12/17/2023 0 Comments Media nerve tonalisUS depicting the median nerve at the level of the pronator teres muscle: axial A) and sagittal B) views. Apart from the supracondylar process, MR and US images may show an anatomic relationship with the median nerve (Figure 1). The pronator teres and more rarely coracobrachialis muscles may insert at the supracondylar process. Anatomical variations are described regarding the course of the nerve which can pass beneath or over the ligament of Struthers. This congenital osteofibrous arcade can cause a median nerve neuropathy which can be acute in case of fracture. The ligament of Struthers is a fibrous band connecting the supracondylar process to the medial epicondyle, encasing neurovascular structures including the median nerve and the brachial artery but also the ulnar nerve, the ulnar artery and a branch of the musculocutaneous nerve. The supracondylar process is a congenital bony spur located medially at the distal humerus, approximately 4–8 cm proximal to the medial epicondyle and 2–20 mm long. The supracondylar process syndrome is a very rare neuropathy that affects the median nerve (0.5% of cases). In the proximal part of the forearm, the anterior interosseous nerve, which is the largest branch of the median nerve, can be compressed. – The fibrous arch of the origin of the flexor digitorum superficialis.– Between the humeral and the ulnar heads of the pronator teres muscle,.– The lacertus fibrosus (where the course of the MN is superficial),.– The supracondylar process continued by the ligament of Struthers,.Actually, from proximal to distal, the median nerve can also be entrapped at four locations around the elbow, including: However in 7 to 10% of cases entrapment of the median nerve occurs at various sites along its course. The carpal tunnel is the most common site of compression. Although the anatomic course of the MN is largely protected, a compression of the nerve can occur in particular at the joints. Median nerve mononeuropathy is the most common peripheral nerve neuropathy. The median nerve is also responsible for the cutaneous innervation of part of the hand including the thenar eminence, the lateral side of the palm, the palmar side of the index, the thumb and middle finger and the dorsal side of the distal phalanx of index and middle finger and half the ring finger. The median nerve only provides motor function to the forearm, and motor and sensory function to the wrist and hand. Distal to the carpal tunnel, it gives off a motor branch (for the thenar compartment and the first and second lumbricals) and a sensory branch which subdivides into four digital palmar branches. The MN passes under the flexor retinaculum and into the carpal tunnel running anteriorly and laterally to the tendons of the flexor digitorum superficialis. After entering the cubital fossa, the MN passes beneath the bicipital aponeurosis (also known as lacertus fibrosus), over the brachialis muscle and then between the two heads of the pronator teres.Īs the nerve enters the anterior antebrachial compartment, it runs under the aponeurotic arch of the flexor digitorum superficialis before coursing between the flexor digitorum superficialis and profundus muscles. After originating from the brachial plexus in the axilla, the MN lies laterally close to the brachial artery and then crosses it anteriorly to medially by drawing a “S-Shape”. The median nerve arises from the anteromedial and anterolateral cords of the brachial plexus and is innervated by the C6, C7, C8 and T1 nerve roots.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |