What type of nerve injury presents with weakness in finger abduction, adduction, thumb opposition, and wrist flexion?

The type of nerve injury that presents with weakness in finger abduction, adduction, thumb opposition, and wrist flexion is associated with a T1 nerve root injury. This is primarily linked to symptoms involving the intrinsic muscles of the hand, which are responsible for the fine motor movements of the fingers.

The T1 nerve root innervates the majority of the intrinsic muscles of the hand, including the interossei (responsible for finger abduction and adduction) and the thenar muscles (which allow for thumb opposition). When there is an injury to this nerve root, individuals typically exhibit weakness or paralysis in these movements due to loss of motor function in the muscles supplied by the T1 root.

In contrast, a radial nerve injury would result in wrist drop and weakened extension of the wrist and fingers. A median nerve injury would primarily affect thumb opposition and flexion of the wrist but not the abduction and adduction of the fingers. An ulnar nerve injury would lead to weakness in finger abduction and adduction but would not affect wrist flexion or thumb opposition as distinctly as a T1 nerve root injury would. Thus, the combination of motor deficits described aligns specifically with T1 nerve root involvement.