearm rotation.

Scapholunate injury — the caveat

It is often repeated that DTM is SL-protective because the scaphoid and lunate barely move during the motion. That claim holds for healthy wrists. It does not hold cleanly once the scapholunate interosseous ligament is injured.

In SL-deficient wrists, the scaphoid and lunate begin to move differently from each other during DTM. A dynamic CT study of six wrists with scapholunate instability found the scaphoid shifting toward the radial styloid far more than the lunate during DTM, opening an SL gap; its authors could not recommend dart-throwing exercises after SL ligament repair unless the joint is stabilized with wires or screws (Garcia-Elias et al., 2014). The IFSSH report likewise notes that DTM exercises applied tensile forces to the SL ligament in patients with SL dissociation (Moritomo et al., 2014). A scoping review of the evidence concluded that caution is warranted, particularly at end-range motion where the gap tends to be largest (Bergner et al., 2020).

The safe clinical position: DTM is not unconditionally safe for SL injury. In the conservative or early post-repair setting, use caution, limit motion to mid-range arcs, avoid end-range loading, and consider a dart-thrower orthosis that blocks orthogonal planes during early rehabilitation. DTM becomes appropriate later in recovery, once the joint is stable — either naturally or after surgical stabilization — and should be introduced with physician clearance.

How to train DTM using WristSkill™

WristSkill's D1 and D2 planes correspond to the diagonal patterns that include the DTM plane at the wrist. A clinician who wants to work the DTM arc with a patient can:

1. Pick the right mode. Use Performance Mode when you want all three metrics — Targets Hit, Time to Target, and Path Efficiency — captured and saved. Use Free Play when you only need targets-hit tracking during an open practice session.
2. Select the appropriate hand. The mapping of D1 and D2 to specific wrist motions differs between right and left — the app handles this once the hand is selected.
3. Position the patient. There is no single published forearm position for DTM training; the plane varies by task and patient. The guiding principle is that the screen must remain visible to the patient throughout the trial — adjust posture, forearm support, or phone grip as needed to keep the screen in view.
4. Focus the session. Run the D1 or D2 diagonal plane based on the clinical goal. The D2 plane is the closer approximation of DTM at the wrist.
5. Track change. Compare session-over-session performance against the patient's own baseline.

Frequently asked questions

What is the Dart Thrower's Motion?

The Dart Thrower's Motion (DTM) is an oblique path of wrist movement from radial extension to ulnar flexion, the arc the wrist traces when throwing a dart or hammering a nail. Its angle varies from person to person: in 24 healthy adults, the plane ranged from 28 to 57 degrees relative to the flexion-extension axis.

Why is the Dart Thrower's Motion clinically important?

In healthy wrists, the scaphoid and lunate move significantly less along the DTM path than in any other direction of wrist movement, so DTM can allow functional wrist motion while keeping radiocarpal motion to a minimum. Many everyday tasks follow this plane, including hammering a nail, drinking from a glass, and pouring from a jug.

Is DTM safe after a scapholunate ligament injury?

Not unconditionally. In healthy wrists the scaphoid and lunate move minimally during DTM, but in wrists with scapholunate instability, dynamic CT has shown a scapholunate gap opening during the motion, and a scoping review advises caution, particularly at end range. Early rehabilitation should limit DTM to mid-range arcs, consider an orthosis that blocks orthogonal planes, and progress with physician clearance.

What is the difference between Pure DTM and Functional DTM?

Pure DTM follows an oblique plane that passes through the neutral wrist position, and occurs almost entirely at the midcarpal joint with near-zero scaphoid and lunate motion. Functional DTM is the plane used in real tasks such as hammering. It runs almost parallel to the pure plane but is offset toward extension, about 36 degrees in one hammering study, and involves more scaphoid and lunate motion. Functional DTM is the version most patients actually use.

How does DTM relate to PNF D2?

PNF D2 is a full upper-extremity diagonal pattern defined primarily at the shoulder. Its wrist endpoints, extension with radial deviation (D2 flexion) and flexion with ulnar deviation (D2 extension), are the endpoints of the Dart Thrower's Motion. In other words, the wrist component of PNF D2 is DTM. DTM is defined at the wrist alone; D2 integrates the kinetic chain through the shoulder, forearm, and hand.

What diagnoses is DTM-based rehabilitation appropriate for?

DTM is appropriate for distal radius fracture rehabilitation: in a pilot randomized trial after open reduction and internal fixation, home exercise in the DTM plane gave outcomes similar to sagittal-plane exercise, with higher patient satisfaction. It is generally appropriate for lunotriquetral injury with the forearm in neutral, where later-stage training can add ECU and FCR activation in the reverse dart-throwing motion, and for triangular fibrocartilage complex injury once DRUJ stability is confirmed. Scapholunate injury requires caution; see the scapholunate caveat.