Sacra Plexus - Part 2 Flashcards
The perforating cutaneous nerve contains fibers from?
S2 and S3
Why is the perforating cutaneous nerve so named?
Because it travels through the sacrotuberous ligament
The perforating cutaneous nerve ultimately reaches what area?
Lower medial aspect of the buttocks
The perforating cutaneous nerve may be formed alternately by what? Or it could be _____.
A branch off the pudendal nerve
absent
The posterior cutaneous nerve of the thigh is formed by what?
Anterior division - S2 and S3
Posterior division - S1 and S2
The posterior cutaneous nerve of the thigh leaves the pelvis via what?
Greater sciatic foramen
How does the posterior cutaneous nerve of the thigh descend?
Posterior thigh and inferior to the leg
The posterior cutaneous nerve of the thigh will ultimately communicate with which nerve?
sural nerve
What does the posterior cutaneous nerve supplies?
Skin on the posterior and medial thigh
What is the largest nerve in the human body?
The sciatic nerve
How large is the sciatic nerve usually?
2cm
The sciatic nerve is a combination of what two nerves?
Tibial nerve
Common fibular nerve
Which is more laterally located? Tibial or common fibula?
common fibular nerve
Which is more medically located? Tibial or common fibula?
Tibial nerve
The tibial nerve is from what?
The anterior divisions of L4-S3
The common fibular nerve is formed from what?
Posterior divisions of L4-S2
The sciatic nerve leaves the pelvis through what?
Greater sciatic foramen
What is different about the sciatic nerve in the pelvis and as it leaves the greater sciatic foremen?
Enclosed in a common sheath
The sciatic nerve is below what muscle?
piriformis
After the sciatic nerve leaves the pelvis it continues to travel inferior on the _______?
Posterior aspect of the adductor magnus
What can cause sciatica?
Piriformis syndrome
When does the sciatic nerve split into the common fibula and tibial nerve?
Usually about 2/3 of the way to the knee, but variable
The common fibula nerve is composed of fibers from what?
L4-S2
The common fibular nerve gives off branches to what muscle in the thigh?
Biceps femoris (short head)
When does the common fibular nerve give off branches to the biceps femoris (short head) in the thigh?
Before separating from the tibial nerve fibers
After separating from the tibial nerve, the common fibular nerve courses around the ____ aspect of what?
Lateral
fibula
The common fibula nerve gives off what type of branch and to where?
Articular
knee joint
What part of the leg doe the common fibular nerve reach when it gives off the articular branch to the knee joint?
antero-lateral aspect of the leg
When are two sensory branches given off by the common fibular nerve?
As the nerve courses along the lateral aspect of the popliteal fossa
What are the names of the two sensory branches of the common fibular nerve?
Lateral sural branch
Fibular communicating branch
The lateral sural branch supplies what area?
Skin on lateral aspect of leg
The fibular communicating branch combines with which nerve?
Medial sural cutaneous nerve
After the fibula communicating branch combines with the medial sural cutaneous nerve, it forms/becomes what nerve?
Sural nerve
The medial sural cutaneous nerve is from which nerve?
Tibial nerve
The common fibula nerve then divides what two nerves?
Superficial fibular nerve
Deep fibular nerve
The superficial fibular nerve travels inferior between what? All the way down to where?
fibularis longus
Fibula
dorsum of the foot
The superficial fibula nerve supplies what two muscles?
Fibularis longus
Fibularis brevis
The superficial fibular nerve divides into what?
Medial dorsal cutaneous nerve
Intermediate dorsal cutaneous nerve
The medial and intermediate dorsal cutaneous nerves supply what area together?
Dorsum of the foot EXCEPT the skin between the first two toes.
The deep fibular nerve runs inferiorly along what?
tibialis anterior
The deep fibular nerve supplies what basically?
Extension muscles of foot and toes
The deep fibular nerve supplies what muscles specifically? (6)
Tibialis anterior
Extension digitorum longus and brevis
Extension hallucis longus and brevis
Fibularis tertius
The terminal branch of the deep fibular nerve supplies what area a skin?
Skin between first two toes
What is a clinical consideration for the superficial and deep fibular nerves?
Steppage gait
What is stoppage gait?
Foot drop, causing a high stepping
What supplies the anterior compartment of leg?
Deep fibular nerve
What supplies the lateral compartment of the leg?
Superficial fibular nerve
Does the tibial nerve supply ALL plantar flexors?
NO, because the fibularis longus and brevis (weak) are common fibular nerve
The tibial nerve is made up of fibers from?
L4-S3
While still combine with the common fibular nerve, the tibial nerve fibers are sent to these muscles? (4)
Biceps femoris (long head)
semitendinosus
semimembranosus
Adductor Magnus (last 3 quads)
Where does the tibial nerve give of articular, muscular, and popliteal branches?
Popliteal fossa
The articular branches of the tibial nerve supply what?
Knee joint
The muscular branches of the tibial nerve given off in the popliteal fosse supply what muscles? (4)
popliteus
Gastrocnemius
Soles
plantaris
The popliteal branch of the tibial nerve gives rise to what nerve?
interosseous nerve of the leg
The interosseous nerve of the leg travels inferiorly along what?
The interosseous membrane
The interosseous nerve carries sensory information from where?
Tibial periosteum
Ankle
tibiofibular joints
In the leg, the tibial nerve gives rise to what?
Muscular and sensory (medial calcaneal branches) branches
The muscular branches given off by the tibial nerve in the leg supply what muscles?
Flexor digitorum longus
Flexor hallucis longus
Tibialis posterior
The sensory branches given off in the leg by the tibial nerve are called what?
Medial calcaneal branches
The medial calcaneal branches supply what?
Skin over the medial heel
The tibial nerve after traveling inferior in leg travels around what?
Medial malleolus
The tibial nerve travels around the medial malleolus to what?
Plantar surface of the foot
Once the tibial nerve reaches the plantar surface of the foot, it divides into two terminal branches called?
Medial plantar nerve
Lateral plantar nerve
The medial plantar nerve sends motor fibers to what muscles?
Abductor hallucis
Flexor digitorum brevis
Flexor hallucis brevis
The medial plantar nerve divides into what?
Common plantar digital nerves
The common plantar digital nerves are motor supply to what?
lumbricals 1 and 2
The common plantar digital nerves are sensory supply to what?
Skin between the toes
The skin between the toes sensory supply is by way of what nerves?
Proper plantar digital nerves
The lateral plantar nerve divides into what?
Superficial and deep branches
The superficial branch supplies what?
Skin around the 5th digit (baby toe)
The deep branch supplies motor fibers to what? (6)
Adductor hallucis Flexor digiti minimi brevis Abductor digiti Minami Quadratus plantar Lateral lumbricals interossei muscles
What are some clinical considerations with the tibial nerve?
Flexor paralysis
Hammer toes***
claw foot
What is claw foot and hand?
Extension of proximal joints
Flexion of DIP and PIP joints
The coccygeal plexus if formed by what?
The anterior primary ram of S4, S5, Co1 nerves
The nerves of the coccygeal plexus combine to form what?
anococcygeal nerves
The anococcygeal nerves supply what?
Sensory info from the skin adjacent to the coccyx and angus.