Horn - H.S.

horn

(horn) A cutaneous outgrowth or projection composed chiefly of keratin. SYN: cornu.

 h. of Ammon Hippocampus.

 anterior h. The column of neuronal cell bodies and processes (gray matter) found in the anterior quadrant of each half of the spinal cord. In stained cross-sections of spinal cord, the gray matter forms the rough shape of a butterfly; the anterior horns are the lower wings. SYN: ventral h. SEE: spinal cord.

 cicatricial h. A cutaneous horn originating in scar tissue.

 cutaneous h. A hard, horny outgrowth from the skin. It is slow-growing, benign, and may be small or large, 10 to 12 cm, in diameter.

 dorsal h. The main column of neuron cell bodies and unmyelinated cell processes, i.e., gray matter, running through the dorsal quadrant of each half of the spinal cord. In stained cross-sections of spinal cord, the gray matter forms the rough shape of a butterfly; the dorsal horns are the upper wings. SYN: posterior horn. SEE: spinal cord.

 intermediolateral h. Lateral horn.

 lateral horn A column of neuron cell bodies and gray matter (unmyelinated cell processes) running through the lateral quadrant of spinal cord segments C8–L2 In stained cross-sections of spinal cord, the lateral horns form a small bulge of gray matter between the dorsal (posterior) and ventral (anterior) horns. The lateral horns contain the preganglionic cell bodies of the sympathetic nervous system. SYN: intermediolateral h.; intermediolateral cell column; zona intermedia. SEE: spinal cord.

 posterior h. Dorsal horn.

 sebaceous h. A hard protrusion from a sebaceous gland.

 uterine h. Either of the two upper corners of the uterus into which the uterine tubes enter.

 ventral h. Anterior horn.

 warty h. A hard outgrowth from a wart.

Horner syndrome

(hor′nĕr) [Johann F. Horner, Swiss ophthalmologist, 1831–1886] A syndrome characterized by contraction of the pupil, partial ptosis of the eyelid, enophthalmos, and sometimes loss of sweating over one side of the face. The syndrome is caused by paralysis of the cervical sympathetic nerve trunk, often as a result of an anesthetic mishap or a tumor in the superior sulcus of the lung.

horopter

(hō-rŏp′tĕr) [Gr. horos, limit, + opter, observer] The sum of all points in space that have a corresponding point on the retina of the eye.

horror

(hor′ŏr) [L. horror, shuddering (from fear)] Intense fear, revulsion, or dread caused by seeing or hearing something that is terrifying, shocking, or perceived to be life threatening.

horse chestnut

(hors ches′nŭt″) [translation of L. Castanea ...