A bungalow in Chicago with a hipped roof

A hip roof on a rectangular plan

A square hip roof (also known as a "pyramid roof")

A hip roof, or hipped roof, is a type of roof where all sides slope downwards to the walls, usually with a fairly gentle slope. Thus it is a house with no gables or other vertical sides to the roof. A square hip roof is shaped like a pyramid. Hip roofs on the houses could have two triangular side and two trapezoidal one. A hip roof on a rectangular plan has four faces. They are almost always at the same pitch or slope, which makes them symmetrical about the centerlines. Hip roofs have a consistent level fascia, meaning that a gutter can be fitted all around. Hip roofs often have dormer slanted sides.

Construction[link]

Hip roofs are more difficult to construct than a gabled roof, requiring somewhat more complex systems of trusses. Although the roof itself is harder to construct, the walls that carry the roof are easier to build, being all one level. Hip roofs can be constructed on a wide variety of plan shapes. Each ridge is central over the rectangle of building below it. The triangular faces of the roof are called the hip ends, and they are bounded by the hips themselves. The hips sit on an external corner of the building and rise to the ridge. Where the building has an internal corner a valley makes the join between the sloping surfaces. They have the advantage of giving a compact, solid appearance to a structure.

Use[link]

In modern domestic architecture, hip roofs have been seen to represent comfort, practicality, and solidness. They are thus commonly seen in bungalows and cottages, and have been integral to styles such as the American Foursquare. However, the hip roof has been used in many different styles of architecture and in a wide array of structures. A hip roof is self-bracing. It does not need the same amount of diagonal bracing (wind bracing) that a gable roof requires.

Advantages and disadvantages[link]

A possible disadvantage of a hip roof, compared with a gable roof on the same plan, is that there is less room inside the roof space. Access is more difficult for maintenance.

Variants[link]

Mansard roof[link]

A mansard roof is a variation on a hip roof, with two different roof angles, one much steeper than the other.

Tented roof[link]

A tented roof, popular in Russian church architecture, is a steep, square hip roof, often with multiple angles.

Gablet roof or Dutch gable[link]

Gablet roof

Another variation is the gablet (UK terminology) or Dutch gable roof (US and Australasian terminology), which has a hip with a small gable (the gablet) above it. This type simplifies the construction of the roof; no girder trusses are required, but it still has level walls and consistent eaves.

Half-hip roof[link]

Half-hip roof

A half-hip, clipped-gable or jerkin head roof has a gable, but the upper point of the gable is replaced by a small hip, squaring off the top of the gable. The lower edge of the half-hip may have a gutter which leads back on to the remainder of the roof on one or both sides. Both the gablet roof and the half-hipped roof are intermediate between the gabled and fully hipped types: the gablet roof has a gable above a hip, while a half-hipped roof has a hip above a gable.

Half-hipped roofs are very common in Denmark, Germany and especially in Austria and Slovenia. They are also typical of traditional timber frame buildings in the Wealden area of South East England.

Half hip roofs are sometimes referred to as "Dutch hip", but this term is easily confused with "Dutch gable".

Pavilion roof[link]

A shallow, polygonal hip roof typically found topping gazebos and other pavilion structures.

Rhenish helm or Helm roof[link]

A pointed roof seen on spires or towers oriented so that has four gable ends. See Church of St Mary the Blessed Virgin, Sompting, Speyer Cathedral or Limburg Cathedral.

See also[link]

• Domestic roof construction

External links[link]

• Hip Roof - Encyclopædia Britannica
• Hip Roof layout
• Roofs and roofing Hip roof geometry.
• Google SketchUp 3D model where each roof member and bevel can be interrogated

For other uses of the term, see hip (disambiguation).

Hip (anatomy)
Bones of the hip
Latin	coxa
Gray's	subject #92 333
MeSH	Hip

In vertebrate anatomy, hip (or "coxa"^[1] in medical terminology) refer to either an anatomical region or a joint.

The hip region is located lateral to the gluteal region (i.e. the buttock), inferior to the iliac crest, and overlying the greater trochanter of the femur, or "thigh bone".^[2] In adults, three of the bones of the pelvis have fused into the hip bone which forms part of the hip region.

The hip joint, scientifically referred to as the acetabulofemoral joint (art. coxae), 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 (e.g. standing) and dynamic (e.g. walking or running) postures. The hip joints are the most important part in retaining balance. The pelvic inclination angle, which is the single most important element of human body posture, is adjusted at the hips.

Anatomy[link]

Region[link]

The five or so tubercles and the lower lateral borders of the sacrum, and the ischial tuberosity ("sitting bone").^[3]

• Proximally the femur is largely covered by muscles and, as a consequence, the greater trochanter is often the only palpable bony structure. Distally on the femur some more palpable bony structures are the condyles.^[4]

Articulation[link]

Radiograph of a healthy human hip joint

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, pubis, and ischium.^[5] The Y-shaped growth plate that separates them, the triradiate cartilage, is fused definitively at ages 14–16.^[6] It is a special type of spheroidal or ball and socket joint where the roughly spherical femoral head is largely contained within the acetabulum and has an average radius of curvature of 2.5 cm.^[7] The acetabulum grasps almost half the femoral ball, a grip augmented by a ring-shaped fibrocartilaginous lip, the acetabular labrum, which extends the joint beyond the equator.^[5] The head of the femur is attached to the shaft by a thin neck region that is often prone to fracture in the elderly, which is mainly due to the degenerative effects of osteoporosis.

Transverse and sagittal angles of acetabular inlet plane.

The acetabulum is oriented inferiorly, laterally and anteriorly, while the femoral neck is directed superiorly, medially, and anteriorly.

Articular angles[link]

• The transverse angle of the acetabular inlet (also called Sharp's angle and is generally the angle referred to by acetabular angle without further specification)^[8] can be determined by measuring the angle between a line passing from the superior to the inferior acetabular rim and the horizontal plane; an angle which normally measures 51° at birth and 40° in adults, and which affects the acetabular lateral coverage of the femoral head and several other parameters.^[9]
• 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.^[9]
• Wiberg's centre-edge angle (CE 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,^[10] as seen on an anteroposterior radiograph.^[11]
• The vertical-centre-anterior margin angle (VCA) is an angle formed from a vertical line (V) and a line from the centre of the femoral head (C) and the anterior (A) edge of the dense shadow of the subchondral bone slightly 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.^[11]
• The articular cartilage angle (AC angle, also called Hilgenreiner angle) is an angle formed parallel to the weight bearing dome, that is, the acetabular sourcil, and the horizontal plane,^[10] or a line connecting the corner of the triangular cartilage and the lateral acetabular rim.^[12]

Femoral neck angle[link]

The angle between the longitudinal axes of the femoral neck and shaft, called the caput-collum-diaphyseal angle or CCD angle, normally measures approximately 150° in newborn and 126° in adults (coxa norma).^{[13][dubious – discuss]} An abnormally small angle is known as coxa vara and an abnormally large angle as coxa valga. Because changes in shape of the femur naturally affects the knee, coxa valga is often combined with genu varum (bow-leggedness), while coxa vara leads to genu valgum (knock-knees). ^[14]

Changes in trabecular patterns due to altered CCD angle. Coxa valga leads to more compression trabeculae, coxa vara to more tension trabeculae.^[13]

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, neck, 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, and 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.^[15]

On the lateral side of the hip joint the fascia lata is strengthened to form the iliotibial tract which functions as a tension band and reduces the bending loads on the proximal part of the femur.^[13]

Capsule[link]

Main article: Capsule of hip joint

The capsule attaches to the hip bone outside the acetabular lip which thus projects into the capsular space. On the femoral side, the distance between the head's cartilaginous rim and the capsular attachment at the base of the neck is constant, which leaves a wider extracapsular part of the neck at the back than at the front.^{[16] [17]} The strong but loose fibrous capsule of the hip joint permits the hip joint to have the second largest range of movement (second only to the shoulder) and yet support the weight of the body, arms and head.

The capsule has two sets of fibers: longitudinal and circular.

• The circular fibers form a collar around the femoral neck called the zona orbicularis.
• The longitudinal retinacular fibers travel along the neck and carry blood vessels.

Ligaments[link]

Extracapsular ligaments. Anterior (left) and posterior (right) aspects of right hip.

Intracapsular ligament. Left hip joint from within pelvis with acetabular floor removed (left); right hip joint with capsule removed, anterior aspect (right).

The hip joint is reinforced by five ligaments, of which four are extracapsular and one intracapsular.

The extracapsular ligaments are the iliofemoral, ischiofemoral, and pubofemoral ligaments attached to the bones of the pelvis (the ilium, ischium, and pubis respectively). All three strengthen the capsule and prevent an excessive range of movement in the joint. Of these, the Y-shaped and twisted iliofemoral ligament is the strongest ligament in the human body. ^[17] In the upright position, it prevents the trunk from falling backward without the need for muscular activity. In the sitting position, it becomes relaxed, thus permitting the pelvis to tilt backward into its sitting position. The iliofemoral ligament prevents excessive adduction and internal rotation of the hip. The ischiofemoral ligament prevents medial (internal) rotation while the pubofemoral ligament restricts abduction and internal rotation of the hip joint. ^[18] The zona orbicularis, which lies like a collar around the most narrow part of the femoral neck, is covered by the other ligaments which partly radiate into it. The zona orbicularis acts like a buttonhole on the femoral head and assists in maintaining the contact in the joint. ^[17]

The intracapsular ligament, the ligamentum teres, is attached to a depression in the acetabulum (the acetabular notch) and a depression on the femoral head (the fovea of the head). It is only stretched when the hip is dislocated, and may then prevent further displacement. ^[17] It is not that important as a ligament but can often be vitally important as a conduit of a small artery to the head of the femur. This arterial branch is not present in everyone but can become the only blood supply to the bone in the head of the femur when the neck of the femur is fractured or disrupted by injury in childhood.^[19]

Blood supply[link]

The hip joint is supplied with blood from the medial circumflex femoral and lateral circumflex femoral arteries, which are both usually branches of the deep artery of the thigh (profunda femoris), but there are numerous variations and one or both may also arise directly from the femoral artery. There is also a small contribution from a small artery in the ligament of the head of the femur which is a branch of the posterior division of the obturator artery, which becomes important to avoid avascular necrosis of the head of the femur when the blood supply from the medial and lateral circumflex arteries are disrupted (e.g. through fracture of the neck of the femur along their course).^[19]

The hip has two anatomically important anastomoses, the cruciate and the trochanteric anastomoses, the latter of which provides most of the blood to the head of the femur. These anastomoses exist between the femoral artery or profunda femoris and the gluteal vessels.^[20]

Muscles and movements[link]

The hip muscles act on three mutually perpendicular main axes, all of which pass through the center of the femoral head, resulting in three degrees of freedom and three pair of principal directions: Flexion and extension around a transverse axis (left-right); lateral rotation and medial rotation around a longitudinal axis (along the thigh); and abduction and adduction around a sagittal axis (forward-backward); ^[21] and a combination of these movements (i.e. circumduction, a compound movement in which the leg describes the surface of an irregular cone).^[18] It should be noted that some of the hip muscles also act on either the vertebral joints or the knee joint, that with their extensive areas of origin and/or insertion, different part of individual muscles participate in very different movements, and that the range of movement varies with the position of the hip joint. ^[22] Additionally, the inferior and superior gemelli may be termed triceps coxae together with the obturator internus, and their function simply is to assist the latter muscle.^[23]

The movements of the hip joint is thus performed by a series of muscles which are here presented in order of importance^[22] with the range of motion from the neutral zero-degree position^[21] indicated:

• Lateral or external rotation (30° with the hip extended, 50° with the hip flexed): gluteus maximus; quadratus femoris; obturator internus; dorsal fibers of gluteus medius and minimus; iliopsoas (including psoas major from the vertebral column); obturator externus; adductor magnus, longus, brevis, and minimus; piriformis; and sartorius. The iliofemoral ligament inhibits lateral rotation and extension, this is why the hip can rotate laterally to a greater degree when it is flexed.
• Medial or internal rotation (40°): anterior fibers of gluteus medius and minimus; tensor fascia latae; the part of adductor magnus inserted into the adductor tubercle; and, with the leg abducted also the pectineus.
• Extension or retroversion (20°): gluteus maximus (if put out of action, active standing from a sitting position is not possible, but standing and walking on a flat surface is); dorsal fibers of gluteus medius and minimus; adductor magnus; and piriformis. Additionally, the following thigh muscles extend the hip: semimembranosus, semitendinosus, and long head of biceps femoris. Maximal extension is inhibited by the iliofemoral ligament.
• Flexion or anteversion (140°): the hip flexors: iliopsoas (with psoas major from vertebral column); tensor fascia latae, pectineus, adductor longus, adductor brevis, and gracilis. Thigh muscles acting as hip flexors: rectus femoris and sartorius. Maximal flexion is inhibited by the thigh coming in contact with the chest.
• Abduction (50° with hip extended, 80° with hip flexed): gluteus medius; tensor fascia latae; gluteus maximus with its attachment at the fascia lata; gluteus minimus; piriformis; and obturator internus. Maximal abduction is inhibited by the neck of the femur coming into contact with the lateral pelvis. When the hips are flexed, this delays the impingement until a greater angle.
• Adduction (30° with hip extended, 20° with hip flexed): adductor magnus with adductor minimus; adductor longus, adductor brevis, gluteus maximus with its attachment at the gluteal tuberosity; gracilis (extends to the tibia); pectineus, quadratus femoris; and obturator externus. Of the thigh muscles, semitendinosus is especially involved in hip adduction. Maximal adduction is impeded by the thighs coming into contact with one another. This can be avoided by abducting the opposite leg, or having the legs alternately flexed/extended at the hip so they travel in different planes and do not intersect.

Sexual dimorphism and cultural significance[link]

Dancers often stand with hands on hips.

In humans, unlike other animals, the hip bones are substantially different in the two sexes. The hips of human females widen during puberty.^[24] The femora are also more widely spaced in females, so as to widen the opening in the hip bone and thus facilitate childbirth. Finally, the ilium and its muscle attachment are shaped so as to situate the buttocks away from the birth canal, where contraction of the buttocks could otherwise damage the baby.

The female hips have long been associated with both fertility and general expression of sexuality. Since broad hips facilitate child birth and also serve as an anatomical cue of sexual maturity, they have been seen as an attractive trait for women for thousands of years. Many of the classical poses women take when sculpted, painted or photographed, such as the Odalisque, serve to emphasize the prominence of their hips. Similarly, women's fashion through the ages has often drawn attention to the girth of the wearer's hips.

See also[link]

• Belly dancer
• Body shape
• Femoral Acetabular Impingement
• Haunch
• Hip dysplasia (human)
• Hip examination
• Hip replacement
• Obstetrical Dilemma
• Sexual dimorphism
• Snapping hip syndrome
• Waist-hip ratio

Notes[link]

References[link]

• Clemente, Carmine D. (2006). Clemente's Anatomy Dissector. Lippincott Williams & Wilkins. ISBN 0-7817-6339-8. http://books.google.com/books?id=oEMvo2exmJgC&pg=RA2-PA227. 
• Diab, Mohammad (1999). Lexicon of Orthopaedic Etymology. Taylor & Francis. ISBN 90-5702-597-3. http://books.google.com/books?id=fstFQVnw8-wC&pg=PA200#PPA77,M1. 
• Faller, Adolf; Schuenke, Michael; Schuenke, Gabriele (2004). The Human Body: An Introduction to Structure and Function. Thieme. ISBN 3-13-129271-7. 
• Field, Derek (2001). Anatomy: palpation and surface markings (3rd ed.). Elsevier Health Sciences. ISBN 0-7506-4618-7. 
• "Hip Region". MediLexicon. http://www.medilexicon.com/medicaldictionary.php?t=77165. 
• Palastanga, Nigel; Field, Derek; Soames, Roger (2006). Anatomy and human movement: structure and function (5th ed.). Elsevier Health Sciences. ISBN 0-7506-8814-9. http://books.google.com/books?id=rRtPExr9Hz8C&pg=PA353. 
• Platzer, Werner (2004). Color Atlas of Human Anatomy, Vol. 1: Locomotor System (5th ed.). Thieme. ISBN 3-13-533305-1. 
• Thieme Atlas of Anatomy: General Anatomy and Musculoskeletal System. Thieme. 2006. ISBN 1-58890-419-9. 

External links[link]

Look up hip in Wiktionary, the free dictionary.

Wikimedia Commons has media related to: Hip

Wikimedia Commons has media related to: Hip joint

• Hip Preservation Awareness, information and support for hip impingement, hip dysplasia, and related issues in young adults (12-adult)
• Hip anatomy video
• High-performance hips

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