Glenoid hypoplasia is a reportedly rare and frequently overlooked congenital abnormality of the scapula that can have a variety of presentations. In 1931, Valentine initially described hypoplastic glenoid, also known as glenoid dysplasia and dentated glenoid, as a rare congenital anomaly. 1 Borenstein Z.C. Mink J. Oppenheim W. Rimoin D.L. Lachman R.S. Case report 665: Congenital glenoid dysplasia. Skeletal Radiol. 1991; 20: 134-136 PubMed Google Scholar , 7 Valentine B. Die kongenitale schulterluxation. Orthop Chir. 1931; 55: 229 Google Scholar It is a bony glenoid deficiency that presents in a variety of patterns, including shoulder pain, instability, stiffness, or completely asymptomatic. 3 Edelson J.G. Localized glenoid hypoplasia an anatomic variation of possible clinical significance. Clin Orthop Relat Res. 1995; 321: 189-195 PubMed Google Scholar , 5 Sperling J.W. Cofield R.H. Steinman S.P. Shoulder arthroplasty for osteoarthritis secondary to glenoid dysplasia. J Bone Joint Surg Am. 2002; 84: 541-546 PubMed Google Scholar , 7 Valentine B. Die kongenitale schulterluxation. Orthop Chir. 1931; 55: 229 Google Scholar Associated findings may include dysplasia of the humeral head, glenoid neck, or coracoid, hooking of the lateral part of the clavicle, irregular or notched glenoid surface, widening of the glenohumeral space from thickened articular cartilage, glenoid retroversion, deficiency of the posteroinferior glenoid, osteoarthrosis, enlargement of the acromion, and labral changes. As these patients are sometimes asymptomatic, or their shoulder symptoms are attributed to other causes, its true incidence is not accurately reported. Edelson, in 1995, found 9 of 12 patients seen for multidirectional instability had evidence of glenoid hypoplasia. 3 Edelson J.G. Localized glenoid hypoplasia an anatomic variation of possible clinical significance. Clin Orthop Relat Res. 1995; 321: 189-195 PubMed Google Scholar He also examined 1150 scapulae from museum collections. A localized hypoplasia of the posteroinferior glenoid was found in 20-35% of the populations studied.