Inferior transverse scapular ligament

At a glance

English

Inferior transverse scapular ligament

Latin (TA2)

Ligamentum transversum scapulae inferius

System

Ligament

Region

Upper limb

Side

Paired, left and right

About the inferior transverse scapular ligament

The spine of the scapula ends laterally in a free, thick border that curves up into the acromion. Between this border and the back of the neck of the scapula is a broad notch, the spinoglenoid notch, which connects the supraspinous fossa above with the infraspinous fossa below. The inferior transverse scapular ligament, also called the spinoglenoid ligament, is a thin band that runs from the lateral border of the spine to the posterior margin of the glenoid cavity, turning the notch into an opening. It is variable and is weak or absent in some people.

Through this opening pass the suprascapular nerve and the suprascapular vessels as they go from the supraspinous into the infraspinous fossa. Further up, the same nerve has already passed beneath the superior transverse scapular ligament at the suprascapular notch, while the artery usually runs above that ligament. By the time it reaches the spinoglenoid notch the nerve has given its branches to supraspinatus and carries mainly fibres for infraspinatus.

Compression of the nerve here weakens infraspinatus alone, so outward rotation of the arm becomes weaker while supraspinatus is spared, often with wasting below the spine of the scapula. It is seen in overhead athletes such as volleyball players, and a common cause is a cyst that forms beside a tear of the posterior glenoid labrum and fills the notch.

Attachments and function

Attaches from

Lateral border of the spine of the scapula.

Attaches to

Posterior margin of the glenoid cavity and the back of the neck of the scapula.

Function

Converts the spinoglenoid notch into a foramen and roofs the passage of the suprascapular nerve and vessels into the infraspinous fossa.