Background Long head of biceps tendon (LHBT) instability is an important source of pain and disability for the shoulder. Supraspinatus and subscapularis tendons contribute to the formation of the biceps pulley system, which maintains biceps stability during shoulder movements. The aim of this study is to evaluate the effect of morphology of bicipital groove on the stability of LHBT. Also, to evaluate the relationship between bicipital groove morphology and subscapularis rupture and supraspinatus rupture. Material and methods Surgical images and magnetic resonance images of 200 patients who underwent shoulder arthroscopy surgery in our clinic between January 2016 and December 2017 were retrospectively analyzed. The depth of groove, medial wall angle and opening angle values of 200 patients were measured on MRI. The stability of the biceps long head tendon, rotator cuff tear and SLAP lesions was recorded by monitoring the shoulder arthroscopy records in each groups. Results There were 200 patients, 131 male and 69 female, with an average age of 40.9 +/- 14.2 (range: 17.0-79.0) years. In 69 (34.5%) patients, long head of the biceps tendon (LHBT) instability was detected. The patients were divided into two groups according to LHBT instability.The subscapularis rupture was significantly more frequent in the group with LHBT instability (52.2%) than the group without LHBT instability (4.6%) (p < 0.001). The supraspinatus tear was observed in 72.5% in the group with instability and 56.5% in the non-instability group, which shows a statistical difference between the two groups (p = 0.027). The presence of SLAP was observed in similar rates in both groups (p = 0.053). Mean depth of groove, medial wall angle, and opening angle measurements were similar in both groups (p = 0.568, p = 0.393 and p = 0.598, respectively). Conclusion To conclude, the morphology of the bicipital groove is not related to the stability of LHBT, and the soft tissue factors above the bicipital groove rather than bone morphology are important in stability. In addition, subscapularis rupture is a pre-disposing factor for LHBT instability; therefore, we recommend a more careful examination of LHBT in patients with subscapularis rupture.