The document discusses the anatomy of the gluteal region. It describes that the gluteal region lies between the iliac crest and gluteus maximus muscle, and contains gluteal muscles, ligaments, vessels and nerves. The gluteal muscles are divided into a superficial group including the gluteus maximus, medius and minimus, and a deep group including the piriformis, obturator internus and quadratus femoris muscles. Several important nerves pass through the gluteal region including the superior and inferior gluteal nerves. The safest site for intramuscular injections in the gluteal region is the upper outer quadrant to avoid injuring the sciatic nerve

1. THE GLUTEAL REGION
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2. • It lies posterior to the pelvis between the level of
the iliac crest and inferior border of gluteus
maximus muscle.
• This region is made up of the gluteal muscles,
ligaments, vessels (arteries & veins) and gluteal
nerves.
• The two buttocks formed mostly by the three
most prominent gluteal muscles are separated
from each other by the intergluteal cleft.
• The inferior border is demarcated from the
superior border of the thigh by the gluteal sulcus
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3. The buttock
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4. Gluteal ligaments
• Two main ligaments make up the ligament
components of the gluteal region and they
include;
• Sacrotuberous and sacrospinous ligaments.
• These two ligaments converts the sciatic notch
of the hip bone into a greater and lesser sciatic
foramina.
• The greater sciatic foramen forms a passageway
through which structures entering and leaving
the pelvis passes e.g. sciatic nerve.
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5. • The lesser foramen serves as a
passageway for structures entering and
leaving the perineum. E.g. pudendal
nerve.
• It is therefore worthy of note that the greater
sciatic foramen can be likened to a ‘door’
through which all arteries and nerves leave
the pelvis to enter the gluteal region,
including the piriformis muscle which almost
fill the foramen.
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8. Gluteal muscles
• Muscles of the gluteal region are mainly in
two groups:
• a deep group of small muscles, which are
mainly lateral rotators of the femur at the hip
joint and include;
• piriformis, obturator internus, gemellus
superior, gemellus inferior, and quadratus
femoris.
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9. • A more superficial group of larger muscles,
which mainly abduct and extend the hip and
include;
• The gluteus minimus, gluteus medius, and
gluteus maximus-an additional muscle in this
group, the tensor fasciae latae.
• The tensor fasciae latae stabilizes the knee in
extension by acting on a specialized
longitudinal band of deep fascia (the iliotibial
tract) that passes down the lateral side of the
thigh to attach to the proximal end of the tibia
in the leg.
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10. Superficial group
• Gluteus maximus;
• Is the largest muscle in the gluteal region and
overlies most of the other gluteal muscles
except for the posterior 3rd of the gluteus
medius and also forms a pad over the ischial
tuberosity.
• origin/proximal attachment- ilium,posterior
to the posterior gluteal line, posterior surface
of the sacrum, coccyx and sacrotuberous
ligament.
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11. • Insertion/distal attachment- iliotibial
tract and gluteal tuberosity.
• Innervation- innervation is by the inferior
gluteal nerve with root values L5, S1-2.
• Action- main action is extension and
lateral rotation of the thigh.
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13. • Gluteus medius and minimus ;
• These are fan-shaped small gluteal muscles
and their fibres passes the same direction.
• Origin- medius originates from the external
surface of the ilium between the anterior and
posterior gluteal line, while the minimus
originates from the external surface of the
ilium between the anterior and inferior
gluteal line.
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14. • Insertion- medius inserts on the lateral surface
of greater trochanter while minimus inserts on
anterior surface of greater trochanter of
femur.
• innervation- both by the superior gluteal
nerve with root values L5 & S1.
• Action- both medially rotates and abducts the
lower limb at the hip joint.
• Also keeps the pelvis at level when opposite
leg is raised.
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16. Actions of the G. medius & minimus
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17. • Tensor fasciae latae;
• The tensor fasciae latae muscle is the most
anterior of the superficial group of muscles in
the gluteal region and overlies the gluteus
minimus and the anterior part of the gluteus
medius.
• Origin- Tensor fasciae latae originates from
the outer margin of the iliac crest from the
anterior superior iliac spine to approximately
the tubercle of the crest.
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18. • Insertion- anterior aspect of the iliotibial tract
of deep fascia, which runs down the lateral
side of the thigh.
• Action- Stabilizes the knee in extension.
• Working with the gluteus maximus muscle on
the iliotibial tract lateral to the greater
trochanter, Stabilizes the hip joint by holding
the head of the femur in the acetabulum.
• Innervation- superior gluteal nerve with root
value L5 & S1.
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19. Deep group of gluteal muscles
• Piriformis;
• A narrow pear-shaped muscle is the most
superior of the deep group of gluteal muscles.
• It is a muscle of the pelvic wall and of the
gluteal region.
• Origin- from the superior surface of the
sacrum and the sacrotuberous ligaments.
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20. • Insertion- superior surface of the greater
trochanter of femur.
• Innervation- innervation is by the nerve to
piriformis which are branches from ventra
rami of S1 & S2.
• Action- acts as a stabilizer of the head of the
femur in the acetabulum and also extends
rotated thigh laterally and abducts flexed
thigh.
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21. Piriformis (A)
A
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22. • Obturator internus, gamelli superior &
inferior;
• These three fan-shaped muscles form a
tricipital (3 heads).
• Often called triceps coxae.
• They occupy the space between the piriformis
and the quadratus femoris muscle.
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23. • Obturator internus;
• Origin- pelvic surface of obturator
membrane and surrounding bone.
• Insertion- medial border of greater
trochanter of femur.
• Innervation- nerve to obturator internus
with root value L5-S2.
• Action- same as piriformis muscle.
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24. Obturator internus (B)
B
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25. • Gemellus superior and inferior;
• (gemelli is Latin for twins) are a pair of
triangular muscles associated with the upper
and lower margins of the obturator internus
tendon.
• Origin- superior is from ischial spine,
Infererior is from ischial tuberosity.
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26. • Insertion- its tendons blends with that of the
obturator internus and inserts on the medial
side of the greater trochanter of femur.
• Innervation- superior gamelli is by nerve to
obturator while inferior gamelliis by nerve to
quadratus femoris.
• Action- same as obturator internus and
piriformis
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27. Superior & inferior Gamelli (C)
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28. • Quadratus femoris;
• The most inferior of the deep group of muscles in
the gluteal region.
• It is a flat rectangular muscle below the obturator
internus muscle and its associated gemellus
muscles.
• Origin- lateral border of ischial tuberosity
• Insertion- the quadrate tubercle on the
intertrochanteric crest of the proximal femur.
• Innervation- nerve to quadratus femoris.
• Action- laterally rotates the femur at the hip joint
and also assist in steadying the head of the femur
in the acetabulum.
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29. Quadratus femoris (D)
D
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30. GLUTEAL NERVES
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31. • Several important nerves arise from the sacral
plexus and either supply the gluteal region or
pass through it to supply the perineum and
thigh.
• Many of the nerves in the gluteal region are
in the plane between the superficial and deep
groups of muscles.
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32. Superficial Gluteal Nerves
• The skin of the gluteal region is richly
innervated by the clunial nerves
(superior,middle and inferior).
• These nerves supply the skin over the iliac
crest, between the posterior superior iliac
spines, and over the iliac tubercles.
• Consequently, these nerves are vulnerable to
injury when bone is taken from the ilium for
grafting.
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33. • The superior clunial nerves are lateral
cutaneous branches of the dorsal rami of L1- L3
nerves.
• They supply the skin of the gluteal region as
far as the greater trochanter.
• The middle clunial nerves also lateral
branches of the dorsal rami of S1 -S3 nerves,
• Supplies the skin and subcutaneous tissue
over the sacrum and adjacent area of the
buttock.
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34. • The inferior clunial nerves are gluteal
branches of the posterior cutaneous nerve of
the thigh, a derivative of the sacral plexus
(ventral rami S1-S3).
• These nerves curl around the inferior border
of the gluteus maximus.
• Supplies the inferior half of the buttock.
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35. • The perforating cutaneous nerve (S2 and S3)
passes through the sacrotuberous ligament
and the inferior part of the gluteus maximus.
• Supplies the skin over the inferior half of the
buttock and the medial part of the gluteal
fold.
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36. Deep Gluteal Nerves
• Seven deep gluteal nerves enter the gluteal
region from the pelvis through the greater sciatic
foramen:
• The superior gluteal nerve, sciatic nerve, nerve to
the quadratus femoris, nerve to the obturator
internus, posterior cutaneous nerve of the thigh,
pudendal nerve, and inferior gluteal nerve.
• An additional nerve, the perforating cutaneous
nerve, enters the gluteal region by passing
directly through the sacrotuberous ligament
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37. • Superior gluteal nerve ;
• The only gluteal nerve that passes superior to
the piriformis muscle.
• It loops up over the inferior margin of gluteus
minimus and travels anteriorly and laterally in
the plane between the gluteus minimus and
medius muscles.
• Innervates G. minimus, medius and tensor
fascia latae.
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38. DIAGRAM OF GLUTEAL NERVE

39. • Sciatic nerve;
• The sciatic nerve enters the gluteal region
through the greater sciatic foramen inferior to
the piriformis muscle.
• It descends in the plane between the superficial
and deep group of gluteal region muscles.
• It lies just deep to the gluteus maximus at the
midpoint between the ischial tuberosity and the
greater trochanter.
• At the lower margin of the quadratus femoris
muscle, the sciatic nerve enters the posterior
thigh.
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40. • The sciatic nerve is the largest nerve in the
body and innervates all muscles in the
posterior compartment of the thigh.
• All muscles that flex the knee.
• All muscles that work the ankle and foot.
• It also innervates a large area of skin in the
lower limb.
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41. • Nerve to quadratus femoris;
• Enters the gluteal region through the greater
sciatic foramen inferior to the piriformis
muscle and deep to sciatic nerve.
• It descends along the ischium deep to the
tendon of obturator internus and gamellus
muscle.
• Supplies quadratus femoris and a small branch
to gamellus inferior.
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42. • Nerve to obturator internus;
• This nerve enters the gluteal region through
the greater sciatic foramen inferior to the
piriformis muscle and between the posterior
cutaneous nerve of the thigh and the
pudendal nerve.
• It supplies a small branch to the gemellus
superior and then passes over the ischial spine
and through the lesser sciatic foramen to
innervate the obturator internus muscle.
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43. • Pudendal nerve Body;
• Lies medial to the sciatic nerve.
• It passes over the sacrospinous ligament and
immediately passes through the lesser sciatic
foramen to enter the perineum.
• The nerve is often hidden by the overlying
upper margin of the sacrotuberous ligament.
• The pudendal nerve is the major somatic
nerve of the perineum and has no branches in
the gluteal region.
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44. • Inferior gluteal nerve;
• Passes along the posterior surface of the
sciatic nerve.
• It penetrates and supplies the gluteus
maximus muscle.
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45. • Posterior cutaneous nerve of the thigh;
• It descends through the gluteal region just deep
to the gluteus maximus and enters the posterior
thigh.
• It has a number of gluteal branches, which loop
around the lower margin of the gluteus maximus
muscle to innervate skin over the gluteal fold.
• A small perineal branch passes medially to
contribute to the innervation of skin of the
scrotum or labia majora in the perineum.
• The main trunk of the posterior cutaneous nerve
of the thigh passes inferiorly, giving rise to
branches that innervate skin on the posterior
thigh and leg.
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46. Intramuscular injections
• From time to time it is necessary to administer
drugs intramuscularly: that is, by direct injection
into muscles.
• This procedure must be carried out without
injuring neurovascular structures.
• A typical site for an intramuscular injection is the
gluteal region.
• The sciatic nerve passes through this region and
needs to be avoided.
• The safest place to inject is the upper outer
quadrant of either gluteal region.
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47. • It is important to remember that the gluteal
region extends as far forward as the anterior
superior iliac spine.
• The sciatic nerve curves through the upper lateral
corner of the lower medial quadrant and
descends along the medial margin of the lower
lateral quadrant.
• Occasionally, the sciatic nerve bifurcates into its
tibial and common fibular branches in the pelvis,
in which case the common fibular nerve passes
into the gluteal region through, or even above,
the piriformis muscle.
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48. • The superior gluteal nerve and vessels
normally enter the gluteal region above the
piriformis and pass superiorly and forward.
• The anterior corner of the upper lateral
quadrant is normally used for injections to
avoid injuring any part of the sciatic nerve or
other nerves and vessels in the gluteal region.
• A needle placed in this region enters the
gluteus medius anterosuperior to the margin
of the gluteus maximus.
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49. QUADRANT FOR INTERMUSCULAR INJECTION

50. GLUTEAL ARTERIES
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51. • Two arteries enter the gluteal region from the
pelvic cavity through the greater sciatic
foramen, the inferior gluteal artery and the
superior gluteal artery.
• They supply structures in the gluteal region
and posterior thigh and have important
collateral anastomoses with branches of the
femoral artery.
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52. • Superior gluteal artery;
• Originates from the posterior trunk of the internal iliac
artery in the pelvic cavity.
• It leaves the pelvic cavity with the superior gluteal nerve
through the greater sciatic foramen above the piriformis
muscle.
• In the gluteal region, it divides into a superficial branch and
a deep branch: the superficial branch passes onto the deep
surface of the gluteus maximus muscle;
• the deep branch passes between the gluteus medius and
minimus muscles.
• In addition to adjacent muscles, the superior gluteal artery
contributes to the supply of the hip joint.
• Branches of the artery also anastomose with the lateral and
medial femoral circumflex arteries from the deep femoral
artery in the thigh, and with the inferior gluteal artery.
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54. • Inferior gluteal artery;
• Oiginates from the anterior trunk of the internal
iliac artery in the pelvic cavity. It leaves the pelvic
cavity with the inferior gluteal nerve through the
greater sciatic foramen inferior to the piriformis
muscle.
• The inferior gluteal artery supplies adjacent
muscles and descends through the gluteal region
and into the posterior thigh where it supplies
adjacent structures and anastomoses with
perforating branches of the femoral artery.
• It also supplies a branch to the sciatic nerve.
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57. GOODMORNING
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