Sensory nerve-endings and sensation in the anal region of man

Abstract

'THE anal region in man (circumanal skin and anal canal) is extremely sensitive, yet a search of the literature reveals that little work, histological or experimental, has been done on its sensory innervation. The histological investigations of Ottaviani (1940) were mainly on small animals and mostly concerned with the rectum. However, he did note that there were nerve-plexuses made up of thick and thin fibres beneath the columnar epithelium of the rectal columns. No mention was made of organized sensory nerve-endings. In work on human adult and embryonic material Seto (I940), using his own modification of the Bielschowsky-Gros method, described intra-epithelial free endings in the anal canal and illustrated them by means of diagrams. His study was concerned particularly with the nerves crf the epithelium and no organized endings were described. Using a Cajal silver technique Sotelo (1954) demonstrated nerve-fibres at the anal canal ducts in human fetuses, although no organized endings were described. The nerve-fibres apparently supplied both endings in the skin and other endings in the glandular epithelial surface. Using Seto's method, Izumi (1955), one of his pupils, described organized endings in the anal region of man and illustrated them by drawings. He noted large and small end-formations which he believed to be two types of genital bodies. He also described and illustrated branching nerve-fibres which were thought to be simple or complex terminations according to the number of subdivisions involved in the termination. In addition, in the subcutaneous fat he found Pacinian corpuscles which he thought were rather smaller than those usually found elsewhere. He emphasized that the nerves and endings diminished markedly in number in the zona columnaris. In a study on human sigmoid colon and rectum Wang Wei Fan (1955) found myelinated fibres and branching non-myelinated fibres to which he attributed a sensory function. No end-formations were shown in connexion with these fibres. However, he noted some tangled glomerular endings lying close to the basal membrane of the epidermis at the mucocutaneous junction. These he considered to resemble genital corpuscles. Two types of ending have been described by Kantner (1957) in connexion with a deep and superficial network of fibres in the 38 submucosa at the mucocutaneous junction. He remarked on the presence of occasional Pacinian corpuscles near the anal sphincters. The rectum he found to lack organized endings and networks and to have submucosal nerve-fibres the branches of which were in close relationship to blood-vessels near the epithelium.The present study was undertaken to investigate the sensory nerve-endings in the perianal skin, the anal canal, and the adjoining rectal mucosa. A preliminary report of the findings has already been published (Duthie and Gairns, 1958). M T E R I A L AND METHODSHistological.-Material for the investigation was obtained from ten human beings whose ages ranged from 34 to 70 years. Three of the specimens were from early autopsies...

Afferent Impulses in the Pudendal Nerves of the Cat

“…Impulses from receptors in this region can certainly rise into consciousness and play a part in the maintenance of feecal continence. The clinical investigations of Duthie and Gairns [1960] indicate that all the normal modalities of cutaneous sensation are represented, and indeed with increased sensitivity, in the lining membrane of the human anal canal. Todd [1959] pointed out that the sensitivity of the human anal canal is such that a distinction can be made between fseces and flatus.…”

“…The sensitivity of the lining membrane of the anal canal in man was tested clinically by Duthie and Gairns [1960] who found that all the modalities in normal skin were present here; indeed the sensitivity seemed to be more acute than in the majority of cutaneous surfaces. In keeping with this acute sensitivity, Duthie and Gairns found a profuse innervation with highly specialized receptors in the lining membrane of the anal canal of man: but they foumd no receptors in the mucosa of the rectum.…”

Diagnosis and Management of Fecal Incontinence

“…This process may be facilitated by transient relaxations of the internal anal sphincter that allows the movement of stool or flatus from the rectum into the upper anal canal where they may come into contact with specialized sensory end organs such as the numerous Krause end-bulbs, Golgi-Mazzoni bodies and genital corpuscles and the relatively sparse Meissner's corpuscles and Pacinian corpuscles (20). Specialized afferent nerves for touch, cold, tension, and friction subserve these organized nerve endings.…”

“…Specialized afferent nerves for touch, cold, tension, and friction subserve these organized nerve endings. An intact "sampling reflex" allows the individual to choose whether to discharge or retain their rectal contents, whereas an impaired "sampling reflex" may predispose to incontinence (19,20).…”

Abaixamento endoanal do colón no tratamento da moléstia de Hirschsprung

“…Na anastomose coloanal abaixo da linha pectínea, o paciente perde a sensibilidade do canal anal em diferenciar entre gás, líquido ou sólido, levando a incontinência fecal (Duthie & Gairns, 1960).…”