Abstract: A sigmoidoscope (1) adapted for use in conjunction with a removable obturator to facilitate internal examination of the sigmoid colon of a patient. The sigmoidoscope includes a generally tubular speculum (2) having a sidewall defining a forward insertion end (3), a rearward observation end (4) and an internal lumen (5). The lumen (5) defines a substantially unobstructed viewing path between the observation end and the insertion end. Manually operable insufflation means (10) in fluid communication with the lumen of the speculum are provided for insufflation of the sigmoid colon with an insufflation medium. A coupling element (20) has a proximal end (21) for releasable connection to the observation end (4) of the speculum, a distal end (26) adapted for releasable connection to an optical head (30), and an optically transparent observation window (32) effectively isolating the distal end from the proximal end.

Abstract: A medical instrument used as a sigmoidoscope (1) for internal examination of the rectum and sigmoid colon of a patient. The instrument includes an outer tubular member in the form of a speculum (2) having a forward insertion end (3) and a rearward observation end (4). An inner tapered guide tube (10) is disposed at least partially within the speculum (2). A retractable obturation tube (15) is disposed between the speculum (2) and the inner guide tube (10) for relative movement between a retracted position substantially within the speculum (2) and an extended position in which the obturation tube (15) protrudes longitudinally beyond the forward end (3) of the speculum (2).