---
title: "cormack_lehane"
description: "The Cormack-Lehane system classifies views obtained by direct laryngoscopy based on the structures seen."
---

The Cormack-Lehane system classifies views obtained by direct laryngoscopy based on the structures seen.

**Purpose.** To describe the structures visible during direct laryngoscopy and indirectly to indicate the likely difficulty of laryngeal intubation.

## Source

| Model | Leg | Role |
|---|---|---|
| `openEHR-EHR-OBSERVATION.cormack_lehane.v1` | openEHR | defines this table |

## Columns

| Column | Type | Null | Description | Source |
|---|---|---|---|---|
| `id` | `uuid primary key` | no | Primary key. | — |
| `form_id` | `uuid` → [`form`](/docs/tables/form) | no | The form this entry was recorded on. | — |
| `form_block_id` | `uuid` | yes | The block within the form, when the entry is bound to one. | — |
| `grading`<br />`grading_code`<br />`grading_system`<br />`grading_valueset_id` | coded text<br />`text`, `text`, `text`, `text` | yes | Grading | `/data[at0007]/events[at0008]/data[at0009]/items[at0001]` |
| `comment` | `text` | yes | Comment | `/data[at0007]/events[at0008]/data[at0009]/items[at0006]` |

## Constraints

```sql
check ((grading_code is null and grading_system is null and grading_valueset_id is null and grading is null) or (grading is not null and grading_code is not null and grading_system is not null and grading_valueset_id is not null))
```

## Unique

- `form_block_id`

## References

| Columns | Target | On delete |
|---|---|---|
| `form_id` | [`form`](/docs/tables/form) | cascade |
| `form_id, form_block_id` | [`form_block`](/docs/tables/form_block) | cascade |
| `grading_valueset_id, grading_code, grading_system, grading` | [`valueset_code`](/docs/tables/valueset_code) | restrict |

## Indexes

- `cormack_lehane_form_id_idx` on `form_id`

## Value sets

| Value set | Codes |
|---|---|
| `org.openehr::openEHR-EHR-OBSERVATION.cormack_lehane.v1/grading` | 4 |