Upper Limb Nerves Flashcards
Which cord of the brachial plexus does the musculocutaneous nerve originate from?
The lateral cord
Describe the course of the musculocutaneous nerve down the arm.
Originates from the lateral cord of the brachial plexus
Pierces coracobrachialis and travels down the arm anterior to brachialis, but posterior to biceps brachii.
Emerges laterally to biceps tendon.
Does the musculocutaneous nerve continue into the forearm?
Yes, as the lateral cutaneous nerve
Which muscles does the musculocutaneous nerve innervate?
Biceps brachii
Brachialis
Coracobrachialis
What are the motor functions of the musculocutaneous nerve?
Flexion at the elbow, supination of the forearm.
What is the sensory function of the musculocutaneous nerve?
The lateral cutaneous nerve (which it becomes in the forearm) supplies the skin of the lateral aspect of the forearm
Which cord of the brachial plexus is the ulnar nerve a continuation of?
Medial cord
Which nerve roots does the ulnar nerve originate from?
C8 and T1
Describe the anatomical course of the ulnar nerve, from the brachial plexus to the elbow
Originates from medial cord of brachial plexus
Descends down medial side of arm
Passes posteriorly to the medial epicondyle at elbow
Describe the anatomical course of the ulnar nerve in the forearm and hand
Gives rise to the muscular branch just distally to the elbow
Descends the forearm medially, alongside the ulna
At the wrist, gives off dorsal branch and palmar branch
Travels into the hand superficially to flexor retinaculum, via the Guyon’s canal
Terminates in hand by splitting into deep and superficial branches
Where are the muscles that the ulnar nerve innervates?
Anterior compartment of the forearm
Intrinsic muscles of the hand
Which muscles in the anterior forearm does the ulnar nerve innervate?
Flexor carpi ulnaris
Medial half of flexor digitorum profundus
Which intrinsic muscles of the hand are innervated by the ulnar nerve?
Hypothenar muscles
Medial 2 lumbricals
Adductor pollicis
Interossei
What are the motor functions of the ulnar nerve in the anterior compartment of the forearm?
Flexion of the fingers
Flexion and ulnar deviation of the wrist
What are the 3 branches of the ulnar nerve which have sensory functions?
Palmar cutaneous branch
Dorsal cutaneous branch
Superficial branch
Which area of skin is supplied by the ulnar nerve?
Break this down into the 3 branches.
The skin of the medial 1 1/2 fingers, and the corresponding dorsal and palmar surfaces
Skin of medial half of palm = palmar cutaneous branch
Skin of medial 1 1/2 fingers and the dorsal surface = dorsal branch
Skin of medial 1/2 fingers palmar side = superficial branch
Which nerve is a continuation of the posterior cord of the brachial plexus?
Radial nerve
Give the nerve roots of the radial nerve
C5, C6, C7, C8 and T1
Describe the course of the radial nerve, from its origin to its termination
Originates as posterior cord of brachial plexus
Exits axilla posterior to brachial artery
Travels down posterior aspect of humerus, in radial groove
Supplies triceps brachii
Wraps laterally around humerus and passes anteriorly over lateral epicondyle at elbow, passing through the cubital fossa
Terminates in forearm by splitting into deep and superficial branches
Which of the following is the sensory branch, and which is the motor branch - deep and superficial?
Sensory = superficial Motor = deep
What muscles are innervated by the radial nerve?
In the arm = triceps brachii
In the forearm = posterior compartment
What are the motor functions of the radial nerve?
Extension at the elbow
Extension at the wrist
Extension at the fingers
What are the 4 sensory branches of the radial nerve?
Lower lateral
Posterior cutaneous branch of forearm
Posterior cutaneous branch of arm
Superficial branch
Which areas of skin of the upper limb are supplied by the radial nerve?
Lateral aspect of arm, below the deltoid
Posterior surface of arm
Strip of skin down middle of posterior forearm
Dorsal surface of lateral 3 fingers (not finger tips)
What are the nerve roots of the axillary nerve?
C5 and C6
Which cord of the brachial plexus does the axillary nerve originate from?
Posterior cord
Which structure does the axillary nerve exit the axilla with?
Posterior circumflex humeral artery
Which muscles are innervated by the axillary nerve?
Teres minor
Deltoid
What is the motor function of the axillary nerve?
Abduction of the arm at the shoulder
Which area is innervated by the axillary nerve?
Which branch of the nerve is responsible for this?
The regimental badge area - skin over lower deltoid
Lateral cutaneous nerve of arm
Which cords of the brachial plexus does the median nerve arise from?
The medial and lateral cords
What are the nerve roots of the median nerve?
C5 - T1
Describe the anatomical course of the median nerve down the arm
Descends the arm first of all laterally to the brachial artery, and then medially to it, but pretty much straight down the middle of the anterior side.
At the elbow, passes through the cubital fossa
Describe the course of the median nerve through the forearm
Enters anterior compartment of forearm via cubital fossa
Descends forearm between flexor digitorum superficialis and flexor digitorum profundus.
Gives off anterior interosseous nerve - supplies the deep compartment of the anterior forearm
Describe the course of the median nerve into the hand
Enters the hand via the carpal tunnel
Once in the hand, splits into recurrent branch and palmar digital branch
Which forearm muscles are supplied by the median nerve?
Superficial compartment - all but flexor carpi ulnaris, i.e. PT, FCR, PL
Intermediate compartment - FDS
Deep compartment - lateral half of FDP, and all others
Which branch of the median nerve supplies the deep compartment of the forearm?
The anterior interosseous branch
Which branch of the median nerve supplies the thenar muscles?
The recurrent branch
Which muscles are supplied by the palmar digital branch of the median nerve?
The lateral 2 lumbricals
What are the names of the sensory branches of the median nerve?
Palmar cutaneous branch
Palmar digital branch
Which skin is innervated by the palmar cutaneous branch of the median nerve?
Lateral aspect of hand
Where does the palmar cutaneous branch of the median nerve arise?
How does it travel to its destination?
Arises in forearm
Travels into hand but not via carpal tunnel
Where does the palmar digital branch of the median nerve arise?
In the hand
What skin is innervated by the palmar digital branch of the median nerve?
Palmar surface of the lateral 3 1/2 digits, and palm below
Finger tips on the dorsal surface of 3 1/2 digits
Which nerve roots does the musculocutaneous nerve originate from?
C5 - C7
