The bicipital groove, also known as the intertubercular groove, is a distinct anatomical feature in the shoulder region. It serves as a significant landmark for understanding the structure and function of the upper arm. This groove guides a specific tendon, ensuring smooth and stable arm motion.
Anatomical Placement
The bicipital groove is located on the humerus, the long bone of the upper arm. It is situated on the proximal end of the humerus, close to the shoulder joint. This groove forms a prominent indentation on the anterior surface of the bone.
This depression is found between two bony projections: the greater tubercle and the lesser tubercle. The greater tubercle is a larger, more laterally placed prominence, while the lesser tubercle is smaller and positioned medially. The bicipital groove runs vertically between these two tubercles. Its length ranges from 66 to 87 millimeters, and its width is between 8 and 11 millimeters.
Function and Contained Structures
The primary function of the bicipital groove is to provide a protected pathway for the long head of the biceps brachii tendon. This tendon, which is part of the biceps muscle, originates within the shoulder joint and extends down into the upper arm. The groove acts like a natural channel, guiding the tendon as it moves during arm elevation, rotation, and other movements.
This arrangement helps to stabilize the tendon, preventing it from slipping out of place. A fibrous band of tissue called the transverse humeral ligament stretches across the top of the groove, essentially converting the groove into a tunnel. This ligament further secures the long head of the biceps tendon, ensuring its efficient function and reducing friction during movement. The groove also transmits a branch of the anterior humeral circumflex artery to the shoulder joint.
Clinical Relevance and Palpation
The bicipital groove holds clinical importance because the long head of the biceps brachii tendon can be a source of shoulder pain. Conditions such as bicipital tendinitis involve inflammation of this tendon as it passes through the groove, often due to repetitive motion or overuse. Another issue is subluxation or dislocation, where the biceps tendon can partially or completely displace from the groove, leading to instability and discomfort.
Palpating the bicipital groove can help identify these issues. To locate it, find the bony prominence at the front of the shoulder, just below the collarbone. By gently pressing and slowly rotating the arm inward and outward, one might feel a distinct indentation or groove as the greater and lesser tubercles move under the fingertips. Tenderness upon light pressure in this area can indicate inflammation or other problems with the biceps tendon.