Palmaris longus

A muscle that is not universal

Palmaris longus has a long distal tendon leading toward the palm. This atlas includes it because it is present in the selected source geometry.

Studies document absence on one or both sides, with prevalence differing between studied populations. Presence in a single atlas model is therefore not evidence that everyone has the same structure.

Sources: Variation study

An attachment to fascia, not a metacarpal

Palmaris longus arises through the common flexor origin at the medial humeral epicondyle. Its distal attachments include the flexor retinaculum and palmar aponeurosis, the strong sheet of fascia in the palm.

This distinguishes it from FCR’s metacarpal attachments. Do not assign a bony endpoint just because the displayed tendon lies near the radius or ulna.

Sources: Loyola anatomy

Tensioning the palm

Palmaris longus assists wrist flexion and tightens the palmar aponeurosis. The latter is a fascial action, not movement of an individually selected finger.

The hand and wrist bones are not loaded here. Camera rotation changes the view, not wrist position; this model does not simulate contraction, tendon gliding or a range of motion.

Sources: Loyola anatomy

Median-nerve supply

The median nerve provides motor supply. Ulnar arterial branches contribute to the muscle’s blood supply.

Nerves and vessels are not loaded in this subset, so the text describes connections you cannot select in the viewer.

The model cannot establish whether this muscle is present or absent in a visitor’s own arm; it is an educational example, not a self-examination test.

Sources: Loyola anatomy · Anatomy tables

Read the model

Explore palmaris longus in 3D

1. Inspect its long distal region. Use the isolated view to follow the source mesh from the broader region toward its thin continuation. The display does not separately label belly and tendon.
2. Place it beside FCR. Choose Show context, then alternate Palmaris longus and Flexor carpi radialis in the list. Use Focus selection if a thin part is difficult to see.
3. Recognize the missing destination. The palmar aponeurosis and flexor retinaculum are not loaded. A visible end in the viewer must not be interpreted as the complete fascial attachment.

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.

1. Loyola University Chicago — LUMEN, Palmaris longus

   Origin, retinacular and palmar fascial attachments, action and nerve supply.

2. Texas Tech University Health Sciences Center El Paso — Forearm & Wrist anatomy tables

   Palmaris longus row: ulnar arterial contribution.

3. Absence of the palmaris longus tendon in Indian population (2010)

   Population study documenting absence and discussing variation between populations. No prevalence figure is generalized to all people.

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