ANA 211 Gluteal region ror 200l health science students

Anatomy for 200l students

1. COURSE: GROSS ANATOMY COURSE CODE: ANA 211 GLUTEAL REGION

2. It is the transitional region between the trunk and the free lower limb. It includes two parts of the lower limb: the rounded, prominent posterior region ( buttocks), and the lateral, usually less prominent hip (coxa) or hip region. The gluteal region is bounded superiorly by the iliac crest, medially by the intergluteal (natal) cleft, and inferiorly by the skin fold (groove) underlying the buttock, the gluteal fold (sulcus glutealis ). The gluteal muscles constitute the bulk of this region. Gluteal region

3. Buttocks separated at midline by the natal cleft. Gluteal folds; Transverse skin folds at the inferior aspect of the region Ischial tuberosity: a large bony prominence which lies deep to the lower border of gluteus maximus. Greater trochanter of femur: a large bony prominence situated on the side of the hip. Iliac crest is a thick curved bony ridge felt in the groove in the lower margin of the waist. Posterior superior iliac spine lies in the floor of a dimple about 5 cm from the median plane. Sacrum lies posteriorly between the two hip bones. Coccyx lies just behind the anus which is slightly mobile under pressure. Surface Landmarks

4. Surface Landmarks

5. Superficial fascia: It is heavily laden with fat (more in females) and is tough and stringy over the ischial tuberosity where it forms an efficient cushion for supporting the body weight in the sitting posture. It contains cutaneous nerves, vessels and lymphatics. Deep fascia: The deep fascia above and in front of the gluteus maximus, i.e. over the gluteus Medius is thick, dense, opaque and pearly white. Over the gluteus maximus, however, it is thin and transparent. The deep fascia splits and encloses the gluteus maximus muscle. Fascia

6. The parts of the bony pelvis (hip bones, sacrum, and coccyx) are bound together by dense ligaments. The sacrotuberous and sacrospinous ligaments convert the sciatic notches in the hip bones into the greater and lesser sciatic foramina. The sacrotuberous : Is a long and strong ligament extending between the medial margin of ischial tuberosity and the posterior iliac spines . It forms the posteriorlateral boundary of the outlet of the pelvis. Sacrospinous ligaments: Is a short, thick, triangular band situated deep to the sacrotuberous ligament. It is attached: Laterally to the ischial spine Medially to the sacrococcygeal junction Gluteal Ligaments

7. These are two foramina of the gluteal region, which provide a path for entrance and exit of structures to and from pelvis. The sacrotuberous and sacrospinous ligaments convert the sciatic notches into foramina. The greater sciatic foramen is the passageway for structures entering or leaving the pelvis (e.g., sciatic nerve), whereas the lesser sciatic foramen is the passageway for structures entering or leaving the perineum (e.g., pudendal nerve). The greater sciatic foramen (major conduit of neurovascular structures) is the door through which all lower limb arteries and nerves leave the pelvis and enter the gluteal region. Sciatic Foramina

8. Structures Related to Greater Sciatic Foramina The greater sciatic foramen is bounded anterosuperiorly by the greater sciatic notch, posteriorly by the sacrotuberous ligament and inferiorly by the sacrospinous ligament and ischial spine. Structures passing through the greater sciatic foramen (Gate of gluteal region) It is partly filled by the emerging piriformis (key muscle of the region). Above the piriformis are the superior gluteal vessels and nerve leaving the pelvis. Below the piriformis are the inferior gluteal vessels and nerve, internal pudendal vessels and pudendal nerve, sciatic and posterior femoral cutaneous nerves and the nerves to obturator internus and quadratus femoris all leave the pelvis.

9. The lesser sciatic foramen is an opening between the pelvis and the back of the thigh. It is bounded anteriorly by the ischial body, superiorly by its spine and sacrospinous ligament, and posteriorly by the sacrotuberous ligament. Structures passing through the lesser sciatic foramen It transmits the tendon of obturator internus, the nerve to obturator internus, and the internal pudendal vessels and pudendal nerve. Structures Related to Lesser Sciatic Foramina

10. The gluteal muscles have a common compartment but are organized into superficial and deep layers: The superficial layer consists of the three large glutei (maximus, medius , and minimus ) and the tensor of the fascia lata . The deep layer consists of smaller muscles (piriformis, obturator internus, externus gemelli, and quadratus femoris) covered by the inferior half of the gluteus maximus. Gluteus Maximus The gluteus maximus is the most superficial gluteal muscle. It is the largest, heaviest, and most coarsely fibered muscle of the body. The gluteus maximus covers all of the other gluteal muscles except for the anterosuperior third of the gluteus medius . Muscles of the Gluteal Region

11. Gluteus Maximus Origin Ilium posterior to posterior gluteal line; dorsal surface of sacrum and coccyx ; sacrotuberous ligament . Insertion Most fibers end in iliotibial tract , which inserts into lateral condyle of tibia ; some fibers insert on gluteal tuberosity. Nerve supply Inferior gluteal nerve (L5, S1, S2 ). Actions Chief extensor of the thigh at the hip joint. Assist in lateral rotation of the thigh. Abduction of the thigh (by its upper fibres ) Along with the tensor fasciae latea the muscle stabilizes the knee through the iliotibial tract. Muscles of the Gluteal Region

12. Gluteus medius and minimus They are smaller gluteal muscles and are fan shaped, and their fibers converge in the same manner toward essentially the same target. They share the same actions and nerve supply and are supplied by the same blood vessel, the superior gluteal artery. Origin Gluteus medius : External surface of ilium between anterior and posterior gluteal lines Gluteus minimus : External surface of ilium between anterior and inferior gluteal lines Insertion Gluteus medius : Lateral surface of greater trochanter of femur Gluteus minimus : Anterior surface of greater trochanter of femur Nerve Supply Superior gluteal nerve ( L5 , S1) Muscles of the Gluteal Region

13. Gluteus medius and minimus Actions They are powerful abductors of the thigh. Their anterior fibers are medial rotators of the thigh. Their most important action is to maintain the balance of the body when opposite foot is off the ground as in walking and running. They do this by preventing the opposite side of the pelvis from tilting downwards under the influence of gravity. Muscles of the Gluteal Region

14. Gluteal bursae separate the gluteus maximus from adjacent structures. Bursae are membranous sacs lined by a synovial membrane containing a capillary layer of slippery fluid resembling egg white. Bursae are located in areas subject to friction; their purpose is to reduce friction and permit free movement. Usually three bursae are associated with the gluteus maximus: The trochanteric bursa separates superior fibers of the gluteus maximus from the greater trochanter. The trochanteric bursa is commonly the largest of the bursae formed in relation to bony prominences and is present at birth. Other such bursae appear to form as a result of postnatal movement. The ischial bursa separates the inferior part of the gluteus maximus from the ischial tuberosity; it is often absent. The gluteofemoral bursa separates the iliotibial tract from the superior part of the proximal attachment of the vastus lateralis, a thigh muscle. Gluteal Bursae

15. Gluteal Bursae

16. Tensor of fascia lata The tensor of the fascia lata is a fusiform muscle approximately 15 cm long that is enclosed between two layers of fascia lata . Origin Anterior superior iliac spine; anterior part of iliac crest Insertion Iliotibial tract, which attaches to lateral condyle of tibia Nerve supply Superior gluteal nerve ( L5 , S1) Actions Lateral rotator of the thigh at the hip joint Abductor and medial rotator of thigh and extensor of knee joint. Muscles of the Gluteal Region

17. Piriformis The narrow, pear-shaped piriformis is located partly on the posterior wall of the lesser pelvis and partly posterior to the hip joint. Origin Anterior surface of sacrum; sacrotuberous ligament Insertion Superior border of greater trochanter of femur Nerve supply Branches of anterior rami of S1 , S2 Actions Laterally rotate extended thigh and abduct flexed thigh; steady femoral head in acetabulum Muscles of the Gluteal Region

18. Obturator internus It is a fan-shaped flattened belly that lies in the pelvis and the tendon in the gluteal region Origin Pelvic surface of obturator membrane and surrounding bones. Insertion Medial surface of greater trochanter (trochanteric fossa) of femur. Nerve supply Nerve to obturator internus (L5, S1 ) Actions Laterally rotate extended thigh and abduct flexed thigh; steady femoral head in acetabulum Muscles of the Gluteal Region

19. Obturator Externus It is triangular in shape that covers the outer surface of the anterior wall of the pelvis. Origin Outer surface of the obturator membrane and outer surface of the bony margins of obturator foramen. Insertion Trochanteric fossa (on medial side of the greater trochanter). Nerve supply Posterior division of obturator nerve (L2, L3, l4 ) Actions Laterally rotate extended thigh and abduct flexed thigh; steady femoral head in acetabulum Muscles of the Gluteal Region

20. Superior and inferior gemelli It is triangular in shape that covers the outer surface of the anterior wall of the pelvis. Origin Superior: ischial spine Inferior: ischial tuberosity. Insertion Trochanteric fossa (on medial side of the greater trochanter). Nerve supply Superior: Nerve to obturator internus (L5, S1, S2), Inferior: Nerve to quadratus femoris (L4, L5, S1) Actions Laterally rotate extended thigh and abduct flexed thigh; steady femoral head in acetabulum Muscles of the Gluteal Region

21. Quadratus Femoris Is a short, flat quadrangular muscle located inferior to the obturator internus and gemelli. True to its name, the quadratus femoris is a rectangular muscle. Origin Lateral border of ischial tuberosity Insertion Quadrate tubercle on intertrochanteric crest of femur and area inferior to it. Nerve supply Nerve to quadratus femoris (L5, S1) Actions It is a strong lateral rotator of the thigh. Steady femoral head in acetabulum Muscles of the Gluteal Region

22. The arteries of the gluteal region arise, directly or indirectly, from the internal iliac arteries, but the patterns of origin of the arteries varies. Superior gluteal artery The largest branch of the posterior division of the internal iliac artery. Course The superior gluteal artery leaves the pelvis through the greater sciatic foramen, superior to the piriformis, and divides immediately into superficial and deep branches . Distribution The superficial branch supplies the gluteus maximus and skin over the proximal attachment of this muscle. The deep branch supplies the gluteus medius , gluteus minimus , and tensor of the fascia lata . The superior gluteal artery anastomoses with the inferior gluteal and medial circumflex femoral arteries. Arteries of Gluteal Region

23. Inferior gluteal artery The inferior gluteal artery arises from the anterior division of the internal iliac artery Course Enters gluteal region through greater sciatic foramen inferior to piriformis; descends on medial side of sciatic nerve; anastomoses with superior gluteal artery and participates in cruciate anastomosis of thigh, involving first perforating artery of deep femoral and medial and lateral circumflex arteries. Distribution Supplies gluteus maximus, obturator internus, quadratus femoris, and superior parts of hamstrings Arteries of Gluteal Region

24. Internal Pudendal artery It arises from the anterior division of the internal iliac artery and lies anterior to the inferior gluteal artery. Course Enters gluteal region through greater sciatic foramen and has a very short course in the gluteal region. descends posterior to ischial spine; enters perineum through lesser sciatic foramen. Distribution Supplies external genitalia and muscles in perineal region; does not supply gluteal region Others are the arteries involved in the trochanteric anastomosis and Cruciate anastomosis Arteries of Gluteal Region

25. The gluteal veins are tributaries of the internal iliac veins that drain blood from the gluteal region. The superior and inferior gluteal veins accompany the corresponding arteries through the greater sciatic foramen, superior and inferior to the piriformis, respectively. The internal pudendal veins accompany the internal pudendal arteries and join to form a single vein that enters the internal iliac vein. Veins of Gluteal Region

26. Lymph from the deep tissues of the buttocks follows the gluteal vessels to the superior and inferior gluteal lymph nodes and from them to the internal, external, and common iliac lymph nodes and from them to the lateral aortic lumbar ( caval /lymph) nodes. Lymph from the superficial tissues of the gluteal region enters the superficial inguinal lymph nodes, which also receive lymph from the thigh. Lymphatic Drainage of the Gluteal Region

27. Clunial (Superficial Gluteal) Nerves The skin of the gluteal region is richly innervated by superior, middle, and inferior clunial nerves (L. clunes , buttocks). These superficial 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. Nerves of the Gluteal Region

28. The following are the deep nerves to the gluteal region Superior gluteal nerve Inferior gluteal nerve Sciatic nerve Posterior cutaneous nerve of the thigh Nerve to quadratus femoris Sciatic Nerve Pudendal nerve Nerve to the obturator internus Deep Nerves of the Gluteal Region

29. Gluteal Muscles Intramuscular injections are given in the anterosuperior quadrant of the gluteal region (in the glutei medius and minimus to avoid injury to large vessels and nerves which passes through the lower part of this region). When the gluteus maximus is paralyzed as in muscular dystrophy, the patent cant stand up from a sitting posture without support. When the glutei medius and minimus (of right side) are paralyzed , the patient cannot walk normally. He/she bends waddles on the right side or paralyzed side to clear the opposite foot i.e. left off the ground. This is known as lurching gait (Trendelenburg) ; when bilateral, it is called the waddling gait. Clinicals

30. Ischial Bursitis Recurrent microtrauma resulting from repeated stress (e.g., as from cycling, rowing, or other activities involving repetitive hip extension while seated) may overwhelm the ischial bursa's ability to dissipate applied stress. The recurrent trauma results in inflammation of the bursa (ischial bursitis). Trochanteric Bursitis Inflammation of the trochanteric bursae, or trochanteric bursitis, may result from repetitive actions such as climbing stairs while carrying heavy objects or running on a steeply elevated treadmill. These movements involve the gluteus maximus which causes deep diffuse pain in the lateral thigh region. This type of friction bursitis is characterized by point tenderness over the great trochanter; however, the pain radiates along the iliotibial tract that extends from the iliac tubercle to the tibia. Clinicals

31. Briefly discuss on the following Trochanteric anastomosis Cruciate anastomosis Write in a tabular form the Origin, Course and Distribution of the following nerves: Superior gluteal nerve Inferior gluteal nerve Sciatic nerve Posterior cutaneous nerve of the thigh Nerve to quadratus femoris Sciatic Nerve Pudendal nerve Nerve to the obturator internus Assignment

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