A medical holding arm is described, at least one joint (24, 26, 28, 30, 32) having two joint bodies (40, 42) rotatable relative to each other with respect to an axis of rotation (D) The first joint body (40) has a plurality of fixing pins (46), the second joint body (42) has a plurality of fixing recesses (48), and the number of fixing pins (46). Unlike the number of fixing recesses (48), each of the fixing pins (46) has an engaging portion (66) tapered in the axial direction, and each of the fixing recesses (48) has a joint (24, 26, 28, 30, 32) are axially tapered to selectively receive each of the engagement portions (66) to secure the joints (24, 26, 28, 30, 32). When at least one of the fixing pins (46) is tapered One of the locking recesses (48) has its tapered engagement portion (66) fully received, and at least one of the other locking pins (46) is of the other tapered locking recess (48). One is only partially received in its tapered engagement portion (66). Each of the engaging portions (66) of the fixing pin (46) has at least one flat first contact surface (68), and each of the fixing recesses (48) has at least one flat second contact surface. (72) When each engaging portion (66) of the locking pin (46) is received in the locking recess (48), the first contact surface (68) and the second contact surface (72) are at least partially relative to each other. In flat contact. [Selection] Figure 3医療用保持アームが説明され、回転軸（Ｄ）に対して相互に関連して回転可能な２つの継ぎ手体（４０、４２）を有する少なくとも１つの継ぎ手（２４、２６、２８、３０、３２）を備え、第１の継ぎ手体（４０）は複数の固定ピン（４６）を有し、第２の継ぎ手体（４２）は複数の固定凹部（４８）を有し、固定ピン（４６）の数は固定凹部（４８）の数と異なり、固定ピン（４６）のそれぞれは軸方向に先細りにされた係合部分（６６）を有し、固定凹部（４８）のそれぞれは継ぎ手（２４、２６、２８、３０、３２）を固定するために係合部分（６６）のそれぞれを選択的に受け入れるように軸方向に先細りに形成され、継ぎ手（２４、２６、２８、３０、３２）が固定されたとき、固定ピン（４６）の少なくとも１つは先細りにされた固定凹部（４８）の１つにその先細りにされた係合部分（６６）が完全に受け入れられ、他の固定ピン（４６）の少なくとも１つは他の先細りにされた固定凹部（４８）の１つにその先細りにされた係合部分（６６）に部分的にのみ受け入れられる。固定ピン（４６）の係合部分（６６）のそれぞれは少なくとも１つの平坦な第１の接触面（６８）を有し、固定凹部（４８）のそれぞれは少なくとも１つの平坦な第２の接触面（７２）を有する。固定ピン（４６）の係合部分（６６）のそれぞれが固定凹部（４８）に受け入れられるとき、
