The cervical plexus is derived from what spinal roots?
C1 - C4
What nerve is a loop between C1,C2, and C3 and is the only spinal nerve loop?
What nerve is derived from C3, C4, and C5 (part of the brachial plexus) and what muscle does it innervate?
The Phrenic nerve; the Diaphragm
The cervical plexus innervates what portion of the head?
The posterior portion (back from about the ears)
Skin and superficial structures of the neck
What innervates (sensory) the part of the head the cervical plexus does not?
CN V (Trigeminal)
How many roots are in the Cervical Plexus?
4 (C1- C4)
How many trunks are in the cervical plexus?
None (the roots give rise directly to branches)
The brachial plexus is derived from what spinal roots?
C5, C6, C7, C8, and T1
How many roots are in the brachial plexus?
5 (C5 - T1)
How many trunks are in the brachial plexus?
3 (Upper, Middle, Lower)
How many anterior divisions are in the brachial plexus?
How many posterior divisions are in the brachial plexus?
How many cords are in the brachial plexus and how are they formed?
The Posterior cord is formed by the junction of all 3 posterior divisions
The Lateral cord is formed by the junction of the upper and middle anterior divisions
The Medial cord is formed from the lower anterior division
In the brachial plexus, what nerve(s) rise from the posterior cord?
In the brachial plexus, what nerve(s) rise from the lateral cord?
Median (half comes from here, half from the medial cord)
In the brachial plexus, what nerve(s) rise from the medial cord?
Median (half comes from here, half from the lateral cord)
In the brachial plexus, there is a major nerve that rises from 2 cords. It is the only major nerve that does this. Name the nerve and the 2 cords it rises from.
The Median nerve rises from the lateral and medial cords
What nerve arises from the roots of C5, C6, and C7?
The long thoracic nerve
What does the long thoracic nerve innervate and what does paralysis of this nerve cause?
The Serratus Anterior muscle; paralysis causes 'winging' of the scapula
How many roots are in the lumbosacral plexus?
9 (L1 - S4)
The sciatic nerve is the combination of what two nerves?
Common Fibular (or Peroneal)
Roots L4 - S3 give rise to what two major nerves?
Common Fibular and Tibial
If the common fibular and the tibial nerves arise from the same roots, what makes them different?
The Common Fibular arises from the anterior divisions and the Tibial arises from the posterior divisions
Roots L2 - L4 give rise to what two major nerves?
If the obturator and femoral nerves arise from the same roots, what makes them different?
The Obturator nerve arises from the posterior divisions and the Femoral nerve arises from the anterior divisions
T/F: The sciatic nerve is a combination of the peroneal nerve and the common fibular nerve.
False, the sciatic nerve is a combination of the tibial nerve and the common fibular nerve (peroneal = common fibular)
T/F: The obturator nerve and the tibial nerve both arise from the anterior divisions but from different roots.
False, the Obturator nerve and the Tibial nerve both arise from the posterior divisions but from different roots.
T/F: The femoral and obturator nerves arise from the same roots in the lumbosacal plexus.
T/F: Scapular winging is caused by paralysis of a nerve arising from C4, C5, C6, and C7 called the long thoracic nerve.
False, C4 is not a root of this nerve
Why are the thoracic nerve roots not involved in plexuses?
a. They innervate the viscera of the thorax
b. They form the intercostal nerves
c. They directly innervate muscles of the back
d. They form the ganglia of the sympathetic nervous system
e. They form the ganglia of the parasympathetic nervous system
B and D
If I lose feeling in the skin along my jawline, then I know there is a problem with:
T/F: Roots of the cervical plexus give rise directly to branches (no trunks, divisions, or cords).
T/F: Roots of the lumbosacral plexus give rise directly to branches (no trunks, divisions, or cords).
False, there are anterior and posterior divisions in the lumbosacral plexus, but no trunks or cords
T/F: Trunks and cords are only found in the brachial plexus.
T/F: Unlike the ulnar and musculocutaneous nerves, the median nerve arises from all three cords in the brachial plexus, not just one or two.
The median nerve arises from the lateral and medial cords (the anterior division).
The ulnar arises only from the medial cord.
The musculocutaneous arises from the lateral cord.
The radial and axillary nerves rise from the posterior cord.
Muscle innervations and plexuses
A list of muscles and their innervations plus a breakdown of the nerve plexuses