Abstract
Objective To study the anatomy of the medial coracoclavicular ligament and assess the contribution
of the acromioclavicular, coracoclavicular and medial coracoclavicular ligaments to
the stability of the acromioclavicular joint.
Methods Twenty-six shoulders from 16 fresh cadavers were dissected after placement in dorsal
recumbency with a 15-cm cushion between the shoulder blades. An extended deltopectoral
approach was performed proximally and medially, followed by plane dissection and ligament
identification. The acromioclavicular and coracoclavicular distances were measured
using points previously marked with a millimeter caliper. Six of these specimens were
submitted to a biomechanical study. The acromioclavicular ligament, the coracoclavicular
ligament and the medial coracoclavicular ligament were sectioned sequentially, and
a cephalic force of 20 N was applied to the lateral clavicle. The acromioclavicular
and coracoclavicular distances were measured in each of the ligament section stages.
Results The right medial coracoclavicular ligament presented, on average, 48.9 mm in length
and 18.3 mm in width. On the left side, its mean length was 48.65 mm, with a mean
width of 17.3 mm. Acromioclavicular, coracoclavicular and medial coracoclavicular
ligament section resulted in a statistically significant increase in the coracoclavicular
distance and posterior scapular displacement.
Conclusion The medial coracoclavicular ligament is a true ligamentous structure found in all
dissected shoulders. Our results showed that the scapular protraction relaxed the
medial coracoclavicular ligament, while scapular retraction tensioned it; in addition,
our findings demonstrate that this ligament contributes to the vertical and horizontal
stability of the acromioclavicular joint.
Keywords
acromioclavicular joint - joint dislocations - anatomy - dissection
