Long Head of the Triceps: Anatomy, Function, and Targeted Exercises

Where is the Long Head of the Tricep?

The long head of the triceps brachii is one of three heads of the triceps muscle, uniquely originating from the infraglenoid tubercle of the scapula (shoulder blade), distinguishing it from the medial and lateral heads which originate directly from the humerus.

Anatomy of the Triceps Brachii

The triceps brachii, Latin for "three-headed arm muscle," is the sole muscle on the posterior aspect of the upper arm. Its primary function is extension of the elbow joint, straightening the arm. It comprises three distinct heads that converge into a common tendon, inserting onto the olecranon process of the ulna (the bony prominence of the elbow). These three heads are:

• Long Head: The focus of this discussion, distinguished by its origin.
• Lateral Head: Originates from the posterior surface of the humerus, superior to the radial groove.
• Medial Head: Originates from the posterior surface of the humerus, inferior to the radial groove.

While all three heads contribute to elbow extension, their differing origins provide unique functional capabilities, particularly for the long head.

The Distinctive Long Head: Origin, Course, and Insertion

The long head of the triceps is anatomically unique among the three heads due to its proximal attachment point.

• Origin: Unlike the lateral and medial heads which originate directly from the humerus (upper arm bone), the long head originates from the infraglenoid tubercle of the scapula. This small bony projection is located just below the glenoid cavity, which is where the humerus articulates with the scapula to form the shoulder joint.
• Course: From its origin on the scapula, the long head runs distally (downwards) along the posterior aspect of the humerus, nestled between the lateral and medial heads. It is the most medial of the three heads as it descends.
• Insertion: All three heads of the triceps converge to form a strong common tendon that inserts onto the olecranon process of the ulna, the prominent bony tip of the elbow.

Because the long head originates on the scapula and inserts on the ulna, it crosses two joints: the shoulder joint and the elbow joint. This bi-articular nature is key to its distinct functions.

Functional Significance of the Long Head

While all three heads are elbow extensors, the long head's unique origin grants it additional roles:

• Elbow Extension: This is the primary function shared by all triceps heads, essential for pushing movements and straightening the arm.
• Shoulder Extension: Due to its attachment on the scapula, the long head can assist in extending the shoulder joint, moving the arm backward from a flexed position (e.g., during a pull-over motion).
• Shoulder Adduction: It can also contribute to adduction of the shoulder, drawing the arm closer to the midline of the body (e.g., during a lat pulldown).
• Shoulder Joint Stabilization: The long head plays a significant role in stabilizing the head of the humerus within the glenoid cavity, particularly during movements that involve the shoulder joint.

Its bi-articular nature means its contribution to elbow extension can be influenced by the position of the shoulder joint. When the shoulder is flexed (arm overhead), the long head is put into a stretched position, which can increase its active contribution to elbow extension.

Exercises Targeting the Long Head

Understanding the long head's anatomy allows for more targeted training. Exercises that place the shoulder in a flexed (overhead) position tend to emphasize the long head due to its stretched starting position, optimizing its force production:

• Overhead Triceps Extensions (e.g., Dumbbell Overhead Extension, Cable Overhead Extension): These are perhaps the most effective exercises for emphasizing the long head, as the arm is fully flexed at the shoulder, pre-stretching the long head and increasing its activation during elbow extension.
• Lying Triceps Extensions (Skullcrushers): While effective for overall triceps development, the long head is heavily involved, especially if the arms are positioned slightly behind the head to induce a greater stretch.
• Close-Grip Bench Press: All three heads contribute significantly, but the long head is actively involved in the pressing motion.
• Triceps Pushdowns (especially with a rope attachment): By allowing for a greater range of motion that includes shoulder extension at the end of the movement, the long head can be further engaged.

Why Understanding Its Anatomy Matters for Training

For fitness enthusiasts, personal trainers, and kinesiologists, a clear understanding of the long head's location and function is crucial for several reasons:

• Optimized Muscle Activation: Knowing which exercises best target the long head allows for more effective program design to ensure balanced triceps development and strength.
• Injury Prevention: Understanding its role in shoulder stability can inform warm-up routines and exercise selection, potentially reducing the risk of shoulder-related issues.
• Rehabilitation: For individuals recovering from shoulder or elbow injuries, specific targeting of the long head may be crucial for restoring function and strength.
• Functional Strength: Training the long head specifically contributes to improved performance in sports and daily activities requiring powerful pushing, throwing, or overhead movements.

Conclusion

The long head of the triceps brachii is a unique and functionally significant muscle head due to its origin on the scapula. This anatomical distinction allows it to not only extend the elbow but also contribute to shoulder extension and adduction, and provide crucial shoulder joint stability. Recognizing its specific location and bi-articular nature is fundamental for anyone looking to comprehensively understand and effectively train the triceps for optimal strength, performance, and injury resilience.