The bulbospongiosus muscle is one of the superficial muscles of the perineum. It has a different origin and function in males and females. In males, it covers the bulb of the penis. In females, it covers the vestibular bulb. In both sexes, it is innervated by the deep/muscular branch of the perineal nerve, a branch of the pudendal nerve. In males, the bulbospongiosus is located in front of the anus, it consists of two symmetrical parts, united along the median line by a tendinous perineal raphe. It arises from the central tendinous point of the perineum and from the median perineal raphe in front. In females, there is a tendinous perineal raphe, its fibers diverge. The latter fibers are best seen by dividing the muscle longitudinally, reflecting it from the surface of the corpus cavernosum urethra. In males it contributes to the contractions of orgasm and ejaculation. In females it contributes to clitoral erection and the contractions of orgasm, closes the vagina; this muscle serves to empty the canal of the urethra.
The middle fibers are supposed by Krause to assist in the erection of the corpus spongiosum, by compressing the erectile tissue of the bulb. The anterior fibers contribute to the erection of the penis by compressing the deep dorsal vein of the penis as they are inserted into, continuous with, the fascia of the penis; this article incorporates text in the public domain from page 428 of the 20th edition of Gray's Anatomy Anatomy figure: 42:04-02 at Human Anatomy Online, SUNY Downstate Medical Center—"Muscles of the male superficial perineal pouch." Anatomy photo:41:11-0102 at the SUNY Downstate Medical Center—"The Female Perineum: Muscles of the Superficial Perineal Pouch" Anatomy figure: 43:04-11 at Human Anatomy Online, SUNY Downstate Medical Center—"The urinary bladder and the urethra as seen in a frontal section of the female pelvis." Anatomy image:9162 at the SUNY Downstate Medical Center Anatomy image:9197 at the SUNY Downstate Medical Center
Gray's Anatomy is an English language textbook of human anatomy written by Henry Gray and illustrated by Henry Vandyke Carter. Earlier editions were called Anatomy: Descriptive and Surgical, Anatomy of the Human Body and Gray's Anatomy: Descriptive and Applied, but the book's name is shortened to, editions are titled, Gray's Anatomy; the book is regarded as an influential work on the subject, has continued to be revised and republished from its initial publication in 1858 to the present day. The latest edition of the book, the 41st, was published in September 2015; the English anatomist Henry Gray was born in 1827. He studied the development of the endocrine glands and spleen and in 1853 was appointed Lecturer on Anatomy at St George's Hospital Medical School in London. In 1855, he approached his colleague Henry Vandyke Carter with his idea to produce an inexpensive and accessible anatomy textbook for medical students. Dissecting unclaimed bodies from workhouse and hospital mortuaries through the Anatomy Act of 1832, the two worked for 18 months on what would form the basis of the book.
Their work was first published in 1858 by John William Parker in London. It was dedicated by Gray to 1st Baronet. An imprint of this English first edition was published in the United States in 1859, with slight alterations. Gray prepared a second, revised edition, published in the United Kingdom in 1860 by J. W. Parker. However, Gray died the following year, at the age of 34, having contracted smallpox while treating his nephew, his death had come just three years after the initial publication of his Anatomy Descriptive and Surgical. So, the work on his much-praised book was continued by others. Longman's publication began in 1863, after their acquisition of the J. W. Parker publishing business; this coincided with the publication date of the third British edition of Gray's Anatomy. Successive British editions of Gray's Anatomy continued to be published under the Longman, more Churchill Livingstone/Elsevier imprints, reflecting further changes in ownership of the publishing companies over the years.
The full American rights were purchased by Blanchard and Lea, who published the first of twenty-five distinct American editions of Gray's Anatomy in 1862, whose company became Lea & Febiger in 1908. Lea & Febiger continued publishing the American editions until the company was sold in 1990; the first American publication was edited by Richard James Dunglison, whose father Robley Dunglison was physician to Thomas Jefferson. Dunglison edited the next four editions; these were: the Second American Edition. W. W. Keen edited the next two editions, namely: the New American from the Eleventh English Edition. In September 1896, reference to the English edition was dropped and it was published as the Fourteenth Edition, edited by Bern B. Gallaudet, F. J. Brockway, J. P. McMurrich, who edited the Fifteenth Edition. There is an edition dated 1896 which does still reference the English edition stating it is "A New Edition, Thoroughly Revised by American Authorities, from the thirteenth English Edition" and edited by T. Pickering Pick, F.
R. C. S. and published by Lea Brothers & Co. Philadelphia and New York; the Sixteenth Edition was edited by J. C. DaCosta, the Seventeenth by DaCosta and E. A. Spitzka. Spitzka edited the Eighteenth and Nineteenth editions, in October 1913, R. Howden edited the New American from the Eighteenth English Edition; the "American" editions continued with consecutive numbering from the Twentieth onwards, with W. H. Lewis editing the 20th, 21st, 22nd, 23rd, 24th. C. M. Gross edited the 25th, 26th, 27th, 28th, 29th. Carmine D. Clemente extensively revised the 30th edition. With the sale of Lea & Febiger in 1990, the 30th edition was the last American Edition. Sometimes separate editing efforts with mismatches between British and American edition numbering led to the existence, for many years, of two main "flavours" or "branches" of Gray's Anatomy: the U. S. and the British one. This can cause misunderstandings and confusion when quoting from or trying to purchase a certain edition. For example, a comparison of publishing histories shows that the American numbering kept apace with the British up until the 16th editions in 1905, with the American editions either acknowledging the English edition, or matching the numbering in the 14th, 15th and 16th editions.
The American numbering crept ahead, with the 17th American edition published in 1908, while the 17th British edition was published in 1909. This increased to a three-year gap for the 18th and 19th editions, leading to the 1913 publication of the New American from the Eighteenth English, which brought the numbering back into line. Both 20th editions were published in the same year. Thereafter, it was the British numbering that pushed ahead, with the 21st British edition in 1920, the 21st American edition in 1924; this discrepancy continued to increase, so that the 30th British edition was published in 1949, while the 30th and last American edition was published in 1984. The newest, 41st edition of Gray's Anatomy was published on 25 September 2015 by Elsevier in both print and online versions, and
The ischiocavernosus muscle is a muscle just below the surface of the perineum, present in both men and women. It arises by tendinous and fleshy fibers from the inner surface of the tuberosity of the ischium, behind the crus penis. From these points fleshy fibers succeed, end in an aponeurosis, inserted into the sides and under surface of the crus penis, it helps tense the vagina during orgasm. Ischiocavernosus compresses the crus penis, retards the return of the blood through the veins, thus serves to maintain the organ erect; this article incorporates text in the public domain from page 428 of the 20th edition of Gray's Anatomy Anatomy photo:41:11-0101 at the SUNY Downstate Medical Center - "The Female Perineum: Muscles of the Superficial Perineal Pouch" Anatomy figure: 41:05-01 at Human Anatomy Online, SUNY Downstate Medical Center - "Muscles of the female superficial perineal pouch." Anatomy figure: 42:04-01 at Human Anatomy Online, SUNY Downstate Medical Center - "Muscles of the male superficial perineal pouch.
The pudendal canal is an anatomical structure in the pelvis through which the internal pudendal artery, internal pudendal veins, the pudendal nerve pass. The pudendal canal is formed by obturator fascia, it encloses the following: Internal pudendal artery Internal pudendal veins Pudendal nerveThese vessels and nerve cross the pelvic surface of the obturator internus. Femoral canal Inguinal canal This article incorporates text in the public domain from page 421 of the 20th edition of Gray's Anatomy Anatomy image: apmalefrontal4-16 at the College of Medicine at SUNY Upstate Medical University Cross section image: pelvis/pelvis-e12-15—Plastination Laboratory at the Medical University of Vienna Anatomy photo:41:08-0100 at the SUNY Downstate Medical Center — "The Female Perineum: Contents of the Pudendal Canal" Diagram at pudendal.info Anatomy image:9087 at the SUNY Downstate Medical Center Anatomy image:9448 at the SUNY Downstate Medical Center
Superficial perineal pouch
The superficial perineal pouch is a compartment of the perineum. The superficial perineal pouch is an open compartment, due to the fact that anteriorly, the space communicates with the potential space lying between the superficial fascia of the anterior abdominal wall and the anterior abdominal muscles: its inferior border is the fascia of Colles, the deeper membranous layer of the superficial perineal fascia that covers the inferior border of the muscles of the superficial perineal pouch.. Its superior border is the perineal membrane. Muscles Ischiocavernosus muscle Bulbospongiosus muscle Superficial transverse perineal muscle Erectile bodies Corpus cavernosum Corpus spongiosus Vessels Posterior scrotal arteries /Labial arteries Artery to bulb /vestibule Urethral artery Nerves Posterior scrotal nerves /Posterior Labial nerves Other Crura of penis / Crura of clitoris Bulb of penis / Bulb of vestibule Bartholin's glands Deep perineal pouch Anatomy photo:41:09-0100 at the SUNY Downstate Medical Center - "The Female Perineum: The Superficial Perineal Pouch" perineum at The Anatomy Lesson by Wesley Norman
Anatomical terms of motion
Motion, the process of movement, is described using specific anatomical terms. Motion includes movement of organs, joints and specific sections of the body; the terminology used describes this motion according to its direction relative to the anatomical position of the joints. Anatomists use a unified set of terms to describe most of the movements, although other, more specialized terms are necessary for describing the uniqueness of the movements such as those of the hands and eyes. In general, motion is classified according to the anatomical plane. Flexion and extension are examples of angular motions, in which two axes of a joint are brought closer together or moved further apart. Rotational motion may occur at other joints, for example the shoulder, are described as internal or external. Other terms, such as elevation and depression, describe movement above or below the horizontal plane. Many anatomical terms derive from Latin terms with the same meaning. Motions are classified after the anatomical planes they occur in, although movement is more than not a combination of different motions occurring in several planes.
Motions can be split into categories relating to the nature of the joints involved: Gliding motions occur between flat surfaces, such as in the intervertebral discs or between the carpal and metacarpal bones of the hand. Angular motions occur over synovial joints and causes them to either increase or decrease angles between bones. Rotational motions move a structure in a rotational motion along a longitudinal axis, such as turning the head to look to either side. Apart from this motions can be divided into: Linear motions, which move in a line between two points. Rectilinear motion is motion in a straight line between two points, whereas curvilinear motion is motion following a curved path. Angular motions occur when an object is around another object decreasing the angle; the different parts of the object do not move the same distance. Examples include a movement of the knee, where the lower leg changes angle compared to the femur, or movements of the ankle; the study of movement is known as kinesiology.
A categoric list of movements of the human body and the muscles involved can be found at list of movements of the human body. The prefix hyper- is sometimes added to describe movement beyond the normal limits, such as in hypermobility, hyperflexion or hyperextension; the range of motion describes the total range of motion. For example, if a part of the body such as a joint is overstretched or "bent backwards" because of exaggerated extension motion it can be described as hyperextended. Hyperextension increases the stress on the ligaments of a joint, is not always because of a voluntary movement, it may be other causes of trauma. It may be used in surgery, such as in temporarily dislocating joints for surgical procedures; these are general terms. Most terms have a clear opposite, so are treated in pairs. Flexion and extension describe movements; these terms come from the Latin words with the same meaning. Flexion describes a bending movement that decreases the angle between a segment and its proximal segment.
For example, bending the elbow, or clenching a hand into a fist, are examples of flexion. When sitting down, the knees are flexed; when a joint can move forward and backward, such as the neck and trunk, flexion refers to movement in the anterior direction. When the chin is against the chest, the head is flexed, the trunk is flexed when a person leans forward. Flexion of the shoulder or hip refers to movement of the leg forward. Extension is the opposite of flexion, describing a straightening movement that increases the angle between body parts. For example, when standing up, the knees are extended; when a joint can move forward and backward, such as the neck and trunk, extension refers to movement in the posterior direction. Extension of the hip or shoulder moves the leg backward. Abduction is the motion of a structure away from the midline while adduction refer to motion towards the center of the body; the centre of the body is defined as the midsagittal plane. These terms come from Latin words with similar meanings, ab- being the Latin prefix indicating "away," ad- indicating "toward," and ducere meaning "to draw or pull".
Abduction refers to a motion that pulls a part away from the midline of the body. In the case of fingers and toes, it refers to spreading the digits apart, away from the centerline of the hand or foot. Abduction of the wrist is called radial deviation. For example, raising the arms up, such as when tightrope-walking, is an example of abduction at the shoulder; when the legs are splayed at the hip, such as when doing a star jump or doing a split, the legs are abducted at the hip. Adduction refers to a motion that pulls a structure or part toward the midline of the body, or towards the midline of a limb. In the case of fingers and toes, it refers to bringing the digits together, towards the centerline of the hand or foot. Adduction of the wrist is called ulnar deviation. Dropping the arms to the sides, bringing the knees together, are examples of adduction. Ulnar deviation is the hand moving towards the ulnar styloid. Radial deviation is the hand moving towards the radial styloid; the terms elevation and depression refer to movement below the horizontal.
They derive from the Latin terms with similar meaningsElevation refers to movement in a superior direction. For example
Defecation is the final act of digestion, by which organisms eliminate solid, semisolid, or liquid waste material from the digestive tract via the anus. Humans expel feces with a frequency varying from a few times daily to a few times weekly. Waves of muscular contraction in the walls of the colon move fecal matter through the digestive tract towards the rectum. Undigested food may be expelled this way, in a process called egestion. Open defecation, the practice of defecating outside without using a toilet of any kind, is still widespread in some developing countries, for example in India; the rectum ampulla temporarily stores fecal waste. As the waste fills the rectum and expands the rectal walls, nervous system stretch receptors in the rectal walls stimulate the desire to defecate; this urge to defecate arises from the reflex contraction of rectal muscles, relaxation of the internal anal sphincter, an initial contraction of the skeletal muscle of the external anal sphincter. If the urge is not acted upon, the material in the rectum is returned to the colon by reverse peristalsis, where more water is absorbed and the faeces is stored until the next mass peristaltic movement of the transverse and descending colon.
If defecation is delayed for a prolonged period the fecal matter may harden, resulting in constipation. If defecation occurs too fast, before excess liquid is absorbed, diarrhea may occur; when the rectum is full, an increase in intra-rectal pressure forces apart the walls of the anal canal, allowing the fecal matter to enter the canal. The rectum shortens as material is forced into the anal canal and peristaltic waves push the feces out of the rectum; the internal and external anal sphincters along with the puborectalis muscle allow the feces to be passed by muscles pulling the anus up over the exiting feces. Defecation is assisted by taking a deep breath and trying to expel this air against a closed glottis; this contraction of expiratory chest muscles, abdominal wall muscles, pelvic diaphragm exerts pressure on the digestive tract. Ventilation at this point temporarily ceases as the lungs push the chest diaphragm down to exert the pressure. Thoracic blood pressure rises and as a reflex response the amount of blood pumped by the heart decreases.
Death has been known to occur in cases where defecation causes the blood pressure to rise enough to cause the rupture of an aneurysm or to dislodge blood clots. In releasing the Valsalva maneuver blood pressure falls. During defecation, the external sphincter muscles relax; the anal and urethral sphincter muscles are linked. Experiments by Harrison Weed at the Ohio State University Medical Center have shown they can only be contracted together, not individually, that both show relaxation during urination; this explains why defecation is accompanied by urination. Defecation may be voluntary. Young children learn voluntary control through the process of toilet training. Once trained, loss of control, called fecal incontinence, may be caused by physical injury, nerve injury, prior surgeries, diarrhea, loss of storage capacity in the rectum, intense fright, inflammatory bowel disease, psychological or neurological factors, childbirth, or death; the positions and modalities of defecation are culture-dependent.
Squat toilets are used by the vast majority of the world, including most of Africa and the Middle East. The use of sit-down toilets in the Western world is a recent development, beginning in the 19th century with the advent of indoor plumbing. Attempting forced expiration of breath against a closed airway is sometimes practiced to induce defecation while on a toilet. Cardiac arrest and other cardiovascular complications can in rare cases occur due to attempting to defecate using the valsalva maneuver. Valsalva retinopathy is another pathological syndrome associated with the Valsalva maneuver; the anus and buttocks may be cleansed after defecation with toilet paper, similar paper products, or other absorbent material. In many cultures, such as Hindu and Muslim, water is used for anal cleansing after defecation, either in addition to using toilet paper or exclusively; when water is used for anal cleansing after defecation, toilet paper may be used for drying the area afterwards. Some peoples have culturally significant stories.
For example: In an Alune and Wemale legend from the island of Seram, Maluku Province, the mythical girl Hainuwele defecates valuable objects. One of the traditions of Catalonia relates to the caganer, a figurine depicting the act of defecation which appears in nativity scenes in Catalonia and neighbouring areas with Catalan culture; the exact origin of the caganer is lost, but the tradition has existed since at least the 18th century. Eric P. Widmaier. Vanders' Human Physiology: The Mechanisms of Body Function. Chapter 15. 10th ed. McGraw Hill. ISBN 9780071116770