Intertubercular sulcus of the humerus: biometry and morphology of 100 dry bones.

The dimensions and morphology of a critical zone of the intertubercular sulcus (ITS) of the humerus were specified for 100 dry bones. The upper part of the ITS was narrow and at an angle with the lower part. The tendon of the long head of the biceps brachii muscle (TLBB) was particularly worn down during its course through this critical zone. The critical zone extended from the first perceptible proximal depression to the distal extremity of the lesser tubercle. It showed a proximal part of 12.4 mm (standard deviation = 2.23) and a distal part of 15.1 mm (s.d. = 3.37). The two parts made an angle of 142 degrees (s.d. = 7.87). Its total length was 28.5 mm (s.d. = 4.74), depth 2.44 mm (s.d. = 0.49), width 6.33 mm (s.d. = 0.84). The supratubercular ridge was the only bony variation, found in 45% of the bones of this series. Bony abnormalities were of three types: (1) calcifications in 39% of the bones, (2) lateral spurs in 32% and medial spurs in 23%, (3) degenerative changes in 9% of the bones. Biometric considerations showed that the TLBB inside the ITS was unstable. The supratubercular ridge could increase this instability and thus favor disease of the tendon. Bony abnormalities which may be associated with TLBB lesions, can be seen in radiographs.