SOMATIC NERVESSOMATIC NERVES (SACRAL (SACRAL PLEXUS)PLEXUS)

It is situated on the It is situated on the posterolateral wall posterolateral wall of the pelvic cavity, of the pelvic cavity, in front of the in front of the piriformis musclepiriformis muscle..

RELATIONSRELATIONS

AnteriorAnterior: : 11 . .Parietal pelvic fascia Parietal pelvic fascia

separating it from the separating it from the internal iliac vesselsinternal iliac vessels..

22 . .RectumRectum..PosteriorPosterior: :

Piriformis musclePiriformis muscle..

STRUCTURESTRUCTURE

It is formed from It is formed from the the ventral rami ventral rami of (S1- S4) and aof (S1- S4) and a contribution contribution from the from the lumbosacral lumbosacral trunktrunk..

LUMBOSACRAL TRUNKLUMBOSACRAL TRUNK

It is formed of It is formed of part of part of the ventral ramus of the ventral ramus of L4 L4 and and all of the all of the ventral ramus of L5ventral ramus of L5..

It descends vertically It descends vertically anterior to the anterior to the sacroiliac jointsacroiliac joint..

BRANCHES OF S.PBRANCHES OF S.P))AA ( (Passing through the Passing through the

greater sciatic foramen to greater sciatic foramen to supply the L.Lsupply the L.L::

11 . .Sciatic nerveSciatic nerve (L4-S3) (L4-S3)..It is the largest nerve It is the largest nerve

of the plexus and of of the plexus and of the bodythe body..

It supplies all posterior It supplies all posterior muscles of back of muscles of back of thigh and leg and all thigh and leg and all muscles of the solemuscles of the sole..

BRANCHESBRANCHES22 . .Superior gluteal Superior gluteal

nerve nerve (to glutei (to glutei medius & minimus and medius & minimus and tensor fascia lata)tensor fascia lata)..

33 . .Inferior gluteal Inferior gluteal nerve nerve (to gluteus (to gluteus maximus)maximus)..

44 . .Nerve to obturatorNerve to obturator internusinternus (and superior (and superior gemellus)gemellus)..

BRANCHESBRANCHES

44 . .Nerve to Nerve to quadratus femoris quadratus femoris (and inferior (and inferior gemellus)gemellus)..

55 . .Posterior Posterior cutaneous nerve of cutaneous nerve of the thighthe thigh::

It supplies the skin It supplies the skin of the buttock and of the buttock and back of the thighback of the thigh..

BRANCHESBRANCHES

))BB ( (Branches to the Branches to the pelvis and perineum:pelvis and perineum: (muscles & viscera)(muscles & viscera)

11 . .Pudendal Pudendal nerve(S2,3 &4)nerve(S2,3 &4): :

It enters the It enters the perineum through perineum through the lesser sciatic the lesser sciatic foramenforamen..

BRANCHESBRANCHES

22 . .Nerve to Nerve to piriformispiriformis..

33 . .Pelvic splanchnic Pelvic splanchnic nerves (S2,3 &4)nerves (S2,3 &4)..

))cc ( (Perforating Perforating cutaneouscutaneous : to the skin : to the skin of the lower medial part of the lower medial part of the buttockof the buttock..

OBTURATOR NERVEOBTURATOR NERVE

It accompanies the It accompanies the lumbosacral trunk lumbosacral trunk to enter the pelvisto enter the pelvis..

It runs on the It runs on the lateral pelvic walllateral pelvic wall..

OBTURATOR NERVEOBTURATOR NERVE

It lies in the angle It lies in the angle between the between the external external and internal iliac and internal iliac vesselsvessels..

At the At the obturator canal,obturator canal, it splits into anterior it splits into anterior and posterior divisions and posterior divisions that pass through the that pass through the canal to enter the canal to enter the thighthigh..

It gives sensory supply It gives sensory supply to the parietal to the parietal peritoneumperitoneum..

AUTONOMIC SUPPLY (PELVIC AUTONOMIC SUPPLY (PELVIC SYMPATHETIC TRUNK)SYMPATHETIC TRUNK)

It is the It is the continuation of the continuation of the abdominal trunkabdominal trunk..

It is formed of (4- It is formed of (4- 5) ganglia5) ganglia..

It descends It descends in front in front of the ala sacrum, of the ala sacrum, medial to the medial to the lumbosacral trunklumbosacral trunk..

))PELVIC SYMPATHETIC TRUNKPELVIC SYMPATHETIC TRUNK((

On the anterior On the anterior surface of the surface of the sacrum, it is sacrum, it is medial to themedial to the

anterior sacral anterior sacral foraminaforamina..

It is It is behind the behind the rectumrectum..

PELVIC SYMPATHETIC TRUNKPELVIC SYMPATHETIC TRUNK

Inferiorly, the two Inferiorly, the two trunks unite in trunks unite in front of the coccyx front of the coccyx and form a single and form a single ganglion ganglion (ganglion (ganglion impar)impar)..

BRANCHESBRANCHES

11 . .Gray rami Gray rami communicantescommunicantes to the to the lumbar and sacral lumbar and sacral nervesnerves..

22 . .Fibers to Fibers to hypogastrichypogastric plexusesplexuses..

HYPOGASTRIC PLEXUSES HYPOGASTRIC PLEXUSES (1) SUPERIOR(1) SUPERIOR

Site :Site : in front of the in front of the promontry of the promontry of the sacrumsacrum..

StructureStructure : : 11 . .continuation of the continuation of the

aortic plexusesaortic plexuses . .22 . .from the 3from the 3rdrd and 4 and 4thth

lumbar ganglialumbar ganglia..

SUPERIOR HYPOGASTRIC SUPERIOR HYPOGASTRIC PLEXUSPLEXUS

Contained fibers:Contained fibers: Postganglionic Postganglionic sympathetic, sympathetic, parasympathetic and parasympathetic and visceral afferentvisceral afferent..

TerminationTermination::It divides intoIt divides into::Right and Left Right and Left

hypogastric nerveshypogastric nerves..

))22 ( (INFERIOR HYPOGASTRIC INFERIOR HYPOGASTRIC PLEXUSPLEXUS

Site :Site : on each on each side of rectum, side of rectum, bladder and bladder and vaginavagina..

StructureStructure: : Right and left Right and left

hypogastric hypogastric nervesnerves . .

pelvic splanchnic pelvic splanchnic nervesnerves..

INFERIOR HYPOGASTRIC INFERIOR HYPOGASTRIC PLEXUSPLEXUS

Contained fibersContained fibers: : Postganglionic Postganglionic

sympatheticsympathetic..Pre and post Pre and post

ganglionic ganglionic parasympatheticparasympathetic..

Visceral afferentVisceral afferent..DistributionDistribution: :

To the pelvic viscera To the pelvic viscera through small through small subsidary plexusessubsidary plexuses..

PELVIC SPLANCHNIC NERVESPELVIC SPLANCHNIC NERVESIt is the It is the parasympathetic parasympathetic

component of the pelviscomponent of the pelvis..It arises from It arises from (S2,3 &4)(S2,3 &4)..

The fibers synapse in the The fibers synapse in the inferior hypogastric plexusinferior hypogastric plexus or in the walls of the or in the walls of the visceraviscera..

Some fibers can ascend to Some fibers can ascend to the the inferior mesenteric inferior mesenteric plexusplexus and distribute and distribute among the branches of the among the branches of the inferior mesentericinferior mesenteric arteryartery..

EXTERNAL ILIAC ARTERYEXTERNAL ILIAC ARTERYOriginOrigin: :

One of terminal branches of One of terminal branches of the common iliac artery in the common iliac artery in front of the sacroiliac jointfront of the sacroiliac joint..

CourseCourse: : It descends along the medial It descends along the medial

border of posoas majorborder of posoas major..It enters the thigh by It enters the thigh by

passing deep to the inguinal passing deep to the inguinal ligament and becomes the ligament and becomes the femoral arteryfemoral artery..

EXTERNAL ILIAC ARTERYEXTERNAL ILIAC ARTERY

Branches (in the Branches (in the false pelvis)false pelvis): :

Inferior epigastricInferior epigastric..Deep circumflex Deep circumflex

iliaciliac..

INTERNAL ILIAC ARTERYINTERNAL ILIAC ARTERYOriginOrigin: :

The other terminal The other terminal branch of the common branch of the common iliac arteryiliac artery..

CourseCourse: : It descends inferiorly It descends inferiorly

over the pelvic inletover the pelvic inlet..TerminationTermination: :

At the upper border of At the upper border of the greater sciatic the greater sciatic foramen, it divides intoforamen, it divides into anterior and posterioranterior and posterior divisionsdivisions..

POSTERIOR DIVISIONPOSTERIOR DIVISIONIt suppliesIt supplies: :

Posterior abdominal wall, Posterior abdominal wall, posterior pelvic wall and the posterior pelvic wall and the gluteal regiongluteal region..

BranchesBranches: : ))11 ( (Iliolumbar arteryIliolumbar artery::

It ascends behind the It ascends behind the external iliac vessels, psoas external iliac vessels, psoas and iliacusand iliacus..

It divides into It divides into lumbarlumbar branch branch (it supplies the muscles of (it supplies the muscles of the posterior abdominal the posterior abdominal wall) and wall) and iliac iliac branch for branch for iliacus muscle and boneiliacus muscle and bone..

POSTERIOR DIVISIONPOSTERIOR DIVISION))22 ( (Lateral sacral Lateral sacral

arteriesarteries: : Usually twoUsually two..

They descend in front They descend in front of the sacral plexusof the sacral plexus..

They give branches that They give branches that pass into the anterior pass into the anterior sacral foramina to sacral foramina to supply structures in the supply structures in the vertebral canal, vertebral canal, muscles and skinmuscles and skin..

POSTERIOR DIVISIONPOSTERIOR DIVISION

))33 ( (Superior gluteal Superior gluteal arteryartery: :

It leaves the pelvis It leaves the pelvis through the greater through the greater sciatic foramen, sciatic foramen, above the piriformisabove the piriformis..

It supplies the It supplies the gluteal regiongluteal region..

ANTERIOR DIVISIONANTERIOR DIVISION

It suppliesIt supplies: : Pelvic visceraPelvic viscera..

PerineumPerineum..Gluteal regionGluteal region..

Adductor region Adductor region of the thighof the thigh..

The fetusThe fetus..

ANTERIOR DIVISIONANTERIOR DIVISION

) ) AA ( (Visceral branchesVisceral branches::11 . .Umbilical arteryUmbilical artery: :

It gives the It gives the superiorsuperior vesicalvesical artery artery (to the (to the upper part of the urinary upper part of the urinary bladder) from its patent bladder) from its patent proximal partproximal part..

The distal fibrous part of The distal fibrous part of the artery becomes the the artery becomes the medial umbilical ligamentmedial umbilical ligament..

ANTERIOR DIVISIONANTERIOR DIVISION

22 . .Inferior vesical Inferior vesical arteryartery: :

It supplies the base It supplies the base of the bladderof the bladder..

In the male it In the male it supplies, the supplies, the prostate and the prostate and the seminal vesiclesseminal vesicles..

It gives the It gives the artery to artery to the vas deferensthe vas deferens..

ANTERIOR DIVISIONANTERIOR DIVISION

))33 ( (Middle rectal arteryMiddle rectal artery ::

It usually arises with It usually arises with the inferior vesicalthe inferior vesical..

It supplies the muscle It supplies the muscle layer of the lower layer of the lower rectumrectum. .

It anastomoses with It anastomoses with the superior and the superior and inferior rectal arteriesinferior rectal arteries..

ANTERIOR DIVISIONANTERIOR DIVISION

))44 ( (Vaginal arteryVaginal artery: : It replaces the It replaces the

inferior vesical artery inferior vesical artery in the femalein the female..

It supplies the It supplies the base base of the bladder and of the bladder and vaginavagina..

ANTERIOR DIVISIONANTERIOR DIVISION))55 ( (Internal pudendal Internal pudendal

arteryartery: : It is the main arterial It is the main arterial

supply to the supply to the perineum perineum (skin & muscles) and (skin & muscles) and the anal canalthe anal canal..

It leaves the pelvis It leaves the pelvis through the through the lower part lower part of the GSF below the of the GSF below the piriformispiriformis..

It enters the perineum It enters the perineum through the LSFthrough the LSF..

ANTERIOR DIVISIONANTERIOR DIVISION))66 ( (Uterine arteryUterine artery: :

It runs on the pelvic It runs on the pelvic floorfloor..

It crosses the It crosses the ureterureter superiorlysuperiorly..

It passes between the It passes between the layers of the broad layers of the broad ligament along the ligament along the lateral margin of the lateral margin of the uterusuterus..

It anastomoses with It anastomoses with the ovarian arterythe ovarian artery..

ANTERIOR DIVISIONANTERIOR DIVISION

))BB ( (Parietal branchesParietal branches::11 . .Inferior glutealInferior gluteal: :

It leaves the pelvis It leaves the pelvis through the lower through the lower part of the GSF part of the GSF below piriformisbelow piriformis..

It passes between It passes between the the sacral nerves sacral nerves (S1- S2) or (S2- S3)(S1- S2) or (S2- S3)

ANTERIOR DIVISIONANTERIOR DIVISION

22 . .Obturator arteryObturator artery::It accompanies the It accompanies the

obturator nerve obturator nerve along the lateral along the lateral pelvic wallpelvic wall..

It leaves the pelvis It leaves the pelvis through the through the obturator canalobturator canal . .

OVARIAN ARTERYOVARIAN ARTERY

It arises from the It arises from the abdominal aortaabdominal aorta..

Unlike the testicular Unlike the testicular artery, it enters the artery, it enters the pelvis behind the pelvis behind the peritoneumperitoneum..

It enters the It enters the suspensory suspensory ligament of the ligament of the ovary andovary and passes passes into the into the broad broad ligamentligament..

MEDIAN SACRAL ARTERYMEDIAN SACRAL ARTERY

It originates from It originates from the the posterior posterior surface of the surface of the aorta just superior aorta just superior to its bifurcation to its bifurcation..

It descends in the It descends in the midline, in front of midline, in front of the anterior the anterior surface of the surface of the sacrum and sacrum and coccyxcoccyx..

EXTERNAL ILIAC VEINEXTERNAL ILIAC VEIN

It begins behind the It begins behind the inguinal ligament as inguinal ligament as a continuation of the a continuation of the femoral veinfemoral vein..

It ascends along the It ascends along the medial side of its medial side of its corresponding arterycorresponding artery..

It receives the It receives the inferior epigastric inferior epigastric andand deep circumflex deep circumflex veinsveins..

INTERNAL ILIAC VEININTERNAL ILIAC VEIN

It has tributaries It has tributaries corresponding to corresponding to the branches of the the branches of the internal iliac arteryinternal iliac artery..

It ascends in front It ascends in front of the sacroiliac of the sacroiliac jointjoint..

It joins the external It joins the external iliac vein to form iliac vein to form thethe common iliac common iliac veinvein..

MEDIAN SACRAL VEINMEDIAN SACRAL VEIN

It accompanies It accompanies its arteryits artery..

It terminates in It terminates in the the left common left common iliac veiniliac vein..

LYMPH DRAINAGELYMPH DRAINAGE

The lymph nodes The lymph nodes and vessels are and vessels are arranged in a chain arranged in a chain along the main along the main blood vesselsblood vessels..

They are named They are named according to these according to these vessels: vessels: Internal Internal iliac,iliac, External iliac External iliac and and Common iliacCommon iliac..

SACROILIAC JOINTSSACROILIAC JOINTS

They are strong They are strong synovial jointssynovial joints..

Articular surfacesArticular surfaces: : Auricular surfaces Auricular surfaces

of the sacrum and of the sacrum and the iliac bonesthe iliac bones..

SACROILIAC JOINTSSACROILIAC JOINTS

StabilityStability: : It depends on the It depends on the

strong ligamentsstrong ligaments: : 11 . .PosteriorPosterior..

22 . .interosseous interosseous sacroiliac ligamentssacroiliac ligaments..

The The anterior anterior ligamentligament is thin is thin..

SACROILIAC JOINTSSACROILIAC JOINTS

FunctionFunction: : Transmitting the weight Transmitting the weight

of the body from the of the body from the vertebral column to the vertebral column to the bony pelvisbony pelvis..

ROTATION OF THE SACRUMROTATION OF THE SACRUM

The weight of the The weight of the body tends to body tends to thrust the upper thrust the upper end of the sacrum end of the sacrum downwards and downwards and rotates the lower rotates the lower end upwardsend upwards..

ROTATION OF THE SACRUMROTATION OF THE SACRUM

This is prevented by This is prevented by the following the following ligamentsligaments: :

SacrospinousSacrospinous..SacrotuberousSacrotuberous..

IliolumbarIliolumbar : : It is between the tip It is between the tip

of the transverse of the transverse process of L5 and the process of L5 and the iliac crestiliac crest..

SYMPHSIS PUBISSYMPHSIS PUBIS

It is a It is a secondary secondary cartilagenous jointcartilagenous joint..

The two pubic The two pubic bones are covered bones are covered by by hyaline cartilage hyaline cartilage and connected and connected together by a together by a fibrocartilagenous fibrocartilagenous discdisc..

The joint allows The joint allows no no movementmovement..

SACROCOCCYGEAL JOINTSACROCOCCYGEAL JOINT

It is a It is a cartilagenouscartilagenous joint between the joint between the bodies of the bodies of the last last sacral vertebrae and sacral vertebrae and the 1the 1stst coccygeal coccygeal vertebravertebra..

It has a great It has a great amount of amount of movementmovement..