The suprascapular nerve is the lateral branch of the superior trunk of the brachial plexus. It receives nerve fibers that originate in the nerve roots C5 and C6 (and sometimes C4). The suprascapular nerve is a mixed nerve, meaning that it provides both sensory and motor supply for the suprascapular region.
The main function of this nerve is to provide motor innervation for two muscles, which are the supraspinatus and infraspinatus muscles. These muscles are part of the muscle group called the rotator cuff muscles. In addition, the suprascapular nerve provides a sensory supply for the joints of the scapula (glenohumeral and acromioclavicular joints).
This article will discuss the anatomy and function of the suprascapular nerve.
|Origin||Superior trunk of brachial plexus|
|Branches||Motor muscular branches, sensory articular branches|
|Supply||Motor supply: supraspinatus muscle, infraspinatus muscle
Sensory supply: glenohumeral and acromioclavicular joints
- Origin and course
- Branches and innervation
- Clinical relations
Origin and course
The suprascapular nerve (root value C5, C6) originates from the superior trunk of the brachial plexus. It is considered to be one of the preterminal branches or supraclavicular branches of the brachial plexus together with the dorsal scapular nerve, long thoracic nerve, subclavian nerve and accessory phrenic nerve. Note that the cords of the brachial plexus are called the infraclavicular branches of the brachial plexus, while the nerves that branch off from the cords are the terminal branches of the brachial plexus.
From its origin, the suprascapular nerve courses laterally, passing superior to the brachial plexus and through the posterior triangle of neck. It then traverses the scapular notch (inferior to the superior transverse scapular ligament) into the supraspinous region of the scapula. Here, it gives off a branch to the supraspinatus muscle and continues through the greater scapular (spinoglenoid) notch between the root of the spine of the scapula and the glenoid cavity, to reach the infraspinous fossa.
The nerve finally terminates within the infraspinatus muscle, innervating it. To avoid confusion, the path of the suprascapular nerve differs from the suprascapular artery and vein, that course above the superior transverse scapular ligament.
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Branches and innervation
The suprascapular nerve is a mixed nerve. Its main function is to provide motor supply for two of five muscles of the rotator cuff, including:
- Supraspinatus muscle
- Infraspinatus muscle
On its course, the nerve gives off a sensory branch that provides sensory innervation for two joints:
- Glenohumeral (shoulder) joint
- Acromioclavicular joint
Do you want to know more about the organization and function of the most complex nerve plexus in the human body? Check out our study unit about the brachial plexus!
Suprascapular nerve entrapment
Suprascapular nerve entrapment (suprascapular neuropathy) is a rare syndrome characterized by pain and muscle weakness in the posterior shoulder region, resulting in weakened abduction and external rotation of the shoulder. It is usually caused by a traumatic injury to the suprascapular nerve which causes the damage of its nerve fibers and consequential weakness of the supraspinatus and infraspinatus muscles. The other frequent cause is traumatic or non-traumatic compression of the nerve on its path through the suprascapular notch.
Suprascapular nerve: want to learn more about it?
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