Triangular muscle

A triangular muscle (a.k.a. a convergent muscle), is a skeletal muscle distinguished by its broad area of origin (base) and its fibres that converge toward a single, narrow insertion point (apex) via a tendon.

Key Characteristics

• Shape & Arrangement: It has a fan-shaped appearance. The muscle fascicles are spread widely at the origin but gather to exert force from a large area onto a single tendon or bone.

• Force & Stability: The broad origin provides stability and strength, incorporating more contractile mass to generate a powerful force at the insertion.

• Action & Versatility: The converging fibre arrangement grants the muscle directional versatility. Different portions of the muscle can be activated independently, allowing it to perform multiple actions at a joint (e.g., flexion, abduction, and extension).

Examples

• Pectoralis major (chest) — fibres converge from the clavicle, sternum, and ribs to insert on the humerus.

• Temporalis (side of the head) — fibres fan out from the temporal fossa to converge on the coronoid process of the mandible.

• Deltoid