Upper and Lower Extremity Muscle Quiz

The 'rotator cuff' includes all of the following EXCEPT:

• Teres minor

• Subscapularis

• Deltoid

• Supraspinatus

Answer explanation

The deltoid is not part of the rotator cuff. The rotator cuff consists of the teres minor, subscapularis, and supraspinatus muscles, which stabilize the shoulder joint.

Which muscle is the primary abductor of the shoulder joint?

• Supraspinatus

• Infraspinatus

• Deltoid

• Biceps brachii

Answer explanation

The deltoid muscle is the primary abductor of the shoulder joint, responsible for lifting the arm away from the body. The supraspinatus assists in the initial phase, but the deltoid is the main muscle for this action.

What is the function of the brachialis muscle?

• Supinates the forearm

• Extends the elbow

• Flexes the elbow

• Abducts the arm

Answer explanation

The brachialis muscle primarily functions to flex the elbow. It is located beneath the biceps and is a key muscle involved in bending the arm at the elbow joint.

The triceps brachii extends the shoulder and elbow.

Answer explanation

The statement is false. The triceps brachii primarily extends the elbow, not the shoulder. While it can assist in shoulder extension, its main function is elbow extension.

Which muscle is the most powerful hip extensor?

• Gluteus medius

• Rectus femoris

• Gluteus maximus

• Iliopsoas

Answer explanation

The gluteus maximus is the largest and most powerful muscle responsible for hip extension, making it the primary muscle used in movements like standing up, climbing, and running.

The quadriceps femoris group is responsible for:

• Hip extension

• Knee extension

• Hip abduction

• Ankle dorsiflexion

Answer explanation

The quadriceps femoris group primarily functions to extend the knee. It is composed of four muscles that work together to straighten the leg at the knee joint, making 'Knee extension' the correct answer.

The gastrocnemius and soleus muscles insert onto:

• Navicular

• Talus

• Tibial tuberosity

• Calcaneus

Answer explanation

The gastrocnemius and soleus muscles insert onto the calcaneus via the Achilles tendon, which is crucial for plantar flexion of the foot.

The vastus medialis obliquus helps to stabilize the patella.

Answer explanation

The vastus medialis obliquus is a part of the quadriceps muscle group and plays a crucial role in stabilizing the patella during knee movements, thus the statement is true.

The tibialis anterior muscle is responsible for plantarflexion.

Answer explanation

The tibialis anterior muscle is primarily responsible for dorsiflexion, not plantarflexion. Therefore, the statement is false.