ulna nerve

Question 1

Where does the ulna nerve originate from?

Answer 1

• medial cord of brachial plexus C8-T1

Question 2

describe the course of the ulna nerve?

Answer 2

ARM

• Lies postermedial to brachial artery in anterior compartment off upper arm
• Thru medial IM septum at Arcade of Struthers
• 8cm from medial epicondyle
• medial to triceps
• aponeurotic band extending medial IM septum to medial head of triceps

ELBOW

• runs behind medial epicondyle with superior ulnar collateral artery
• thru Cubital tunnel
  
  • roof Osborne ligament ( fascia between heads of fcu)

FOREARM

• enters between 2 heads of FCU
• runs between FCU and FDP

WRIST

• the ulna n and artery pass Superficial to the transverse carpal ligament
• Bifurcates into sensory and deep motor branches in Guyon’s canal

Question 3

What is the motor innervation of the ulna nerve?

Answer 3

• Forearm
  
  • FCU
  • FDP ring and little
• Thenar
  
  • Adductor pollicis- Fromens test
  • Deep head of flexor pollicis brevis
• Fingers
  
  • Interossei ( dorsal /palmar)- paper test
  • 3/4th lumbricals
• Hypothenar
  
  • Abductor digit minimi
  • Opponens digit minimi
  • Flexor digiti minimi

Question 4

What is the sensory branches of the ulna nerve?

Answer 4

• Dorsal cutaneous branch
• Palmar cutaneous branch
• Superificial terminal branch

Question 5

What clinical compression syndromes happen to the ulna nerve?

Answer 5

• Cubital tunnel syndrome
  
  • compression sites - MAM CAAA
    
    • Medial intermusclar septum
    • Arcade of Struthers
    • Medial Epicondyle ( osteophytes)
    • Cubital tunnel retinaculum- osborne lig
    • Aconeus epitrochlearis
    • Aponeurosis of 2 heads FCU
    • Apoenurosis of flexor/pronator
• ulnar tunnel syndrome
  
  • compression Guyon canal