During dissection an anomalous muscle was found on the medial aspect in the distal half of one left upper extremity. This muscle arose from the humerus between the m. coracobrachialis and the m. brachialis, passed obliquely across the front of the brachial artery and median nerve and blended with the common origin of the forearm flexor muscles. It does not appear to be an additional head of the biceps brachii or the brachialis muscles. The existence of this anomalous muscle should be kept in mind in a patient presenting with a high median nerve palsy together with symptoms of brachial artery compression.
During routine dissection classes to undergraduate medical students, we have observed some important anatomic variations in the right upper limb of a 45-year-old cadaver. The anomalies were superficial ulnar artery, persistent median artery, variant superficial palmar arch, third head for biceps brachii, accessory head for flexor pollicis longus, variant insertion of pectoralis major, absence of musculocutaneous nerve, coracobrachialis muscle supplied by lateral root of median nerve and anomalous branching of median nerve in arm and forearm. Although there are individual reports about these variations, the combination of these variations in one cadaver has not previously been described in the literature consulted. Awareness of these variations is necessary to avoid complications during radiodiagnostic procedures or surgeries in the upper limb.
Rheumatoid arthritis (RA) is a well and widely recognized cause of carpal tunnel syndrome (CTS). In the rheumatoid wrist, synovial expansion, joint erosions and ligamentous laxity result in compression of the median nerve due to increased intracarpal pressure. We evaluated the published studies to determine the prevalence of CTS and the characteristics of the median nerve in RA and its association with clinical parameters such as disease activity, disease duration and seropositivity. A total of 13 studies met the eligibility criteria. Pooled data from 8 studies with random selection of RA patients revealed that 86 out of 1561 (5.5%) subjects had CTS. Subclinical CTS, on the other hand, had a pooled prevalence of 14.0% (30/215). The cross sectional area of the median nerve of the RA patients without CTS were similar to the healthy controls. The vast majority of the studies (8/13) disclosed no significant relationship between the median nerve findings and the clinical or laboratory parameters in RA. The link between RA and the median nerve abnormalities has been overemphasized throughout the literature. The prevalence of CTS in RA is similar to the general population without any correlation between the median nerve characteristics and the clinical parameters of RA.