The anterior division of the twelfth thoracic nerve is larger than the others. It runs in front of the quadratus lumborum, innervates the transversus, passes forward between it and the obliquus internus to be distributed in the same manner as the lower intercostal nerves, it communicates with the iliohypogastric nerve of the lumbar plexus, gives a branch to the Pyramidalis. It gives off a lateral cutaneous branch that supplies sensory innervation to the skin over the hip. Subcostal artery subcostal vein This article incorporates text in the public domain from page 948 of the 20th edition of Gray's Anatomy posteriorabdomen at The Anatomy Lesson by Wesley Norman glutealregion at The Anatomy Lesson by Wesley Norman Atlas image: abdo_wall70 at the University of Michigan Health System - "Posterior Abdominal Wall, Anterior View" Anatomy figure: 40:07-00 at Human Anatomy Online, SUNY Downstate Medical Center - "Muscles and nerves of the posterior abdominal wall." Anatomy image:8982 at the SUNY Downstate Medical Center
Thoracic spinal nerve 3
The thoracic spinal nerve 3 is a spinal nerve of the thoracic segment. It originates from the spinal column from below the thoracic vertebra 3
The piriformis is a muscle in the gluteal region of the lower limbs. It is one of the six muscles in the lateral rotator group, it was first named by Adriaan van den Spiegel, a professor from the University of Padua in the 16th century. The piriformis muscle originates from the anterior part of the sacrum, the part of the spine in the gluteal region, from the superior margin of the greater sciatic notch, it exits the pelvis through the greater sciatic foramen to insert on the greater trochanter of the femur. Its tendon joins with the tendons of the superior gemellus, inferior gemellus, obturator internus muscles prior to insertion; the piriformis is a flat muscle, pyramidal in shape, lying parallel with the posterior margin of the gluteus medius. It is situated within the pelvis against its posterior wall, at the back of the hip-joint, it arises from the front of the sacrum by three fleshy digitations, attached to the portions of bone between the first, second and fourth anterior sacral foramina, to the grooves leading from the foramina: a few fibers arise from the margin of the greater sciatic foramen, from the anterior surface of the sacrotuberous ligament.
The muscle passes out of the pelvis through the greater sciatic foramen, the upper part of which it fills, is inserted by a rounded tendon into the upper border of the greater trochanter behind, but partly blended with, the common tendon of the obturator internus and superior and inferior gemellus muscles. In 17 % of people, the piriformis muscle is pierced by all of the sciatic nerve. Several variations occur, but the most common type of anomaly is the Beaton's type B, when the common peroneal nerve pierces the piriformis muscle, it may be united with the gluteus medius, send fibers to the gluteus minimus, or receive fibers from the superior gemellus. It may have two sacral attachments; the piriformis muscle is part of the lateral rotators of the hip, along with the quadratus femoris, gemellus inferior, gemellus superior, obturator externus, obturator internus. The piriformis laterally rotates the femur with hip extension and abducts the femur with hip flexion. Abduction of the flexed thigh is important in the action of walking because it shifts the body weight to the opposite side of the foot being lifted, which prevents falling.
The action of the lateral rotators can be understood by crossing the legs to rest an ankle on the knee of the other leg. This causes the femur to point the knee laterally; the lateral rotators oppose medial rotation by the gluteus medius and gluteus minimus. When the hip is flexed to 90 degrees, piriformis abducts the femur at the hip and reverses primary function, internally rotating the hip when the hip is flexed at 90 degrees or more. Piriformis syndrome occurs when the piriformis irritates the sciatic nerve, which comes into the gluteal region beneath the muscle, causing pain in the buttocks and referred pain along the sciatic nerve; this referred. Seventeen percent of the population has their sciatic nerve coursing through the piriformis muscle; this subgroup of the population is predisposed to developing sciatica. Sciatica can be described by pain, tingling, or numbness deep in the buttocks and along the sciatic nerve. Sitting down, climbing stairs, performing squats increases pain. Diagnosing the syndrome is based on symptoms and on the physical exam.
More testing, including MRIs, X-rays, nerve conduction tests can be administered to exclude other possible diseases. If diagnosed with piriformis syndrome, the first treatment involves progressive stretching exercises, massage therapy and physical treatment. Corticosteroids can be injected into the piriformis muscle. Findings suggest the possibility that Botulinum toxin type B may be of potential benefit in the treatment of pain attributed to piriformis syndrome. A more invasive, but sometimes necessary treatment involves surgical exploration. Surgery should always be a last resort; the piriformis is a important landmark in the gluteal region. As it travels through the greater sciatic foramen, it divides it into an inferior and superior part; this determines the name of the vessels and nerves in this region – the nerve and vessels that emerge superior to the piriformis are the superior gluteal nerve and superior gluteal vessels. Inferiorly, it is the same, the sciatic nerve travels inferiorly to the piriformis.
This article incorporates text in the public domain from page 476 of the 20th edition of Gray's Anatomy "Piriformis" University of Washington Anatomy photo:13:st-0408 at the SUNY Downstate Medical Center - "Gluteal Region: Muscles" Anatomy photo:43:15-0101 at the SUNY Downstate Medical Center - "The Female Pelvis: The Posterolateral Pelvic Wall"
Internal obturator muscle
The internal obturator muscle or obturator internus muscle originates on the medial surface of the obturator membrane, the ischium near the membrane, the rim of the pubis. It exits the pelvic cavity through the lesser sciatic foramen; the internal obturator is situated within the lesser pelvis, 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, it arises from the inner surface of the antero-lateral wall of the pelvis, where it surrounds the greater part of the obturator foramen, being attached to the inferior pubic ramus and ischium, at the side to the inner surface of the hip bone below and behind the pelvic brim, reaching from the upper part of the greater sciatic foramen above and behind to the obturator foramen below and in front. It arises from the pelvic surface of the obturator membrane except in the posterior part, from the tendinous arch which completes the canal for the passage of the obturator vessels and nerve, to a slight extent from the obturator fascia, which covers the muscle.
The fibers converge toward the lesser sciatic foramen, end in four or five tendinous bands, which are found on the deep surface of the muscle. The tendon inserts on the greater trochanter of the proximal femur; the internal obturator muscle is innervated by the nerve to internal obturator. This bony surface is covered by smooth cartilage, separated from the tendon by a bursa, presents one or more ridges corresponding with the furrows between the tendinous bands; these bands leave the pelvis through the lesser sciatic foramen and unite into a single flattened tendon, which passes horizontally across the capsule of the hip-joint, after receiving the attachments of the superior and inferior gemellus muscles, is inserted into the forepart of the medial surface of the greater trochanter above the trochanteric fossa. A bursa and elongated in form, is found between the tendon and the capsule of the hip-joint; this article incorporates text in the public domain from page 477 of the 20th edition of Gray's Anatomy Anatomy photo:13:st-0407 at the SUNY Downstate Medical Center - "Gluteal Region: Muscles" Anatomy photo:43:st-0603 at the SUNY Downstate Medical Center - "The Female Pelvis: Muscles" Cross section image: pelvis/pelvis-e12-15—Plastination Laboratory at the Medical University of Vienna pelvis at The Anatomy Lesson by Wesley Norman perineum at The Anatomy Lesson by Wesley Norman Int.
J. Morphol. 25:95-98, 2007
Quadratus plantae muscle
The quadratus plantae is separated from the muscles of the first layer by the lateral plantar vessels and nerve. It acts to aid in flexing the 2nd to 5th toes and is one of the few muscles in the foot with no homolog in the hand, it arises by two heads, which are separated from each other by the long plantar ligament: the medial or larger head is muscular, is attached to the medial concave surface of the calcaneus, below the groove which lodges the tendon of the flexor hallucis longus. The two portions join at an acute angle, end in a flattened band, inserted into the lateral margin and upper and under surfaces of the tendon of the flexor digitorum longus, forming a kind of groove, in which the tendon is lodged, it sends slips to those tendons of the Flexor digitorum longus which pass to the second and fourth toes. Lateral head wanting. Variation in the number of digital tendons to which fibers can be traced. Most frequent offsets are sent to the second and fourth toes; this article incorporates text in the public domain from page 493 of the 20th edition of Gray's Anatomy PTCentral
The gluteus medius one of the three gluteal muscles, is a broad, radiating muscle, situated on the outer surface of the pelvis. Its posterior third is covered by the gluteus maximus, its anterior two-thirds by the gluteal aponeurosis, which separates it from the superficial fascia and integument; the gluteus medius muscle starts, or "originates," on the outer surface of the ilium between the iliac crest and the posterior gluteal line above, the anterior gluteal line below. The fibers of the muscle converge into a strong flattened tendon that inserts on the lateral surface of the greater trochanter. More the muscle's tendon inserts into an oblique ridge that runs downward and forward on the lateral surface of the greater trochanter. A bursa separates the tendon of the muscle from the surface of the trochanter; the posterior border may be more or less united to the piriformis, or some of the fibers end on its tendon. The posterior fibres of gluteus medius contract to produce hip extension, lateral rotation and abduction.
During gait, the posterior fibres help to decelerate internal rotation of the femur at the end of swing phase. • The anterior part acting alone helps to flex and internally rotate the hip. • The posterior part acting alone helps to extend and externally rotate the hip. • The anterior and posterior parts working together abduct the hip and stabilize the pelvis in the coronal plane. Dysfunction of the gluteus medius or the superior gluteal nerve can be indicated by a positive Trendelenburg's sign. Trendelenburg gait This article incorporates text in the public domain from page 474 of the 20th edition of Gray's Anatomy Anatomy photo:13:st-0404 at the SUNY Downstate Medical Center Cross section image: pelvis/pelvis-e12-15—Plastination Laboratory at the Medical University of Vienna
The gluteus maximus is the main extensor muscle of the hip. It is the largest and most superficial of the three gluteal muscles and makes up a large portion of the shape and appearance of each side of the hips, its thick fleshy mass, in a quadrilateral shape, forms the prominence of the buttocks. Its large size is one of the most characteristic features of the muscular system in humans, connected as it is with the power of maintaining the trunk in the erect posture. Other primates can not sustain standing erectly; the muscle is remarkably coarse in function and structure, being made up of muscle fascicles lying parallel with one another, collected together into larger bundles separated by fibrous septa. It arises from the posterior gluteal line of the inner upper ilium, a pelvic bone, the portion of the bone including the crest of the ilium above and behind it; the fibers are lateralward. Three bursae are found in relation with the deep surface of this muscle: One of these, of large size, separates it from the greater trochanter.
When the gluteus maximus takes its fixed point from the pelvis, it extends the acetabulofemoral joint and brings the bent thigh into a line with the body. Taking its fixed point from below, it acts upon the pelvis, supporting it and the trunk upon the head of the femur, its most powerful action is to cause the body to regain the erect position after stooping, by drawing the pelvis backward, being assisted in this action by the biceps femoris, semitendinosus and adductor magnus. The gluteus maximus is a tensor of the fascia lata, by its connection with the iliotibial band steadies the femur on the articular surfaces of the tibia during standing, when the extensor muscles are relaxed; the lower part of the muscle acts as an adductor and external rotator of the limb. The upper fibers act as abductors of the hip joints; the gluteus maximus is involved from running to weight-lifting. A number of exercises focus on the gluteus maximus as well as other muscles of the upper leg. Hip thrusts Glute bridge Quadruped hip extensions Kettlebell swings Squats and variations like split squats, pistol squats and wide-stance lunges Deadlift Reverse hyperextension Four-way hip extensions Glute-ham raise Functional assessment can be useful in assessing injuries to the gluteus maximus and surrounding muscles.
These tests include: 30 Second Chair to Stand testThis test measures a participant's ability to stand up from a seated position as many times as possible in a thirty-second period of time. Testing the number of times a person can stand up in a thirty-second period helps assess strength, flexibility and endurance, which can help determine how far along a person is in rehabilitation, or how much work is still to be done. Passive piriformis stretch; the piriformis test measures flexibility of the gluteus maximus. This requires a trained professional and is based on the angle of external and internal rotation in relation to normal range of motion without injury or impingement. In other primates, gluteus maximus consists of ischiofemoralis, a small muscle that corresponds to the human gluteus maximus and originates from the ilium and the sacroiliac ligament, gluteus maximus proprius, a large muscle that extends from the ischial tuberosity to a more distant insertion on the femur. In adapting to bipedal gait, reorganization of the attachment of the muscle as well as the moment arm was required.
Table of muscles of the human body Coccyx This article incorporates text in the public domain from page 474 of the 20th edition of Gray's Anatomy Anatomy photo:13:st-0403 at the SUNY Downstate Medical Center Cross section image: pelvis/pelvis-female-17—Plastination Laboratory at the Medical University of Vienna Cross section image: pelvis/pelvis-e12-15—Plastination Laboratory at the Medical University of Vienna Cross section image: pembody/body18b—Plastination Laboratory at the Medical University of Vienna Muscles/GluteusMaximus at exrx.net