Question

multiple choice question

the pectoralis major and temporalis muscles are examples of ______ muscles.

triangular
circular
fusiform
parallel

Explanation:

Identify the muscle shapes described

Using the Skeletal Muscle Shapes knowledge point, we classify skeletal muscles based on the arrangement of their fascicles. The question asks to classify the pectoralis major and temporalis muscles.

Analyze pectoralis major and temporalis

Using the Skeletal Muscle Shapes knowledge point, we examine the structural layout of these two muscles:

• The pectoralis major and temporalis muscles have fascicles that spread out over a broad area and converge at a single, common attachment site (a tendon).
• This fan-shaped or convergent arrangement is structurally classified as a triangular (or convergent) muscle.

Evaluate the other options

Using the Fusiform Muscle and Circular Muscle Structure knowledge points:

• circular: Fascicles are arranged in concentric rings (e.g., orbicularis oculi).
• fusiform: Muscles are thick in the middle and tapered at each end (e.g., biceps brachii).
• parallel: Fascicles run parallel to the long axis of the muscle (e.g., rectus abdominis).

Thus, triangular is the correct classification.

Answer:

• triangular (Correct answer)
• circular
• fusiform
• parallel