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Lesser Sciatic Foramen
The lesser sciatic foramen is an opening (foramen) between the pelvis and the back of the thigh. The foramen is formed by the sacrotuberous ligament which runs between the sacrum and the ischial tuberosity and the sacrospinous ligament which runs between the sacrum and the ischial spine. Structure The lesser sciatic foramen has the following boundaries: * Anterior: the tuberosity of the ischium * Superior: the spine of the ischium and sacrospinous ligament * Posterior: the sacrotuberous ligament Alternatively, the foramen can be defined by the boundaries of the lesser sciatic notch and the two ligaments. Function The following pass through the foramen: * the tendon of the Obturator internus * internal pudendal vessels * pudendal nerve * nerve to the obturator internus See also *Greater sciatic foramen The greater sciatic foramen is an opening (foramen) in the posterior human pelvis. It is formed by the sacrotuberous and sacrospinous ligaments. The piriformis muscle pass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pelvis
The pelvis (plural pelves or pelvises) is the lower part of the trunk, between the abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also called bony pelvis, or pelvic skeleton). The pelvic region of the trunk includes the bony pelvis, the pelvic cavity (the space enclosed by the bony pelvis), the pelvic floor, below the pelvic cavity, and the perineum, below the pelvic floor. The pelvic skeleton is formed in the area of the back, by the sacrum and the coccyx and anteriorly and to the left and right sides, by a pair of hip bones. The two hip bones connect the spine with the lower limbs. They are attached to the sacrum posteriorly, connected to each other anteriorly, and joined with the two femurs at the hip joints. The gap enclosed by the bony pelvis, called the pelvic cavity, is the section of the body underneath the abdomen and mainly consists of the reproductive organs (sex organs) and the rectum, while the pelvic f ... [...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 and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sacrum
The sacrum (plural: ''sacra'' or ''sacrums''), in human anatomy, is a large, 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 pel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ischial Tuberosity
The ischial tuberosity (or tuberosity of the ischium, tuber ischiadicum), also known colloquially as the sit bones or sitz bones, or as a pair the sitting bones, is a large swelling posteriorly on the superior ramus of the ischium. It marks the lateral boundary of the pelvic outlet. When sitting, the weight is frequently placed upon the ischial tuberosity. The gluteus maximus provides cover in the upright posture, but leaves it free in the seated position.Platzer (2004), p 236 The distance between a cyclist's ischial tuberosities is one of the factors in the choice of a bicycle saddle. Divisions The tuberosity is divided into two portions: a lower, rough, somewhat triangular part, and an upper, smooth, quadrilateral portion. * The ''lower portion'' is subdivided by a prominent longitudinal ridge, passing from base to apex, into two parts: ** The outer gives attachment to the adductor magnus ** The inner to the sacrotuberous ligament * The ''upper portion'' is subdivided into ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sacrospinous Ligament
The sacrospinous ligament (small or anterior sacrosciatic ligament) is a thin, triangular ligament in the human pelvis. The base of the ligament is attached to the outer edge of the sacrum and coccyx, and the tip of the ligament attaches to the spine of the ischium, a bony protuberance on the human pelvis. Its fibres are intermingled with the sacrotuberous ligament. Structure The sacrotuberous ligament passes behind the sacrospinous ligament. In its entire length, the sacrospinous ligament covers the equally triangular coccygeus muscle, to which its closely connected.Gray's Anatomy 1918 Function The presence of the ligament in the greater sciatic notch creates an opening (foramen), the greater sciatic foramen, and also converts the lesser sciatic notch into the lesser sciatic foramen.Platzer (2004), p 188 The greater sciatic foramen lies above the ligament, and the lesser sciatic foramen lies below it. The pudendal vessels and nerve pass behind the sacrospinous ligament directl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ischial Spine
The ischial spine is part of the posterior border of the body of the ischium bone of the pelvis. It is a thin and pointed triangular eminence, more or less elongated in different subjects. Structure The pudendal nerve travels close to the ischial spine. Clinical significance The ischial spine can serve as a landmark in pudendal anesthesia, as the pudendal nerve The pudendal nerve is the main nerve of the perineum. It carries sensation from the external genitalia of both sexes and the skin around the anus and perineum, as well as the motor supply to various pelvic muscles, including the male or fem ... lies close to the ischial spine. Additional images File:Sciatic notches.png, Right hip bone, external surface, showing the greater and lesser sciatic notches, separated by the ischial spine. File:Gray319.png, Articulations of pelvis. Anterior view. File:Slide3ADA.JPG, PELVIS. ANTERIOR VIEW. References External links * - "The Female Perineum: Osteology" * - "Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tuberosity Of The Ischium
The ischial tuberosity (or tuberosity of the ischium, tuber ischiadicum), also known colloquially as the sit bones or sitz bones, or as a pair the sitting bones, is a large swelling posteriorly on the superior ramus of the ischium. It marks the lateral boundary of the pelvic outlet. When sitting, the weight is frequently placed upon the ischial tuberosity. The gluteus maximus provides cover in the upright posture, but leaves it free in the seated position.Platzer (2004), p 236 The distance between a cyclist's ischial tuberosities is one of the factors in the choice of a bicycle saddle. Divisions The tuberosity is divided into two portions: a lower, rough, somewhat triangular part, and an upper, smooth, quadrilateral portion. * The ''lower portion'' is subdivided by a prominent longitudinal ridge, passing from base to apex, into two parts: ** The outer gives attachment to the adductor magnus ** The inner to the sacrotuberous ligament * The ''upper portion'' is subdivided into ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spine Of The Ischium
The ischial spine is part of the posterior border of the body of the ischium bone of the pelvis. It is a thin and pointed triangular eminence, more or less elongated in different subjects. Structure The pudendal nerve travels close to the ischial spine. Clinical significance The ischial spine can serve as a landmark in pudendal anesthesia, as the pudendal nerve The pudendal nerve is the main nerve of the perineum. It carries sensation from the external genitalia of both sexes and the skin around the anus and perineum, as well as the motor supply to various pelvic muscles, including the male or fem ... lies close to the ischial spine. Additional images File:Sciatic notches.png, Right hip bone, external surface, showing the greater and lesser sciatic notches, separated by the ischial spine. File:Gray319.png, Articulations of pelvis. Anterior view. File:Slide3ADA.JPG, PELVIS. ANTERIOR VIEW. References External links * - "The Female Perineum: Osteology" * - "Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lesser Sciatic Notch
Below the ischial spine is a small notch, the lesser sciatic notch; it is smooth, coated in the recent state with cartilage, the surface of which presents two or three ridges corresponding to the subdivisions of the tendon of the Obturator internus, which winds over it. It is converted into a foramen, the lesser sciatic foramen, by the sacrotuberous and sacrospinous ligament The sacrospinous ligament (small or anterior sacrosciatic ligament) is a thin, triangular ligament in the human pelvis. The base of the ligament is attached to the outer edge of the sacrum and coccyx, and the tip of the ligament attaches to the s ...s, and transmits the tendon of the Obturator internus, the nerve which supplies that muscle, and the internal pudendal (other), internal pudendal vessels and pudendal nerve. See also * Lesser sciatic foramen * Greater sciatic notch References External links * - The Male Perineum and the Penis: Osteology" * - "The Male Pelvis: Hip Bone" {{Auth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pudendal Nerve
The pudendal nerve is the main nerve of the perineum. It carries sensation from the external genitalia of both sexes and the skin around the anus and perineum, as well as the motor supply to various pelvic muscles, including the male or female external urethral sphincter and the external anal sphincter. If damaged, most commonly by childbirth, lesions may cause sensory loss or fecal incontinence. The nerve may be temporarily blocked as part of an anaesthetic procedure. The pudendal canal that carries the pudendal nerve is also known by the eponymous term "Alcock's canal", after Benjamin Alcock, an Irish anatomist who documented the canal in 1836. Structure The pudendal nerve is paired, meaning there are two nerves, one on the left and one on the right side of the body. Each is formed as three roots immediately converge above the upper border of the sacrotuberous ligament and the coccygeus muscle. The three roots become two cords when the middle and lower root join to fo ... [...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. It exits the 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 the obturator membra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
