Ileocaecal valve
The valve-like junction between the small and large intestine that prevents backflow of colon contents into the small intestine.
Ileocolic artery
The terminal branch of the superior mesenteric artery to the junction of small and large bowel, from which the appendicular artery also arises. It is divided centrally in right hemicolectomy.
See also: Superior mesenteric artery, Appendicular artery
Impaired consciousness
Umbrella term for reduced wakefulness (e.g. somnolence, stupor, coma) or altered content of consciousness such as confusion. Any new impairment of consciousness is an emergency that must be assessed quickly.
See also: Delirium
Incapacity for work
A state in which an employee cannot work because of illness, certified by a doctor’s sick note.
Incentive spirometer
A device for practising deep, slow breaths with visual feedback. After surgery it is intended to prevent atelectasis and pneumonia.
See also: Atelectasis
Indwelling urinary catheter
A catheter inserted through the urethra into the bladder, held in place by a small balloon and draining urine continuously. The risk of infection increases with the duration of use.
Inferior alveolar artery
A branch of the maxillary artery that runs with the nerve of the same name in the mandibular canal and supplies the teeth and bone of the lower jaw.
See also: Maxillary artery, Mandibular canal
Inferior epigastric artery
The artery from the external iliac artery that runs upwards behind the rectus abdominis muscle. It helps distinguish direct from indirect inguinal hernias and is used in breast reconstruction with the patient’s own tissue (DIEP flap).
See also: External iliac artery
Inferior gluteal artery
A branch of the internal iliac artery that leaves the pelvis below the piriformis muscle and supplies the gluteus maximus. It accompanies the sciatic nerve.
See also: Superior gluteal artery, Internal iliac artery
Inferior mesenteric artery
The artery arising from the abdominal aorta that supplies the descending colon, sigmoid colon and upper rectum. In bowel ischaemia, the region near the left colic flexure is often at risk.
See also: Superior mesenteric artery
Inferior pancreaticoduodenal artery
A branch of the superior mesenteric artery that supplies the head of the pancreas and the duodenum and forms an arcade with the superior artery. This connection can provide collateral circulation when vessels are narrowed.
See also: Superior mesenteric artery
Inferior phrenic artery
A paired artery from the abdominal aorta that supplies the underside of the diaphragm and contributes to the adrenal glands. In liver tumours it can form additional feeding vessels.
Inferior thyroid artery
The artery from the thyrocervical trunk that supplies the thyroid and parathyroid glands. In thyroid surgery its close relationship to the recurrent laryngeal nerve is important.
Inferior vesical artery
A branch of the internal iliac artery supplying the bladder base and, in men, also the prostate and seminal vesicles.
See also: Internal iliac artery
Informed consent discussion
Conversation before a procedure about how it works, its risks and alternatives; it is a prerequisite for valid consent.
Infraorbital artery
A branch of the maxillary artery that runs beneath the orbital floor and emerges through the infraorbital foramen onto the cheek. It supplies the upper front teeth and midface.
See also: Maxillary artery
Innate lymphoid cells
Lymphocytes without antigen-specific receptors that rapidly release messengers, especially at mucous membranes, thereby controlling defence, tissue repair and inflammation. Their functions resemble those of T helper cells.
Internal carotid artery
The artery arising from the division of the common carotid artery that gives off no branches in the neck. It supplies large parts of the brain and the eye; narrowing at its origin is an important cause of stroke.
See also: Carotid artery, Circle of Willis
Internal iliac artery
The artery branching from the common iliac artery that supplies the pelvic organs, buttock muscles and external genitalia. In severe pelvic bleeding it can be deliberately blocked.
Internal pudendal artery
The artery from the internal iliac artery that supplies the perineum, external genitalia and erectile tissue. Narrowing of this artery can contribute to vascular erectile dysfunction.
See also: Internal iliac artery
Internal thoracic artery
The artery running on each side next to the breastbone that supplies the front chest wall. In heart surgery it is the preferred bypass vessel because it stays open for a long time.
See also: Bypass
Interproximal caries
Caries on the contact surfaces between neighbouring teeth, often hard to see with the naked eye. Floss or interdental brushes help prevent it, and X-rays are often used to detect it.
Intervertebral disc
A cartilage disc between two vertebral bodies with a gel-like core that absorbs shocks and keeps the spine flexible.
See also: Slipped disc
Intraocular pressure
The pressure inside the eye; raised values are a risk factor for glaucoma.
Intravenous urography
An X-ray examination in which contrast medium is given intravenously and its excretion through the kidneys and urinary tract is imaged. It has largely been replaced by CT and ultrasound.
See also: Computed tomography (CT)
Iliac crest
Upper edge of the iliac wing that can be felt as the rim of the pelvis. It serves as a landmark in examinations and often as a site for taking bone marrow or bone grafts.
See also: Ilium
Ilium
Largest part of the hip bone, with the palpable iliac wing. Bone marrow can be taken from the iliac crest for examination if needed.
See also: Pelvis
Incisive canal
Bony canal behind the upper central incisors that connects the nasal and oral cavities and carries the nasopalatine nerve. It must be taken into account when placing implants in the front teeth region.
Infant colic
Bouts of inconsolable crying in healthy babies in the first months of life that subside on their own.
Inferior colliculus
Lower mound of the tectal plate, an important relay station of the auditory pathway between the brainstem and thalamus.
See also: Superior colliculus
Inferior nasal concha
Largest nasal turbinate, a separate bone on the side wall of the nose with swellable mucosa. Its enlargement often obstructs nasal breathing.
Inflammatory bowel disease (IBD)
Umbrella term for Crohn’s disease and ulcerative colitis: chronic inflammation of the bowel that occurs in flare-ups.
See also: Ulcerative colitis
Intermittent claudication
Exercise-related pain in the calf or buttock when walking that eases after a short rest. It is the typical symptom of peripheral arterial disease.
Internal capsule
Densely packed bundle of fibres between the thalamus and basal ganglia through which motor and sensory pathways run. Even small strokes here can cause marked weakness of one side of the body.
See also: Basal ganglia
Interstitial cells of Cajal
Specialised pacemaker cells in the wall of the stomach and intestine that generate rhythmic electrical waves and so set the rhythm of gut movement. Gastrointestinal stromal tumours (GIST) arise from them.
Intestinal barrier
Protective layer of mucus, gut cells and immune cells that lets nutrients through and keeps germs out.
Intestinal malrotation
Congenital abnormal position of the bowel due to incomplete rotation during embryonic development. It can lead to life-threatening volvulus, often with bilious vomiting in the newborn.
Intestinal villi
Finger-like projections of the small intestinal lining that greatly increase the surface area for nutrient absorption. They flatten in coeliac disease.
See also: Small intestine