With the increase of hand pathologies in the last decade, the need to better understand the anatomy of the hand is becoming more vital. The cutaneous innervation of the hand is classically described to be supplied by palmar cutaneous branch of the median nerve (PCBMN), common digital nerves (CDNs), ulnar nerve (UN), palmar cutaneous branch of the ulnar nerve, dorsal branch of the ulnar nerve (DBUN), superficial branch of the radial nerve (SBRN) and occasionally the lateral antebrachial cutaneous nerve (LABCN). Although the sensory distribution of the hand has been described in the literature, reports have often shown contradicting views and occasionally different or incomplete descriptions. Furthermore, clinical procedures in the hand and wrist can result in painful and/or disabling postoperative complications. This thesis outlines, categorizes and describes the distribution and branching patterns of cutaneous branches supplying the palmar and dorsal surface of the hand and their relationship to the distal area of the forearm and wrist. It also investigates the palmar and dorsal communicating branches, their patterns and common locations. Moreover, the project discusses the impact of the distribution and branching patterns of the cutaneous nerves on surgical and diagnostic procedures performed in the hand, wrist and distal forearm. 160 cadaveric hands were dissected in the Centre for Anatomy and Human Identification (CAHID), University of Dundee. All cadavers were musculoskeletally mature adults with mean age of 82.5±9.4 (range: 53-101) years. Skin was removed from the distal half of the forearm to the metacarpophalangeal joints. Nerves under investigation were identified, dissected, and traced. Sketches, photographs, and measurements to predefined landmarks including the wrist crease (WC), bistyloid line (BSL) and the third metacarpophalangeal (MCP) joint were taken and results expressed as means, standard deviations and ranges. Patterns are classified and expressed with frequencies. The PCBMN was found to originate from the main trunk of the median nerve (MN) 54.1±15.7 mm proximal to the WC and course distally between flexor carpi radialis and palmaris longus (if present) to innervate the proximal palmar surface of the hand by branching into one of three types identified. Furthermore, two PCBMN were found in 8.9% of cases. The second, third, fourth CDNs were found to divide into proper digital nerves at a point located distal to the 70% of the distance between the third MCP joint and the BSL in 88% of cases. The cutaneous innervation of the palm was found to be relatively constant with the lateral 3½ digits being supplied by the MN and the medial 1½ being supplied by the UN. A palmar CB was found between the third CDN-MN and fourth CDN-UN in 86.9% of the cases coursing in different patterns and changing the palmar sensory innervation of that previously described. The sensory innervation of the dorsum of the hand was variable. The most common pattern was being supplied by the SBRN innervating the lateral dorsal skin and the skin covering the lateral 2½ digits and the DBUN innervating the medial dorsal skin and the skin covering the medial 1½ digits found in 37.3%. All radial supply to the dorsum of the hand with the absence of the DBUN was found in 6.7%. The SBRN connected with the LABCN in 30.7% and with the DBUN in 26.4% complicating the sensory innervation in the dorsum of the hand. Understanding the cutaneous innervation of the hand, appreciation of the possible variations and presence of communicating branches will result in a better evaluation of signs and symptoms, establishing a proper therapeutic plan, avoiding iatrogenic injuries during surgical interventions, and properly diagnose postoperative complications leading to an increased quality of medical service and patient satisfaction.
|Date of Award||2014|
|Supervisor||Roger Soames (Supervisor) & Clare Lamb (Supervisor)|
- Cutaneous nerves
- Anatomical variations
- Hand anatomy