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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 passes through the foramen and occupies most of its volume. The greater sciatic foramen is wider in women than in men. Structure It is bounded as follows: * anterolaterally by the greater sciatic notch of the ilium. * posteromedially by the sacrotuberous ligament. * inferiorly by the sacrospinous ligament and the ischial spine. * superiorly by the anterior sacroiliac ligament. Function The piriformis The piriformis muscle () is a flat, pyramidally-shaped muscle in the 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 in ..., which exits the pelvis through the foramen, occupies most of its volume. The following structures also exit the pelvis through the greater sciatic foramen: S ... [...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] |
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 ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internal Pudendal Vessels
The internal pudendal artery is one of the three pudendal arteries. It branches off the internal iliac artery, and provides blood to the external genitalia. Structure The internal pudendal artery is the terminal branch of the anterior trunk of the internal iliac artery. It is smaller in the female than in the male. Path It arises from the anterior division of internal iliac artery. It runs on the lateral pelvic wall. It exits the pelvic cavity through the greater sciatic foramen, inferior to the piriformis muscle, to enter the gluteal region. It then curves around the sacrospinous ligament to enter the perineum through the lesser sciatic foramen. It travels through the pudendal canal with the internal pudendal veins and the pudendal nerve. Branches The internal pudendal artery gives off the following branches: The deep artery of clitoris is a branch of the internal pudendal artery and supplies the clitoral crura. Another branch of the internal pudendal artery is the do ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 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 o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nerve To Quadratus Femoris
The nerve to quadratus femoris is a nerve that provides innervation to the quadratus femoris muscle and gemellus inferior muscle. Structure The nerve to quadratus femoris is a sacral plexus nerve. It arises from the ventral divisions of the fourth lumbar spinal nerve, fifth lumbar spinal nerve, and first sacral spinal nerve. It leaves the pelvis through the greater sciatic foramen, below piriformis muscle. It runs down in front of the sciatic nerve, the superior and inferior gemellus muscles, and the tendon of the obturator internus. It enters the anterior surfaces of quadratus femoris muscle and gemellus inferior muscle. It gives an articular branch to the hip joint. Variation Rarely, the nerve to quadratus femoris may also innervate the gemellus superior muscle, or the upper part of adductor magnus muscle. Function The nerve to quadratus femoris provides motor innervation to quadratus femoris muscle and inferior gemellus muscle. It also provides sensory inner ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nerve To Obturator Internus
The nerve to obturator internus, also known as the obturator internus nerve, is a nerve that innervates the obturator internus and gemellus superior muscles. Structure The nerve to obturator internus originates in the lumbosacral plexus. It arises from the ventral divisions of the fifth lumbar and first and second sacral nerves. It leaves the pelvis through the greater sciatic foramen below the piriformis muscle, and gives off the branch to the gemellus superior, which enters the upper part of the posterior surface of the muscle. It then crosses the ischial spine, re-enters the pelvis through the lesser sciatic foramen, and pierces the pelvic surface of the obturator internus. See also * Obturator nerve * Nerve to quadratus femoris The nerve to quadratus femoris is a nerve that provides innervation to the quadratus femoris muscle and gemellus inferior muscle. Structure The nerve to quadratus femoris is a sacral plexus nerve. It arises from the ventral divisions of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Posterior Femoral Cutaneous Nerve
The posterior cutaneous nerve of the thigh (also called the posterior femoral cutaneous nerve) is a sensory nerve in the thigh. It supplies the skin of the posterior surface of the thigh, leg, buttock, and also the perineum. Structure The posterior cutaneous nerve of the thigh is a nerve from the sacral plexus. It arises partly from the dorsal divisions of the S1 and S2, and from the ventral divisions of S2 and S3 sacral spinal nerves. It leaves the pelvis through the greater sciatic foramen below the piriformis muscle. It then descends beneath the gluteus maximus muscle with the inferior gluteal artery, and runs down the back of the thigh beneath the fascia lata. It runs over the long head of the biceps femoris to the back of the knee. It then pierces the deep fascia, and accompanies the small saphenous vein to about the middle of the back of the leg. Its terminal branches communicate with the sural nerve. Branches Its branches are all cutaneous, and are distributed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sciatic Nerve
The sciatic nerve, also called the ischiadic nerve, is a large nerve in humans and other vertebrate animals which is the largest branch of the sacral plexus and runs alongside the hip joint and down the lower limb. It is the longest and widest single nerve in the human body, going from the top of the leg to the foot on the posterior aspect. The sciatic nerve has no cutaneous branches for the thigh. This nerve provides the connection to the nervous system for the skin of the lateral leg and the whole foot, the muscles of the back of the thigh, and those of the leg and foot. It is derived from spinal nerves L4 to S3. It contains fibers from both the anterior and posterior divisions of the lumbosacral plexus. Structure In humans, the sciatic nerve is formed from the L4 to S3 segments of the sacral plexus, a collection of nerve fibres that emerge from the sacral part of the spinal cord. The lumbosacral trunk from the L4 and L5 roots descends between the sacral promontory and al ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inferior Gluteal Nerve
The inferior gluteal nerve is the main motor neuron that innervates the gluteus maximus muscle. It is responsible for the movement of the gluteus maximus in activities requiring the hip to extend the thigh, such as climbing stairs. Injury to this nerve is rare but often occurs as a complication of posterior approach to the hip during hip replacement. When damaged, one would develop gluteus maximus lurch, which is a gait abnormality which causes the individual to 'lurch' backwards to compensate lack in hip extension. Anatomy The largest muscle of the posterior hip, gluteus maximus, is innervated by the inferior gluteal nerve.Skalak, A. F., et al. "Relationship of Inferior Gluteal Nerves and Vessels: Target for Application of Stimulation Devices for the Prevention of Pressure Ulcers in Spinal Cord Injury." Surgical and Radiologic Anatomy 30.1 (2008): 41-45. Print. It branches out and then enters the deep surface of the gluteus maximus, the principal extensor of the thigh, and suppl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superior Gluteal Nerve
The superior gluteal nerve is a nerve that originates in the pelvis. It supplies the gluteus medius muscle, the gluteus minimus muscle, the tensor fasciae latae muscle, and the piriformis muscle. Structure The superior gluteal nerve originates in the sacral plexus. It arises from the posterior divisions of L4, L5 and S1. It leaves the pelvis through the greater sciatic foramen above the piriformis muscle. It is accompanied by the superior gluteal artery and the superior gluteal vein.''Thieme Atlas of Anatomy'' (2006), p 476 It then accompanies the upper branch of the deep division of the superior gluteal artery. It ends in the gluteus minimus muscle and tensor fasciae latae muscle. Function The superior nerve supplies: * tensor fasciae latae muscle.Platzer (2004), p 420 * gluteus minimus muscle. * gluteus medius muscle. * piriformis muscle. The superior gluteal nerve also has a cutaneous branch. Clinical significance Gait In normal gait, the small gluteal muscl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
