[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anaesthesia and ICU](https://durgical.com/en/anaesthesia/) › [Anaesthesia basics](https://durgical.com/en/anaesthesia/areas/basics/) › Positioning and its injuries

# Positioning and its injuries

- Concept

Under anaesthesia the patient cannot feel pressure or strain, so the team positions and pads the body to protect nerves, skin and eyes.

Updated Nov 13, 2026

## Key points

- The ulnar nerve is the most commonly injured peripheral nerve under anaesthesia; keep the forearm supine or neutral and pad the elbow.
- Brachial plexus injury: arm abducted beyond 90 degrees, head turned away, shoulder braces in steep head-down tilt.
- Lithotomy: common fibular nerve at the fibular head, plus compartment syndrome and rhabdomyolysis in long cases.
- Prone spine surgery: postoperative visual loss from ischaemic optic neuropathy or pressure on the globe; never let the eyes bear weight.
- Head-down tilt can push the tracheal tube into a main bronchus; recheck tube position after any change in position.

On this page

- The basics Key points
- What it is
- Key points
- Components
- How it works
- Step by step
- In practice
- Next step
- Elsewhere in DurgiPedia

- Study Test yourself

- Connections Typical position-related injuries and how they are prevented
- Connections

## What it is

Anaesthetised patients lose pain sensation and muscle tone and cannot shift their weight or protest when a limb is overstretched, so positions that would soon hurt an awake person can cause injury within hours. Each position is chosen to give the surgeon access while keeping the airway secure, the circulation stable and pressure points protected. Supine is the commonest; lithotomy, lateral decubitus, prone, sitting (beach-chair) and head-down (Trendelenburg) or head-up (reverse Trendelenburg) tilts each bring their own physiology and risks. Peripheral nerve injury is the classic complication: the ulnar nerve at the elbow is most often affected, followed by the brachial plexus (arm abducted beyond 90 degrees, head turned away, shoulder supports), and the common fibular nerve at the fibular head in lithotomy stirrups. Other injuries include pressure ulcers over the sacrum, heels and occiput, corneal abrasion from eyes left open, facial and breast pressure in prone, postoperative visual loss after long prone spine surgery (ischaemic optic neuropathy or retinal artery occlusion from pressure on the globe), and compartment syndrome or rhabdomyolysis of the legs after prolonged lithotomy. Positioning also changes physiology: head-down tilt pushes the diaphragm up, lowers lung volume and can move the tracheal tube into a main bronchus; head-up and sitting positions pool blood in the legs, lower blood flow to the brain and allow venous air embolism; prone position can compress the abdomen and vena cava if the abdomen is not left free. Positioning is a shared team responsibility and is checked again after every move.

## Key points

- Anaesthesia removes the pain that normally warns of pressure, stretch or a cold, ischaemic limb.
- Most nerve injuries come from stretch, compression or ischaemia, and the risk grows with duration.
- Risk is higher with diabetes, peripheral neuropathy, extremes of body weight, smoking, vascular disease and long procedures.
- Eyes are taped closed after induction to prevent corneal abrasion, the commonest eye injury.
- Tube, lines, catheters and monitoring are rechecked after every turn or tilt.

## Components

- Supine: arms on boards at less than 90 degrees of abduction, or tucked at the sides with padding; heels off-loaded.
- Lithotomy: both legs raised and lowered together; no pressure at the lateral knee; limit the time in stirrups.
- Lateral decubitus: head on a pillow in line with the spine; chest support just below the axilla, not in it, to protect the dependent brachial plexus.
- Prone: head neutral on a support that keeps eyes and nose free; abdomen hanging free; padding at chest, pelvis and knees.
- Sitting or beach-chair and head-up tilts: blood pools in the legs; venous air embolism is possible when the wound is above the heart.

## How it works

- Stretch beyond the nerve's slack or pressure over a superficial course reduces its blood supply and causes conduction block or axon damage.
- Arterial pressure measured at arm level overestimates the pressure at the brain in sitting or head-up positions.
- Head-down tilt raises intracranial and intraocular pressure and lowers functional residual capacity.
- Pressure on the abdomen in prone compresses the inferior vena cava, lowers venous return and raises epidural venous bleeding.

## Step by step

- Agree the position at the checklist and assess risks (weight, neuropathy, joint limits) — plan padding and devices beforehand.
- Move the patient with enough staff, with the anaesthetist controlling the head and airway — prevents tube loss and neck injury.
- Keep the neck neutral and limbs within comfortable range — avoids stretch of the brachial plexus and spinal cord.
- Pad bony prominences and superficial nerves at elbow, fibular head and heels — spreads pressure and protects nerves.
- Protect the eyes: tape closed and keep all pressure off the globe — prevents corneal abrasion and retinal ischaemia.
- Recheck airway, lines and pressure points after every move and at intervals in long cases — positions slip.
- Document the position, padding and checks — supports care and later review if an injury appears.

## Typical position-related injuries and how they are prevented

| Position | Typical injury | Prevention |
| --- | --- | --- |
| Supine | Ulnar nerve at the elbow, occipital and heel pressure | Forearm supine or neutral, padding, heels off-loaded |
| Arms abducted or shoulder braces | Brachial plexus stretch | Abduction below 90 degrees, head neutral, avoid braces |
| Lithotomy | Common fibular nerve, compartment syndrome | Pad the lateral knee, move legs together, limit duration |
| Lateral | Dependent brachial plexus, ear and eye | Chest support below the axilla, head in line, check the ear |
| Prone | Eyes, face, breasts, genitalia; visual loss | Head support with eyes free, abdomen free, regular checks |
| Sitting or head-up | Low brain perfusion, venous air embolism | Account for height difference in blood pressure, close monitoring |

## In practice

- New numbness or weakness after surgery: examine and document the distribution early; most sensory ulnar injuries recover, but motor loss needs specialist review.
- Sudden loss of vision after prone surgery is an emergency: ask for urgent ophthalmology review.
- Leg pain out of proportion, swelling or dark urine after lithotomy: think of compartment syndrome and rhabdomyolysis.
- Unexplained desaturation or high airway pressure after head-down tilt: suspect a tube moved into a bronchus.
- Hypotension in sitting or head-up positions: remember the brain sits above the measuring point.

## Next step

- Examine nerve function, skin and eyes in recovery and record any new deficit with its distribution.
- Refer early to neurology for motor deficits or deficits that do not improve, and to ophthalmology at once for visual loss.
- Inform the senior anaesthetist and surgeon of any suspected positioning injury and tell the patient honestly.
- Report the event through the institution's safety system and review padding and devices with the team.
- Follow up sensory deficits until they resolve; arrange nerve conduction studies if they persist.

## Test yourself

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

## Which peripheral nerve is most often injured during anaesthesia, and how is it protected?

The ulnar nerve at the elbow; keep the forearm supine or neutral, avoid pressure over the cubital tunnel and pad the elbow.

## Which positioning factors stretch the brachial plexus?

Arm abduction beyond 90 degrees, head turned to the opposite side, external rotation of the arm and shoulder braces in steep head-down tilt.

## What are the main risks of prolonged lithotomy?

Common fibular nerve compression at the fibular head, sciatic and femoral stretch, and compartment syndrome with rhabdomyolysis of the legs.

## What causes postoperative visual loss after prone spine surgery?

Mainly ischaemic optic neuropathy linked to long duration, blood loss and low pressure, and retinal artery occlusion from external pressure on the globe.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/anaesthesia/positioning-and-its-injuries/)

## Elsewhere in DurgiPedia

- [Patient positions: Fowler, supine, lateral, prone and others](https://durgical.com/en/nursing/patient-positions-fowler-supine-lateral-prone-and-others/)
- [Preventing pressure injuries: risk scales, repositioning and skin care](https://durgical.com/en/nursing/preventing-pressure-injuries-risk-scales-repositioning-and-skin-care/)
- [Traumatic and entrapment neuropathies](https://durgical.com/en/general-pathology/traumatic-and-entrapment-neuropathies/)

## Connections

## Related 6

- [The surgical safety checklist from the anaesthesia side](https://durgical.com/en/anaesthesia/the-surgical-safety-checklist-from-the-anaesthesia-side/)
- [General anaesthesia: induction, maintenance and emergence](https://durgical.com/en/anaesthesia/general-anaesthesia-induction-maintenance-and-emergence/)
- [Orthopaedic surgery: tourniquets, cement and blood loss](https://durgical.com/en/anaesthesia/orthopaedic-surgery-tourniquets-cement-and-blood-loss/)
- [Neurosurgery and raised intracranial pressure](https://durgical.com/en/anaesthesia/neurosurgery-and-raised-intracranial-pressure/)
- [Intraoperative hypotension](https://durgical.com/en/anaesthesia/intraoperative-hypotension/)
- [The recovery unit: monitoring and discharge criteria](https://durgical.com/en/anaesthesia/the-recovery-unit-monitoring-and-discharge-criteria/)

## Related conditions 7

- [Brachial plexus injury](https://durgical.com/en/conditions/brachial-plexus-injury/)
- [Common Fibular (Peroneal) Nerve Injury](https://durgical.com/en/conditions/common-fibular-nerve-injury/)
- [Pressure injury (pressure ulcer)](https://durgical.com/en/conditions/pressure-injury/)
- [Corneal abrasion and ocular foreign body](https://durgical.com/en/conditions/corneal-abrasion-and-ocular-foreign-body/)
- [Acute compartment syndrome](https://durgical.com/en/conditions/acute-compartment-syndrome/)
- [Rhabdomyolysis](https://durgical.com/en/conditions/rhabdomyolysis/)
- [Non-arteritic anterior ischaemic optic neuropathy](https://durgical.com/en/conditions/non-arteritic-anterior-ischaemic-optic-neuropathy/)

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Educational content; it does not replace supervised training, your institution's protocols or the anaesthetist's or intensivist's decision. It contains no doses and no ventilator or infusion settings.

Sources: [General Anesthesia for Surgeons](https://www.ncbi.nlm.nih.gov/books/NBK493199/) (StatPearls (NCBI Bookshelf), 2023).

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License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anaesthesia/positioning-and-its-injuries/