housemaid’s kneeInflammation of the
bursathat acts as a cushion over the
kneecap. The inflammation is usually
caused by prolonged kneeling but may
develop after a blow to the front of the
knee. (See also bursitis.)
HPVThe abbreviation for human papil-
lomavirus.
HRTSee hormone replacement therapy.
5HTSee serotonin agonists; serotonin
antagonists.
human chorionic gonadotrophinSee
gonadotrophin, human chorionic.
human genomeSee genome, human.
human leukocyte antigen (HLA)A
type of protein belonging to the group
known as histocompatibility antigens,
which play a role in the immune system.
human papillomavirusA type of virus
that is responsible for wartsand genital
warts. There are over 50 strains of human
papillomavirus. Infection with some of
these strains is thought to be a causative
factor in cervical cancerand anal cancer.
humerusThe bone of the upper arm. The
dome-shaped head of the bone lies at an
angle to the shaft and fits into a socket
in the scapula to form the shoulder
joint. Below its head, the bone narrows
to form a cylindrical shaft. It flattens
and widens at its lower end, forming a
prominence on each side called an epi-
condyle. At its base, it articulates with
the ulnaand radiusto form the elbow.
humerus, fracture ofThe humerusis
most commonly fractured at its neck
(the upper end of the shaft, below the
head), particularly in elderly people.
Fractures of the shaft occur in adults of
all ages. Fractures of the lower humerus
occur most commonly in children.
An X-raycan show a fracture of the
humerus. A fracture of the bone’s neck
usually requires only a slingto immobi-
lize the bone; a fracture of the shaft or
lower bone normally needs a plaster
cast. Most fractures of the humerus heal
in 6–8 weeks.
humoursLiquid or jelly-like substances
in the body. The term humours usually
refers to the aqueous humourand vit-
reous humourthat occur in the eye.
hunchbackSee kyphosis.
hungerA disagreeable feeling caused
by the need for food. Hunger occurs
when the stomach is empty and the
blood glucose level is low, often follow-
ing strenuous exercise. In response to
these stimuli, messages from the hypo-
thalamuscause the muscular stomach
wall to contract in a rhythmic manner;
these contractions, if they are pro-
nounced, produce hunger pains.
Hunger due to a low blood sugar level
can also occur in thyrotoxicosis, and in
diabetes mellituswhen an incorrect bal-
ance between insulin and carbohydrate
intake causes hypoglycaemia.
Huntington’s diseaseAn uncommon
disease in which degeneration of the
basal gangliaresults in choreaand dem-
entia. Symptoms of Huntington’s disease
do not usually appear until age 35–50.
The disease is due to a defective gene
and is inherited in an autosomal domi-
nant manner (see genetic disorders).
The chorea usually affects the face,
arms, and trunk, resulting in random
grimaces and twitches, and clumsiness.
Dementia takes the form of irritability,
personality and behavioural changes,
memory loss, and apathy.
At present, there is no cure for Hunt-
ington’s disease, and treatment is aimed
at reducing symptoms with drugs.
Hurler’s syndromeA rare, inherited
condition caused by an enzymedefect.
The syndrome is a type of inborn error
of metabolism (see metabolism, inbornHOUSEMAID’S KNEE HURLER’S SYNDROME
H
HUMERUSHumerusScapulaUlnaRadiusEpicondylesClavicleRib