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# Oblique cord

The oblique cord is a small band near the elbow that runs from the [ulna](https://durgical.com/en/anatomy/ulna/) to the radius; it helps tie the two forearm bones together.

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## What it is

A small band from the ulna down to the radius, above the interosseous membrane.

## What it does

Helps tie the two forearm bones together.

## Key points

- Runs down and outward from the ulnar tuberosity to the [radius](https://durgical.com/en/anatomy/radius/), the opposite direction to most fibres of the interosseous membrane
- The gap between it and the upper edge of the interosseous membrane lets the posterior interosseous vessels pass from the front to the back of the forearm

## Key facts

**Attaches**
Ulnar tuberosity to just below the radial tuberosity

**Function**
Ties radius to ulna proximally

**Tight in**
Supination

## Relations

**Above**
Radial tuberosity, where the [distal biceps tendon](https://durgical.com/en/anatomy/distal-biceps-tendon/) inserts just above its radial end

**Below**
Upper border of the interosseous membrane, with the gap for the posterior interosseous vessels ([interosseous arteries](https://durgical.com/en/anatomy/interosseous-arteries-of-the-forearm/))

**Medial**
Ulnar tuberosity, where the [brachialis](https://durgical.com/en/anatomy/brachialis/) inserts

## On imaging

Not visible on radiographs and rarely reported on its own. On MRI it can appear as a thin low-signal band running from the ulna near its tuberosity down to the radius just below the radial tuberosity. Imaging of the proximal forearm instead assesses the radial head, the proximal radioulnar joint, the interosseous membrane and the biceps insertion.

## Clinical notes

- Contracture of the oblique cord has been described as one cause of lost supination after forearm injury, and its release is sometimes part of surgery to restore rotation
- Heterotopic bone between the upper radius and ulna, after proximal forearm fractures or a two-incision distal biceps repair, can bridge this region (radioulnar synostosis) and block rotation

## Anatomical variants

- Inconstant: absent or thin in some forearms; some texts regard it as a remnant of a muscle slip ([flexor pollicis longus](https://durgical.com/en/anatomy/flexor-pollicis-longus/) or [supinator](https://durgical.com/en/anatomy/supinator/))

## Test yourself

Think of the answer, then tap the question to see it.

## What are the attachments of the oblique cord?

From the ulnar tuberosity down and outward to just below the radial tuberosity, opposite to most interosseous membrane fibres.

## What passes through the gap between the oblique cord and the interosseous membrane?

The posterior interosseous vessels, going from the front to the back of the forearm.

## What forearm movement can a contracted oblique cord limit after injury?

Supination; the oblique cord is taut in supination, and its release is sometimes part of surgery to restore rotation.

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Educational information, not medical advice. For any symptom, see a health professional.

## Its names

**Official Latin (TA2)**
chorda obliqua TA2 1762

**Official Spanish (DeCS)**
Cuerda oblicua

**English (TA2)**
Oblique cord

## Related

- [Radius](https://durgical.com/en/anatomy/radius/)
- [Ulna](https://durgical.com/en/anatomy/ulna/)

Sources: Terminologia Anatomica (TA2); [Anatomy, Shoulder and Upper Limb, Forearm Bones](https://www.ncbi.nlm.nih.gov/books/NBK545260/); [Anatomy, Shoulder and Upper Limb, Proximal Radio-Ulnar Joint](https://www.ncbi.nlm.nih.gov/books/NBK551614/).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/anatomy/oblique-cord/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/oblique-cord/