Lying is a type of human position

Human position

Human positions refers to the different positions that the human body can take.There are several synonyms that refer to the human position, often used interchangeably, but having specific flavors....

 in which the body is more or less horizontal and supported along its length by the surface underneath.

When in lying position, the body may assume a great variety of shapes and positions. The following are the basic recognized positions.

• Supine
  Supine position
  The supine position is a position of the body: lying down with the face up, as opposed to the prone position, which is face down, sometimes with the hands behind the head or neck. When used in surgical procedures, it allows access to the peritoneal, thoracic and pericardial regions; as well as the...
  
  : lying on the back with the face up.
• Prone: lying on the chest with the face down ("lying down" or "going prone"). See also "Prostration
  Prostration
  Prostration is the placement of the body in a reverentially or submissively prone position. Major world religions employ prostration either as a means of embodying reverence for a noble person, persons or doctrine, or as an act of submissiveness to a supreme being or beings...
  
  ".
• Lying on either side, with the body straight or bent/curled forward or backward.
  • The fetal position
    Fetal position
    Fetal position is a medical term used to describe the positioning of the body of a prenatal fetus as it develops...
    
     is lying or sitting curled, with limbs close to the torso and the head close to the knees.
  • The recovery position
    Recovery position
    The recovery position refers to one of a series of variations on a lateral recumbent or three-quarters prone position of the body, in to which an unconscious but breathing casualty can be placed as part of first aid treatment.An unconscious person The recovery position refers to one of a series of...
    
     (coma position), one of a series of variations on a lateral recumbent or three-quarters prone position of the body, in to which an unconscious
    Unconsciousness
    Unconsciousness is the condition of being not conscious—in a mental state that involves complete or near-complete lack of responsiveness to people and other environmental stimuli. Being in a comatose state or coma is a type of unconsciousness. Fainting due to a drop in blood pressure and a...
    
     but breathing casualty can be placed as part of first aid
    First aid
    First aid is the provision of initial care for an illness or injury. It is usually performed by non-expert, but trained personnel to a sick or injured person until definitive medical treatment can be accessed. Certain self-limiting illnesses or minor injuries may not require further medical care...
    
     treatment

Lying is the most common position while being immobilized, e.g. in bedrest while sleeping or being struck by injury or disease.

As a treatment

Bedrest as a medical treatment refers to staying in bed day and night as a treatment for an illness or medical condition, especially when prescribed or chosen rather than resulting from severe prostration or imminent death. Even though most patients in hospitals spend most of their time in the hospital beds, bedrest more often refers to an extended period of recumbence at home.

Long-term risks

Prolonged bedrest carries some medical risks such as demineralization

Osteopenia

Osteopenia is a condition where bone mineral density is lower than normal. It is considered by many doctors to be a precursor to osteoporosis. However, not every person diagnosed with osteopenia will develop osteoporosis...

 of the bone

Bone

Bones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...

s and atrophy

Atrophy

Atrophy is the partial or complete wasting away of a part of the body. Causes of atrophy include mutations , poor nourishment, poor circulation, loss of hormonal support, loss of nerve supply to the target organ, disuse or lack of exercise or disease intrinsic to the tissue itself...

 of the muscle

Muscle

Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...

s, as well as economic and social costs, and is much less commonly prescribed today. Preterm labor with threatened miscarriage

Miscarriage

Miscarriage or spontaneous abortion is the spontaneous end of a pregnancy at a stage where the embryo or fetus is incapable of surviving independently, generally defined in humans at prior to 20 weeks of gestation...

 remains one of the few conditions for which bedrest remains a standard treatment.

It is also a major cause of thrombosis

Thrombosis

Thrombosis is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel is injured, the body uses platelets and fibrin to form a blood clot to prevent blood loss...

.

Errors in usage

The verb 'to lie' is an intransitive verb. People sometimes mistakenly use the verb 'to lay' intransitively when they mean 'to lie,' for example *'The cat is laying in the sun' instead of, correctly, 'The cat is lying in the sun.'

The transitive verb 'to lay' means to place a thing or person on a more or less horizontal surface. The direct object of the verb is the thing/person being placed in a horizontal position. Usually extra information is given in the complement of the sentence, telling us where the thing/person is being placed. For example, 'I lay my clothes on the bed when I'm packing for a holiday.'

The confusion between these two verbs may arise because 'lay' is the past form of 'to lie.'

For example:

'I lie in the sun every day on holiday' (present) vs 'I lay in the sun every day last week' (past)

and

'I lay my clothes out on the bed in the morning before I get dressed' (present) vs 'I laid my clothes out on the bed while I was packing for my holiday' (past)