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Piriformis Muscle
The piriformis muscle () is a flat, pyramidally-shaped muscle in the buttock, gluteal region of the lower limbs. It is one of the six muscles in the lateral rotator group. The piriformis muscle has its origin upon the front surface of the sacrum, and inserts onto the greater trochanter of the femur. Depending upon the given position of the leg, it acts either as external (lateral) rotator of the thigh or as abductor of the thigh. It is innervated by the piriformis nerve. Structure The piriformis is a flat muscle, and is pyramidal in shape. Origin The piriformis muscle originates from the Pelvic surface of sacrum, anterior (front) surface of the sacrum by three fleshy digitations attached to the Sacrum, second, third, and fourth sacral vertebra. It also arises from the superior margin of the greater sciatic notch, the gluteal surface of the Ilium (bone), ilium (near the posterior inferior iliac spine), the sacroiliac joint capsule, and (sometimes) the sacrotuberous ligament (m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lateral Rotator Group
The lateral rotator group is a group of six small muscles of the hip which all Anatomical terms of motion#Rotation, externally (laterally) rotate the femur in the hip, hip joint. It consists of the following muscles: Piriformis muscle, piriformis, Superior gemellus muscle, gemellus superior, Internal obturator muscle, obturator internus, Inferior gemellus muscle, gemellus inferior, Quadratus femoris muscle, quadratus femoris and the External obturator muscle, obturator externus. All muscles in the lateral rotator group Anatomical terms of muscle#Origin, originate from the hip bone and Anatomical terms of muscle#Insertion, insert on to the Upper extremity of femur, upper extremity of the femur. The muscles are innervated by the sacral plexus (Lumbar nerves#Fourth lumbar nerve, L4-Sacral spinal nerve 2, S2), except the External obturator muscle, obturator externus muscle, which is innervated by the lumbar plexus. Individual muscles Other lateral rotators This group does not includ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greater Trochanter
The greater trochanter of the femur is a large, irregular, quadrilateral eminence and a part of the skeletal system. It is directed lateral and medially and slightly posterior. In the adult it is about 2–4 cm lower than the femoral head.Standring, Susan, editor. ''Gray’s Anatomy: The Anatomical Basis of Clinical Practice''. Forty-First edition, Elsevier Limited, 2016, p. 1327. Because the pelvic outlet in the female is larger than in the male, there is a greater distance between the greater trochanters in the female. It has two surfaces and four borders. It is a traction epiphysis. Surfaces The ''lateral surface'', quadrilateral in form, is broad, rough, convex, and marked by a diagonal impression, which extends from the postero-superior to the antero-inferior angle, and serves for the insertion of the tendon of the gluteus medius. Above the impression is a triangular surface, sometimes rough for part of the tendon of the same muscle, sometimes smooth for the interp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Obturator Internus
The internal obturator muscle or obturator internus muscle originates on the medial surface of the obturator membrane, the ischium near the membrane, and the rim of the pubis (bone), pubis. It exits the pelvis, pelvic cavity through the lesser sciatic foramen. The internal obturator is situated partly within the lesser pelvis, and partly at the back of the hip-joint. It functions to help laterally rotate femur with hip extension and abduct femur with hip flexion, as well as to steady the femoral head in the acetabulum. Structure Origin The internal obturator muscle arises from the inner surface of the antero-lateral wall of the pelvis. It surrounds the obturator foramen. It is attached to the inferior pubic ramus and ischium, and at the side to the inner surface of the hip bone below and behind the pelvic brim. It reaches from the upper part of the greater sciatic foramen above and behind to the obturator foramen below and in front. It also arises from the pelvic surface of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inferior Gemellus
The gemelli muscles are the inferior gemellus muscle and the superior gemellus muscle, two small accessory fasciculi to the tendon of the internal obturator muscle. The gemelli muscles belong to the lateral rotator group of six muscles of the hip that rotate the femur in the hip joint. Superior gemellus muscle The gemelli muscles are two small muscular fasciculi, accessories to the tendon of the internal obturator muscle which is received into a groove between them. The superior gemellus muscle is the higher placed gemellus muscle that arises from the outer (gluteal) surface of the ischial spine, and blends with the upper part of the tendon of the internal obturator. It is smaller than the inferior gemellus. In some people, the fibres of the gemellus superior extend further than average, and are prolonged onto the medial surface of the greater trochanter of the femur. The superior and inferior gemelli are supplied by the inferior gluteal artery. Nerve supply to the superior geme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tendon
A tendon or sinew is a tough band of fibrous connective tissue, dense fibrous connective tissue that connects skeletal muscle, muscle to bone. It sends the mechanical forces of muscle contraction to the skeletal system, while withstanding tension (physics), tension. Tendons, like ligaments, are made of collagen. The difference is that ligaments connect bone to bone, while tendons connect muscle to bone. There are about 4,000 tendons in the adult human body. Structure A tendon is made of dense regular connective tissue, whose main cellular components are special fibroblasts called tendon cells (tenocytes). Tendon cells synthesize the tendon's extracellular matrix, which abounds with densely-packed collagen fibers. The collagen fibers run parallel to each other and are grouped into fascicles. Each fascicle is bound by an endotendineum, which is a delicate loose connective tissue containing thin collagen fibrils and elastic fibers. A set of fascicles is bound by an epitenon, whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sacrotuberous Ligament
The sacrotuberous ligament (great or posterior sacrosciatic ligament) is situated at the lower and back part of the pelvis. It is flat, and triangular in form; narrower in the middle than at the ends. Structure It runs from the sacrum (the lower transverse sacral tubercles, the inferior margins sacrum and the upper coccyx) to the tuberosity of the ischium. It is a remnant of part of biceps femoris muscle. The sacrotuberous ligament is attached by its broad base to the posterior superior iliac spine, the posterior sacroiliac ligaments (with which it is partly blended), to the lower transverse sacral tubercles and the lateral margins of the lower sacrum and upper coccyx. Its oblique fibres descend laterally, converging to form a thick, narrow band that widens again below and is attached to the medial margin of the ischial tuberosity. It then spreads along the ischial ramus as the falciform process, whose concave edge blends with the fascial sheath of the internal pudendal vessels ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sacroiliac Joint
The sacroiliac joint or SI joint (SIJ) is the joint between the sacrum and the ilium bones of the pelvis, which are connected by strong ligaments. In humans, the sacrum supports the spine and is supported in turn by an ilium on each side. The joint is strong, supporting the entire weight of the upper body. It is a synovial plane joint with irregular elevations and depressions that produce interlocking of the two bones. The human body has two sacroiliac joints, one on the left and one on the right, that often match each other but are highly variable from person to person. Structure Sacroiliac joints are paired C-shaped or L-shaped joints capable of a small amount of movement (2–18 degrees, which is debatable at this time) that are formed between the auricular surfaces of the sacrum and the ilium bones. However, mostBogduk, Nicolai "Clinical and Radiological Anatomy of the Lumbar Spine" Elsevier Health Sciences, 2022, p. 172. agree that only slight movements occur on thes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Posterior Inferior Iliac Spine
Posterior may refer to: * Posterior (anatomy), the end of an organism opposite to anterior ** Buttocks, as a euphemism * Posterior horn (other) * Posterior probability The posterior probability is a type of conditional probability that results from updating the prior probability with information summarized by the likelihood via an application of Bayes' rule. From an epistemological perspective, the posteri ..., the conditional probability that is assigned when the relevant evidence is taken into account * Posterior tense, a relative future tense {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ilium (bone)
The ilium () (: ilia) is the uppermost and largest region of the coxal bone, and appears in most vertebrates including mammals and birds, but not bony fish. All reptiles have an ilium except snakes, with the exception of some snake species which have a tiny bone considered to be an ilium. The ilium of the human is divisible into two parts, the body and the wing; the separation is indicated on the top surface by a curved line, the arcuate line, and on the external surface by the margin of the acetabulum. The name comes from the Latin ('' ile'', ''ilis''), meaning "groin" or "flank". Structure The ilium consists of the body and wing. Together with the ischium and pubis, to which the ilium is connected, these form the pelvic bone, with only a faint line indicating the place of union. The body () forms less than two-fifths of the acetabulum; and also forms part of the acetabular fossa. The internal surface of the body is part of the wall of the lesser pelvis and gives o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greater Sciatic Notch
The greater sciatic notch is a notch in the ilium, one of the bones that make up the human pelvis. It lies between the posterior inferior iliac spine (above), and the ischial spine (below). The sacrospinous ligament changes this notch into an opening, the greater sciatic foramen. The notch holds the piriformis, the superior gluteal vein and artery, and the superior gluteal nerve; the inferior gluteal vein and artery and the inferior gluteal nerve; the sciatic and posterior femoral cutaneous nerves; the internal pudendal artery and veins, and the nerves to the internal obturator and quadratus femoris muscles. Of these, the superior gluteal vessels and nerve pass out above the piriformis, and the other structures below it. The greater sciatic notch is wider in females (about 74.4 degrees on average) than in males (about 50.4 degrees). [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pelvic Surface Of Sacrum
The sacrum (: sacra or sacrums), in human anatomy, is a triangular bone at the base of the spine that forms by the fusing of the sacral vertebrae (S1S5) between ages 18 and 30. The sacrum situates at the upper, back part of the pelvic cavity, between the two wings of the pelvis. It forms joints with four other bones. The two projections at the sides of the sacrum are called the alae (wings), and articulate with the ilium at the L-shaped sacroiliac joints. The upper part of the sacrum connects with the last lumbar vertebra (L5), and its lower part with the coccyx (tailbone) via the sacral and coccygeal cornua. The sacrum has three different surfaces which are shaped to accommodate surrounding pelvic structures. Overall, it is concave (curved upon itself). The base of the sacrum, the broadest and uppermost part, is tilted forward as the sacral promontory internally. The central part is curved outward toward the posterior, allowing greater room for the pelvic cavity. In all ot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
