Department of Human Anatomy.

Medical University of Białystok

Beata Klim

Gluteal region

It lies posterior to the pelvis between the level of the iliac crests and the inferior borders of the gluteus maximus muscles.

The intergluteal (natal) cleft separates the buttocks from each other.

The gluteal sulcus demarcates the inferior boundary of the buttock and the superior boundary of the thigh.

Gluteal region

The gluteal muscles

(maximus, medius and

minimus) form the

bulk of the buttock.

Pelvic girdle- muscles

The anterior compartment:

Psoas major

Psoas minor

Iliacus

They are called - Iliopsoas

Iliopsoas

Proximal attachments:

Psoas major- sides of T12-L5

vertebrae & discs between

them; transverse processes of all

lumbar vertebrae

Psoas minor- sides of T12-L1

& intervertebral disc

Iliacus- iliac crest, iliac fossa,

ala of sacrum & anterior

sacroiliac ligaments

Iliopsoas

Distal attachments:

Psoas major- lesser

trochanter of femur

Psoas minor- pectineal line,

iliopectineal eminence via

iliopectineal arch

Iliacus- tendon of psoas

major, lesser trochanter, and

femur distal to it

Iliopsoas

Innervation:

Psoas major- ventral rami of

lumbar nerves L1, L2, L3

Psoas minor- ventral rami of

lumbar nerves L1, L2

Iliacus- femoral nerve L2,

L3

Iliopsoas

Main action:

It is the chief flexor of the

thigh, and when the thigh is

fixed, it flexes the trunk on

the hip.

It is also a postural muscle

that is active during standing

by preventing hyperextension

of the hip joint.

The gluteal muscles

The gluteal muscles consist of:

Three large glutei (maximus, medius & minimus), which are

mainly extensors and abductors of the thigh.

A deeper group of smaller muscles (piriformis, obturator

internus, obturator externus, gemelli and quadratus femoris),

which are covered by the inferior part of the gluteus maximus.

They are the lateral rotators of the thigh, and also stabilize the

hip joint by steadying the femoral head in the acetabulum.

Gluteus maximus

The most superficial gluteal

muscle.

It is the largest, heaviest,

and the most coarsely

fibered muscle.

It covers the other gluteal

muscles except the posterior

third of the gluteus medius.

It forms a pad over the

ischial tuberosity.

Gluteus maximus

The ischial tuberosity can be felt on deep palpation through the muscle just superior to the medial part of the gluteal fold

When the thigh is flexed, the inferior border moves superiorly, leaving the ischial tuberosity subcutaneous. You do not sit on your gluteus maximus; you sit on the fatty fibrous tissue, and the ischial bursa that lie between the IT & the skin

Gluteus maximus

Proximal attachment: ilium

posterior to the posterior gluteal

line, dorsal surface of sacrum

and coccyx, and sacrotuberous

ligament

Distal attachment: most fibers

end in iliotibial tract that inserts

into lateral condyle of tibia;

some fibers insert on gluteal

tuberosity of femur

Innervation: inferior gluteal

nerve (L5, S1 and S2)

Gluteus maximus

The main actions are extension

and lateral rotation of the thigh

It acts when force is necessary

and functions primarily between

the flexed and standing (straight)

position of the thigh, as when

rising from the sitting position,

straightening from the bending

position, walking upstairs, and

running. It is also able to assist in

making the knee stable by

iliotibial tract

Tensor of fascia lata

Proximal attachment: anterior superior iliac spine and anterior part of iliac crest

Distal attachment: iliotibial tract

Innervation: superior gluteal nerve (L4- L5)

Main Action: abduction, medial rotation, and flexion thigh; helps to keep knee extended; steadies trunk on thigh

Iliotibial tract

The deep fascia of the thigh is called fascia lata

The lateral part, which is thickened and strengthened by additional longitudinal fibers to form Iliotibial tract

This broad band of fibers is the conjoint aponeurosis of the tensor of fascia lata and gluteus maximus muscle

It extends from the iliac tubercle to a tubercle on the lateral condyle of the tibia. It crosses the knee and attaches to the tibia in the extends position of the knee.

Gluteus medius et minimus

They are fan-shaped , and their fibers pass in the same direction

They have the same actions, nerve and arterial supply.

The gluteus minimus and most of the gluteus medius lie deep to the gluteus maximus on the external surface of the ilium

Innervation- Superior gluteal nerve (L5 and S1)

Gluteus medius et minimus

Proximal attachment of gluteus medius: external surface of ilium between anterior et posterior gluteal line

Distal attachment: lateral surface of greater trochanter

Proximal attachment of gluteus minimus: external surface of ilium between anterior et inferior gluteal line

Distal attachment: anterior surface of greater trochanter

Gluteus medius et minimus

They abducts the thigh and rotate it medially

They play the essential role during locomotion and are largely responsible for preventing sagging of the unsupported side of the pelvis during walking. Keeping the pelvis level enables the nonweightbearing foot to clear the groung as it is brought forward during walking

Action of the

gluteus medius

and minimus

A- when the weight is on the both

feet, the pelvis is evenly supported

and does not sag

B- when it is borne by one foot,

muscles of the same side hold the

pelvis so that the pelvis will not sag

on the side of the raised limb

C- when this muscles are inactive

owning to injury of the superior

gluteal nerve, the supporting and

steadying action is lost and the

pelvis falls on the side of the raised

limb (positive Trendelenburg sign)

So recapitulate- this muscles are

cause of movement is fluent!!!

Piriformis This narrow, pear- shaped muscle is located partly on the posterior wall of the lesser pelvis and partly posterior to the hip joint

Proximal attachment: anterior surface of sacrum and sacrotuberous ligament

It leaves the pelvis through the greater sciatic foramen and attaches to the superior border of the greater trochanter of femur

Innervation: branches of ventral rami of S1 & S2.

Piriformis

Because of it key position in the

buttock, the piriformis is the

landmark of the gluteal region

It is provides the key to

understanding relationship in the

gluteal region because it

determines the names of the blood

vessels and nerves:

The superior gluteal vessels and

nerve emerge superior to it

The inferior gluteal vessels and

nerve emerge inferior to it.

Piriformis

The surface marking of

the superior border of the

piriformis is indicated by

a line joining the skin

dimple formed by the

posterior superior iliac

spine to the superior

border of the greater

trochanter of the femur.

Obturator internus and gemelli

The obturator internus and the

superior and inferior gemelli

form a tricipital (three- headed)

muscle, which is called the

triceps coxae

They occupies the interval

between the piriformis and

quadratus femoris

The tricipital tendon of this

muscle lies horizontally in the

buttock and finishes on the

greater trochanter of femur.

Obturator internus It is located partly in the pelvis, where it covers most of the lateral wall

Proximal attachement: pelvic surface of obturator membrane and surranding bones

It leaves the pelvis through the lesser sciatic foramen, becoming tendinous as it attaches to the medial surface of the greater trochanter

Innervation: together with superior gemellus (L5 & S1)

Superior and inferior gemelli

The gemelli muscle assist to the obturator

internus

The superior and inferior gemelli arise

from the ischial spine, and ischial

tuberosity, respectively

They run to the medial surface of greater

trochanter (trochanteric fossa) of femur

The triceps coxae: laterally rotate

extended thigh and abduct flexed thigh;

steady femoral head in acetabulum

Quadratus femoris

This is a short, flat, quadrangular muscle, which is located inferior to the obturator internus and gemelli

It runs from lateral border of the ischial tuberosity to the quadrate tubercle on intertrochanteric crest of femur and area inferior to it

Together with inferior gemellus is innervated by nerve to quadratus femoris (L5- S1)

Main action: laterally rotation and steadies femoral head in acetabulum.

Obturator externus

It lies deep in the thigh, posterior to the pectineus and the superior ends of the adductor muscles

Obturator foramen & membrane

The tendon passes deep to the quadratus femoris on the way to its attachments to the trochanteric fossa of the femur

With other short muscles around the hip joint, stabilizes the head of the femur in the acetabulum. It is also a lateral rotator of the thigh and adductor

Greater and lesser sciatic foramen

Greater sciatic foramen is boundaried by greater sciatic notch and sacrospinous ligament

Boundaries of the lesser sciatic foramen: lesser sciatic notch and ligaments: sacrospinous and sacroturerous

Greater sciatic foramen

Piriformis muscle leaves

the pelvis through the

median part of the greater

sciatic foramen

In this way are formed

two smaller orifices (one

superior to this muscle,

and another inferior to it)

Greater sciatic foramen

This is the passageway for structures entering or leaving the pelvis:

piriformis muscle

superiorly- gluteal superior vessels and nerve

inferiorly- gluteal inferior vessels and nerve

- sciatic nerve

- posterior cutaneous nerve of thigh

- internal pudendal vessels

- pudendal nerve

Lesser sciatic foramen

Through this opening run:

the tendon of the obturator

internus

pudendal nerve

internal pudendal vessels

Lumbar Plexus

It is located in the posterior

part of the psoas major,

anterior to the lumbar

transverse processes

This nerve network is

composed of the ventral

rami of L1 through L4

nerves

All this rami receive gray

communicanting rami from

the sympathetic trunks

Lumbar plexus The largest branches are:

the femoral nerve

the obturator nerve

the lumbosacral trunk (descends

into the pelvis to participate in

the formation of the sacral

plexus)

the ilioinguinal and

iliohypogastric nerves (they pass

inferolaterally, anterior to the

quadratus lumborum. They

pierce the transverse abdominal

and oblique muscles to supply

the skin of the suprapubic and

inguinal regions.

Lumbar Plexus

the genitofemoral nerve (pierces the anterior surface of the psoas major and runs inferiorly on it deep to the psoas fascia; it divides into femoral and genital branches

the lateral femoral cutaneous nerve (runs inferolaterally on the iliacus and enters the thigh posterior to the inguinal ligament, just medial to the anterior superior iliac spine. It supplies on the anterolateral surface of the thigh

Femoral nerve

(L2-L4)- the largest branch

It emerges from the lateral

border of the psoas major and

descends posterolaterally

through the pelvis to the

midpoint of the inguinal

ligament

It passes deep to this

ligament and enters the

femoral triangle, lateral to the

femoral vessels

Femoral nerve

After entering the triangle divides

into several branches to the

anterior thigh muscles

It also sends articular branches to

the hip and the knee joints and

provides several cutaneous

branches to the anteromedial side

of thigh

The terminal cutaneous branch of

the femoral nerve is called the

saphenous nerve

The saphenous nerve

It accompanies the femoral

artery and vein through the

adductor canal

It passes between the sartorius

and gracilis when the femoral

vessels traverse the adductor

hiatus at the distal end of the

canal

It runs anteroinferiorly to

supply the skin and fascia on

the anteromedial aspect of the

knee, leg and foot

The obturator nerve

It arises from the lumbar

plexus in the abdomen and

enters the lesser pelvis

It runs in the extraperitoneal

fat along the lateral wall of the

pelvis to the obturator canal

It divides into anterior and

posterior parts that leave the

pelvis through this canal and

supply the medial (adductors)

thigh muscles

Obturator canal

This space is boundaried

by the obturator groove

and opening in the

obturator membrane.

The obturator nerve and

vessels pass from the

pelvic cavity into the

thigh.

Sacral plexus

It is located on the

posterolateral wall of the

lesser pelvis

It is related to the anterior

surface of the piriformis

This nerve network is

composed of the ventral rami

of L5 through S4 nerves

Connection between the

lumbar and sacral-

lumbosacral trunk

Sacral plexus

Two main nerves arising

from the plexus (sciatic and

pudendal) lie external to the

parietal pelvic fascia

Most branches of the sacral

plexus leave the pelvis

through the greater sciatic

foramen

Sciatic nerve

It is the largest nerve in the

body (L4-S3)

It passes through the greater

sciatic foramen inferior to the

piriformis to enter the gluteal

region

It descends along the

posterior aspect of the thigh

and supply the flexors of

knee in thigh and all muscles

in leg and foot

Pudendal nerve

(S2-S4)

The main nerve of the

perineum and chief sensory

nerve of the external genitalia

Accompanied by the internal

pudendal vessels

It leaves the pelvis through the

GSF, then hooks around the

ischial spine and sacrospinous

ligament and enters the

perineum through the LSF

Superior gluteal nerve

L4- S1

It leaves the pelvis through

the GSF superior to the

piriformis and supply three

muscles of the gluteal region:

Gluteus medius and minimus

Tensor of fascia lata

Inferior gluteal nerve

L5- S2

It leaves the pelvis through

the GSF inferior to the

piriformis and superficial to

the sciatic nerve

It supplies:

Gluteus maximus

Posterior femoral cutaneous nerve

S2- S3

It leaves the pelvis through the

GSF inferior to the piriformis

It supplies:

Skin of the buttock and

uppermost medial and posterior

surfaces of thigh

Common iliac artery

They begin at the aortic

bifurcation at the level of

L4.

They diverge and run

inferolaterally, following

the medial border of the

psoas muscles to the pelvic

brim.

Here each artery divides

into the internal and

external iliac arteries.

External iliac artery

It follows the iliopsoas

muscle.

Just before leaving the

abdomen, the external

iliac artery gives rise to

the inferior epigastric and

deep circumflex iliac

arteries that supply the

anterolateral abdominal

wall.

Inferior epigastric

Runs superiorly and

enters rectus sheath

Runs deep to the rectus

abdominis

It distributes rectus

abdominis and the

medial part of the

anterolateral abdominal

wall

Deep circumflex iliac

Runs on deep aspect of

anterior abdominal wall,

parallel to inguinal ligament

It distributes iliacus muscle

and inferior part of the

anterolateral abdominal wall

External iliac artery

It finishes at the level of the

inguinal ligament, passing

midway between the anterior

superior iliac spine and the pubic

symphysis.

It continuation is called the

femoral artery

Femoral sheath

Funnel- shaped fascial tube

It extends 3 to 4 cm inferior to the inguinal ligament and encloses proximal parts of the femoral vessels and the femoral canal

It is formed by an inferior prolongation of transversalis and iliopsoas fascia from the abdomen

It does not enclose the femoral nerve

Femoral sheath

The femoral sheath allows the

femoral artery and vein to glide

deep to the inguinal ligament

during movements of the hip joint

The femoral sheath is subdivided

into three compartments by vertical

septa derived from extraperitoneal

connective tissue of the abdomen

that extends along the vessels.

Femoral sheath

The compartments of the

femoral sheath are the:

Lateral compartment for the

femoral artery

Intermediate compartment for

the femoral vein.

Medial compartment, which is

the femoral canal.

Internal Iliac artery

Each IIA begins anterior to the sacriiliac joint (separated from it by the internal iliac vein and lumbosacral trunk) at the bifurcation of the common iliac artery and descends posteriorly to the greater sciatic foramen

It is the artery of the pelvis, however it also sends branches to the buttock, medial thigh regions and the perineum

Internal Iliac artery

The IIA commonly ends at the superior edge of the greater sciatic foramen by dividing into anterior and posterior divisions

The branch of the anterior division are mainly visceral (they supply the bladder, rectum, and reproductive organs)

It also has two parietal branches that pass to the buttock and thigh.

Internal Iliac artery

Branches of the anterior division of the IIA:

Umbilical artery

Obturator artery- It arises close to the umbilical artery, it runs anterolaterally on the obturator fascia on the lateral wall of the pelvis, and passes between the O N&V.

It leaves the pelvis through the obturator canal and supplies medial muscles of the thigh

Internal Iliac artery Inferior vesical artery

Middle rectal artery

Vaginal artery

Uterine artery

Internal pudendal artery- passes

anterolaterally anterior to the

piriformis muscle. It leaves the

pelvis by the inferior part of the

greater sciatic foramen; and

next passes through the

pudendal canal in the lateral

wall of the ischioanal fossa,

after this it divides into the deep

and dorsal arteries of the penis

and clitoris.

Internal Iliac artery Inferior gluteal artery- passes

between the sacral nerves and

leaves the pelvis by the

inferior part of the GSF.It

supplies the muscles and skin

of the buttock and the

posterior surface of the thigh.

Superior gluteal artery-runs

between the lumbosacral

trunk and the VR of S1. It

leaves by the superior part of

the GSF, and supply the

gluteal muscle in the

buttocks.

Iliolumbar & lateral sacral

artery