Sacral plexus its formation, course, innervation and clinicals

1. SACRAL PLEXUS
Dr. Saneed Khaliq
MBBS, MPHIL ANATOMY
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2. • To explain sacral plexus, its formation, course and Innervation
with clinical aspects
OBJECTIVE
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3. FORMATION OF SACRAL PLEXUS
• The sacral plexus is a network of
nerve fibers that lies on the posterior
pelvic wall in front of the piriformis
muscle
• It is formed by anterior rami of L4-
L5 (lumbosacral trunk) and S1-S4
• The lumbosacral trunk joins the
sacral nerves as they emerge from the
anterior sacral foramina
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4.  Anteriorly:
• The internal iliac vessels
and their branches and the
rectum
 Posteriorly:
• The piriformis muscle
RELATIONS
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5. 1. Superior gluteal nerve
2. Inferior gluteal nerve
3. Posterior cutaneous femoral nerve
4. Nerve to piriformis
5. Nerve to Obturator internus
6. Nerve to Quadratus femoris
7. Sciatic nerve
• Tibial portion
• Common peroneal portion
8. Pudendal nerve
BRANCHES OF SACRAL PLEXUS
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6. SUPERIOR GLUTEAL NERVE
• Course:
• Leaves the pelvis via the greater
sciatic foramen
• Enters the gluteal region superiorly
to the piriformis muscle
• Innervation:
• Gluteus medius
• Gluteus minimus
• Tensor fasciae latae muscles
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7. INFERIOR GLUTEAL NERVE
• Course:
• Leaves the pelvis via the greater
sciatic foramen
• Enters the gluteal region inferiorly
to the piriformis muscle
• Innervation:
• Gluteus maximus muscle
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8. NERVE TO PERIFORMIS
• Course:
• It arises from the posterior division of
the ventral rami of the first and
second sacral nerves, and enters the
anterior surface of
the piriformis muscle
• Innervation:
• Piriformis muscle
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9. PERIFORMIS SYNDROME
• Piriformis syndrome is a
neuromuscular disorder that is
caused when the piriformis
muscle compresses the sciatic
nerve
• Muscle spasm causes buttock
pain that radiates down the back
of the leg along the sciatic nerve
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10. NERVE TO OBTURATOR INTERNUS
• Course:
• It arises from the anterior rami of
spinal nerves L5, S1 and S2.
• The nerve travels inferior to
piriformis and courses around the
ischial spine
• Innervation:
• Obturator internus
• Superior gemellus muscles
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11. NERVE TO QUADRATUS FEMORIS
• Course:
• It arises from anterior divisions
of the anterior rami of the L4,
L5 and S1 spinal nerves
• Travels inferior to sciatic nerve
• Innervation:
• Quadratus femoris
• Inferior gemellus muscles
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12. PERFORATING CUTANEOUS NERVE
• Course:
• It arises from fibers of the
anterior rami of spinal
nerves S2 and S3
• Passes through the greater
sciatic foramen
• Pierces the sacrotuberous
ligament and gluteus maximus.
• Innervation:
• Skin over medial aspect of
buttock 12
Perforating
cutaneous neve

13. POSTERIOR CUTANEOUS NERVE OF THE THIGH
• Course:
• It receives fibers from both anterior
and posterior divisions of anterior
rami.
• Posterior divisions: S1 and S2
• Anterior divisions: S2 and S3.
• Innervation:
• Skin over posterior surface of thigh
• Popliteal fossa
• Lower part of buttock
• Scrotum or labium majus 13

14. SCIATIC NERVE
(L4, 5; S1, 2, 3)
• Course:
• It enters the gluteal region via
greater sciatic foramen
• Inferiorly to the piriformis muscle
and descends in an inferolateral
direction
• At popliteal fossa, it bifurcates into
the tibial and common fibular
nerves.
• Divisions:
• Tibial nerve
• Common fibular nerve 14

15. TIBALAND COMMON FIBULAR NERVE
• Tibial nerve
• It innervates posterior compartment of the
thigh and the hamstring component of
adductor magnus. Innervates all the muscles
in the posterior compartment of the leg and
sole of the foot.
• Common fibular nerve
• Short head of biceps femoris, all muscles in
the anterior and lateral compartments of the
leg and extensor digitorum brevis
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16. SCIATICA
• Sciatica is a condition in which
patients have pain along the sensory
Innervation of the sciatic nerve
• Causes:
• Prolapse of an intervertebral disc
• Pressure on sciatic nerve
• Nerve inflammation
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17. PUDENDAL NERVE
• Course:
• It leaves the pelvis via the greater
sciatic foramen, then re-enters via
the lesser sciatic foramen
• Innervation:
• Muscles of perineum
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