Abstract:

Objective　To study the anatomical mechanism of the suprascapular nerve entrapment, to provide the basis for clinical diagnosis and treatment of this disease.　Methods　In 22 (male 13, female 9) 44 sides of cadaveric specimens, the anatomic features of the suprascapular notch, spinoglenoid notch, the branches and distribution of supraspinatus were observed. The data were analyzed statistically.　Results　The suprascapular notch could be divided into four types. U type 40.91%（18 sides）， shallow U type 22.73%（10 sides）, arc type 27.27% （12 sides）, square type 9.01%（4 sides）. The thickness of suprascapular notch was (1.55±0.36) mm; The angle of between the trunk of suprascapular nerve and the branch of the supraspinatus was ( 86.04±1.28)°. The position of the branches of infraspinatus that entered infraspinatus was located near the origin of the infraspinatus in 10 sides. The thickness of the spinoglenoid notch was (6.82±1.21) mm.The heights of suprascapular nerve from the suprascapular hole to the base of scapular averaged(11.13±0.21) mm. And the horizontal distance from the suprascapular hole to the spinoglenoid notch was (14.03±0.64) mm. The angle of the suprascapular nerve was (49.65±1.63)°.  Conclusion　The risk factors that can lead to suprascapular nerve entrapment include: the types of scapular notch, the thickness of the suprascapular notch and the spinoglenoid notch, the angles of suprascapular nerve, the angles between the trunk of suprascapular nerve and the branches of supraspinatus, the position of the branches of infraspinatus that enter it.

Key words: Suprascapular nerve, Nerve entrapment, Suprascapular notch, Applied anatomy