Brachial Plexus Flashcards
Pathway of musculocutaneous nerve
1. C5, C6, C7
- Superior and middle trunk
- Anterior division
- Lateral cord
- Pierces coracobrachialis
- Descends between biceps brachii & brachialis
- continues into the forearm as the lateral cutaneous Nerve
Motor innervation of musculocutaneous nerve?
Coracobrachialis, Biceps Brachii and Brachialis
Sensory Innervation of musculocutaneous nerve?
Anterior arm
Pathway of axillary nerve
- C5/C6
- superior trunk
- posterior division
- posterior cord
- quadrangular space
- surgical neck of humerus with posterior humeral circumflex vessels
Motor Innervation of axillary nerve?
Deltoid and Teres Minor
Sensory Innervation of axillary nerve?
Superior, lateral arm
Boundaries of quadrangular space?
Teres Minor, Teres Major, Humerus and Long head of triceps brachii
Pathway of radial nerve?
- C5-C8/T1
- posterior divisions of all 3 trunks
- posterior cord
- Passes from axilla to posterior compartment of arm through the triangular interval
- Winds around shaft of humerus together with deep radial artery in the radial groove between medial and lateral heads of triceps brachii
- Descends between brachialis and brachioradialis
- Passes anterior lateral epicondyle of humerus and divides into:
Superficial sensory branch
descends in posterolateral compartment of forearm deep to brachioradialis with radial artery
Posterior arm, posterior forearm, lateral dorsal 3.5 digits except fingertips
Deep motor branch (Posterior interosseous nerve) Penetrates supinator to travel to posterior compartment of forearm Posterior arm (triceps brachii + anconeus), posterolateral forearm (extensors)
Motor Innervation of radial nerve?
Posterior arm (triceps brachii + anconeus), posterolateral forearm (extensors)
Sensory Innervation of radial nerve?
Posterior arm, posterior forearm, lateral dorsal 3.5 digits except fingertips
Pathway of ulnar nerve?
- C8, T1
- lower trunk
- anterior division
- Medial cord
- Passes posteriorly through medial intermuscular septum -> descends superficially to medial head of triceps brachii -> medial epicondyle of humerus (posteriorly)
- Through cubital tunnel -> passes between two heads of FCU -> descend between FCU & FDP -> passes flexor retinaculum -> enters hand through Guyon’s (ulnar) canal
- Superficial branch immediately distal to pisiform and supplies Palmaris Brevis and medial 1.5 digits (palmar surface)
- Deep branch travels through pisohamate hiatus
- Emerges, travels across the palm, deep to FDS & FDP tendons. The deep branch supplies all intrinsic muscles of the hand EXCEPT the 3 thenar muscles and 1st & 2nd lumbricales.
Motor Innervation of Ulnar nerve?
Anterior forearm- FCU, ½ FDP
Hand- Intrinsic muscles of the hand including: palmaris brevis, lumbricals, hypothenar and interossei muscles
Sensory Innervation of ulnar nerve?
Skin of medial 1/3 of hand (Palmar and dorsal surface)
Pathway of the median nerve?
- C6-T1
- Superior, Middle, Inferior trunk
- Anterior division
- Lateral and medial cord
- Arises lateral to axillary artery, through anterior compartment of arm, between biceps brachii and brachialis, anterior to brachial artery
- Travels medial to brachial artery at the elbow into the forearm through the cubital fossa
- Descends between two heads of pronator teres: humeral and ulnar heads + gives rise to largest branch (Anterior Interosseous Nerve)
- Palmar cutaneous branch (runs superficial to flexor retinaculum)
- Recurrent branch innervates the 3 thenar muscles, and palmar digital nerves which innervate:the skin on the palmar side of digits
1-3 and the radial ½ of the 4th digit; the dorsal aspects of the same digits distal to the DIP joints; the 1st & 2nd lumbricales. - Travels into carpal tunnel together with 4 FDS, 4 FDP, FPL tendons to the hand
Motor Innervation of Median nerve?
Flexors of anterior forearm and intrinsic thenar muscles
