Nerve
Long thoracic nerve
Long surface route to serratus anterior
High-yield
Serratus anterior keeps the scapula close to the chest and helps rotate it during arm elevation. Nerve injury can therefore disrupt shoulder-blade control and overhead movement.
Overview
Small contributions from the upper brachial-plexus roots join to supply serratus anterior. The nerve then follows the side of the chest on the muscle's outer surface, where it is relatively exposed.
Learning this group? Read How to learn the brachial plexus.
Reference facts
- Root value
- Usually anterior rami C5-C7, branching near the roots of the brachial plexus
- Course
- Passes from the lower neck beneath the clavicle and down the lateral chest wall on superficial serratus anterior
- Motor
- Serratus anterior muscle
- Sensory
- No defined cutaneous territory; its branches serve the muscle rather than a patch of skin
Mnemonic
Link C5-C6-C7 to serratus anterior, then picture the muscle holding the shoulder blade against the ribs as the arm rises.
Clinical correlation
Injury may make the medial scapular border lift away from the chest. Partial or distal injury can cause pain and poor shoulder function without obvious winging, so the visible sign is not required in every case.
Frequently asked questions
What are the roots of the long thoracic nerve?
Usually anterior rami C5-C7, branching near the roots of the brachial plexus.
What muscles does the long thoracic nerve supply?
The long thoracic nerve supplies the serratus anterior muscle.
What is the sensory distribution of the long thoracic nerve?
No defined cutaneous territory; its branches serve the muscle rather than a patch of skin.
What is the course of the long thoracic nerve?
Passes from the lower neck beneath the clavicle and down the lateral chest wall on superficial serratus anterior.