Boundaries of Gluteal Region

Superiorly: iliac crest

Inferiorly: gluteal fold
Medially: natal cleft
Laterally: a line drawn from the
anterior superior iliac spine to
the greater trochanter

Iliac
crest

Natal
cleft

Gluteal
fold
A) 3 large gluteal muscles; gluteus maximus,
gluteus medius, gluteus minimus

B) 6 small lateral rotators of femur;

piriformis, obturator internus, obturator
externus, the 2 gemelli (superior & inferior),
and quadratus femoris

C) Tensor fasciae latae

(N.B.) All are supplied by nerves derived from
sacral plexus except obturator externus,
which is supplied by the obturator nerve
from the lumbar plexus.
 Tubercle of iliac
crest
Muscles of Gluteal Region
Anterior superior
iliac spine

[1] Tensor fascia lata muscle Tensor

fascia lata

Origin: from the outer lip of the iliac crest

between the anterior superior iliac spine and
the iliac tubercle
Iliotibial
Insertion: into the anterior border of the tract

iliotibial tract
Nerve supply: from the superior gluteal nerve
Action:
a) It assists in abduction of the thigh
b) Through its insertion into the ilio-tibial
tract;
●It assists in extension of the knee
● It helps to steady the pelvis on femur
and tibia during standing and walking
 Tensor fasciae
latae muscle
Tensor fasciae
latae muscle

Ilio-tibial tract
Ilio-tibial tract
[2] Gluteus maximus muscle
Origin:
a) Outer (gluteal) surface of ilium, behind the
posterior gluteal line
b) Back of sacrum and coccyx
c) Back of sacrotuberous ligament
Insertion:
 Superficial ¾ are inserted into iliotibial tract
 Deep ¼ is inserted into gluteal tuberosity of
femur
Nerve supply; inferior gluteal nerve (from the
sacral plexus)
Action
1) It is the main extensor of the hip joint,
especially from the position of extreme
flexion (as in running and climbing)
2) Lateral rotation of the hip joint
3) Through its insertion into the iliotipial tract
it stabilizes the pelvis on femur, and femur
on the tibia during standing and walking
 Action:
1) It is the main extensor of the hip joint,
especially from the position of extreme
flexion (as in rising from the sitting
position, running and climbing)
2) Lateral rotation of the hip joint
3) Through its insertion into the iliotipial tract,
it helps in extension of the knee joint, and
stabilizes the pelvis on femur, and femur on
the tibia during standing and walking

[N.B.] Gluteus maximus together with tensor fasciae

latae are called the great deltoid muscle of the
gluteal region.
Deep relations of gluteus maximus
A) Bones
a) Ilium
b) Sacrum & coccyx
c) Ischial tuberosity
d) Greater trochanter
B) Ligaments
a) Sacrotuberous ligament
b) Sacrospinous ligament
C) Muscles Sacrospinous
ligament
a) Muscles attached to the greater
trochanter
Sacrotuberous
 Gluteus medius and minimus ligament

 Piriformis
 Obturator internus and 2 gemelli
 Quadratus femoris
 Obturator externus
b) Muscles attached to the ischial
tuberosity
 Semimembranosus
 Semitendinosus
 Long head of biceps femoris
 Ischial part of adductor magnus
 Gluteus minimus muscle Gluteus medius
muscle

Piriformis muscle
Superior and
Sacro-tuberous
inferior
ligament
gemellus
Gluteus Obturator muscles
maximus internus muscle
Greater
muscle
Quadratus trochanter
femoris muscle
Gluteus
maximus
Semitendinosus
muscle
muscle
Long head of
Ilio-tibial tract biceps femoris
muscle

Semimembranosus
muscle
 D) Nerves
a) Nerves appearing above piriformis; Superior gluteal nerve
b) Nerves appearing below piriformis;
 Inferior gluteal nerve
 Sciatic nerve
 Posterior cutaneous nerve of thigh
 Pudendal nerve
 Nerves to obturator internus and quadratus femoris

Gluteus medius
Gluteus maximus
muscle
muscle

Superior gluteal
Inferior gluteal nerve
nerve

Nerve to obturator Piriformis

internus muscle
Posterior
Pudendal nerve cutaneous nerve
of thigh
Nerve to
Sciatic nerve
quadratus
femoris
 Gluteus medius
muscle

Gluteus maximus
muscle
Gluteus minimus
muscle
Superior
gluteal nerve Tensor fasciae
latae muscle

Piriformis
muscle
Pudendal nerve

Inferior
Nerve to obturator gluteal nerve
internus

Posterior cutaneous Sciatic nerve

nerve of thigh

Gluteus maximus
muscle
E) Vessels
a) Superior gluteal vessels
b) Inferior gluteal vessels
c) Internal pudendal vessels
F) Bursae
Trochanteric bursa; between the
muscle and greater trochanter
Ischial bursa; between the
muscle and ischial tuberosity
Vastus lateralis bursa
[3] Gluteus medius muscle
Origin; gluteal surface of ilium, between the
posterior & anterior gluteal lines
Insertion; into lateral surface of the greater
trochanter

[4] Gluteus minimus muscle

Origin; gluteal surface of ilium, between the
anterior and inferior gluteal lines
Insertion; into front of the greater trochanter
Nerve supply of gluteus medius and
minimus; superior gluteal nerve (from
sacral plexus)
Action of gluteus medius and minimus;
1) Abduction of the hip joint
2) Anterior fibers of both muscles produce
medial rotation of the hip joint
3) Acting from their insertion, both
muscles prevent tilting (sagging) of
pelvis to the opposite side when the foot
is raised from the ground (off the
ground). This is very important during
walking
Applied anatomy; injury of superior gluteal nerve and paralysis of gluteus medius & minimus
leads to gait disturbance in the following way:
a) Lurching (limping) gait; when the paralysis is unilateral
b) Waddling gait (trunk is flexed from side to side with every step); when the paralysis is
bilateral

In unilateral paralysis of gluteus medius and minimus, there

is a positive Trendlenberg’s sign; on standing on the Gluteus medius
muscle
affected side, the pelvis tilts towards the unsupported side.

Gluteus minimus
Gluteus medius muscle
and minimus
muscles
The 6 Lateral Rotators of the Hip

[1] Piriformis muscle

Origin: from the front of the middle 3 sacral Piriformis

muscle
vertebrae
Insertion: it leaves the pelvis through the
greater sciatic foramen to enter the gluteal
region and insert into the tip of the greater
trochanter of femur
Nerve supply: S1 and S2 ventral rami of the
sacral plexus
Action: lateral rotation of the thigh at hip joint
(N.B.) Piriformis is a key structure in the
identification of the nerves and vessels of
the gluteal region (discussed later in the
greater sciatic foramen)
[2] Obturator internus muscle
Origin: from pelvic surface of the obturator membrane and margin of the obturator foramen
Insertion: its tendon leaves the pelvis through the lesser sciatic foramen to enter the gluteal
region, where it bends laterally and crosses the back of the hip joint to insert into the medial
surface of the greater trochanter
Nerve supply: nerve to obturator internus from the sacral plexus
Action: lateral rotation of the thigh at hip joint

Obturator
internus
muscle
Obturator internus muscle
[3] Superior gemellus muscle
Origin: from the upper margin of the lesser
sciatic foramen
Insertion: into the upper border of the
tendon of obturator internus muscle
Nerve supply: nerve to obturator internus
from the sacral plexus
Action: lateral rotation of the thigh at hip
joint

[4] Inferior gemellus muscle

Origin: from the lower margin of the lesser
sciatic foramen
Insertion: into the lower border of the
tendon of obturator internus muscle
Nerve supply: nerve to quadratus femoris
from the sacral plexus
Action: lateral rotation of the thigh at hip
Obturator
joint internus muscle

Superior gemellus
muscle

Tendon of obturator
internus muscle
Inferior gemellus Quadratus
muscle femoris muscle
[5] Quadratus femoris muscle
Origin: from the lateral margin of the ischial
tuberosity
Insertion: into the quadrate tubercle and
lower part of inter-trochanteric crest of
femur
Nerve supply: nerve to quadratus femoris
from the sacral plexus Quadratus
Action: lateral rotation of the thigh at hip femoris muscle

joint

[6] Obturator externus muscle Obturator externus muscle

Origin: from the outer surface of the

obturator membrane and lower margin of
the obturator foramen
Insertion: its tendon passes backwards
below the hip joint then bends laterally
behind neck of femur to insert into the
trochanteric fossa on medial surface of the
greater trochanter
Nerve supply: posterior division of
obturator nerve from the lumbar plexus
Action: lateral rotation of the thigh at hip
joint
Ligaments of Gluteal Region

[1] Sacro-tuberous ligament: extends

from the posterior superior iliac spine
and dorsal aspect of lateral margin of
the sacrum and coccyx to the medial Sacrotuberous ligament
margin of the ischial tuberosity (it is
continuous below with the origin of
long head of biceps femoris)
[2] Sacro-spinous ligament: extends
from the last piece of sacrum and first
piece of coccyx to the ischial spine (it
is considered as the degenerated
posterior part of coccygeus muscle) Tendon of
origin long head
of biceps
Function of the 2 ligaments: femoris

1) They stabilize the sacrum by

preventing its tilting (rotation) at Sacrospinous ligament

the sacro-iliac joint under effect of

body weight transmission
2) They convert the greater and lesser
sciatic notches into foramina
Sacrospinous ligament

Sacrotuberous
ligament

Sacrospinous ligament Coccygeus muscle

Foramina of Gluteal Region

Sacrotuberous ligament
[1] Greater sciatic foramen:
Boundaries:
• Greater sciatic notch Sacrospinous ligament

• Sacro-tuberous ligament
• Sacro-spinous ligament
Contents:
Greater sciatic foramen
1) Piriformis muscle
2) Structures above piriformis; Superior gluteal
nerve and vessels
superior gluteal nerve and vessels
Piriformis muscle
3) Structures below piriformis; Inferior gluteal
nerve and vessels
• Inferior gluteal nerve and vessels
Pudendal nerve
• Sciatic nerve
Internal pudendal
• Posterior cutaneous nerve of thigh vessels
(superficial to sciatic nerve) Nerve to obturator
• Nerve to quadratus femoris (deep internus

to sciatic nerve) Posterior cutaneous

nerve of thigh
• Nerve to obturator internus
• Internal pudendal vessels Sciatic nerve

• Pudendal nerve
[2] Lesser sciatic foramen:
Sacrotuberous ligament
Boundaries:
• Lesser sciatic notch
• Sacro-tuberous ligament
Sacrospinous ligament
• Sacro-spinous ligament
Contents:
1) Tendon of obturator internus
muscle Greater sciatic foramen

2) 3 structures passing from the

Superior gluteal
greater to the lesser sciatic nerve and vessels
foramen; Piriformis muscle

• Nerve to obturator internus Inferior gluteal

nerve and vessels
(over the ischial spine)
• Internal pudendal vessels (over Pudendal nerve
Internal pudendal
the tip of the ischial spine) vessels
• Pudendal nerve (over the Nerve to obturator
sacro-spinous ligament) internus
Posterior cutaneous
nerve of thigh

Sciatic nerve
 It is the thickest nerve in the body
Origin: it is the largest branch of the sacral plexus, arises
in the pelvis from the anterior and posterior divisions
of the ventral primary rami of L4, 5 and S1, 2 and 3

L4
L4
L5
L5
S1
S2
S1 S3
Superior
gluteal nerve
S2

S3

Inferior Sciatic
S4
gluteal nerve nerve
S5
Sciatic nerve

Common peroneal Pudendal nerve

nerve
Posterior cutaneous nerve of thigh
Tibial nerve
 Piriformis muscle Obturator internus muscle
Course and relations:
Gluteus maximus muscle Superior and inferior
A) In the gluteal region; it leaves the gemelli
pelvis and enters the gluteal region by
passing through the greater sciatic Greater
foramen, below piriformis muscle sciatic
foramen
Superficial relations;
• Skin, superficial fascia, deep fascia
• Gluteus maximus muscle
• Posterior cutaneous nerve of thigh
Deep relations;
• Back of ischium
• Tendon of obturator internus with
the 2 gemelli
• Nerve to quadratus femoris
• Quadratus femoris, separating the
nerve from obturator externus
Capsule
muscle and hip joint of hip
joint

Quadratus
Posterior cutaneous nerve of thigh femoris
muscle
Sciatic nerve Nerve to quadratus femoris
 Piriformis
muscle

Gluteus
maximus
muscle Sciatic
nerve
 B) In the back of the thigh; it leaves the
gluteal region and enters the back of thigh
midway between the ischial tuberosity and
the greater trochanter, then descends along
Piriformis Gluteus
the midline of the back of thigh maximus

Superficial relations;
• Skin, superficial fascia, deep fascia Sciatic
nerve
• Long head of biceps femoris muscle Long
head of
Deep relations; adductor magnus muscle biceps
Adductor femoris
magnus
Termination: at the junction of the upper 2/3
and lower 1/3 of the thigh, by dividing into 2
terminal branches;
Tibial (medial popliteal) nerve
Common peroneal (lateral popliteal) nerve

[N.B.] Occasionally, sciatic nerve divides into its

Common
2 terminal branches at a higher level, in the Tibial
peroneal
thigh, gluteal region or even the pelvis, and in nerve
nerve
this case, the common peroneal nerve pierces
piriformis, while the tibial nerve runs below it
Companion artery of the sciatic nerve: it is a
slender artery that arises from the inferior
gluteal artery and penetrates the sciatic
nerve and runs within it as far as its 2
terminal branches

Superior gluteal
artery

Inferior gluteal Piriformis muscle

artery

Sciatic nerve

Companion artery
of sciatic nerve
Branches:
A) Muscular branches;
a) From the tibial part; to the following
muscles;
• Semitendinosus
• Semimembranosus
• Long head of biceps femoris
• Ischial part of adductor magnus
Semitendinosus
b) From the common peroneal part; to Long
head of
the short head of biceps femoris
biceps
Adductor femoris
B) Articular branches; to the hip joint magnus

C) Terminal branches;
Semi-
1) Tibial (medial popliteal) nerve; the membranosus
larger of the 2 terminal branches Short head
of biceps
2) Common peroneal (lateral popliteal) femoris
nerve; the smaller of the 2 terminal
branches
Surface anatomy of sciatic nerve:
It is represented by a broad band about 1
cm thick, connecting 3 points;
1) A point midway between the posterior
superior iliac spine and the ischial Sciatic nerve
tuberosity
2) A point midway between the ischial
tuberosity and the greater trochanter
3) A point along the midline of the back
of the thigh, at junction of the upper Common peroneal
2/3 with the lower 1/3 nerve

Posterior superior
iliac spine Tibial nerve

Sciatic nerve

Greater trochanter
Sural nerve

Ischial tuberosity
 Sciatic
Piriformis nerve
muscle

Sciatic nerve
 Superior gluteal
nerve
Proper location for intra-muscular injection in
the gluteal region: it is the upper outer quadrant
of the gluteal region, as it does not contain any
major nerve trunks
• The upper medial quadrant contains the superior
gluteal nerve
• The lower medial quadrant contains the sciatic
nerve and inferior gluteal nerve
• The lower lateral quadrant contains trochanteric
bursa

Trochanteric
bursa

Sciatic nerve

Inferior gluteal
nerve
Applied Anatomy of the Sciatic Nerve:

A) Sciatica;
Definition; pain along the course of
sciatic nerve in the gluteal region and
back of the thigh, as well as the
sensory distribution of the branches of
sciatic nerve in the leg and foot
(N.B.) the pain varies from tingling to
burning or shooting electric-like
pain
Causes;
• Inter-vertebral disc prolapse (90%)
• Tumors compressing the roots of the
sciatic nerve, e.g. spinal cord
tumors, intra-pelvic tumors, tumors
of gluteal region
• Inflammation of sciatic nerve, e.g.
herpes zoster, meningitis, auto-
immune diseases
• Sciatic endometriosis (rare)
B) Kernig’s sign;
Description; resistance or pain in
response to passive extension of the
knees more than 135 degrees while the
hip is flexed in cases with meningitis Kernig’s sign
(in severe cases, patients could not
extend their knees past 90 degrees)
Anatomical basis;
• Roots of the spinal nerves are
enclosed in meningeal sheaths as
far as the intervertebral foramina
Arachnoid
• Inflammation of meninges increases
mater Dura mater
the sensitivity of the related nerve
roots
• Passive extension of the knee while
the hip is flexed causes stretch of
the sciatic nerve and its roots, Spinal nerve
which are surrounded with trunk
inflamed meninges
C) Sciatic nerve injury;
Causes;
• Posterior dislocation of hip joint with
fracture of acetabulum
• Faulty intra-muscular injection into the
lower medial quadrant of the gluteal
region (iatrogenic injury)
• Piriformis syndrome; hypertrophy of Piriformis muscle
piriformis muscle, leading to
compression of the common peroneal
nerve if it passes through the muscle
Sciatic nerve
Effects;
Motor effect; paralysis of hamstring
muscles as well as all muscles of the
leg and foot
Sensory effect; in early cases
paraesthesia, and in late cases sensory
loss in the leg and foot except the Foot drop with
medial side (supplied by saphenous equinovarus
branch of femoral nerve)
Defect; foot drop with equinovarus
Choose the only correct answer:

1) The muscles inserted into the iliotibial tract are:

a) Tensor fasciae latae and gluteus medius

b) Tensor fasciae latae and gluteus minimus
c) Tensor fasciae latae and deep ¼ of gluteus maximus
d) Tensor fasciae latae and superficial 3/4 of gluteus maximus

2) Lymph from the external genitalia drains first into:

a) Deep inguinal lymph nodes

b) Vertical group of superficial inguinal lymph nodes
c) Superomedial group of superficial inguinal lymph nodes
d) Superlateral group of superficial inguinal lymph nodes
3) The strongest flexor of the thigh at the hip joint is:

a) Pectineus
b) Ilio-psoas
c) Sartorius
d) Rectus femoris

4) The muscle responsible for putting the lower limb in the cross-legged
tailor’s position is:

a) Sartorius
b) Ilio-psoas
c) Gracilis
d) Rectus femoris
5) The guy robe muscles that stabilize the pelvis on the
femur include the following muscles except:

a) Sartorius
b) Semimembranosus
c) Gracilis
d) Semitendinosus

6) The anterior inferior iliac spin gives attachment to:

a) Sartorius
b) Straight head of rectus femoris
c) Reflected head of rectus femoris
d) Tensor fasciae latae
5) The guy robe muscles that stabilize the pelvis on the femur
include the following muscles except:

a) Sartorius
b) Semimembranosus
c) Gracilis
d) Semitendinosus

6) The anterior inferior iliac spin gives attachment to:

a) Sartorius
b) Straight head of rectus femoris
c) Reflected head of rectus femoris
d) Tensor fasciae latae
These ligaments stabilize the sacrum on
the pelvic bones by resisting the upward
tilting of the inferior aspect of the
sacrum. They also convert the greater and
lesser sciatic notches of the pelvic bone
into foramina
 [Pages 79-81]

[L2, 3, 4 dorsal divisions]

[L2, 3, 4 ventral divisions]
 External iliac artery

Superficial epigastric artery

Sartorius muscle
Superficial circumflex
iliac artery
Femoral artery

Superficial external
pudendal artery
Deep external
pudendal artery
Profunda femoris artery

Popliteal artery
Superior gluteal artery

Cruciate anastomosis

Fourth perforating artery

 Lumbar plexus

Iliopsoas
(iliopectineal)
bursa