Which parts of the body are affected depends on which plexus is damaged: Rostral brachial plexus: Shoulders Caudal brachial plexus: Hands Lumbar plexus: Legs Sacral plexus: Pelvis and legs Plexuses Plexus disorders (plexopathies) are usually due to physical compression or injury: In infants, traction during birth if it damages nerves in the brachial plexus In adults, usually trauma (typically, for the brachial plexus, a fall that forces the head away from the shoulder) or invasion by metastatic cancer (typically, breast or lung cancer for the brachial plexus and intestinal or genitourinary tumors for the lumbosacral plexus) In patients receiving anticoagulants, a hematoma may compress the lumbosacral plexus.