Ooizcalling, maybe that is so in your country, but it is not the general case.
Jeppesen is not the authority so presumably the description of the MSA is taken from your AIP.
PANS-OPS definitions:
Minimum sector altitude. The lowest altitude which may be used which will provide a minimum clearance of 300 m (1000 ft) above all objects located in an area contained within a sector of a circle of 46 km (25 NM) radius centred on a radio aid to navigation.
PANS-OPS Vol 1 Part 3
3.2.1 Omnidirectional or sector arrivals can be provided taking into account minimum sector altitudes (MSA) (see 1.2.5).
1.2.5 Minimum sector altitudes are established for each aerodrome and provide at least 300 m (984 ft) obstacle clearance within 46 km (25 NM) of the homing facility associated with the approach procedure for that aerodrome.