which provides motor and sensory nerves for the posterior thigh, most of the lower leg, the entire foot, and part of the
. It is part of the
The nerves forming the sacral plexus converge toward the lower part of the greater sciatic foramen, and unite to form a flattened band, from the anterior and posterior surfaces of which several branches arise.
; these two nerves sometimes arise separately from the plexus, and in all cases their independence can be shown by dissection.
. The
The sacral plexus lies on the back of the pelvis between the piriformis muscle and the
. In front of it are the
. The
All the nerves entering the plexus, with the exception of the third sacral, split into ventral and dorsal divisions, and the nerves arising from these are as follows of the table below:
Nerves of the sacral plexus
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! Nerve !! Segment !! Innervated muscles !! Cutaneous branches>
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| Superior gluteal
| L4-S1
| Gluteus mediusThe gluteus medius , one of the three gluteal muscles, is a broad, thick, radiating muscle, situated on the outer surface of the pelvis....
Gluteus minimusThe gluteus minimus , the smallest of the three gluteal muscles, is situated immediately beneath the gluteus medius.-Origin and insertion:...
Tensor fascia latae
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|
| Inferior glutealThe inferior gluteal nerve is a nerve in the pelvis that innervates the gluteus maximus muscle.-Structure:The inferior gluteal nerve originates in the sacral plexus...
| L5-S2
| Gluteus maximusThe gluteus maximus is the largest and most superficial of the three gluteal muscles...
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|
| Posterior cutaneous femoralThe posterior cutaneous nerve of the thigh provides innervation to the skin of the posterior surface of the thigh and leg, as well as to the skin of the perineum.-Structure:...
| S1-S3
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|
Posterior cutaneous femoral
- • Inferior cluneal nerves
The inferior clunial nerves innervate the skin of the lower part of the buttocks. They arise as branches of the posterior cutaneous nerve of the thigh....
- • Perineal branches
The perineal branches of the posterior femoral cutaneous nerve are distributed to the skin at the upper and medial side of the thigh.One long perineal branch, inferior pudendal , curves forward below and in front of the ischial tuberosity, pierces the fascia lata, and runs forward beneath the...
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| colspan="4" | Direct branches from plexus>
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- • Piriformis
| S1-2
| PiriformisThe piriformis is a muscle in the gluteal region of the lower limb. It was first named by Spigelius, a professor from the University of Padua in the 16th century.- Origin and insertion :...
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|
|
- • Obturator internus
The nerve to obturator internus is a nerve that innervates the obturator internus and gemellus superior muscles.-Course:The nerve to obturator internus originates in the sacral plexus...
| L5-S2
| Obturator internusThe obturator internus muscle originates on the medial surface of the obturator membrane, the ischium near the membrane, and the rim of the pubis.It exits the pelvic cavity through the lesser sciatic foramen....
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|
|
- • Quadratus femoris
The nerve to quadratus femoris is a nerve that provides innervation to the quadratus femoris and gemellus inferior muscles.-Course:The nerve to quadratus femoris is a sacral plexus nerve...
| L4-S1
| Quadratus femorisThe quadratus femoris is a flat, quadrilateral skeletal muscle. Located on the posterior side of the hip joint, it is a strong external rotator and adductor of the thigh, but also acts to stabilize the femoral head in the Acetabulum.- Course :...
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| Sciatic |
|
| SciaticThe sciatic nerve is a large nerve fiber in humans and other animals. It begins in the lower back and runs through the buttock and down the lower limb...
| L4-S3
| SemitendinosusThe semitendinosus is a muscle in the back of the thigh; it is one of the hamstrings.-Structure:The semitendinosus, remarkable for the great length of its tendon of insertion, is situated at the posterior and medial aspect of the thigh ....
(Tib)
SemimembranosusThe semimembranosus is a muscle in the back of the thigh. It is the most medial of the three hamstring muscles.-Structure:The semimembranosus, so called from its membranous tendon of origin, is situated at the back and medial side of the thigh....
(Tib)
Biceps femorisThe biceps femoris is a muscle of the posterior thigh. As its name implies, it has two parts, one of which forms part of the hamstrings muscle group.-Origin and insertion:It has two heads of origin;...
- • Long head (Tib)
- • Short head (Fib)
Adductor magnusThe adductor magnus is a large triangular muscle, situated on the medial side of the thigh.It consists of two parts. The portion which arises from the ischiopubic ramus is called the "adductor portion", and the portion arising from the tuberosity of the ischium is called the "hamstring portion"...
(medial part, Tib)
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|
| Common fibularThe common fibular nerve , about one-half the size of the tibial nerve, is derived from the dorsal branches of the fourth and fifth lumbar and the first and second sacral nerves.It descends obliquely along the lateral side of the popliteal fossa to the head of the fibula,...
| L4-S3
|
| Lateral sural cutaneousThe lateral sural cutaneous nerve supplies the skin on the posterior and lateral surfaces of the leg. The lateral sural cutaneous nerve originates from the Common fibular nerve.One branch, the peroneal anastomotic The lateral sural cutaneous nerve (lateral cutaneous branch) supplies the skin on...
Communicating fibularThe sural communicating branch of common fibular nerve is a nerve which gives rise to the sural nerve.It is absent 20% of the time....
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|
|
- • Superficial fibular
The superficial fibular nerve innervates the fibularis longus and fibularis brevis muscles and the skin over the greater part of the dorsum of the foot .It passes forward between the fibularis muscles and the extensor digitorum longus, pierces the deep...
|
| Peroneus longus
Peroneus brevis
| Medial dorsal cutaneousThe medial dorsal cutaneous nerve passes in front of the ankle-joint, and divides into two dorsal digital branches, one of which supplies the medial side of the great toe, the other, the adjacent side of the second and third toes.It also supplies the integument of the medial side of the foot and...
Intermediate dorsal cutaneousThe intermediate dorsal cutaneous nerve , the smaller, passes along the lateral part of the dorsum of the foot, and divides into dorsal digital branches, which supply the contiguous sides of the third and fourth, and of the fourth and fifth toes.It also supplies the skin of the lateral side of the...
>
|
|
- • Deep fibular
The deep fibular nerve begins at the bifurcation of the common fibular nerve, between the fibula and upper part of the fibularis longus, passes infero-medially, deep to extensor digitorum longus, to the anterior surface of the interosseous membrane, and comes into relation with the anterior...
|
| Tibialis anteriorIn human anatomy, the tibialis anterior is a muscle that originates in the upper two-thirds of the lateral surface of the tibia and inserts into the medial cuneiform and first metatarsal bones of the foot. Its acts to dorsiflex and invert the foot. This muscle is mostly located near the shin.It is...
Extensor digitorum longusThe Extensor digitorum longus is a pennate muscle, situated at the lateral part of the front of the leg.-Origin and insertion:It arises from the lateral condyle of the tibia; from the upper three-fourths of the anterior surface of the body of the fibula; from the upper part of the interosseous...
Extensor digitorum brevisThe extensor digitorum brevis muscle is a muscle on the upper surface of the foot that helps extend digits 2 through 4.-Structure:...
Extensor hallucis longusThe Extensor hallucis longus is a thin muscle, situated between the Tibialis anterior and the Extensor digitorum longus that functions to extend the big toe, dorsiflex the foot, and assists with foot inversion....
Extensor hallucis brevisThe extensor hallucis brevis is a muscle on the top of the foot that helps to extend the big toe.-Structure:The extensor hallucis brevis is essentially the medial part of the extensor digitorum brevis muscle...
Peroneus tertius
| Lateral cutaneous nerve of big toeThe medial terminal branch accompanies the dorsalis pedis artery along the dorsum of the foot, and, at the first interosseous space, divides into two dorsal digital nerves The medial terminal branch (internal branch) accompanies the dorsalis pedis artery along the dorsum of the foot, and, at the...
Intermediate dorsal cutaneousThe intermediate dorsal cutaneous nerve , the smaller, passes along the lateral part of the dorsum of the foot, and divides into dorsal digital branches, which supply the contiguous sides of the third and fourth, and of the fourth and fifth toes.It also supplies the skin of the lateral side of the...
>
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| Tibial nerveThe tibial nerve is a branch of the sciatic nerve. The tibial nerve passes through the popliteal fossa to pass below the arch of soleus.In the popliteal fossa the nerve gives off branches to gastrocnemius, popliteus, soleus and plantaris muscles, an articular branch to the knee joint, and a...
| L4-S2
| Triceps suraeThe triceps surae is a pair of muscles located at the calf - the gastrocnemius and the soleus...
PlantarisPlantaris is a vestigial structure and one of the superficial muscles of the posterior crural compartment of the leg.It is innervated by the tibial nerve ....
PopliteusThe popliteus muscle in the leg is used to unlock the knee during walking/running by laterally rotating the femur on the tibia during a closed chain movement ....
Tibialis posteriorThe Tibialis posterior is the most central of all the leg muscles, and is located in the posterior compartment of the leg.It is the key stabilizing muscle of the lower leg....
Flexor digitorum longusThe Flexor digitorum longus is situated on the tibial side of the leg. At its origin it is thin and pointed, but it gradually increases in size as it descends...
Flexor hallucis longusThe Flexor hallucis longus muscle is a muscle of the leg.It is one of the deep muscles of the posterior compartment of the leg. The other deep muscles of the leg are flexor digitorum longus and tibialis posterior. Tibialis posterior is most powerful of these deep muscles.The Flexor hallucis...
| Medial sural cutaneousThe medial sural cutaneous nerve originates from the tibial nerve of the sciatic, descends between the two heads of the Gastrocnemius, and, about the middle of the back of the leg, pierces the deep fascia, and unites with the anastomotic ramus of the common peroneal to form the sural nerve....
Lateral calcaneal
Medial calcanealThe medial calcaneal branches of the tibial nerve perforate the laciniate ligament, and supply the skin of the heel and medial side of the sole of the foot.-See also:* Cutaneous innervation of the lower limbs...
Lateral dorsal cutaneousThe lateral dorsal cutaneous nerve is a cutaneous branch of the foot. The turns into a dorsal digital nerve and supplies the lateral side of the fifth toe....
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- • Medial plantar
The medial plantar nerve , the larger of the two terminal divisions of the tibial nerve, accompanies the medial plantar artery....
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| Abductor hallucisThe Abductor hallucis lies along the medial border of the foot and covers the origins of the plantar vessels and nerves.It arises from the medial process of the tuberosity of the calcaneus, from the laciniate ligament, from the plantar aponeurosis, and from the intermuscular septum between it and...
Flexor digitorum brevisThe flexor digitorum brevis lies in the middle of the sole of the foot, immediately above the central part of the plantar aponeurosis, with which it is firmly united....
Flexor hallucis brevisThe Flexor hallucis brevis arises, by a pointed tendinous process, from the medial part of the under surface of the cuboid bone, from the contiguous portion of the third cuneiform, and from the prolongation of the tendon of the Tibialis posterior which is attached to that bone.It divides in front...
(medial head)
LumbricalThe lumbricals are four small skeletal muscles, accessory to the tendons of the flexor digitorum longus and numbered from the medial side of the foot; they arise from these tendons, as far back as their angles of division, each springing from two tendons, except the first.The muscles end in...
(first and second)
| Proper digital plantarThe proper plantar digital nerves of medial plantar nerve are nerves of the foot. They primarily arise from the medial plantar nerve's superficial and deep branches. The superficial branch of the medial plantar nerve turns into a proper digital nerve and is responsible for supplies the medial...
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|
- • Lateral plantar
The lateral plantar nerve is a branch of the tibial nerve, in turn a branch of the sciatic nerve and supplies the skin of the fifth toe and lateral half of the fourth, as well as most of the deep muscles, its distribution being similar to that of the ulnar nerve in the hand.It passes obliquely...
|
| Flexor hallucis brevisThe Flexor hallucis brevis arises, by a pointed tendinous process, from the medial part of the under surface of the cuboid bone, from the contiguous portion of the third cuneiform, and from the prolongation of the tendon of the Tibialis posterior which is attached to that bone.It divides in front...
(lateral head)
Quadratus plantaeThe Quadratus plantæ is separated from the muscles of the first layer by the lateral plantar vessels and nerve. It acts to aid in flexing the 2nd to 5th toes and is one of the few muscles in the foot with no homolog in the hand.It arises by two heads, which are separated from each other by the long...
Abductor digiti minimiThe Abductor digiti minimi is a muscle which lies along the lateral border of the foot, and is in relation by its medial margin with the lateral plantar vessels and nerves....
Flexor digiti minimi
LumbricalThe lumbricals are four small skeletal muscles, accessory to the tendons of the flexor digitorum longus and numbered from the medial side of the foot; they arise from these tendons, as far back as their angles of division, each springing from two tendons, except the first.The muscles end in...
(third and fourth)
Plantar interosseiThe plantar interossei, three in number, lie beneath rather than between the metatarsal bones, and each is connected with but one metatarsal bone....
(first to third)
Dorsal interossei (first to fifth)
Adductor hallucisThe Adductor hallucis arises by two heads—oblique and transverse and is responsible for adducting the big toe...
| Proper plantar digitalThe proper plantar digital nerves of lateral plantar nerve are nerves of the foot that arise from the superficial branch of the lateral plantar nerve...
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|
! colspan="4" | Pudendal and coccygeal>
|
| PudendalThe pudendal nerve is a sensory and somatic nerve in the pelvic region which is a large branch of the sacral plexus that innervates the external genitalia of both sexes, as well as sphincters for the bladder and the rectum...
(Pudendal plexus)
| S2-S4
| Muscles of the pelvic floorThe pelvic floor or pelvic diaphragm is composed of muscle fibers of the levator ani, the coccygeus, and associated connective tissue which span the area underneath the pelvis. The pelvic diaphragm is a muscular partition formed by the levatores ani and coccygei, with which may be included the...
:
Levator aniThe levator ani is a broad, thin muscle, situated on the side of the pelvis.It is attached to the inner surface of the side of the lesser pelvis, and unites with its fellow of the opposite side to form the greater part of the floor of the pelvic cavity....
Superficial transverse perineal
Deep transverse perineal
BulbospongiosusBulbospongiosus is one of the superficial muscles of the perineum. It has a slightly different origin, insertion and function in males and females. In males, it covers the bulb of the penis...
IschiocavernosusThe ischiocavernosus muscle is a muscle just below the surface of the perineum, present in both men and women.-Function:It helps flex the anus, and stabilize the erect penis or tense the vagina during orgasm...
Shpincter anus externusThe Sphincter ani externus is a flat plane of muscular fibers, elliptical in shape and intimately adherent to the integument surrounding the margin of the anus.-Anatomy:...
Urethral sphincterThe term urethral sphincter refers to one of two muscles used to control the exit of urine in the urinary bladder through the urethra. The two muscles are the external urethral sphincter and the internal urethral sphincter...
| Inferior rectalThe Inferior rectal nerves usually branch from the pudendal nerve but occasionally arises directly from the sacral plexus; they cross the ischiorectal fossa along with the inferior hemorrhoidal vessels, toward the anal canal and the lower end of the rectum, and is distributed to the Sphincter ani...
PerinealThe perineal nerve is a nerve arising from the pudendal nerve that supplies the perineum.-Structure:The perineal nerve is the inferior and larger of the two terminal branches of the pudendal nerve, is situated below the internal pudendal artery....
- • Posterior scrotal
The posterior scrotal branches or ""posterior labial branches"" are two in number, medial and lateral. They are branches of the perineal nerve, which is itself is a branch of the pudendal nerve...
/labialThe posterior labial nerves are branches of the pudendal nerve.The counterparts in males are the posterior scrotal nerves.-External links: - "The Female Perineum: Muscles of the Superficial Perineal Pouch" - "Inferior view of female perineum, branches of the internal pudendal artery."...
- • Dorsal penis
The dorsal nerve of the penis is the deepest division of the pudendal nerve; it accompanies the internal pudendal artery along the ramus of the ischium; it then runs forward along the margin of the inferior ramus of the pubis, between the superior and inferior layers of the fascia of the...
/clitorisThe dorsal nerve of the clitoris is a nerve in females that branches off the pudendal nerve to innervate the clitoris.-Structure:The dorsal nerve of the clitoris is analogous to the dorsal nerve of the penis in males...
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| Coccygeal-Structure:The coccygeal nerve is the 31st spinal nerve. It arises from the sacral plexus, and its ventral ramus helps form the coccygeal plexus. It does not divide into a medial and lateral branch...
(Coccygeal plexusThe coccygeal plexus is a plexus of nerves near the coccyx bone.-Structure:This plexus is formed by the fifth sacral nerve and the coccygeal nerve...
)
| S5-Co1
| CoccygeusThe Coccygeus is a muscle of the pelvic wall , located posterior to levator ani and anterior to the sacrospinous ligament....
| Anococcygeal
Dorsal branches>
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