Injuries to which nerve are likely to present with an ape hand and hand benediction appearance?

The presentation of an "ape hand" and "hand benediction" signifies injury to the median nerve. The "ape hand" describes a condition where the individual has difficulty in opposing their thumb, leading to a flat appearance of the hand that resembles a primate’s hand. This occurs because the median nerve is responsible for innervating the muscles that allow thumb opposition and movement in the first web space, primarily the opponens pollicis muscle.

The "hand benediction" appearance is observed when a person attempts to make a fist; the index and middle fingers remain extended while the ring and little fingers curl into the fist. This is due to the loss of function in the flexor muscles innervated by the median nerve, which are involved in flexing the fingers.

Given that the median nerve supplies the majority of the flexor muscles in the forearm and intrinsic muscles of the hand, damage to this nerve compromises both grip strength and fine motor control, leading to the noted physical manifestations. Understanding these characteristic signs can help in identifying the involved nerve and addressing the appropriate therapeutic interventions.