14.5- Spinal Nerves Flashcards
What are spinal fevers called after they split?
Rami
Posterior Ramus
Smaller of the two branches of spinal rami. Innervates the deep muscles of the back including the erector spinae and the transversospinalis.
Anterior Ramus
Larger of the two main branches of the rami.
Associated with the autonomic nervous system.
Dermatomes
Special segment of skin innervated by a single spinal nerve.
Referred visceral pain
When pain from an organ is mistakenly referred to a dermatome.
Nerve plexus
Name the four main plexuses.
Network of interweaving anterior rami. Cervical Brachial Lumbar Sacral
T1-T11- What are they called?
Intercostal nerves
Located in the intercostal space.
Subcostal nerve
T12
Intercostal nerves
Don’t form plexuses
Cervical plexus locations
Deep on the side of the neck, lateral to C1-C4. Made up of the anterior rami of C1-C4.
Phrenic Never
Important part of the cervical plexus.
Formed primarily from C4 but some of it from C3 and C5.
Innervates the thoracic diaphragm.
Brachial plexus
networks of nerves the supply the upper limbs.
Made of the anterior rami of C5-T1.
Extend laterally from the neck and pass superior to the first ribs and continue into the axilla.
Innervates the pectoral girdle and the entire upper imbecile of one side.
What are the pars of the brachial plexus from medial to lateral?
Rami, trunks, divisions, and cords.
Superior, middle, and inferior trunks
Where the cervical rami (C5-T1) meet to form the trunks.
C5-C6- Form superior trunk
C7- Middle trunk
C8 and T1- Inferior trunk.
How are the cords fate brachial plexus named?
With respect to the brachial artery.
What are the cords of the brachial plexuses names?
Posterior-C5-T1 posterior parts
Medial- C8-T1- Anterior division of inferior trunk
Lateral cords- C5-C7- Anterior division of the superior and middle trunks.
What are the five major terminal branches that emerge from the three cords?
Axillary nerve- Deltoid and teres minor muscles- Sensory info fro superolateral part of arm.
Median nerve- anterior forearm muscles, thenar, and lateral two lumbrical muscles- sensory info from palmar side of lateral 3.5 fingers.
Musculocutaneous nerve- Innervates the anterior arm muscles- sensory from the lateral surface of the forearm
Radial nerve- Innervates some of the anterior forearm muscles. Sensory from the posterior arm and forearm surface and dorsolateral side of hand.
Ulnar nerve- Innervates the anterior forearm muscles, most of intrinsic hand muscles- Sensory info from the dorsal and palmar portions of the medial 1.5 fingers.
Lumbar plexuses
Formed from L1-L4
Innervates inferior abdominal wall, anterior thigh, midial thigh, and skin of the medial leg.
Femoral nerve
Main nerve of the posterior lumbar plexus.
Innervates anterior thigh
Sensory from anterior and inferomedial thigh and medial aspect of the leg.
Obturator Nerve
Main nerve of the anterior lumbar plexus.
Innervate the medial thigh muscles
Sensory- superomedial skin of thigh
Sacral plexus
Anterior Rami of L4-S4.
Innervate and sense gluteal, pelvis, perineum, posterior thigh, and almost all of leg and foot.
Sciatic Nerve- what are its branches?
Forms portions of the anterior and posterior sacral plexus.
Tibial-
Common fibular
Tibial Neve
Anterior division of sciatic nerve.
Innervates hamstring and hamstring portion of abductor magnus.
Common Fibular nerve
Posterior portion of sciatic nerve
Innervates short head of biceps femoris
This splits into the deep fibular and superficial nerves.
