MMB [009] The Axilla (2) Brachial plexus Flashcards
What is meant by a nerve plexus?
Means of connecting more than one spinal nerve root to a peripheral nerve
Define the dotted figure
Posterior triangle of the neck
This arrow points to :
Brachial plexus
Define the plexuses and their root value
Define the muscles
The meme : “Remember to drink cold beer” is used to remember ?
The structure of the brachial plexus :
- Roots
- Trunks
- Divisions
- Chords
-Branches
The meme “AMMRU“ is used to remember …. Of the brachial plexus.
The 5 main branches:
-axillary
-radial
-musculocutaneous
-ulnar
-median
Mention the chords of the brachial plexus.
-Lateral cord
-Median cord
-Posterior chord
Mention the nerves arrising from the posterior cord :
-Axillary nerve
-Radial nerve
The Axillary nerve supplies … (muscles)
- deltoid m.
- teres minor
The Radial nerve supplies … (muscles)
- Extensor muscles of the arm and forearm
Situations in this figure often injures the … nerve.
Injury of radial nerve
Saturday night ’s palsy , or sleep palsy often injures …(nerve).
Injures the radial nerve
Complications of radial nerve injury ?
-loss of extension of elbow (however, elbow can be extended by gravity)
- weakness of supination
-wrist drop and fingers drop
Radial nerve injury weakens supination , however it doesn’t stop completly . Why ??
The biceps can supinate
Define the condition in this figure , and mention the nerve injury behind it.
What 2 conditions often lead to Axillary nerve injury ?
- Fracture of surgical neck
- Shoulder dislocation
Define the lesion , and the nerve injury behind it.
- Flat shoulder
- Lesion of Axillary nerve
… & … muscles are paralyzed in axillary nerve injury.
deltoid & teres minor
Mention complications of Axillary nerve injury
• Paralysis of deltoid & teres minor muscles → flat shoulder & inability to abduct arm from 15° to 90°
• Loss of sensation over lower 1/2 of deltoid muscle
• Sensation over upper 1/2 of deltoid is normal as it is supplied by lateral supraclavicular nerves C 3,4
In axillary nerve injury , sensation of the upper 1/2 of deltpid is still functioning. Why ??
as it is supplied by lateral supraclavicular nerves C 3,4
Mention root value of supraclavicular nerve
C3 & C4
One nerve arrises from the lateral cord of the brachial plexus , mention it
Musculocutaneous nerve
…. (Nerve) supplies the upper anterior / flexor compartments (BBC).
The Musculocutaneous nerve
…. Is a brachial plexus nerve that has lateral and medial roots.
The median nerve.
The … nerve supplies the Lower anterior/flexor compartments of the forearm and hand ,, and thumb (thenar) muscles.
Median nerve
Mention complications of Median nerve injury.
Ape hand deformity
Ape hand deformity is a complication of … nerve injury
Median nerve injury
…. Nerve injury often follows Supracondylar fractures.
Median
The Ulnar nerve is supplied by the … cord of the brachial plexus.
Medial
Mention the commonest 2 sites of ulnar nerve injury
-wrist
-elbow
Causes of ulnar nerve wrist injury ?
-• Stab wound
-• Entrapment (ulnar tunnel)
Complications of ulnar nerve wrist injury ?
-Partial claw hand
- Anesthesia in mid. 1½ fingers
Causes of ulnar nerve elbow injury ?
fracture med. epicondyle
Mention the nerves supplying each region in the figure.
Mention a common upper trunk lesion in the brachial plexus.
Injury of root values C5 , C6.
Mention a common cause of C5 & C6 upper trunk injuries.
Difficult child birth.
Mention motor complications of ERB’S PARALYSIS
Policeman or Waiter ’s tip position
Upper limb is put in the following position :
• Arm → adducted & medially rotated
• Forearm → extended & pronated
• Wrist → flexed
… is a complication of ERB’S PARALYSIS.
Policeman or Waiter ’s tip position
