Human head

The head receives blood supply through the internal and external carotid arteries. These supply the area outside of the skull (external carotid artery) and inside of the skull (internal carotid artery). The area inside the skull also receives blood supply from the vertebral arteries, which travel up through the cervical vertebrae.

Sensory areas of the head, showing the general distribution of the three divisions of the fifth nerve. From Gray's Anatomy 1918

The twelve pairs of cranial nerves provide the majority of nervous control to the head. The sensation to the face is provided by the branches of the trigeminal nerve, the fifth cranial nerve. Sensation to other portions of the head is provided by the cervical nerves.

Modern texts are in agreement about which areas of the skin are served by which nerves, but there are minor variations in some of the details. The borders designated by diagrams in the 1918 edition of Gray's Anatomy are similar but not identical to those generally accepted today.

The cutaneous innervation of the head is as follows:

• Ophthalmic nerve (green)
• Maxillary nerve (pink)
• Mandibular nerve (yellow)
• Cervical plexus (purple)
• Dorsal rami of cervical nerves (blue) and others are in picture which show following in upper column

A man wearing a straw hat

Headpieces can signify status, origin, religious/spiritual beliefs, social grouping, team affiliation, occupation, or fashion choices.

In many cultures, covering the head is seen as a sign of respect. Often, some or all of the head must be covered and veiled when entering holy places or places of prayer. For many centuries, women in Europe, the Middle East, and South Asia have covered their head hair as a sign of modesty. This trend has changed drastically in Europe in the 20th century, although is still observed in other parts of the world. In addition, a number of religions require men to wear specific head clothing—such as the Islamic taqiyah, Jewish yarmulke, or the Sikh turban. The same goes for women with the Muslim hijab or Christian nun's habit.

A hat is a head covering that can serve a variety of purposes. Hats may be worn as part of a uniform or used as a protective device, such as a hard hat, a covering for warmth, or a fashion accessory. Hats can also be indicative of social status in some areas of the world.

While numerous charts detailing head sizes in infants and children exist, most do not measure average head circumference past the age of 21. Reference charts for adult head circumference also generally feature homogeneous samples and fail to take height and weight into account.[6]

One study in the United States estimated the average human head circumference to be 57 centimetres (22+1⁄2 in) in males and 55 centimetres (21+3⁄4 in) in females.[7] A British study by Newcastle University showed an average size of 57.2 cm for males and 55.2 cm for females with average size varying proportionally with height [8]

Macrocephaly can be an indicator of increased risk for some types of cancer in individuals who carry the genetic mutation that causes Cowden syndrome. For adults, this refers to head sizes greater than 58 centimeters in men or greater than 57 centimeters in women.[9][10]

Some values in the table below may not be correct. In particular, a random biocular breadth measurement showed a value of 101.6 mm for an average adult male. The first percentile value below is 110 mm for an adult male. Another user has also indicate around 100 mm being an average value for biocular breadth. Therefore, the biocular breadth values appear to be increased by around 22 mm.

Static adult human physical characteristics of the head - redrawn.