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 A- when the weight is on the both gluteus medius feet, the pelvis is evenly supported and does not sag and minimus 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!!!  This narrow, pear- shaped Piriformis 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  Inferior vesical artery

Internal Iliac 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.  Inferior gluteal artery- passes Internal Iliac artery 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