L5.2 Spinal nerves Flashcards
1
Q
What is the hierachy of the nerves
A
- (C5 - T1)
- Roots → trunk → cord → branches
2
Q
What are the anomalies of the brachial plexus?
A
- Prefix brachial plexus (C4-C8);
- Postfix brachial plexus (C6-T2)
3
Q
What are the 3 trunk division from the spinal roots?
A
- Superior trunk → C5+6
- Mid trunk → C7
- Inferior Trunk → C8+T1
- Each trunk has an ANT & POS division
4
Q
What are the 3 cord divisions?
A
- Lat cord → from ANT Sup & Mid trunk
- Med cord → from ANT Inf trunk
- Lat + Med cords form all ANT innervations
- Pos cord → From all POS trunks
- Supplies all POS compartment
- *Lat/Med/Pos all in relation to the axillary A*
5
Q
Musculocutaneous Nerve
A
- (C5-7)
- Branch of LAT cord
- Depleted motor supply at elbow → becomes the LAT cutaneous N of the forearm
- Landmarks:
- Pierces coracobrachialis → descends between biceps brachii & brachialis
6
Q
Ulnar Nerve
A
- (C8&T1)
- Branch of the MED cord
- Runs medially to brachial A
- Motor supply: Supplies hand (most) & forearm (FCU & med of FDP)
- Cutaneous supply: 1&1/2 MED digits (ANT & POS)
- Landmarks:
- Passes behind Med epicondyle → into Med forearm, covered by flexor carpi ulnaris, over flexor retinaculum → with ulnar A into palm of hand
7
Q
Median Nerve
A
- (C5-T1)
- From Med & Lat cords
- Motor supply: Forearm (most) & Palm (thenar muscles, LAT 2 lumbricals)
- Cutaneous supply: Lat 3 digits of palm (ANT), only LAT 3 nailbeds (POS)
- Palmar cutaneous branches given off before carpal tunnel → goes superior
- Not compressed
- Palmar cutaneous branches given off before carpal tunnel → goes superior
- Landmarks:
- Crosses, then lies medial to brachial A → enters ANT forearm → beneath FDS fibres → Gives off ANT interosseous N (innervates deep muscles) → through carpal tunnel
8
Q
Radial nerve
A
- (C5-T1)
- Branch of POS cord
- Motor supply: All POS
- Cutaneous supply: Dorsum of hand (not the nailbeds)
- Landmarks:
- Huge N, branches given off early, beneath Tmaj & Runs along spiral groove → Branch into POS interosseous N → under brachioradialis
9
Q
Axillary Nerve
A
- (C5-6)
- Branch of POS cord
- Motor supply: Deltoids, Tminor
- Cutaneous supply: Skin overlying deltoids
- Landmarks: Beneath subscarpularis → beneath Tminor & above Tmaj → divides into ANT & POS
- ∴ dislocation of shoulders → danger axillary N
10
Q
Summary of cutaneous nerve innervations
A
11
Q
UL Dermatomes
A
12
Q
UL myotomes
A
13
Q
Shoulders
Ab
Add
Flex/Ex
A
Ab - 5
Add - 6, 7, 8
Flex/ex - 5,6,7,8
14
Q
Elbows
Flex
Extend
A
Flex: 5,6
Ex: 7,8
15
Q
Forearm
Pronation
Supination
A
Pro: 7,8
Sup: 6
