Chauhan Munish, Anand Prashanth, Das Joe M.
Unity Point Health
Imperial College Healthcare NHS Trust, London
Neuropathy of the causing symptoms of tingling, numbness, and shooting pain along the medial aspect of the forearm, also including the medial half of the fourth digit and the fifth digit, usually caused by compression or irritation of the nerve at the elbow. C8 and T1 nerve roots join and give rise to the medial cord of the brachial plexus. Ulnar nerve originates as a branch of the medial cord. The ulnar nerve then travels down the arm along with the brachial artery towards the elbow joint. At the midpoint of the arm, the nerve enters the posterior compartment by piercing the intermuscular septum(arcade of Struthers). It then traverses along the medial aspect of the triceps to enter the cubital tunnel. At this point, the ulnar nerve travels between the olecranon and the medial epicondyle and beneath the Osborne ligament. Once the nerve exits the cubital tunnel, it passes under the aponeurotic head of flexor carpi ulnaris to enter the forearm. The cubital tunnel region is where the ulnar nerve is most likely to be compressed due to its location and anatomy. However, the nerve can also get compressed at the arcade of Struthers or by the aponeurotic head of flexor carpi ulnaris resulting in symptoms of ulnar neuropathy. The ulnar nerve innervates the medial side of the forearm, ulnar side of the palm, the little finger, and ulnar half of the ring finger. It supplies motor branches to flexor carpi ulnaris, flexor profundus of the little and ring fingers, hypothenar muscles, adductor pollicis brevis, all of the interossei and the third and fourth lumbricals. It is noteworthy that the ulnar nerve gives no motor or sensory branches above the elbow.
神经病导致前臂内侧出现刺痛、麻木和放射性疼痛症状，也包括第四指和第五指的内侧半部分，通常是由肘部神经受压或受刺激引起的。C8和T1神经根会合形成臂丛内侧束。尺神经起源于内侧束的一个分支。然后，尺神经与肱动脉一起沿手臂向下走向肘关节。在手臂中点，神经穿过肌间隔（斯特鲁瑟斯弓）进入后骨筋膜室。然后它沿着肱三头肌的内侧走行进入肘管。此时，尺神经在尺骨鹰嘴和内上髁之间以及奥斯本韧带下方走行。一旦神经离开肘管，它会在尺侧腕屈肌的腱膜头下方通过进入前臂。肘管区域因其位置和解剖结构，是尺神经最容易受压的部位。然而，神经也可能在斯特鲁瑟斯弓或尺侧腕屈肌的腱膜头处受压，导致尺神经病变的症状。尺神经支配前臂内侧、手掌尺侧、小指以及环指的尺侧半。它为尺侧腕屈肌、小指和环指的指深屈肌、小鱼际肌、拇短收肌、所有骨间肌以及第三和第四蚓状肌提供运动分支。值得注意的是，尺神经在肘部以上不发出运动或感觉分支。
