Where is the Long Head of the Tricep?

The long head of the triceps brachii muscle originates precisely from the infra-glenoid tubercle of the scapula, a specific bony landmark located on the shoulder blade.

Understanding the Long Head of the Triceps

The triceps brachii is a large muscle located on the posterior (back) aspect of the upper arm. It is responsible for extending the elbow joint and is composed of three distinct parts, or "heads": the long head, the lateral head, and the medial head. Each head originates from a different point, contributing uniquely to the muscle's overall function.

Origin and Anatomical Location

The distinguishing feature of the long head is its unique origin point, which separates it from the other two heads:

• Origin: The infra-glenoid tubercle of the scapula. The scapula is commonly known as the shoulder blade. The infra-glenoid tubercle is a small, rough projection found just below the glenoid cavity, which is the shallow socket where the head of the humerus (upper arm bone) articulates to form the glenohumeral, or shoulder, joint.

Because the long head attaches to the scapula, rather than directly to the humerus like the other two heads, it crosses both the shoulder and elbow joints. This anatomical arrangement gives it a broader range of action.

Functions and Actions

Due to its attachment to the scapula, the long head of the triceps brachii is not solely an elbow extensor but also plays a significant role in movements at the shoulder joint. Its primary actions include:

• Elbow Extension: This is the primary function shared by all three heads of the triceps, allowing for the straightening of the arm.
• Shoulder Joint Action: As it spans the shoulder joint, the long head also contributes to:
  • Extension of the Glenohumeral Joint: Moving the arm backward or pulling it down from an overhead position.
  • Adduction of the Glenohumeral Joint: Bringing the arm closer to the body's midline.

This dual functionality makes the long head particularly important in compound movements that involve both elbow extension and shoulder movement or stabilization, such as overhead presses, pull-overs, or dips.

Practical Relevance and Importance

Understanding the specific origin of the long head is crucial for several reasons:

• Targeted Exercises: Exercises that involve an overhead position or require significant shoulder stability (e.g., overhead triceps extensions, close-grip bench presses, or certain dumbbell rows) tend to emphasize the long head more due to its leverage and involvement in shoulder mechanics.
• Rehabilitation and Injury Prevention: Knowledge of its origin aids physical therapists and medical professionals in diagnosing and treating shoulder or elbow pathologies that may involve the triceps. Injuries to the infra-glenoid tubercle can directly affect the long head.
• Movement Efficiency: Its role in both elbow and shoulder movements highlights its importance in athletic performance and daily activities requiring coordinated upper limb actions.

Overview of Triceps Brachii Heads

The long head of the tricep is located originating from the infra-glenoid tubercle of the scapula, making it a critical component for both elbow extension and specific shoulder joint movements.