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 greater trochanter of the femur is a large, quadrilateral eminence and a part of the skeletal system. It is directed lateral and medially and posterior. In the adult it is about 1 cm lower than the head; 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 four borders, it is a traction epiphysis. The lateral surface, quadrilateral in form, is broad, rough and marked by a diagonal impression, which extends from the postero-superior to the antero-inferior angle, 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 interposition of a bursa between the tendon and the bone. Below and behind the diagonal impression is a smooth triangular surface, over which the tendon of the gluteus maximus lies, a bursa being interposed; the medial surface, of much less extent than the lateral, presents at its base a deep depression, the trochanteric fossa, for the insertion of the tendon of the obturator externus, above and in front of this an impression for the insertion of the obturator internus and superior and inferior gemellus muscles.
The superior border is free. The inferior border corresponds to the line of junction of the base of the trochanter with the lateral surface of the body; the anterior border is somewhat irregular. The posterior border is prominent and appears as a free, rounded edge, which bounds the back part of the trochanteric fossa. Third trochanter This article incorporates text in the public domain from page 244 of the 20th edition of Gray's Anatomy Anatomy figure: 13:01-07 at Human Anatomy Online, SUNY Downstate Medical Center Cross section image: pelvis/pelvis-e12-15—Plastination Laboratory at the Medical University of Vienna lljoints at The Anatomy Lesson by Wesley Norman "Anatomy diagram: 02240.006-3". Roche Lexicon - illustrated navigator. Elsevier. Archived from the original on 2014-01-01
In vertebrate anatomy, hip refers to either an anatomical region or a joint. The hip region is located lateral and anterior to the gluteal region, inferior to the iliac crest, overlying the greater trochanter of the femur, or "thigh bone". In adults, three of the bones of the pelvis have fused into the hip bone or acetabulum which forms part of the hip region; the hip joint, scientifically referred to as the acetabulofemoral joint, is the joint between the femur and acetabulum of the pelvis and its primary function is to support the weight of the body in both static and dynamic postures. The hip joints have important roles in retaining balance, for maintaining the pelvic inclination angle. Pain of the hip may be the result of numerous causes, including nervous, infectious, trauma-related, genetic; the proximal femur is covered by muscles and, as a consequence, the greater trochanter is the only palpable bony structure in the hip region. The hip joint is a synovial joint formed by the articulation of the rounded head of the femur and the cup-like acetabulum of the pelvis.
It forms the primary connection between the bones of the lower limb and the axial skeleton of the trunk and pelvis. Both joint surfaces are covered with a strong but lubricated layer called articular hyaline cartilage; the cuplike acetabulum forms at the union of three pelvic bones — the ilium and ischium. The Y-shaped growth plate that separates them, the triradiate cartilage, is fused definitively at ages 14–16, it is a special type of spheroidal or ball and socket joint where the spherical femoral head is contained within the acetabulum and has an average radius of curvature of 2.5 cm. The acetabulum grasps half the femoral ball, a grip augmented by a ring-shaped fibrocartilaginous lip, the acetabular labrum, which extends the joint beyond the equator; the joint space between the femoral head and the superior acetabulum is between 2 and 7 mm. The head of the femur is attached to the shaft by a thin neck region, prone to fracture in the elderly, due to the degenerative effects of osteoporosis.
The acetabulum is oriented inferiorly and anteriorly, while the femoral neck is directed superiorly and anteriorly. The transverse angle of the acetabular inlet can be determined by measuring the angle between a line passing from the superior to the inferior acetabular rim and the horizontal plane; the sagittal angle of the acetabular inlet is an angle between a line passing from the anterior to the posterior acetabular rim and the sagittal plane. It measures 7° at birth and increases to 17° in adults. Wiberg's centre-edge angle is an angle between a vertical line and a line from the centre of the femoral head to the most lateral part of the acetabulum, as seen on an anteroposterior radiograph; the vertical-centre-anterior margin angle is an angle formed from a vertical line and a line from the centre of the femoral head and the anterior edge of the dense shadow of the subchondral bone posterior to the anterior edge of the acetabulum, with the radiograph being taken from the false angle, that is, a lateral view rotated 25 degrees towards becoming frontal.
The articular cartilage angle is an angle formed parallel to the weight bearing dome, that is, the acetabular sourcil or "roof", the horizontal plane, or a line connecting the corner of the triangular cartilage and the lateral acetabular rim. In normal hips in children aged between 11 and 24 months, it has been estimated to be on average 20°, ranging between 18° to 25°, it becomes progressively lower with age. Suggested cutoff values to classify the angle as abnormally increased include:30° up to 4 months of age. 25° up to 2 years of age. The angle between the longitudinal axes of the femoral neck and shaft, called the caput-collum-diaphyseal angle or CCD angle measures 150° in newborn and 126° in adults. An abnormally small angle is known as an abnormally large angle as coxa valga; because changes in shape of the femur affects the knee, coxa valga is combined with genu varum, while coxa vara leads to genu valgum. Changes in CCD angle is the result of changes in the stress patterns applied to the hip joint.
Such changes, caused for example by a dislocation, changes the trabecular patterns inside the bones. Two continuous trabecular systems emerging on auricular surface of the sacroiliac joint meander and criss-cross each other down through the hip bone, the femoral head and shaft. In the hip bone, one system arises on the upper part of auricular surface to converge onto the posterior surface of the greater sciatic notch, from where its trabeculae are reflected to the inferior part of the acetabulum; the other system emerges on the lower part of the auricular surface, converges at the level of the superior gluteal line, is reflected laterally onto the upper part of the acetabulum. In the femur, the first system lines up with a system arising from the lateral part of the femoral shaft to stretch to the inferior portion of the femoral neck and head; the other system lines up with a system in the femur stretching from the medial part of the femoral shaft to the superior part of the femoral head. On the lateral side of the hip joint the fascia lata is strengthened to
Superior gluteal nerve
The superior gluteal nerve is a nerve that originates in the pelvis and supplies the gluteus medius, the gluteus minimus, the tensor fasciae latae and the piriformis muscles. The superior gluteal nerve originates in the sacral plexus, it arises from the dorsal divisions of the L4, L5 and S1. It leaves the pelvis through the greater sciatic foramen above the piriformis, accompanied by the superior gluteal artery and the superior gluteal vein, it accompanies the upper branch of the deep division of the superior gluteal artery and ends in the gluteus minimus and tensor fasciae latae muscle. The superior nerve starts out in the pelvis and supplies the tensor fasciae latae, the gluteus minimus, the gluteus medius muscle In normal gait, the small gluteal muscles on the stance side can stabilize the pelvis in the coronal plane. Weakness or paralysis of these muscles caused by a damaged superior gluteal nerve can result in a weak abduction in the affected hip joint; this gait disturbance is known as Trendelenburg gait.
In a positive Trendelenburg's sign the pelvis sags toward the normal unsupported side. The opposite, when the pelvis is elevated on the swing side, is known as Duchenne limp. Bilateral loss of the small gluteal muscles results in a waddling gait. Inferior gluteal nerve This article incorporates text in the public domain from page 959 of the 20th edition of Gray's Anatomy Platzer, Werner. Color Atlas of Human Anatomy, Vol. 1: Locomotor System. Thieme. ISBN 3-13-533305-1. Thieme Atlas of Anatomy: General Anatomy and Musculoskeletal System. Thieme. 2006. ISBN 1-58890-419-9. Superior_gluteal_nerve at the Duke University Health System's Orthopedics program
Rectus femoris muscle
The rectus femoris muscle is one of the four quadriceps muscles of the human body. The others are the vastus medialis, the vastus intermedius, the vastus lateralis. All four parts of the quadriceps muscle attach to the patella by the quadriceps tendon; the rectus femoris is situated in the middle of the front of the thigh. Its functions are to extend the leg at the knee joint, it arises by two tendons: the anterior or straight, from the anterior inferior iliac spine. The two unite at an acute angle and spread into an aponeurosis, prolonged downward on the anterior surface of the muscle, from this the muscular fibers arise; the muscle ends in a broad and thick aponeurosis that occupies the lower two-thirds of its posterior surface, becoming narrowed into a flattened tendon, is inserted into the base of the patella. The neurons for voluntary thigh contraction originate near the summit of the medial side of the precentral gyrus; these neurons send a nerve signal, carried by the corticospinal tract down the brainstem and spinal cord.
The signal starts with the upper motor neurons carrying the signal from the precentral gyrus down through the internal capsule, through the cerebral peduncle, into the medulla. In the medullary pyramid, the corticospinal tract decussates and becomes the lateral corticospinal tract; the nerve signal will continue down the lateral corticospinal tract until it reaches spinal nerve L4. At this point, the nerve signal will synapse from the upper motor neurons to the lower motor neurons; the signal will travel through the anterior root of L4 and into the anterior rami of the L4 nerve, leaving the spinal cord through the lumbar plexus. The posterior division of the L4 root is the Femoral nerve; the femoral nerve innervates the quadriceps femoris, a fourth of, the rectus femoris. When the rectus femoris receives the signal that has traveled all the way from the medial side of the precentral gyrus, it contracts, extending the knee and flexing the thigh at the hip; the rectus femoris and iliopsoas are the flexors of the thigh at the hip.
The rectus femoris is a weaker hip flexor when the knee is extended because it is shortened and thus suffers from active insufficiency. The rectus femoris is not dominant in knee extension when the hip is flexed since it is shortened and thus suffers from active insufficiency. In essence: the action of extending the knee from a seated position is driven by the vastus lateralis, vastus medialis, vastus intermedius, less by the rectus femoris. In the other extreme, the muscle's ability to flex the hip and extend the knee can be compromised in a position of full hip extension and knee flexion, due to passive insufficiency; the rectus femoris is a direct antagonist at the hip and at the knee. Rectus femoris strain, referred to as hip flexor strain, is an injury at the tendon that attaches to the patella or in the muscle itself; the injury is a partial tear but could be a full tear. The injury is caused by a forceful movement related to sprinting, jumping, or kicking and is common in sports like football or soccer.
The rectus femoris is prone to injury since it crosses both the hip. Symptoms include a sudden sharp pain at the front of the hip or in the groin and bruising, an inability to contract the rectus femoris with a full tear; this article incorporates text in the public domain from page 470 of the 20th edition of Gray's Anatomy PTCentral
Lateral rotator group
The lateral rotator group is a group of six small muscles of the hip which all externally rotate the femur in the hip joint. It consists of the following muscles: Piriformis, gemellus superior, obturator internus, gemellus inferior, quadratus femoris and the obturator externus. All muscles in the lateral rotator group originate from the hip bone and insert on to the upper extremity of the femur; the muscles are innervated by the sacral plexus, except the obturator externus muscle, innervated by the lumbar plexus. This group does not include all muscles which aid in lateral rotation of the hip joint: rather it is a collection of ones which are known for performing this action. Other muscles that contribute to lateral rotation of the hip include: Gluteus maximus muscle Gluteus medius muscle and gluteus minimus muscle when the hip is extended Psoas major muscle Psoas minor muscle Sartorius muscle Hip anatomy Glutealregion at The Anatomy Lesson by Wesley Norman
Superior gluteal artery
The superior gluteal artery is the largest branch of the internal iliac artery, appears to be the continuation of the posterior division of that vessel. It is a short artery which runs backward between the lumbosacral trunk and the first sacral nerve, divides into a superficial and a deep branch after passing out of the pelvis above the upper border of the piriformis muscle. Within the pelvis, it gives off branches to the iliacus and obturator internus muscles. Just previous to exiting the pelvic cavity, it gives off a nutrient artery which enters the ilium; the superficial branch enters the deep surface of the gluteus maximus, divides into numerous branches, some of which supply the muscle and anastomose with the inferior gluteal artery, while others perforate its tendinous origin, supply the integument covering the posterior surface of the sacrum, anastomosing with the posterior branches of the lateral sacral arteries. The deep branch lies under the gluteus medius and immediately subdivides into the superior and inferior divisions.
The superior division continues the original course of the vessel, passingalong the upper border of the gluteus minimus to the anterior superior spine of the ilium, anastomosing with the deep iliac circumflex artery and the ascending branch of the lateral femoral circumflex artery. The inferior division crosses the gluteus minimus obliquely to the greater trochanter, distributing branches to the gluteal muscles and anastomoses with the lateral femoral circumflex artery; some branches pierce the gluteus supply the hip-joint. This artery takes part in the trochanteric anastomoses, forming a connection between internal iliac and femoral artery. Inferior gluteal artery This article incorporates text in the public domain from page 622 of the 20th edition of Gray's Anatomy Anatomy photo:43:13-0105 at the SUNY Downstate Medical Center - "The Female Pelvis: Branches of Internal Iliac Artery"