Nerve Supply Of Muscles Of Upper Limb

NERVE SUPPLY OF MUSCLES OF UPPER LIMB

Q. 1 All of the following are features of musculocutaneous nerve injury at axilla except
 A Loss of flexion of shoulder
 B Weak elbow flexion
 C Weak forearm supination
 D Loss of sensation on radial side of forearm
Q. 1 All of the following are features of musculocutaneous nerve injury at axilla except
 A Loss of flexion of shoulder
 B Weak elbow flexion
 C Weak forearm supination
 D Loss of sensation on radial side of forearm
Ans. A

Explanation:

 

Loss of flexion of shoulder*

 Flexion at shoulder is done by major muscles like pectoralis major, anterior fibres of deltoid, which are intact here.

 Musculocutaneous nerve (MCN)originates from the lateral cord of the brachial plexus of nerves.

 It pierces the  coracobrachialis muscle and gives off branches to the muscle, as well as to brachialis and biceps brachii, the chief flexors at elbow joint.

Coraco-brachialis is a  flexor at shoulder joint

 Biceps brachii is a powerful supinator, hence supination is weakened.

 MCN terminates as the lateral cutaneous nerve of the forearm.


Q. 2

Which of the following nerves innervates the deltoid muscle?

 A

Axillary

 B

Dorsal scapular

 C

Long thoracic

 D

Suprascapular

Q. 2

Which of the following nerves innervates the deltoid muscle?

 A

Axillary

 B

Dorsal scapular

 C

Long thoracic

 D

Suprascapular

Ans. A

Explanation:

  • The axillary nerve innervates the deltoid muscle, as well as provides sensation over the lateral part of the arm.
  • The dorsal scapular nerve innervates the rhomboids and levator scapulae muscles.
  • The long thoracic nerve innervates the serratus anterior. Injury to this results in winging of the scapula.
  • The suprascapular nerve innervates the supraspinatus and infraspinatus muscle.

Q. 3

True about the Serratus anterior muscle is

 A

Originates from the lower four ribs

 B

Bipennate muscle

 C

Supplied by the subscapular nerve

 D

Helps in forced inspiration

Q. 3

True about the Serratus anterior muscle is

 A

Originates from the lower four ribs

 B

Bipennate muscle

 C

Supplied by the subscapular nerve

 D

Helps in forced inspiration

Ans. D

Explanation:

Serratus anterior helps in vertical overhead abductionQ (assisted by trapezius), forward punchQ (assisted by pectoralis minor) & forced inspirationQ; it’s paralysis leads to winging of scapulaQ


Q. 4

In deltoid paralysis, which nerve is involved :

 A

Circumflex N

 B

Musculocutaneous N

 C

Axillary N

 D

Radial N

Q. 4

In deltoid paralysis, which nerve is involved :

 A

Circumflex N

 B

Musculocutaneous N

 C

Axillary N

 D

Radial N

Ans. C

Explanation:

C. i.e. Axillary nerve


Q. 5

Musculocutaneous nerve is injured at the lateral cord of brachial plexus, positive clinical findings would be:

 A

Loss of flexion at shoulder

 B

Sensory loss on the radial side of the forearm

 C

Loss of extension of forearm

 D

Loss of extension of the wrist

Q. 5

Musculocutaneous nerve is injured at the lateral cord of brachial plexus, positive clinical findings would be:

 A

Loss of flexion at shoulder

 B

Sensory loss on the radial side of the forearm

 C

Loss of extension of forearm

 D

Loss of extension of the wrist

Ans. B

Explanation:

B i.e. Sensory loss on the radial side of forearm


Q. 6

Muscle supplied by median nerve:

 A

Opponens pollicis

 B

Abductor pollicis brevis

 C

Flexor pollicis brevis

 D

All

Q. 6

Muscle supplied by median nerve:

 A

Opponens pollicis

 B

Abductor pollicis brevis

 C

Flexor pollicis brevis

 D

All

Ans. D

Explanation:

A, B, C,  i.e. Opponens pollicis, Abductor pollicis brevis, Flexor pollicis brevis, & First lumbricals


Q. 7

Musculocutaneous nerve supplies all of the following EXCEPT:      

 A

Coracobrachialis

 B

Biceps brachii

 C

Brachialis

 D

Brachioradialis

Q. 7

Musculocutaneous nerve supplies all of the following EXCEPT:      

 A

Coracobrachialis

 B

Biceps brachii

 C

Brachialis

 D

Brachioradialis

Ans. A

Explanation:

Suprascapular nerve arises from the upper trunk (formed by the union of the fifth and sixth cervical nerves).



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