Question 27

The subclavius muscle is present on the anterior thorax.

The subclavius muscle is located beneath the clavicle and extends from the first rib to the clavicle, making it an anterior muscle of the pectoral girdle.

A) Rhomboid minor

The rhomboid minor muscle is located on the posterior side of the thorax, specifically between the spine and the medial border of the scapula. This positioning means it is not situated on the anterior thorax, making it an incorrect option.

B) Subclavius

The subclavius muscle is indeed found on the anterior thorax, as it lies directly beneath the clavicle. Its primary function includes stabilizing the clavicle and assisting with shoulder movements, confirming its status as the correct answer.

C) Trapezius

The trapezius muscle is primarily located on the posterior thorax and extends across the upper back and neck. While it plays a significant role in shoulder movement and stabilization, it does not reside on the anterior thorax, thus making it an incorrect choice.

D) Rhomboid major

Similar to the rhomboid minor, the rhomboid major muscle is also located on the posterior thorax, functioning to retract the scapula. Its position disqualifies it from being considered an anterior muscle of the pectoral girdle, rendering it incorrect.

Conclusion

The subclavius muscle is definitively the correct answer, as it is the only muscle among the options that is located on the anterior thorax. The other choices, including the rhomboid minor, trapezius, and rhomboid major, are all situated on the posterior side, which does not align with the question's requirement for the anterior thorax.