Lacuna Magna (LM)

(1)

Pediatric Surgery, Al Azher University, Cairo, Egypt

Abstract

Lacuna means a small pit or hollow cavity, the lacuna magna is the largest depression in the fossa navicularis. Located deeper within the lacunae are branching mucous tubules called the glands of Littre. Guerin valve is a septum between the lacuna magna and the urethral lumen, which may act as a valve and leads to the manifestations of existence of LM with a different grades of urethral obstruction and other.

Keywords

Lacuna MagnaSinus of GuerinCrypts of MorgagniValve of navicular fossaCongenital urethral stricture

Nomenclature and Synonyms

Sinus of Guerin, Guérin’s fold, lacunae urethralis, urethrae masculinae, valve of navicular fossa or the crypts of Morgagni.

Definition

Generally lacuna means a small pit or hollow cavity, the lacuna magna is the largest depression in the fossa navicularis. Located deeper within the lacunae are branching mucous tubules called the glands of Littre. Guerin valve is a septum between the lacuna magna and the urethral lumen, which may act as a valve and leads to the manifestations of existence of LM with a different grades of urethral obstruction and other symptoms (Fig. 34.1).

Fig. 34.1

Diagram showing location of LM

34.1 Historical Background

This entity, initially described by Morgagni in 1719, Sommer and Stephens reported its association with urological symptoms for the first time in 1980 [1]^, Since then, many cases and series of lacuna magna have been reported in the literature.

34.2 Incidence

Although LM is found in more than 30 % of males during autopsy, it rarely may cause symptoms [2]. The actual incidence of symptomatic LM should be more than reported cases, it was suggested that this anomaly may not be so rare especially in circumcised boys and it can be associated with voiding dysfunction and high detrusor pressures in some patients, also it is suggested that the main difference between symptomatic and silent LM may be the larger size of urethral depression in LM [3].

34.3 Embryology

The embryologic origin of LM is contested, but recent evidence suggests that this septum represent a persistent embryological remanent between the canalized glandular ingrowth of ectodermal tissue and the distally advancing urethra, giving origin to a diverticulum in fossa navicularis.

Only gold members can continue reading. Log In or Register to continue