Endotracheal Intubation: Procedure, Equipment, Tube Size, and Placement

Endotracheal Intubation: Procedure, Equipment, Tube Size, and Placement

pediagenosis    August 29, 2026    Comment   

ENDOTRACHEAL INTUBATION

Endotracheal intubation is a lifesaving procedure that requires familiarity with anatomy, physiology, pharmacology, and the necessary equipment required to perform the procedure.

Choice of the correct size of endotracheal tube is fundamental. The average man will accept a cuffed tube with an inner diameter of 8.0 or 8.5 mm. For women, the tube diameter is 0.5 to 1.0 mm smaller. Smaller tubes have more resistance to airflow and may not allow passage of a bronchoscope, but larger tubes may increase injury to the glottis and lower airway.

Ejaculatory Disorders: Causes, Types, Symptoms, and Treatment

Ejaculatory Disorders: Causes, Types, Symptoms, and Treatment

pediagenosis    August 28, 2026    Comment   

EJACULATORY DISORDERS

Although commonly viewed as a single event, ejaculation is actually two separate processes, termed emission and ejaculation. During emission, the semen is “loaded” into the prostatic urethral chamber. After this, ejaculation is the forcible expulsion of semen from the penis in a series of spurts caused by rhythmic contractions, about 1 second apart, of the pelvic muscles. Ejaculation is different from orgasm or climax, the latter being an event that is centered in the brain that is closely associated with ejaculation.

Normal Birth: Stages of Labor, Fetal Movements, and Delivery Explained

Normal Birth: Stages of Labor, Fetal Movements, and Delivery Explained

pediagenosis    August 27, 2026    Comment   

CARDINAL MOVEMENTS

NORMAL BIRTH

Labor generally begins between the 38th and 42nd week of gestation. Prior to the onset of labor, physicochemical changes occur in the cervix and are collectively called “ripening.” When this is combined with the increasingly frequent and strong uterine contractions of late pregnancy, the cervix begins the process of effacement. In a proposed self-perpetuating process, effacement of the cervix results in the production and liberation of more prostaglandins, further stimulating uterine contractions (Ferguson reflex). Cervical effacement is common before the onset of true labor.

Uterine Inversion: A Rare but Life-Threatening Obstetric Emergency

Uterine Inversion: A Rare but Life-Threatening Obstetric Emergency

pediagenosis    August 26, 2026    Comment   

UTERINE INVERSION

Rarely, the uterus can be turned inside out immediately following the delivery of the placenta. Uncommon and most often iatrogenic, this may be associated with catastrophic bleeding and cardiovascular collapse. Incomplete uterine inversion may also occur. (Rarely the condition has also been reported in nonpregnant patients with intrauterine pathology such as a pedunculated leiomyomata or large endometrial polyp.) The prevalence of uterine inversion is estimated to be about 1 in 6500 to 25,000 deliveries.

Innervation of the Hand: Ulnar, Median and Radial Nerve Anatomy

Innervation of the Hand: Ulnar, Median and Radial Nerve Anatomy

pediagenosis    August 23, 2026   

INNERVATION OF THE HAND

Nerve branches from the ulnar, median, and radial nerve supply motor, sensory, and autonomic vasomotor function in the hand.

ULNAR NERVE

The ulnar nerve (C[7], 8; T1) is the main continuation of the medial cord of the brachial plexus. In the forearm and hand, the ulnar nerve gives off articular, muscular, palmar, dorsal, superficial and deep terminal, and vascular branches. It divides into branches for the areas of skin on the medial side of the back of the hand and fingers (see Plate 4-12). The ulnar nerve enters the hand to the radial side of the pisiform between the palmar carpal ligament and the flexor retinaculum. Just distal to the pisiform, the ulnar nerve divides into superficial and deep branches.

Pressures and Volumes During Normal Breathing: FRC, Intrapleural Pressure and Lung Volumes

Pressures and Volumes During Normal Breathing: FRC, Intrapleural Pressure and Lung Volumes

pediagenosis    August 23, 2026   

Pressures And Volumes During Normal Breathing

Functional residual capacity

The volume left in the lungs at the end of a normal breath is known as the functional residual capacity (FRC). At FRC, the respiratory muscles are relaxed and its volume is determined by the elastic properties of the lungs and chest wall.

The lungs are elastic bodies whose resting volume when removed from the body is very small. The natural resting position of the chest wall, seen when the chest is opened surgically, is about 1 L larger than at the end of a normal breath.

Meckel Diverticulum: Symptoms, Complications, Diagnosis, and Treatment

Meckel Diverticulum: Symptoms, Complications, Diagnosis, and Treatment

pediagenosis    August 22, 2026    Comment   

VARIANTS OF VITELLINE DUCT REMNANTS

Meckel Diverticulum

The vitelline, or omphalomesenteric, duct connects the yolk sac with the primitive tubular gut in the early embryonic stages and normally involutes at about the 7th week of fetal life, leaving no trace of its existence. Failure of the vitelline duct to disappear in its entire extension results in a variety of remnants, which include a diverticulum (Meckel diverticulum) attached to the ileum, omphalomesenteric cysts (enterocysts), omphalomesenteric fistulae that drain through the umbilicus, and fibrous bands from the diverticulum to the umbilicus that predispose to bowel obstruction. The most common form is Meckel diverticulum.

Atrial Septal Defect (ASD): Types, Symptoms, Diagnosis and Treatment

Atrial Septal Defect (ASD): Types, Symptoms, Diagnosis and Treatment

pediagenosis    August 20, 2026    Comment   

ATRIAL SEPTAL DEFECTS

DEFECTS OF THE ATRIAL SEPTUM

The atrial septum normally consists of two overlapping, closely adjacent components. Each forms an incomplete partition. The right-side component, corresponding to the embryonic septum secundum, is muscular and firm and has a posteroinferior oval-shaped opening, the foramen ovale. The left-side component, derived from the embryonic septum primum, is fibrous and thin and has a somewhat round opening anterosuperiorly, the ostium secundum. Together, the two components act as a one-way flap valve, allowing the flow of blood from right to left (normal before birth) but not from left to right. After birth, with the establishment of pulmonary circulation, the increased amount of blood entering the left atrium elevates the pressure in that chamber, thereby closing the flap valve. In most cases, this functional closure is eventually followed by anatomic closure; that is, the two components of the septum fuse. In the minority of cases where fusion fails, an increase in the right atrial pressure due to congenital cardiac anomalies, or any other condition that elevates right ventricular and right atrial pressure, causes the right atrial blood to flow again into the left atrium. Such a probe-patent foramen ovale, however, should not be considered a form of atrial septal defect; it causes no hemodynamic abnormalities by itself. In ASD there is an abnormal opening in the atrial septum allowing blood to flow either way; a predominantly left-to-right shunt usually exists. With associated anomalies or other conditions tending to increase right atrial pressure, the shunt is always from right to left, as in tricuspid valve atresia, or an initially left-to-right shunt reverses, as occurs after pulmonary vascular changes with pulmonary hypertension.

Lymphatic Drainage of Internal Genitalia: Uterus, Ovary, Tube, Cervix & Vagina

Lymphatic Drainage of Internal Genitalia: Uterus, Ovary, Tube, Cervix & Vagina

pediagenosis    August 18, 2026    Comment   

LYMPHATIC DRAINAGE II—INTERNAL GENITALIA

The lymphatics of the uterus are contained within three main networks or plexuses one at the base of the endometrium, another in the myometrium, and a third subperitoneally. No lymphatics, surprisingly, have been detected in the superficial parts of the endometrium. The principal collecting trunks pass outward at the isthmus along the course of the uterine vessels. Drainage from the uterine body and from the cervix is similar, except that, in the region of the fundus, lymphatics are more likely to pass directly along with the ovarian lymphatics to the periaortic nodes. Occasionally, also, lymphatics may extend along the inguinal ligament to the femoral nodes. The number of lymph nodes in the group of parauterine nodes is small; most frequently there is a single node immediately lateral to each side of the cervix and adjacent to the pelvic course of the ureter. Although anatomists frequently do not comment about the parauterine nodes, the group receives special attention in radical surgical operations to treat uterine or cervical malignancy. Primary drainage to this node originates in the vagina, cervix, and uterus. Secondary drainage from this node is to the internal iliac nodes on the same side of the pelvis.

Lymphatic Drainage of the External Genitalia: Inguinal Nodes & Cloquet Node

Lymphatic Drainage of the External Genitalia: Inguinal Nodes & Cloquet Node

pediagenosis    August 17, 2026   

LYMPHATIC DRAINAGE—EXTERNAL GENITALIA

A network of lymphatic anastomoses drains the external genitalia, the lower third of the vagina, and the perineum. Bilateral or crossed extension and drainage is common. The superficial femoral nodes are reached through the superficial external pudendal lymphatic vessels, although the superficial external epigastrics may also play a role. From the region of the clitoris, deeper lymphatic vessels may pass direct to the deep femoral nodes, particularly to Cloquet node in the femoral canal, or through the inguinal canal to the external iliac nodes. Cloquet node is thought to be the sentinel node between the superficial and deep inguinal/obturator lymph nodes. Sometimes, intercalated nodes may be encountered in the prepubic area or at the external inguinal ring. The lowermost portion of the vagina, like the vulva, may drain to the femoral nodes. This complex network of lymph nodes is clinically important, for these are the nodes to which cutaneous and vulvovaginal gland malignancies may drain. Regional lymph node dissections are routinely performed in the surgical treatment of vulvar cancer as the status of regional lymph nodes is essential for therapeutic planning and overall prognosis. Superficial nodes in the groin may also become enlarged when significant inflammation is present in vulvar structures (e.g., Bartholin gland infections).