In thromboasthenia there is a defect in -

Platelet adhesion Platelet adhesion refers to the binding of platelets to subendothelial matrix. Platelet membrane glycoprotein Ib - IX is essential for platelet adhesion to subendothelial matrix. Platelet aggregation Platelet aggregation refers to adherence of platelets to one another. Platelet membrane glycoprotein IIb - IIIa helps in aggregation. Congenital dysfunction of platelet 1.  Bernard-Soulier syndrome Defect in platelet adhesion due to inherited deficiency of glycoprotein Ib - IX. 2. Glanzmann's thrombasthenia Defect in platelet aggregation due to inherited deficiency of glycoprotein IIb - IIIa.