1. The uppermost part of the body, shaped by the skeletal structure (the skull), and containing the brain and the specialized sense organs (the eyes, ears, nose, and tongue), and through which external matter (food and air) is taken in.

   SEE: illus.ARTERIES and VEINS OF THE HEAD.

   Abnormalities: An abnormal fixation of the head may be caused by postpharyngeal abscess, arthritis deformans, swollen cervical gland s, rheumatism, traumatism of the neck, sprains of cervical muscles, congenital spasmodic torticollis, caries of a molar tooth, burn scars, or eye muscle imbalance (hyperphoria). An inability to move the head may be due to caries of the cervical vertebrae and diseases of articulation between the occiput and atlas or paralysis of neck muscles.
2. The larger extremity of any organ.

Abnormal movements of the head include habit spasms such as nodding. Rhythmical nodding is seen in aortic regurgitation, chorea, and torticollis. A retracted head is seen in acute meningitis, cerebral abscess, tumor, thrombosis of the superior longitudinal sinus, acute encephalitis, laryngeal obstruction, tetanus, hydrophobia, epilepsy, spasmodic torticollis, strychnine poisoning, hysteria, rachitic conditions, and painful neck lesions at the back.

(Right lateral view)

after-coming h.Childbirth with the head delivered last.

articular h.A projection on bone that articulates with another bone.

optic nerve h.Optic disk.

ram's head Grifola frondosa.

sheep's head Grifola frondosa.