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   Hand and wrist innervation Hide   


    Innervation of the hand (afferent and efferent):

    Afferent (sensory) innervation

    Answerl2q5_2


    Efferent (motor) innervation

    All the intrinsic muscles of the hand are innervated by the
    Ulnar nerve except for the "LOAF muscles"
    Answerl2q5

    Innervation of the foremarm (efferent):

    Flexors of the wrist:

    All but 2 (flexor carpi ulnaris and a component of flexor digitorum profundus) are innervated by median nerve.

    Flexor carpi ulnaris - Innervated by the ulnar nerve

    Flexor digitorum profundus - Innervated by both ulnar and median nerves
            -    Flexion at the DIP joints of index and middle fingers: median nerve (anterior
                interosseus nerve which also innervates FPL, damaged during distal humeral
                fractures leading to a positive OK sign).
            -    Flexion at the DIP joints of ring and little fingers: ulnar nerve

    Extensors of the wrist (and hand):

    All extensors of the wrist are innervated by the radial nerve (posterior interosseous branch).

    Clinical significance:

    Median nerve entrapment as it traverses through the carpal tunnely causes carpal tunnely syndrome.

    Ulnar nerve injury
        - Proximally in the elbow: Weakness, claw hand
        - Distally: Claw hand worse symptoms - i.e. ulnar paradox


Author: Mr Kasun Wanigasooriya MBCHB, MRCS | Speciality: Anatomy  | Date Added: 16/05/2010

   
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