Flexor Carpi Radialis

Median Nerve, Lateral and Medial Cord, Anterior, Divisions, Upper, Middle and Lower Trunk, C6, C7, ck 

Common tendon from medial epicondyle of humerus. 

Three to four fmgerbreadths distal to the midpoint of a line connecting the medial epicondyle (ME) and biceps tendon (BT). 

If the needle electrode is inserted too deeply it will be in the flexor 

If inserted too laterally it will be in the pronator teres, and if inserted too medially it will be in the palmaris longus. 

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Flexor pronator (medial) group Supplied by the median and ulnar nerves, this group comprises of the pronator teres, flexor carpi radialis, palmaris longus, flexor carpi ulnaris, and the flexor digito-rum superficialis. 

The superficial layer of volar muscles consists of the flexor digitorum superficialis, the pronator teres, the palmaris longus, the flexor carpi radialis and the flexor carpi ulnaris (Fig. 9.2b,c). These muscles take their origin from a strong common tendon which arises from the medial epicondyle (see Chapter 8). The flexor digitorum superficialis, the largest muscle of the superficial layer, consists of three heads - humeral, ulnar and radial - which join at the proximal forearm and continue distally in four distal tendons that insert into the middle phalanx of the... 

Fig. 9.16a-d. Flexor carpi radialis tendon tear, a Photograph of a boy complaining of weakness of wrist flexion and a soft tissue lump (white arrows) on the volar aspect of the wrist after receiving a penetrating wound (open arrow) in the middle forearm by a sharp object, b Longitudinal and c transverse 12-5 MHz US images over the distal lump reveal a retracted tendon end (arrows) of the flexor carpi radialis which appears swollen and diffusely hypoechoic. d At the level of the wound, transverse 12-5 MHz US image demonstrates an empty sheath (arrowheads) of the flexor carpi radialis tendon... 

Fig. 103 a,b. a Photograph of the anterior aspect of the wrist with b cadaveric correlation shows the flexor carpi radialis tendon (black arrow) which serves as a guide to the radial artery (a) which lies just lateral to it. The long lean tendon of the pahnaris longus (arrowhead) is a landmark for the median nerve (MN) which is deep and frequently lateral to it. More medially, the flexor carpi ulna-ris tendon (open arrow) is seen moving down to the pisiform (P). This tendon may be used as a key reference for the ulnar artery and nerve which lie lateral to it... 

On gray-scale US images, the ulnar and radial arteries are readily visible because of their pulsatil-ity. The main landmark for the radial artery is the lateral aspect of the flexor carpi radialis while the ulnar artery passes medial to the flexor carpi ulnaris (Fig. 10.23). More distally, the radial artery moves in a lateral position within the subcutaneous tissue, between the skin and the superficial aspect of the pronator quadratus (Fig. 10.24a). As it approaches the distal radius, this artery deepens to pass on the dorsal aspect of the wrist, within the anatomic snuff-box. Its palmar branch can be imaged in the subcutaneous tissue as a small hypoechoic pulsatile structure. Variations in size of the palmar branch are common and this vessel may also appear as large as the radial artery. The ulnar artery can be found in... 

Fig. 10.33 a,b. Schematic drawings illustrate typical sites of overuse tendinopathies in the a dorsal and b ventral wrist, including Ay de Quervain tenosynovitis B, intersection syndrome C,extensor pollicis longus tenosynovitis, ),extensor carpi ulnaris tenosynovitis E, flexor carpi radialis tenosynovitis F, flexor digitorum superficialis and flexor digitorum profundus tenosynovitis Gy flexor carpi ulnaris tendinopathy... 

Similar to the dorsal wrist, tendinopathies of the flexor tendons are commonly encountered, most often at the insertion of the flexor carpi radialis tendon and within the carpal tunnel for the flexor digitorum tendons (Fig. 10.33b) (Daenen et al. 2004). In addition to tendinopathies, compression neuropathy of the median nerve at the carpal tunnel is the leading pathology of the wrist as regards prevalence of disease and clinical relevance. The entrapment of the ulnar nerve at the Guyon tuimd is rare and, in many cases, secondary to other disorders. 

Fig. 10.45 a-c. Acute tenosynovitis of the flexor carpi radialis tendon, a Short-axis and (b) long-axis 12-5 MHz US images at the wrist demonstrate abnormal distension of the sheath of flexor carpi radialis tendon (fcr) by abundant hypoechoic fluid (asterisks), whereas the tendon echotexture is normal. Note the relationship of the flexor carpi radialis with the median nerve (MN), the flexor digitorum (ft) and the flexor poUicis longus (fpl) tendons, c Photograph of the same patient shows the mass effect (arrows) of tendon sheath effusion on the radial side of the ventral wrist... 

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