The Coracoacromial Ligament: Anatomy, Function, and Clinical Significance

Abstract

The coracoacromial ligament (CAL) was first described as a pain generator by Dr Charles Neer in the early 1970s. Since that time, considerable controversy regarding CAL management during acromioplasty has persisted. This review aims to better understand the role of the CAL in shoulder physiology and pathology. Sixty-six articles from 1958 to 2016 were identified using an electronic search of PubMed, Cochrane Library, AccessMedicine, and MD Consult for case series as well as cohort and prospective studies. The authors used “coracoacromial ligament” and “coracoacromial veil” as medical subject headings (MeSH). In addition, reference lists from all identified articles were reviewed for studies that the search terms may have omitted. The CAL plays an important role in shoulder biomechanics, joint stability, and proprioception. Morphological variance of the CAL is evident throughout the literature. Age-dependent changes due to chronic stress and cellular degradation cause thickening and stiffening of the CAL that may contribute to a spectrum of shoulder pathology from capsular tightness to rotator cuff tear arthropathy and impingement syndrome. The CAL is an integral component of the coracoacromial arch. CAL release during acromioplasty remains controversial. Future clinical outcomes research should endeavor to advance the understanding of the CAL to refine clinical and intraoperative decision making regarding its management.

Efficacy of concomitant acromioplasty in the treatment of rotator cuff tears: A systematic review and meta-analysis

“…Then, several studies stated the potential disadvantages of the CAL resection, involving muscle weakness, adhesive capsulitis in the acromial space that limited shoulder mobility, and anterosuperior glenohumeral instability [ 31 – 33 ]. Rothenberg et al[ 34 ] found the CAL played an important role in mechanosensory feedback loops that helped to dynamically stabilize the entire range of motion of the shoulder. Cay et al[ 35 ] examined 40 patients undergoing rotator cuff repairs via magnetic resonance imaging and found that the acromio-humeral and coraco-humeral distances were narrower than normal limits in patients with rotator cuff tears.…”

A Novel MRI Measurement for Analysing Coracoacromial Morphology

“…The exact role of CAL is still not clear and is debated in the literature. The ligament's own mechanoreceptors and deformation of the ligament on dynamic ultrasound scan are reported, which suggests its function as a restraint and also with a role in proprioception [22] . It is also reported the ligament can reform or regenerate after surgical transection, suggesting its functional importance as an anatomical structure [23][24] .…”

“False” Ligaments: A Review of Anatomy, Potential Function, and Pathology

“…The coracoacromial ligament (CAL) connects two different parts of the scapula: the coracoid process and the acromion (Figure 7 ). It extends from the inferior anterolateral surface of the acromion to insert onto the lateral edge of the coracoid process [ 24 ]. The CAL forms the coracoacromial arch, which serves several anatomical purposes.…”

“…When ossified or calcified, the CAL can contribute to shoulder impingement syndrome (SIS), which occurs as a result of repetitive contact between the coracoacromial arch and rotator cuff muscles, leading to inflammation [ 24 ]. According to Kijima, et al, as the CAL becomes stiffer and more ossified, the pressure exerted by contact between the rotator cuff and the coracoacromial arch increases, aggravating the condition [ 25 ].…”