The present study describes an anterior-inferior portal for arthroscop
ic shoulder instrumentation at the 5 o'clock position along the glenoi
d rim. An anterior-inferior portal was established in 14 cadaver shoul
ders. The portal was created in an inside-to-outside fashion, with the
humerus maximally adducted, directing the guide rod as far lateral as
possible. Using the described technique, a 5 o'clock portal travels t
hrough the subscapularis and lateral to the conjoined tendon. Distance
between the portal and the musculocutaneous nerve was 22.9 +/- 4.9 mm
(mean +/- SD), and 24.4 +/- 5.7 mm between the portal and the axillar
y nerve. Previously described portals were either at, or above the 3 o
'clock position, resulting in an acute, difficult angle of approach to
the glenoid neck. Through a combination of proper arm positioning and
rod insertion technique, the 5 o'clock portal can be created safely a
nd is of great potential utility for arthroscopic shoulder stabilizati
on procedures.