Spinoglenoid septum: a new anatomic finding

Area of Science:

• Anatomy
• Orthopedics
• Sports Medicine

Background:

• The spinoglenoid ligament is often cited as a cause of suprascapular nerve compression.
• This compression can lead to isolated infraspinatus muscle atrophy.

Purpose of the Study:

• To investigate the anatomical structures at the spinoglenoid notch.
• To determine the role of these structures in suprascapular nerve compression.

Main Methods:

• Dissection of 32 shoulders from 16 embalmed cadavers.
• Detailed examination of the spinoglenoid ligament and surrounding fascial structures.

Main Results:

• A distinct spinoglenoid ligament was rarely observed (5/32 shoulders) and was typically thin and weak.
• A spinoglenoid septum, formed by thickened fascial coverings of the supraspinatus and infraspinatus muscles, was consistently identified.
• The suprascapular nerve courses between the bony margin of the spinoglenoid notch and the medial margin of this septum.

Conclusions:

• The spinoglenoid septum, rather than the spinoglenoid ligament, is likely responsible for dynamic compression of the suprascapular nerve.
• This anatomical variation may explain isolated infraspinatus atrophy.
• Further research is warranted to confirm the clinical significance of the spinoglenoid septum.