Ulnar nerve

Ulnar nerve [Ref. Ajai yadav Anaesthesia p 46, Miller’s anaesthesia 6^th/e p 289]

• Most common nerve used for monitoring during anaesthesia is ulnar nerve.
• Ulnar nerve supplies adductor pollicis, and this muscle is most commonly observed during perioperative period.
• Adductor pollicis muscle is monitored for neuromuscular blockade. If adductor pollicis is showing no activity it means laryngeal muscles have already been blocked and intubation can be performed.
• At the reversal, if there is activity in adductor pollicis it means that diaphragmatic activity has already returned and the patient will be able to maintain tidal volume even after extubation.

Also know

• The muscle to show earliest reversal is orbicularis occuli, supplied by the facial nerve.
• Common peroneal nerve can also be used for monitoring.

• Base is formed by an imaginary line passing through the medial and lateral epicondyle of humerus.
• Medial boundary is formed by lateral margin of pronator teres muscle.
• Lateral boundary is formed by medial margin of brachioradialis muscle.
• Apex is located at the crossing of pronator teres and brachioradialis muscle.
• Floor consist of brachialis in the upper part and supinator in the lower part.

D i.e. Median & ulnar nerve 

Ans is i.e., ‘c’ i.e. It causes pressure on the ulnar nerve 

The muscles of hypothenar eminence are:

• Opponens digiti minimi
• Flexor digiti minimi
• Abductor digiti minimi
• Palmar brevis

The intrinsic muscles of hand can be remembered using the mnemonic, “A OF A OF A (P)” for, Abductor pollicis longus, Opponens pollicis, Flexor pollicis brevis, Adductor pollicis (thenar muslces) and Opponens digiti minimi, Flexor digiti minimi, Abductor digiti minimi and Palmar brevis (Hypothenar muscles)

They are all supplied by the deep branch of the ulnar nerve.

Ulnar Nerve In Arm

 Ulnar nerve

Ans. is ‘A’ i.e., Ulnar nerve

Ten structures pass through the carpal tunnel, most of them flexor tendons(not the muscles themselves):

• flexor digitorum profundus (four tendons)
• flexor digitorum superficialis (four tendons)
• flexor pollicis longus (one tendon)
• Median nerve between tendons of flexor digitorum profundus and flexor digitorum superficialis

Various branches of ulnar nerve are :‑

A) In arm : No branch.

B) In forearm : There are following branches :‑

1)  Muscular : In proximal part of forearm it supplies flexor carpi ulnaris and medial half of flexor digitorum profundus.

2)  Cutaneous : There are two cutaneous branches in forearm:-

i)   Palmar cutaneous branch : Supplies skin over the hypothenar eminence.

ii)  Dorsal (posterior) cutaneous branch : Supplies skin over medial 1/3 of dorsum of hand and dorsal surface of medial 11/2 fingers.

C) In hand : Ulnar nerve enters the palm by passing superficial to flexor retunuculum and divides into two terminal branches :‑

1)   Superficial terminal branch : It supplies palmaris brevis and skin of palmar surface of medial 11/2 fingers.

2)  Deep terminal branch : It supplies adductor pollicis, all interossei, medial two (3″¹ & 4^th)lumbricals and all hypothenar muscles except palmaris brevis (i.e. abductor digiti minimi, flexor digiti minimi, opponens digiti minimi).

 1st lumbrical

Ulnar nerve does not have root valve C5, C6,C7 .

Ans. is ‘b’ i.e., Ulnar nerve

Contents of carpal tunnel are 1 nerve and 9 tendons :-

i) Median nerve

ii) 4 tendons of flexor digitorum profunds.

iii) 4 tendons of flexor digitorum superficialis.

iv) 1 tendon of flexor pollicis longus.

Ans. is ‘d’ i.e., Ulnar nerve

Contents of cubital fossa

• Median nerve
• Brachial artery termination and begining of radial and ulnar arteriesQ.
• Biceps tendon
• Radial nerve and Radial collateral artery

Ans. is `d’ i.e., Deep branch of ulnar nerve