Interscalene Nerve Block


The Interscalene Nerve block is a commonly performed regional anesthetic technique at the level of the upper trunks of the brachial plexus to provide anesthesia and analgesia for shoulder, upper arm and clavicle surgery.

Clinical Use: 


Provision of analgesia and anesthesia for surgery of the shoulder, upper arm and clavicle.

Block technique

This peripheral nerve block is most commonly performed with ultrasound guidance, targeting the trunks of the brachial plexus in the neck shortly after they exit the cervical spine. It provides anesthesia and analgesia to the shoulder, upper arm and clavicle. 

The trunks of the upper brachial plexus run between the middle and anterior scalene muscles in the interscalene groove. The trunk of the C5 nerve root and the double trunk of C6 are blocked together in this space as they lie one atop the other, resembling a “traffic light”.

The block is performed via ultrasound guidance with the patient in a supine or lateral position patient using an in-plane approach from posterior to anterior. The probe is placed on the posterior border of the sternocleidomastoid muscle at the C7 vertebral level to identify the interscalene groove. The needle is passed through the skin and usually the middle scalene muscle before entering the interscalene grove. Local anesthetic is administered under direct vision watching for spread around the nerve trunks, filling the groove.

(SCM - Sternocleidomastoid / SA - Anterior Scalene / SM - Middle Scalene / CA Carotid Artery/ VA Vertebral Artery /  V - Vagus Nerve / Sympathetic Nerve  / P - Phrenic Nerve)

Dosing in adult patients >60kg:

Single shot: 10-20 mls of 0.2 - 0.5% ropivacaine 

Infusion: 8ml/hour 0.1-0.2% ropivacaine 

Block Duration 

When performed with 0.5% ropivacaine, the interscalene nerve block has an analgesia duration of hours 8-12 hours.

Special Considerations: 


  • Absolute
    • Patient refusal
    • Coagulopathy 
    • Contralateral recurrent laryngeal or phrenic nerve paresis
    • Contralateral pneumonectomy or pneumothorax
    • Local anesthetic allergy
    • Local infection/inflammation in needle trajectory
  • Relative
    • Chest deformities
    • Reduced pulmonary reserve


  • Ipsilateral phrenic nerve palsy (up to 100% resulting in up to 20% reduction in lung function)
  • Horners Syndrome
  • Infection
  • Hematoma
  • Pneumothorax (0.7%)
  • Nerve damage
  • Epidural/subarachnoid or Vertebral artery injection
  • Local anesthetic systemic toxicity (LAST)

First Image - SonositeTM

Second Image - Dr Zaki Ibrahim 

Abdallah FW, Halpern SH, Aoyama K, et al. : Will the Real Benefits of Single-Shot Interscalene Block Please Stand Up? A Systematic Review and Meta-Analysis. Anesth Analg. 2015;120(5):1114–29