Examining the Forearm Intersection through Palpation and Ultrasonography

Background: Forearm intersection syndrome causes pain, swelling, and a rub at the dorsal distal forearm where the first extensor compartment muscles intersect with the second compartment tendons. Although primary care settings tend to treat mild cases, high-performance athletes may suffer from severe symptoms that require surgery. This proof-of-concept study aims to help detect the anatomical substrate of forearm intersection syndrome using palpation and ultrasonography when available. Methods: Five individuals were studied using independent palpation and ultrasonography to identify the first dorsal compartment muscles and the second dorsal compartment tendons. The distances between the dorsal (Lister’s) tubercle of the radius and the ulnar and radial edges of the first dorsal compartment muscles were measured to determine the location and extent of the muscle–tendon intersection. The palpatory and ultrasonographic measurements were compared using descriptive statistics and the paired t-test. Results: The mean distances from the dorsal tubercle of the radius to the ulnar and radial borders of the first dorsal compartment muscles were 4.0 cm (SE 0.42) and 7.7 cm (SE 0.56), respectively, based on palpation. By ultrasonography, the corresponding distances were 3.5 cm (SD 1.05, SE 0.47) and 7.0 cm (SD 1.41, SE 0.63). Both methods showed a similar overlap length. However, ultrasonography revealed a shorter distance between the dorsal tubercle of the radius and the ulnar border of the first compartment than palpation (p = 0.0249). Conclusions: Our findings indicate that a basic knowledge of anatomy should help health professionals diagnose forearm intersection syndrome through palpation and, if available, ultrasonography.Instituto de Salud Carlos IIIDepto. de Anatomía y EmbriologíaFac. de MedicinaTRUEpu

MRI Inflammation of the Hand Interosseous Tendons occurs in anti-CCP positive at-risk individuals and may precede the development of clinical synovitis

Objectives To investigate, by MRI, ITI in anti-cyclic citrullinated peptide (CCP)-positive at-risk individuals (CCP +at risk) and to describe the anatomy, prevalence and clinical associations across the RA continuum. Methods Hand MRI was performed in 93 CCP + at risk, 47 early RA (ERA), 28 established ‘late’ RA (LRA) and 20 healthy controls (HC) and scored for ITI, flexor tenosynovitis (TSV) and RA MRI scoring at the metacarpophalangeal joints (MCPJs). Cadaveric and histological studies were performed to explore the anatomical basis for MRI ITI. Results The proportion of subjects with ITI and the number of inflamed interosseous tendons (ITs) increased along the disease continuum (p<0.001): 19% of CCP +at risk, 49% of ERA and 57% of LRA had ≥1 IT inflamed . ITI was not found in any HC. ITI was more frequently identified in tender MCPJs compared with nontender MCPJs (28% vs 12%, respectively). No IT tenosynovial sheath was identified in cadavers on dissection or histological studies suggesting MRI findings represent peritendonitis. Dye studies indicated no communication between the IT and the joint. Conclusions ITI occurs in CCP + at-risk individuals and can precede the onset of clinical synovitis. The ITs may be important nonsynovial extracapsular targets in the development and progression of RA