National Physical Therapy Examination (NPTE) Practice Exam

Which nerve innervates both the teres major and subscapularis muscles?

1. Lower subscapularis nerve

2. Dorsal scapular nerve

3. Upper subscapularis nerve

4. Axillary nerve

The correct answer is: Lower subscapularis nerve

The lower subscapular nerve is the correct choice as it is responsible for innervating both the teres major and subscapularis muscles. The teres major is involved in shoulder movements like extension, adduction, and medial rotation, while the subscapularis plays a crucial role in medial rotation and stabilization of the shoulder joint. Both muscles are part of the shoulder girdle and are innervated by branches of the brachial plexus, specifically from the posterior cord. The lower subscapular nerve arises from this cord and provides the necessary motor function to both muscles, allowing for coordinated movements of the shoulder. The other nerves listed do not share this dual innervation function. The upper subscapular nerve innervates only the upper part of the subscapularis muscle, the dorsal scapular nerve primarily innervates rhomboid and levator scapulae muscles, and the axillary nerve primarily innervates the deltoid and teres minor. Understanding this innervation pattern is important for recognizing how different nerves contribute to the function of shoulder muscles in physical therapy assessment and interventions.