| [Objective] To explore the entrapment to the ulnar nerve at the wrist,to assist the surgeon in diagnosis and treatment of Guyon's canal syndrome.[Methods] 20 fresh upper limbs were dissected on loupe(5 ×).Record the relationship between the ulnar nerve and the hypothenar muscles, the course and the arborization patterns of ulnar artery and nerve,the location and the course of the motor nerve branch to the hypothenar muscles,the relationship between the ulnar nerve and the artery and the variations at the ulnar side of the wrist.[Results] The ulnar nerve divides near the pisiform.After division the superficial sensory branch(or the 3th common digital nerve and the ulnar proper digital nerve of the little finger)runs distally over the fascial arch of the hypothenar muscles,then over the hypothenar muscles.The 3th common digital nerve runs deep to the aponeurosis a short distance distal to the pisiform in 16 cases.In one case the superficial sensory branch runs deep to the hypothenar fascia which is thickened at the insertion.The deep motor branch goes distally below the fascial arch of the hypothenar muscles, through the hypothenar muscles,then enters an intermuscular space.The intermuscular space consisits of the the superficial and deep head of theopponens digiti minimi and the hook of the hamate.The space has one entrance and one exit.The entrance consists of the proximal edge of the superficial and deep head of the opponens digiti minimi and the hook of the hamate.The exit is a little hole which consists of the distal edge of the superficial and deep head of the opponens digiti minimi and the medial intermuscular septum containing the deep branch of the ulnar nerve and the artery. We call the intermuscular space as the hiatus of opponens digiti minimi,call the proximal edge of the the superficial head of the opponens digiti minimi as the fascial arch of the opponens digiti minimi which is all tendious prensenting in all cases.There are four types of crossing relationships between the ulnar artery and the nerve:the artery to the hypothenar muscles crosses the deep branch of the ulnar nerve,the deep branch of the ulnar artery crosses the superficial branch of the ulnar nerve, the deep branch of the ulnar artery crosses the trunk of the ulnar nerve(or the superficial and the deep branch of the ulnar nerve) and the ulnar proper digital nerve of the little finger crosses the 3th common digital nerve.The motor branch to the hypothenar muscles originates at three most common places:proximal to the fasical arch of the hypothenar muscles,at or distal to the fasical arch of the hypothenar muscles,distal to the exit of the opponens digiti minimi hiatus.There are two variations:accessory abductor digiti minimi and the connection between the 2th and the 3thcommon digital nerve.[Conclusions] There are two district along the course of the ulnar nerve at the wrist:the Guyon's canal and the hypothenar muscles distrist. A few structures may compress the ulnar nerve besides the fascial arch of the hypothenar muscles.The entrapment at the Guyon's canal: the artery to the hypothenar muscles,the deep branch of the ulnar artery and the accessory abductor digiti minimi. The entrapment to the superficial branch of the ulnar nerve at the hypothenar muscles distristithe hypothenar fascia,the aponeurosis and the ulnar proper digital nerve of the little finger. The entrapment to the deep branch of the ulnar nerve at the hypothenar muscles distristithe hiatus of the opponens digiti minimi and the fascial arch of the oppnens digiti minimi.During decompressing operation we should explore the fascial arch of the opponens digiti minimi as a rule,excise the arch and the superficial head of the opponens digiti minimi and the exit of the the hiatus of the opponens digiti minimi. The ulnar artery and the motor branches to the hypothenar muscles originate or run near the fascial arch of the hypothenar muscles and the exit to the the hiatus of the opponens digiti minimi,so we should protect them during decompressing operation. The motor branches to the abductor digiti minimi originates near the fascial arch of the hypothenar muscles, we should excise the arch to make the pedicle have... |
