Human skull in the context of Intramembranous ossification

Death is the end of life, the irreversible cessation of all biological functions that sustain a living organism. Death eventually and inevitably occurs in all organisms. The remains of a former organism normally begin to decompose shortly after death. Some organisms, such as Turritopsis dohrnii, are biologically immortal; however, they can still die from means other than aging. Death is generally applied to whole organisms; the equivalent for individual components of an organism, such as cells or tissues, is necrosis. Something that is not considered an organism can be physically destroyed but is not said to die, as it is not considered alive in the first place.

As of the early 21st century, 56 million people die per year. The most common reason is aging, followed by cardiovascular disease, which is a disease that affects the heart or blood vessels. As of 2022, an estimated total of almost 110 billion humans have died, or roughly 94% of all humans to have ever lived. A substudy of gerontology known as biogerontology seeks to eliminate death by natural aging in humans, often through the application of natural processes found in certain organisms. However, as humans do not have the means to apply this to themselves, they have to use other ways to reach the maximum lifespan for a human, often through lifestyle changes, such as calorie reduction, dieting, and exercise. The idea of lifespan extension is considered and studied as a way for people to live longer.

In human anatomy, the head is at the top of the human body. It supports the face and is maintained by the skull, which itself encloses the brain.

Trepanning, also known as trepanation, trephination, trephining or making a burr hole (the verb trepan derives from Old French from Medieval Latin trepanum from Greek trúpanon, literally "borer, auger"), is a surgical intervention in which a hole is drilled or scraped into the human skull. The intentional perforation of the cranium exposes the dura mater to treat health problems related to intracranial diseases or release pressured blood buildup from an injury. It may also refer to any "burr" hole created through other body surfaces, including nail beds. A trephine is an instrument used for cutting out a round piece of skull bone to relieve pressure beneath a surface.

Trepanning was sometimes performed on people who were behaving in a manner that was considered abnormal. In some ancient societies it was believed this released the evil spirits that were to blame. Evidence of trepanation has been found in prehistoric human remains from Neolithic times onward. The bone that was trepanned was kept by the prehistoric people and may have been worn as a charm to keep evil spirits away. Evidence also suggests that trepanation was primitive emergency surgery after head wounds to remove shattered bits of bone from a fractured skull and clean out the blood that often pools under the skull after a blow to the head. Hunting accidents, falls, wild animals, and weapons such as clubs or spears could have caused such injuries. Trepanations appear to have been most common in areas where weapons that could produce skull fractures were used. The primary theories for the practice of trepanation in ancient times include spiritual purposes and treatment for epilepsy, head wound, mental disorders, and headache, although the latter may be just an unfounded myth.

The human skeleton is the internal framework of the human body. It is composed of around 270 bones at birth – this total decreases to around 206 bones by adulthood after some bones get fused together. The bone mass in the skeleton makes up about 14% of the total body weight (ca. 10–11 kg for an average person) and reaches maximum mass between the ages of 25 and 30. The human skeleton can be divided into the axial skeleton and the appendicular skeleton. The axial skeleton is formed by the vertebral column, the rib cage, the skull and other associated bones. The appendicular skeleton, which is attached to the axial skeleton, is formed by the shoulder girdle, the pelvic girdle and the bones of the upper and lower limbs.

The human skeleton performs six major functions: support, movement, protection, production of blood cells, storage of minerals, and endocrine regulation.

The Shakespeare funerary monument is a memorial to William Shakespeare located inside Holy Trinity Church at Stratford-upon-Avon in Warwickshire, the church in which Shakespeare was baptised and where he was buried in the chancel two days after his death. The monument, carved in pale blue limestone, is mounted on the north wall of the chancel. It has traditionally been identified as the work of the sculptor Gerard Johnson, but this attribution is challenged by Lena Cowen Orlin, who argues that it was more likely modelled from life by Gerard's brother, Nicholas Johnson.

The monument features a demi-figure of the poet holding a real quill pen in one hand and a piece of paper resting on a cushion in the other. The style, which was popular from the early- to the mid-17th century, was most commonly used to memorialize divines, academics, and those professions with pretensions of learning. The buttoned doublet, with its ornamental slashes, was probably originally painted scarlet, the loose subfusc gown black, the eyes hazel, and the hair and beard auburn. It has been retouched many times, and was painted entirely white in 1793. This demi-figure is one of only two representations definitely accepted as accurately portraying William Shakespeare's physical appearance. The monument is topped with strapwork rising to a heraldic shield displaying Shakespeare's arms, on either side of which sits an allegorical figure: one, representing Labour, holds a spade, the other, representing Rest, holds an inverted torch and a skull.

Death is the end of life, the irreversible cessation of all biological functions that sustain a living organism. Death eventually and inevitably occurs in all organisms. The remains of a former organism normally begin to decompose shortly after death. Some organisms, such as Turritopsis dohrnii, are biologically immortal; however, they can still die from means other than aging. Death is generally applied to whole organisms; the equivalent for individual components of an organism, such as cells or tissues, is necrosis. Something that is not considered an organism may be said to die in a figurative sense when it reaches an inactive state, such as when a star runs out of fuel.

As of the early 21st century, 56 million people die per year. The most common reason is aging, followed by cardiovascular disease, which is a disease that affects the heart or blood vessels. As of 2022, an estimated total of almost 110 billion humans have died, or roughly 94% of all humans to have ever lived. A substudy of gerontology known as biogerontology seeks to eliminate death by natural aging in humans, often through the application of natural processes found in certain organisms. However, as humans do not have the means to apply this to themselves, they have to use other ways to reach the maximum lifespan for a human, often through lifestyle changes, such as calorie reduction, dieting, and exercise. The idea of lifespan extension is considered and studied as a way for people to live longer.

The axial skeleton is the core part of the endoskeleton made of the bones of the head and trunk of vertebrates. In the human skeleton, it consists of 80 bones and is composed of the skull (28 bones, including the cranium, mandible and the middle ear ossicles), the vertebral column (26 bones, including vertebrae, sacrum and coccyx), the rib cage (25 bones, including ribs and sternum), and the hyoid bone. The axial skeleton is joined to the appendicular skeleton (which support the limbs) via the shoulder girdles and the pelvis.

Cerebrospinal fluid (CSF) is a clear, colorless transcellular body fluid found within the meningeal tissue that surrounds the vertebrate brain and spinal cord, and in the ventricles of the brain.

CSF is mostly produced by specialized ependymal cells in the choroid plexuses of the ventricles of the brain, and absorbed in the arachnoid granulations. It is also produced by ependymal cells in the lining of the ventricles. In humans, there is about 125 mL of CSF at any one time, and about 500 mL is generated every day. CSF acts as a shock absorber, cushion or buffer, providing basic mechanical and immunological protection to the brain inside the skull. CSF also serves a vital function in the cerebral autoregulation of cerebral blood flow.

Bone conduction is the conduction of sound to the inner ear primarily through the bones of the skull, allowing the hearer to perceive audio content even if the ear canal is blocked. Bone conduction transmission occurs constantly as sound waves vibrate bone, specifically the bones in the skull, although it is hard for the average individual to distinguish sound being conveyed through the bone as opposed to the sound being conveyed through the air via the ear canal. Intentional transmission of sound through bone can be used with individuals with normal hearing—as with bone-conduction headphones—or as a treatment option for certain types of hearing impairment. Bones are generally more effective at transmitting lower-frequency sounds compared to higher-frequency sounds.

Bone conduction is also called the second auditory pathway and not to be confused with cartilage conduction, which is considered the third auditory pathway.

Intracranial hemorrhage (ICH) refers to any form of bleeding within the skull. It can result from trauma, vascular abnormalities, hypertension, or other medical conditions. ICH is broadly categorized into several subtypes based on the location of the bleed: intracerebral hemorrhage (including intraparenchymal and intraventricular hemorrhages), subarachnoid hemorrhage, epidural hemorrhage, and subdural hematoma. Each subtype has distinct causes, clinical features, and treatment approaches.

Artificial cranial deformation or modification, head flattening, or head binding is a form of body alteration in which the skull of a human being is deformed intentionally. It is done by distorting the normal growth of a child's skull by applying pressure. Flat shapes, elongated ones (produced by binding between two pieces of wood), rounded ones (binding in cloth), and conical ones are among those chosen or valued in various cultures.

Typically, the alteration is carried out on an infant, when the skull is most pliable. In a typical case, head binding begins approximately a month after birth and continues for about six months.

In human anatomy, the forehead is an area of the head bounded by three features, two of the skull and one of the scalp. The top of the forehead is marked by the hairline, the edge of the area where hair on the scalp grows. The bottom of the forehead is marked by the supraorbital ridge, the bone feature of the skull above the eyes. The two sides of the forehead are marked by the temporal ridge, a bone feature that links the supraorbital ridge to the coronal suture line and beyond. However, the eyebrows do not form part of the forehead.

In Terminologia Anatomica, sinciput is given as the Latin equivalent to "forehead" (etymology of sinciput: from semi- "half" and caput "head".).

Craniometry is measurement of the cranium (the main part of the skull), usually the human cranium. It is a subset of cephalometry, measurement of the head, which in humans is a subset of anthropometry, measurement of the human body. It is distinct from phrenology, the pseudoscience that tried to link personality and character to head shape, and physiognomy, which tried the same for facial features.

Today, physical and forensic anthropologists use craniometry to study the evolution of human populations, determining the origin of ancient remains such as the Kennewick Man.

Craniofacial surgery is a surgical subspecialty that deals with congenital and acquired deformities of the head, skull, face, neck, jaws and associated structures. Although craniofacial treatment often involves manipulation of bone, craniofacial surgery is not tissue-specific; craniofacial surgeons deal with bone, skin, nerve, muscle, teeth, and other related anatomy.

Defects typically treated by craniofacial surgeons include craniosynostosis (isolated and syndromic), rare craniofacial clefts, acute and chronic sequelae of facial fractures, cleft lip and palate, micrognathia, Treacher Collins Syndrome, Apert's Syndrome, Crouzon's Syndrome, Craniofacial microsomia, microtia and other congenital ear anomalies, and many others. Training in craniofacial surgery requires completion of a Craniofacial surgery fellowship. Such fellowships are available to individuals who have completed residency in oral and maxillofacial surgery, plastic and reconstructive surgery, or ear, nose, and throat surgery. Those who have completed residency in oral and maxillofacial surgery may be either single degree or dual-degree surgeons with no differences. There is no specific board for craniofacial surgery. In the US, cleft and craniofacial centers are found in many major academic centers.

A trephine (/trɪˈfaɪn/; from Greek τρύπανον, trypanon 'instrument for boring') is a surgical instrument with a cylindrical blade. It can be of one of several dimensions and designs depending on what it is meant to be used for. A trephine may be specially designed for obtaining a cylindrically shaped core of bone that can be used for tests and bone studies, cutting holes in bones (e.g., the skull), or cutting out a round piece of the cornea for eye surgery.

A cylindrically shaped core of bone (or bone biopsy) obtained with a bone marrow trephine is usually examined in the histopathology department of a hospital under a microscope. It shows the pattern and cellularity of the bone marrow as it lay in the bone and is a useful diagnostic tool in certain circumstances such as bone marrow cancer and leukemia.

A skull and crossbones is a symbol consisting of a human skull and two long bones crossed together under or behind the skull. The design originated in the Late Middle Ages as a symbol of death and especially as a memento mori on tombstones. Actual skulls and bones were long used to mark the entrances to Spanish cemeteries (campo santo).

In modern contexts, it is generally used as a hazard symbol, usually in regard to poisonous substances, such as deadly chemicals.