Nerves: Sacral Plexus

Front 1

Superior Gluteal

Back 1

B.F.: L4-S1

M.S.: Gluteus Medius/Minimus, & TFL

C.B.: None

Location:

-E. from dorsal divisions of L4-S1

-Leaves pelvis through greater sciatic foramen(GSF) above pirifomis

-Ends in the TFL and Glute Min

Front 2

Inferior Gluteal

Back 2

B.F.: L5-S2

M.S.: Glute Max

C.B.: None

Location:

-E. from dorsal branches of ventral rami of

L5-S2

-Leaves pelvis through GSF runs underneath piriformis(is superior to sciatic nerve)

Front 3

Posterior Cutaneous Femoral

Back 3

B.F.: S1-3

M.S.: N/A

C.B.:

-Inferior Clunial Nerves

--Innervates skin covering lower/lateral part glute max

-Perineal Branches

--Inn/ skin at upper/medial side of thigh

Location:

-E. dorsal divisions of S1-2 & ventral divisions of S2-3 nerve roots.

-Enters pelvis through GSF below piriformis

-Descends beneath Glute Max, runs down back of thigh, beneath fascia lata, over long head of biceps femoris to back of knee

-Pierces deep fascia and communicates with sural nerve

Front 4

Sciatic

Back 4

B.F.: L4-S3

M.S.: Semitendinosus, Semimembranosus, Biceps femoris(Long/Short Head), Adductor Magnus

-All innervated through the Tibial Branch with exception being made for B.F. short head(Fibular Branch)

C.B.:(Explained in later flash cards)

Location:

-E. from L4-S3, combine, form one nerve that passes under the piriformis, through GSF to exit pelvis

-Travels down post. thigh to popliteal fossa in the posterior compartment of the thigh behind Add. Magnus.

-Is itself in front of one head of biceps femoris.

Front 5

Common Fibular(CF)

Back 5

B.F.: L4-S2

M.S.: Several through it's two main branches(explained in two following cards)

C.B.:

-Lateral Sural Cutaneous

--Supplies skin on post & at. surface of lower leg(Top half of peroneal area)

-Communicating Fibular Nerve

--Gives rise to the Sural nerve

Location:

-Descends obliquely along the popliteal fossa to fibula head

--Lies between Biceps fem. tendon & lat gastroc head

-Palpable where it winds around fib head

--Between Peroneus longus and fibula

---Divides beneath P. longus into it's two branches

Front 6

Superficial Fibular

Back 6

B.F.: Same as CF

M.S.: Peroneous Longus/Brevis

C.B.:

-Medial Dorsal Cutaneous

--Two Branches

---One supplies medial side of big toe

---Other supplies adjacent side of 2nd & 3rd toes.

---Also supplies skin of medial side of foot/ankle

---Communicates with saphenous & deep peroneal nerve

-Intermediate Dorsal Cutaneous

--Supplies contiguous sides of 3rd & 4th, and of 4th & 5th toes

--Supplies skin of lateral foot/ankle

--Communicates w/ sural nerve

--Shared w/ it's sister branch(Deep Peroneal)

Location:

-Passes forward btwn. peroneal muscles & Ext. Dig. Longus

-Pierces deep fascia @ lower 1/3 of leg.

-Then divides into it's 2 cutaneous branches

Front 7

Deep Fibular

Back 7

B.F.: Same as CF

M.S.: Ant. Tib, Ext. Dig. Longus/Brevis, Ext. Hallucis Longus/Brevis, Peroneus Tertius

C.B.:

-Lateral Cutaneous Nerve of big toe & Intermediate dorsal cutaneous

--Supply adjacent sides of 1st & 2nd toe

Location:

-Begins @ bifurcation(seperation) of common nerve @ fib head

-Passes inferomedially, deep to Ext. Dig. Longus=>ant. surface of interosseous membrane.

-Comes into relation with ant tib artery above middle of leg

-Descends with artery to front of ankle, then divides into lateral & medial terminal branch.

Front 8

Tibial

Back 8

B.F.: L4-S3

M.S.: Triceps Surae, Plantaris, Popliteus, Post. Tib, Flex, Dig, Longus, Flex Hal. Longus

C.B.:

-Medial Sural Cutaneous

--Combines w/ anastomotic ramus to form Sural nerve

-Lateral Calcaneal Branch of Sural Nerve

--Provides sensory Info to most lateral aspect of skin of heel

-Medial Calcaneal Branch

--Supply skin of heel and medial side of sole of foot

-Lateral Dorsal Cutaneous Branch

--Turns into Dorsal Digital Nerve, supplies lateral side of 5th toe

Location:

-Branch of Sciatic(much like Fibular Nerve)

-Passes below popliteal fossa(PF) to pass below arch of soleus.

--In PF it give off branches to triceps surae, plantaris & politeus, an articular branch to the knee joint, and a cutaneous branch that will become the sural nerve

-Below soleus nerve lies close to tibia, where it supplies the post tib & Flex. Dig./Hal. Longus.

-Then passes into foot, running post to medial malleolus

-Is bound by flexor retinaculum in company w/ post. tib. artery

Front 9

Medial Plantar

Back 9

B.F.: Tibial Nerve

M.S.: Abductor Hal., Flex. Dig. Bre., Flex Hal. Brevis(Medial Head), Lumbrical(1st & 2nd)

C.B.:

-Proper Digital Plantar

--Supplies medial side of Great Toe

Location:

-Originates under laciniate ligament

-Passes under cover of Abd. Hal.

-Appears between Abd. Hal. & Flex. Dig. Brevis, gives off Proper Digital Plantar Nerve.

-Then divides opposite bass of metatarsals into 3 common digital nerves

Front 10

Lateral Plantar

Back 10

B.F.: Tibial Nerve

M.S.: Flex Hal. Brevis(Lat. Head), Quadratus plantae, Abd. Digiti Minimi, Flex Digiti Minimi, Lumbrical(3rd & 4th), Plantar Interossei(1st-3rd), Dorsal Interossei(1st-5th), Add. Hal

C.B.:

-Proper Digital Plantar

--Supplies skin of 5th toe & lateral half of 4th toe.

---Similar to Ulnar Nerve in hand

Location:

-Passes obliquely forward with lat. plantar artery=>lat. side of foot, btwn Flex. Dig. Brevis & Quadratus plantae

-In interval btwn. former muscle & Abd. Dig Minimi, divides into superficial & deep branch

Front 11

Sural(Sensory Nerve)

Back 11

B.F.: Collateral Branches of Tibial and Common Fib. nerve(L4-S3)

M.S.: N/A

C.B.:

-Transmits sensory signals from the post. lat. corner of the leg, lat. foot & 5th toe towards the spinal cord and brain

Location:

-Medial & Lateral cutaneous branches, which branch form tibial and fibular nerves, form it.

-Two branches are connected by Sural Communicating nerve & form the Sural Nerve

-The exact location of this connection differs from person to person

Front 12

Pudendal(Pudendal Plexus)

Back 12

B.F.: S2-S4

M.S.: Muscles of Pelvic Floor =

-Levator Ani, Superficial Transverse Perineal, Deep Transverse Perineal, Bulbospongiosus, Ischiocavernosus, Sphinter anus externus, Urethral Sphincter.

C.B.:

-Inferior rectal(anal) nerves

--Supply below pectinate line/ external anal sphincter.

-Perineal Nerve

--Supplies perineum

-Posterior Scrotal(male)/Labial(female)

--Supplies skin of scrotum or labia

--Communicate with the perineal branch of Post. Fem. Cut. nerve

-Dorsal Penis/Clitoris Nerve

--Deepest terminal branch of pudendal nerve

--Supplies skin of penis or clitoris depending on gender

Location:

-Passes btwn piriformis & coccygeus muscles, leaves pelvis thru lower part of greater sciatic foramen

-Crosses over lat. part of sacrospinous ligament and reenters the pelvis through lesser sciatic foramen

-Then accompanies internal pudendal artery/internal pudendal vein upwards/forwards along lat. wall of ischiorectal fossa.

--Contained in sheath of obturator fascia termed pudendal canal.

-Inside pudendal canal divides into cutaneous branches explained above.

Front 13

Coccygeal

Back 13

B.F.: S5-Co1

M.S.: Coccygeus

C.B.:

-Anococcygeal

--Supplies skin over the coccyx

-Dorsal Branches

--Explained above

Location:

-Near the coccyx bone...