Suprascapular nerve

Authors

Affiliations

Nathaniel Yomogida, B.S., SPT

Doctor of Physical Therapy

B.S. in Kinesiology

Chloë Kerstein, B.S., SPT

Doctor of Physical Therapy

B.A. in Neuroscience

Anatomy

Origin

The suprascapular nerve originates from nerve roots C5, C6 via the Superior Trunk at Erb’s point².

Path

The suprascapular nerve comes off the Superior Trunk and travels inferiorly and laterally posterior to the brachial plexus, parallel to the omohyoid muscle, and inferior to the trapezius to the superior edge of the scapula then through the suprascapular notch². The suprascapular artery and vein initially run with the suprascapular nerve, but deviate and run superior to the transverse suprascapular ligament over the suprascapular notch².

Termination

• After passing through the notch, the nerve supplies motor innervation to the supraspinatus muscle².
• The nerve also gives off afferent articular branches to the GHJ and ACJ^1,2.
• The suprascapular nerve then passes inferiorly to the scapular spine via the spinoglenoid notch to provide motor innervation to the infraspinatus muscle^1,2.

Motor Innervation

Suprascapular n. Direct Muscle Innervations
Muscle	Origin	Insertion	Innervation	Action
Supraspinatus	Supraspinous Fossa of scapula1 [Supraspinous Fossa of scapula](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Intrinsic Shoulder Muscles/Rotator Cuff/supraspinatus_muscle.qmd#origin) [@gilroyAtlasAnatomy2020]	Greater tubercle of Humerus1 [Greater tubercle of Humerus](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Intrinsic Shoulder Muscles/Rotator Cuff/supraspinatus_muscle.qmd#insertion) [@gilroyAtlasAnatomy2020]	Suprascapular n. (C4, C5, C6)1 C4 - C61 [Suprascapular n. (C4, C5, C6)](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Intrinsic Shoulder Muscles/Rotator Cuff/supraspinatus_muscle.qmd#nerve) [@gilroyAtlasAnatomy2020] [C4](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Intrinsic Shoulder Muscles/Rotator Cuff/supraspinatus_muscle.qmd#nerve) - [C6](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Intrinsic Shoulder Muscles/Rotator Cuff/supraspinatus_muscle.qmd#nerve) [@gilroyAtlasAnatomy2020]	Stabilization1 GHJ ER1 [Stabilization](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Intrinsic Shoulder Muscles/Rotator Cuff/supraspinatus_muscle.qmd#action) [@gilroyAtlasAnatomy2020] GHJ [ER](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Intrinsic Shoulder Muscles/Rotator Cuff/supraspinatus_muscle.qmd#action) [@gilroyAtlasAnatomy2020]

Suprascapular nerve motor innervation

Muscle	Origin	Insertion	Nerve	Action
Supraspinatus	/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Intrinsic Shoulder Muscles/Rotator Cuff/supraspinatus_muscle.html#origin	/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Intrinsic Shoulder Muscles/Rotator Cuff/supraspinatus_muscle.html#insertion	?var:ref-supraspinatus.nerve	/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Intrinsic Shoulder Muscles/Rotator Cuff/supraspinatus_muscle.html#action
Infraspinatus	/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Intrinsic Shoulder Muscles/Rotator Cuff/infraspinatus_muscle.html#origin	/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Intrinsic Shoulder Muscles/Rotator Cuff/infraspinatus_muscle.html#insertion	?var:ref-infraspinatus.nerve	/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Intrinsic Shoulder Muscles/Rotator Cuff/infraspinatus_muscle.html#action

Joint innervation

• Suprascapular nerve provides sensory and sympathetic afferent fibers to the GHJ²
• Suprascapular nerve provides sensory and sympathetic afferent fibers to the ACJ²
• Suprascapular nerve provides sensory and sympathetic afferent fibers to 2/3 of the “shoulder capsule”²

Cutaneous Innervation

The suprascapular nerve has cutaneous branches, which provide sensation to the proximal \(\frac{1}{3}\) of the arm, but their distribution overlaps with that of the supraclavicular and axillary nerves².

Examination

• Empty can / Jobe test can be used to determine suprascapular nerve integrity by testing supraspinatus muscle

Injury

Compression, traction, or laceration can all cause injury to the suprascapular nerve².

Compression Injury

A direct trauma at Erb’s point can cause a compression-type injury². Compression neuropathy of the suprascapular nerve commonly occurs at the scapular notch under the transverse scapular ligament or at the spinoglenoid notch². Compression at either of these notches occurs through extraneural inflammation, lipoma or cyst development, scarring following distal clavicle resection, or ligament entrapment². Ligament entrapment can be caused from an acute trauma resulting from a fall on an outstretched hand (FOOSH), scapular fracture, or overuse injuries due to repetitive overhead motions².

Important

Entrapment of the suprascapular nerve is easily misdiagnosed as rotator cuff tendinitis, RTC tear, or cervical disk disease²

Clinical Presentation

Pain due to suprascapular nerve entrapment can radiate to the lateral neck or posterior and lateral aspects of the glenohumeral joint capsule².

As the suprascapular nerve is a mixed nerve, the patient presentation can include motor and sensory symptoms:

1. A dull, deep ache at the posterior and lateral aspects of the shoulder, which may have a burning quality²
2. Muscle atrophy and weakness of the supraspinatus and infraspinatus²
3. Compensatory GHJ changes due to supraspinatus weakness, such as increased scapular elevation during arm elevation².
   • This may produce impingement-like findings and complicate the diagnosis²
4. Full external rotation of the G-H joint and passive horizontal adduction are painful²

Intervention

Conservative

“Conservative intervention includes rest, ice, analgesics, and a series of perineural injections of corticosteroid to help reduce neural inflammation. A home exercise program of scapular pivoter strengthening (see Chapter 16), scapulohumeral coordination exercises (see Chapter 16), and activity-specific training may be indicated”²

Surgical

“Surgical intervention, involving neurolysis, cyst removal, or the excision of the transverse scapular ligament is indicated if symptoms persist”²

References

1.

Gilroy AM, MacPherson BR, Wikenheiser JC, Voll MM, Wesker K, Schünke M, eds. Atlas of Anatomy. 4th ed. Thieme; 2020.

2.

Dutton M. Dutton’s Orthopaedic Examination, Evaluation, and Intervention. 5th ed. McGraw Hill Education; 2020.