All articles starting with R

Rectopexy

Rectopexy is a colorectal surgical operation that anchors a mobile rectum to the sacrum with sutures or mesh to cure rectal prolapse, performed by open, laparoscopic, or robotic access.

Rector (academia)

Rector (academia): title for a university's head, equivalent to president or vice-chancellor. Covers medieval origins at Bologna and Paris, the Vienna model, and modern appointment methods.

Rectovaginal fistula (RVF), also called anovaginal fistula, is an abnormal passage between rectum and vagina, usually from childbirth injury or Crohn's disease; treated first conservatively, then surgically.

Rectum

The rectum (Latin intestinum rectum, straight intestine) is the 12-15 cm distal segment of the large intestine between the sigmoid colon and anal canal, a distensible reservoir for feces with superior, middle, and inferior rectal arterial supply.

Rectus abdominis muscle

Rectus abdominis, the paired "six pack" muscle of the anterior abdominal wall, runs from the pubic crest and symphysis to the xiphoid process and costal cartilages 5-7, flexes the trunk, and is segmented by tendinous inscriptions.

Rectus femoris muscle

Rectus femoris (Musculus rectus femoris): superficial two-headed quadriceps muscle of the anterior thigh, originating at the anterior inferior iliac spine and supraacetabular groove, extending the knee and flexing the hip, innervated by the femoral nerve (L2-L4).

Rectus sheath block

The rectus sheath block is a fascial plane nerve block that numbs the anterior abdominal wall, used mainly for pain control after midline abdominal surgery such as hernia repair.

Oct 22, 2026

Recuay culture

The Recuay culture was a pre-Columbian culture of Peru's north-central highlands, flourishing in the first millennium CE and known for distinctive white kaolin pottery and stone sculpture.

Sep 19, 2026

Recueil des inscriptions de l'Éthiopie

The Recueil des inscriptions de l'Éthiopie (RIÉ) is the standard corpus of pre-Aksumite and Aksumite inscriptions of Ethiopia and Eritrea, published in Paris from 1991.

Oct 22, 2026

Recuerdos de provincia

Recuerdos de provincia (Memories of a Provincial Past) is an autobiography by Domingo Faustino Sarmiento, published in Santiago de Chile in 1850 during his exile.

Oct 22, 2026

Recuerdos del pasado

Recuerdos del pasado (1814–1860) is an 1882 autobiographical book by the Chilean writer and colonization agent Vicente Pérez Rosales, covering his life from 1814 to about 1860.

Reculan

Reculan is an ancient Roman villa site near Générac, Gard, France, recorded as Pleiades place 148166 (BAtlas 15 C2), with a DARMC location dated AD 300-640; not to be confused with the Spanish verb recular or Swiss place names Reculan.

Reculver

Reculver (Roman Regulbium) is a Kent coastal site with an early 3rd-century Saxon Shore fort, an Anglo-Saxon monastery founded in 669 by King Egbert for Bassa, and 12th-century twin church towers used as a sea-mark.

Recumbent bicycle

A recumbent bicycle is a bicycle with the rider in a reclined, feet-forward seat instead of a saddle; its lower aerodynamic drag makes it the basis of the fastest human-powered vehicles.

Recur Club

Recur Club is a Delhi-based debt marketplace founded by Eklavya Gupta and Abhinav Sherwal that matches startups and SMEs raising debt with banks, NBFCs, and credit funds.

Oct 15, 2026

Recurrence plot

A recurrence plot is a graphical tool from nonlinear time-series analysis that shows when a dynamical system returns to earlier states, introduced by Eckmann, Oliffson Kamphorst, and Ruelle in 1987.

Recurrence quantification analysis

Recurrence quantification analysis (RQA) is a nonlinear time-series method that quantifies a recurrence plot into measures such as determinism, laminarity, and entropy, introduced in the 1990s.

Recurrence relation

A recurrence relation, also called a recurrence equation, defines each term of a sequence as a function of earlier ones; with initial values, like the Fibonacci recurrence, it determines the sequence uniquely.

Recurrence score

A recurrence score is a genomic test result, best known from the 21-gene Oncotype DX assay for early breast cancer, that estimates distant recurrence risk and chemotherapy benefit.

Recurrent AI arbitration

The Recurrent AI arbitration is a Hong Kong arbitration filed in November 2024 by investors in Recurrent AI against Moonshot AI founders Yang Zhilin and Zhang Yutao.

Recurrent cholesteatoma of postmastoidectomy cavity

Recurrent cholesteatoma of postmastoidectomy cavity is the regrowth of cholesteatoma, a skin tissue growth behind the ear, in the mastoid cavity remaining after surgery; recurrence reaches 39% at 15 years.

Recurrent convolutional neural network

A recurrent convolutional neural network, also called a convolutional recurrent network, combines convolutional layers with recurrent connections to process data structured in space and time, such as video and speech.

Recurrent erosion of cornea

Recurrent corneal erosion (RCE, recurrent erosion syndrome): repeated breakdown of the corneal epithelium causing sharp morning eye pain, usually after prior trauma (45–64% of cases) or epithelial basement membrane dystrophy; treated with lubricants, bandage lenses, and surgery.

Recurrent idiopathic neuroretinitis

Recurrent idiopathic neuroretinitis (RINR), a rare inflammatory optic neuropathy with recurrent painless visual loss, optic disc edema, and macular star; poor prognosis, treated with long-term azathioprine and prednisone.

Recurrent infections associated with rare immunoglobulin isotypes deficiency

Recurrent infections associated with rare immunoglobulin isotypes deficiency (ORPHA:183675) covers isolated IgG subclass deficiency, IgG subclass deficiency with IgA deficiency, and kappa chain deficiency, causing recurrent pyogenic sinopulmonary infections with normal total IgG.

Recurrent infections due to specific granule deficiency

Recurrent infections due to specific granule deficiency, also called neutrophil-specific granule deficiency or SGD (ORPHA:169142), is an ultra-rare autosomal recessive neutrophil disorder caused by CEBPE or SMARCD2 variants, causing infantile pyogenic infections, bilobed granule-poor neutrophils, and treatment with prophylactic antibiotics or HSCT.

Recurrent isolated sleep paralysis

Recurrent isolated sleep paralysis (RISP), also called fearful isolated sleep paralysis, is a REM parasomnia of repeated waking paralysis at sleep onset or offset. Coded ICSD-3 G47.51 and ICD-11 7B01.1; lifetime sleep paralysis prevalence 7.6% general population; treated with CBT, sleep hygiene, REM-suppressing antidepressants.