The suprascapular nerve is a

nerve A nerve is an enclosed, cable-like bundle of nerve fibers (called axons) in the peripheral nervous system. A nerve transmits electrical impulses. It is the basic unit of the peripheral nervous system. A nerve provides a common pathway for the e ...

that branches from the upper trunk of the brachial plexus. It is responsible for the innervation of two of the muscles that originate from the

scapula The scapula (plural scapulae or scapulas), also known as the shoulder blade, is the bone that connects the humerus (upper arm bone) with the clavicle (collar bone). Like their connected bones, the scapulae are paired, with each scapula on eithe ...

, namely the supraspinatus and infraspinatus muscles.

Structure

The suprascapular nerve arises from the upper trunk of the brachial plexus which is formed by the union of the

ventral rami The ventral ramus (pl. ''rami'') (Latin for ''branch'') is the anterior division of a spinal nerve. The ventral rami supply the antero-lateral parts of the trunk and the limbs. They are mainly larger than the dorsal rami. Shortly after a spinal n ...

of the fifth and sixth cervical nerves. After branching from the upper trunk, the nerve passes across the posterior triangle of the neck parallel to the inferior belly of the

omohyoid The omohyoid muscle is a muscle that depresses the hyoid. It is located in the front of the neck, and consists of two bellies separated by an intermediate tendon. The omohyoid muscle is proximally attached to the scapula and distally attached to th ...

muscle and deep to the

trapezius The trapezius is a large paired trapezoid-shaped surface muscle that extends longitudinally from the occipital bone to the lower thoracic vertebrae of the spine and laterally to the spine of the scapula. It moves the scapula and supports the ...

muscle. It then runs along the superior border of the scapula through the

suprascapular canal The suprascapular canal is an anatomical passage between two openings found on the upper dorsal aspect of the shoulder. It is found bilaterally running on superio-lateral aspect of the dorsal surface of the scapula underneath the supraspinatus mus ...

, in which it enters via the

suprascapular notch The suprascapular notch (or ''scapular notch'') is a notch in the superior border of the scapula, just medial to the base of the coracoid process. It forms the entrance site into the suprascapular canal. Structure This notch is converted into ...

inferior to the superior transverse scapular ligament and enters the supraspinous fossa. It then passes beneath the supraspinatus, and curves around the lateral border of the spine of the

through spinogleniod notch to the infraspinous fossa.

Function

The suprascapular nerve is a mixed peripheral nerve containing motor and sensory components.

Motor innervation

* Supraspinatus muscle * Infraspinatus muscle (through the

spinoglenoid notch The great scapular notch (or ''spinoglenoid notch'') is a notch which serves to connect the supraspinous fossa and infraspinous fossa. It lies immediately medial to the attachment of the acromion to the lateral angle of the scapular spine. The Su ...

)

Sensory innervation

* Acromioclavicular joint *

Glenohumeral joint The shoulder joint (or glenohumeral joint from Greek ''glene'', eyeball, + -''oid'', 'form of', + Latin ''humerus'', shoulder) is structurally classified as a synovial ball-and-socket joint and functionally as a diarthrosis and multiaxial joint. ...

(shoulder joint) In the supraspinous fossa it gives off two branches to the supraspinatus muscle and in the infraspinous fossa it gives off two branches to the infraspinatus muscle.

Clinical significance

* Suprascapular paralysis, causing back pain, problems with abduction and external rotation of the humerus, and wasting away of supraspinatus and infraspinatus. Supraspinatus muscle helps in 0°-15° arm abduction. And Infraspinatus helps in lateral rotation (external rotation) of humerus. * Suprascapular nerve entrapment syndrome, causing shoulder pain and localized muscular atrophy of the supraspinatus and infraspinatus muscles. This can potentially develop due to suprascapular nerve being entrapped and compressed within the

potential anatomical entrapment sites.

Additional images

File:Gray810.png, Suprascapular and axillary nerves of right side, seen from behind. File:Brachial_plexus_color.svg, Brachial plexus with courses of spinal nerves shown

External links

References

{{Authority control Nerves of the upper limb