Innervation of digital joints: an anatomical overview

Abstract

Introduction The innervation of the digital joints as well as the anatomical relationships of the articular branches is present in this anatomical work to determine the technical feasibility of a selective and efficient denervation of the digital joints. Materials and methods A study of 40 distal interphalangeal (DIP), 40 proximal interphalangeal (PIP), 50 metacarpophalangeal (MCP), 10 interphalangeal (IP) of the thumb, and 10 trapezo-metacarpophalangeal (TMC) joints was performed on ten hands. Under magnification and a proper surgical approach, we collected the course, the source origin, the number of articular nerve branches, and their caliber. Results In total, 118 nerve branches arising from the proper palmar digital nerves were found on 10 DIP of each dissected long finger (n = 40). A total of 226 nerve branches were found on 10 PIPs of each long finger (n = 40), of which 204 branches (90.3%) had a palmar origin. Dorsal innervation was found for the ring and little finger, originating from the dorso-ulnar digital nerve. 212 branches were found on 10 MCP of long fingers (n = 40), including 87 branches of palmar origin (41.1%), 107 branches of dorsal origin (50.4%), and 18 branches of the motor branch of the ulnar nerve (8.5%). 42 articular branches directed to the TMC joint (n = 10) were found. 13 branches (31%) originated from the anterior sensory branch of the radial nerve, 13 branches (31%) originated from the lateral cutaneous nerve of the forearm, 5 branches (12%) originated from the palmar cutaneous branch of the median nerve, and 11 (26%) branches originated from the thenar branch of the median nerve. The involvement of the sensory anterior branch of the radial nerve was always present for the innervation of each TMC. Discussion and conclusion Our research shows that finger joints receive their primary innervation from small branches of the digital nerves with the exception of the MCP joint and the TMC joint. To obtain an efficient and a selective digital denervation for articular pain relief, it is necessary to plan the best surgical approach and it is crucial to recognize the articular nervous branch localization and source.

Distribution of nerve endings in human thumb interphalangeal joint

“…Gandolfi et al. showed that DIP and IP joint denervation are mostly palmar and thus suggested that the dorsal approach should be preferred (Gandolfi et al., 2021). However, even if the nerve entries of the joint capsule are from the volar side, it was found that especially paccini bodies were dense on the dorsal side.…”

“…The thumb IP joint is structurally similar to the DIP joint but is larger and has some differences. While the DIP joint the articuler nerve branches were detached from the source branch and proceeded directly towards the articular capsule , in IP joint one branch arising from the radial proper palmar digital nerve detached from the main trunk to join the joint capsule of the IP in its anterior‐external side (Gandolfi et al., 2021). Additionally, thump has only A1 and A2 annular pulleys but no cruciate pulleys (Leversedge, 2008).…”

Surgical denervation as a treatment strategy for pain in hand osteoarthritis: a systematic literature review

“…The nerves currently known to innervate the hands are summarised in online supplemental appendix 1. [11][12][13][14][15] The innervation of the joints in the hands is still subject to debate and more nerve branches than the ones currently treated with surgical denervation may contribute to the innervation of specific joints. 11 Furthermore, the occurrence of adverse effects has been reported, including wound infection, necrosis of skin flaps, or sensory abnormalities.…”

“…[11][12][13][14][15] The innervation of the joints in the hands is still subject to debate and more nerve branches than the ones currently treated with surgical denervation may contribute to the innervation of specific joints. 11 Furthermore, the occurrence of adverse effects has been reported, including wound infection, necrosis of skin flaps, or sensory abnormalities. 9 10 It is currently unclear whether the advantages of surgical denervation outweigh the disadvantages.…”

Study and implementation of fluxgate current sensor with wireless connectivity for finger exoskeleton rehabilitation

“…This leads to more precise and natural movement of the fingers, which is important in hand rehabilitation. The use of a fluxgate magnetometer in a finger exoskeleton device allows for the monitoring of motor torque in the proximal interphalangeal (PIP) joint 9–11 . This is important because several impairments affect the recovery of the hand, and monitoring motor torque can help assess the effectiveness of rehabilitation programs.…”