Peripheral nerve innervation Flashcards
peripheral nerve lesion
Sensory &/or motor changes in a peripheral nerve distribution result
spinal nerves
31 pairs of spinal nerves:
each divides into a dorsal & ventral ramus
31 pairs of dorsal rami remain segmental
Dorsal rami:
innervate the skin & intrinsic muscles of the back
PLEXUS
an intricate network/web latin = to plait
cervical plexus:
C1-4 ventral rami
- phrenic nerve C3,4,5
brachial plexus:
C5-T1 ventral rami
located in between the base of the neck and the axilla. On its way to the axilla it passes between the clavicle and 1st rib. Its branches supply the majority of muscles that move the upper limb & pectoral girdle.
brachial plexus: RTDCB
Roots (5 - found at cervical Transverse processes )
Trunks (3) - between scalenes, superior, inferior, middle
Divisions (6) - trunk divides into anterior and posterior division. anterior divisions innervate anterior compartment - flxs and 3 posterior innervate posterior e.g extensors
Cords (3) - posterior cord (posterior structures), lateral cord, medial cord … named in reference to axillary artery
Branches - nerves, rami
SUPRACLAVICULAR branches of brachial plexus - Arise from roots and trunks
branches arise from the roots (2 nerves) and trunks (1 nerve) of the brachial plexus.
dorsal scapular - C5
Long thoracic nerve - C5,6,7
INFRACLAVICULAR branches of brachial plexus - Arise from trunks
Suprascapular - C5,6
Subclavian C5,6
INFRACLAVICULAR BRANCHES
Arise from cords • Lateral pectoral Upper subscapular C5,6 Thoracodorsal (Middle subscapular) C6,7,8 Lower subscapular C5,6 • Medial pectoral • Medial brachial cutaneous • Medial antebrachial cutaneous Axillary C5,6 Radial C5-C8 (T1) Musculocutaneous C5,6,7 Median C5-T1 Ulnar C8, T1
Axillary nerve
C5&6 Motor Deltoid and Teres minor Sensory Patch over deltoid • Quadrangular space = 1 bone, 3 muscles - could compromise axillary nerve and surgical head of humerus • Anatomical neck of humerus
Musculocutaneous nerve:
C5, 6, 7
- Continues as lateral cutaneous nerve of forearm
Median nerve
(C5) C6-T1
Ulnar nerve
C8-T1
Thoracic ventral rami
form intercostal nerves
Lumbar Plexus
(L1-L4, parts of T12): - exits the abdominopelvic cavity anteriorly
2 main branches exit pelvis anteriorly or medially
2 main branches:
1. Femoral nerve (L2-4)
travels under the inguinal ligament into the ‘femoral triangle’
2. Obturator nerve (L2-4
exits through obturator foramen
Sacral plexus:
(L4-L5, S1-S4): - exits the pelvic cavity posteriorly Superior gluteal nerve (Gmed & min, TFL) Inferior gluteal nerve (Gmax) Sciatic nerve 1. Tibial nerve (L4-S3) 2. Common Fibular nerve (L4-S2) 3. Deep fibular nerve 4. Superficial fibular nerve Pudendal nerve (supplies the perineum) S2,3,4
Lumbosacral trunk:
L4-L5
connects lumbar & sacral plexuses
Pudendal nerve
exits greater sciatic foramen and enters pelvic cavity to supply perineal cavity
Deep fibular nerve
Anterior leg compartment
Superficial fibular nerve
lateral leg compartment
BRACH. PLEXUS: Root - DORSAL SCAPULA NERVE
ROOT
arising from the C5 ventral rami, piercing middle scalene.
- Levator scap, rhomboids
BRACH. PLEXUS: Root - Long thoracic NERVE
Root
C5, 6 & 7 ventral rami and runs inferiorly over the serratus anterior.
serratus anterior
The superior trunk - brachial plex.
The superior trunk forms from the merging of the C5 & C6 ventral rami. Therefore, the suprascapular nerve carries C5 & C6 axons.
suprascapular nerve C5,6 - supra and infraspinatus
posterior cord
axillary radial upper subscap. lower subscap. thoracodorsal
lat cord
lateral pectoral
musculocutaneous
medial cord
medial pec.
med. brachial cutaneous (sensory only)
medial antebrachial cutaneous (sen. only)
Ulnar
medial and lat cord
Median nerve
