Innervation of the Upper Extremity

What nerve root(s) innervates the rhomboid muscle?

• C5

• C6

• C7

• C8

• T1

Answer explanation

C5 via the dorsal scapular nerve

What nerve root(s) innervates the supraspinatus/infraspinatus muscles?

• C5

• C6

• C7

• C8

• T1

Answer explanation

Primarily C5 via the suprascapular nerve.

What nerve root(s) innervates the deltoid muscle?

• C5

• C6

• C7

• C8

• T1

Answer explanation

Primarily C5 via the axillary nerve.

What nerve root(s) innervates the biceps muscle?

• C5

• C6

• C7

• C8

• T1

Answer explanation

Primarily C5 and C6 via the musculocutaneous nerve.

What nerve root(s) innervates the triceps muscle?

• C5

• C6

• C7

• C8

• T1

Answer explanation

Primarily C7 via the radial nerve.

What nerve root(s) innervates the brachioradialis muscle?

• C5

• C6

• C7

• C8

• T1

Answer explanation

Primarily C6 via the radial nerve.

What nerve root(s) innervates the extensor carpi radialis muscle?

• C5

• C6

• C7

• C8

• T1

Answer explanation

Primarily C6 and C7 via the radial nerve.

What nerve root(s) innervates the extensor pollicis brevis muscle?

• C5

• C6

• C7

• C8

• T1

Answer explanation

Primarily C8 via the radial nerve.

What nerve root(s) innervates the extensor indicis proprius muscle?

• C5

• C6

• C7

• C8

• T1

Answer explanation

Primarily C7 and C8 via the radial nerve.

What nerve root(s) innervates the pronator teres muscle?

• C5

• C6

• C7

• C8

• T1

Answer explanation

Primarily C6 and C7 via the median nerve.