Question

Identify the type of muscle shown in the image below.

• A. Cruciate
• B. Multipennate
• C. Parallel
• D. Unipennate

Hint:

Many oblique fibre rows feeding one tendon, as in pectoralis major.

Answer 1

The Correct Option is B

Step 1: Muscles are classified by the arrangement of their fascicles relative to the tendon. Pennate muscles have fibres that lie at an angle (oblique) to the tendon, like the barbs of a feather, which packs in more fibres and increases force.
Step 2: The image shows the pectoralis major, which has several rows of diagonal fibres converging onto a single tendon. When many strips of oblique fibres feed into one central tendon, the muscle is termed multipennate. Hence the answer is multipennate.
Step 3: Why the others are wrong. Unipennate muscles have fibres on only one side of the tendon (for example extensor digitorum longus), so they look like half a feather. Parallel (strap) muscles have fibres running along the long axis of the muscle (for example sartorius). Cruciate is not a standard fascicular arrangement and is a distractor.