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,