Peripheral Nervous System Flashcards
Components of the PNS
- Cranial Nerves
- Spinal Nerves
- Autonomic Nervous System (Sympathetic and Parasympathetic)
- Enteric
Spinal Nerve System
- Segmental Dorsal Rami – deep axial muscles/posterior skin along spinal column
- Segmental Ventral Rami – limbs and body wall
– Cervical Plexus
– Brachial Plexus
– Intercostal nerves
– Lumbosacral Plexus
Segmental Dorsi Rami
Some have names, some don’t
Subocciptal Nerve (C1)
Greater Occipital Nerve (C2)
Third Occipital Nerve (C3)
C4 – T12 Dorsal Rami
L1-L3 Superior Cluneal Nerves
L4, L5 Dorsal Rami
S1-S3 Middle Cluneal Nerves
S4 – Cx2 Dorsal Rami
- primarily innervate posterior skin and deep spine muscles, and facet joints
C1- intervation may present as: Cranial facial pain, headaches
How to identify type of vertebrae
- Angle of the capsule of the articular process
- Look at the nerves in the spinal cord
Dorsal: Nerve goes to facet joint and muscle (multifidus) in image
Cervical Plexus
- C1 – C5
- Ansa Cervicalis (C1 – C3)
- Cutaneous Nerves (C2 – C4)
- Phrenic Nerve (C3-C5); Diaphram
Specific twigs that send little twigs out to muscles
Ansa Cervicalis: thyroid muscles
Brachial Plexus
C5-T1
RTDCB - MARMU
Splits into 3 anterior and 3 posterior division
Anterior Dividion of BP will innervate
Developmentally Ventral Structures
Posterior Division of BP will innervate
Developmentally Dorsal Structures
The three cords are names based off position to Axillary A.
The Divisions Join to form Three Cords – named for relation to axillary artery – lateral, posterior, medial
Lateral Cord
From Anterior Divisions (to ventral structures, mostly flexors!)
Lateral Pectoral Nerve (C5-C8)
Musculocutaneous Nerve (C5-C7)
Lateral Root to the Median Nerve (C6 & C7)
Median Nerve C6-T1
Medial Cord
From Anterior Divisions (also to ventral structures, mostly flexors)
Medial Pectoral Nerve (C7 – T1)
Medial Brachial Cutaneous Nerve (C8 & T1)
Medial Antebrachial Cutaneous Nerve (C8 & T1)
Medial Root to the Median Nerve (C8 & T1)
Ulnar Nerve (C8 & T1)
Median Nerve C6-T1
Posterior Cord
From Posterior Divisions (to dorsal structures, mostly extensors)
Upper Subscapular Nerve (C5 & C6)
Thoracodorsal Nerve (C6, C7 & C8)
Lower Subscapular Nerve (C5 & C6)
Axillary Nerve (C5 & C6)
Radial Nerve (C5, C6, C7 & C8)
Injuries above the plexus
Dermatome/Myotome Charts
Injuries below, use
peripheral distribution charts
Injury occuring in the middle of the plexus present as
random; individual situation
Upper Arm Compartmentalization - Anterior Arm
Flexes Shoulder and Elbow
Anterior Divisions
Musculocutaneous Nerve
C5, C6, C7
Upper Arm Compartmentalization - Posterior Arm
Extends Elbow
Posterior Divisions
Radial Nerve
C7 & C8
UA Compart - Anterior Forearm
Flexes Wrist and Fingers
Anterior Divisions
Median Nerve (Mostly)
C6, C7 & C8