Illinois Nail Technician Practice Exam

Which of the following is not a shoulder muscle?

1. Deltoid

2. Biceps

3. Triceps

4. Quadriceps

The correct answer is: Quadriceps

The quadriceps are not considered a shoulder muscle because they are a group of muscles located in the front of the thigh, primarily responsible for extending the knee. This group typically includes the rectus femoris and the vastus muscles, which do not have any anatomical or functional connection to the shoulder joint. Understanding muscle groups in relation to their location is essential for effective anatomy knowledge, especially in fields like cosmetology and nail technology, where posture and ergonomics can impact a technician's work. In contrast, the deltoid, biceps, and triceps are all involved in shoulder and arm movement. The deltoid is a prominent shoulder muscle responsible for lifting the arm and giving the shoulder its rounded contour. The biceps brachii, located on the front of the upper arm, assists in flexing the elbow and rotating the forearm, playing a supportive role in shoulder movement as well. The triceps brachii, located at the back of the upper arm, is primarily involved in elbow extension but also contributes to some shoulder functions. This distinction highlights the quadriceps as separate from the shoulder muscle group.