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 The brachial plexus is a network () of nerves formed by the anterior rami of the lower four cervical nerves and first thoracic nerve ( C5, C6, C7, C8, and T1). This plexus extends from the spinal cord, through the cervicoaxillary canal in th ...

. 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 The supraspinatus (plural ''supraspinati'') is a relatively small muscle of the upper back that runs from the supraspinous fossa superior portion of the scapula (shoulder blade) to the greater tubercle of the humerus. It is one of the four rotator ...

and

infraspinatus muscle In human anatomy, the infraspinatus muscle is a thick triangular muscle, which occupies the chief part of the infraspinatous fossa.'' Gray's Anatomy'', see infobox. As one of the four muscles of the rotator cuff, the main function of the infraspi ...

Structure

The suprascapular nerve arises from the

upper trunk The upper (superior) trunk is part of the brachial plexus. It is formed by joining of the ventral rami of the fifth (C5) and sixth (C6) cervical nerves. The upper trunk divides into an anterior and posterior division. The branches of the upper tru ...

of the

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 A spinal nerve is a mixed nerve, which carries motor, sensory, and autonomic signals between the spinal cord and the body. In the human body there are 31 pairs of spinal nerves, one on each side of the vertebral column. These are grouped into the ...

. After branching from the upper trunk, the nerve passes across the

posterior triangle of the neck Posterior may refer to: * Posterior (anatomy), the end of an organism opposite to its head ** Buttocks, as a euphemism * Posterior horn (disambiguation) * Posterior probability, the conditional probability that is assigned when the relevant evidenc ...

parallel to the inferior belly of the omohyoid 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 The superior transverse ligament (transverse or suprascapular ligament) converts the suprascapular notch into a foramen or opening. It is a thin and flat fascicle, narrower at the middle than at the extremities, attached by one end to the base of ...

and enters the

supraspinous fossa The supraspinous fossa (supraspinatus fossa, supraspinatous fossa) of the posterior aspect of the scapula (the shoulder blade) is smaller than the infraspinous fossa, concave, smooth, and broader at its vertebral than at its humeral end. Its med ...

. It then passes beneath the

, and curves around the lateral border of the spine of the

through spinogleniod notch to the

infraspinous fossa The infraspinous fossa (infraspinatus fossa or infraspinatous fossa) of the scapula is much larger than the supraspinatous fossa; toward its vertebral margin a shallow concavity is seen at its upper part; its center presents a prominent convexi ...

Function

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

Motor innervation

Supraspinatus muscle The supraspinatus (plural ''supraspinati'') is a relatively small muscle of the upper back that runs from the supraspinous fossa superior portion of the scapula (shoulder blade) to the greater tubercle of the humerus. It is one of the four rotator ...

Infraspinatus muscle In human anatomy, the infraspinatus muscle is a thick triangular muscle, which occupies the chief part of the infraspinatous fossa.'' Gray's Anatomy'', see infobox. As one of the four muscles of the rotator cuff, the main function of the infraspi ...

(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 The acromioclavicular joint, or AC joint, is a joint at the top of the shoulder. It is the junction between the acromion (part of the scapula that forms the highest point of the shoulder) and the clavicle. It is a plane synovial joint. Structure ...

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

it gives off two branches to the

supraspinatus muscle The supraspinatus (plural ''supraspinati'') is a relatively small muscle of the upper back that runs from the supraspinous fossa superior portion of the scapula (shoulder blade) to the greater tubercle of the humerus. It is one of the four rotator ...

and in the

it gives off two branches to the

infraspinatus In human anatomy, the infraspinatus muscle is a thick triangular muscle, which occupies the chief part of the infraspinatous fossa.''Gray's Anatomy'', see infobox. As one of the four muscles of the rotator cuff, the main function of the infraspina ...

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