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Biceps Brachii

   


- Anatomy:

    - origin:
            - long head:  supraglenoid tuberosity of the scapula
            - short head: apex of coracoid process of scapula;
    - synergists: brachialis, brachioradialis, supinator;
    - innervation: musculocutaneous, C5  > C6;
    - insertion:
             - bicipital tuberosity of the radius and lacertus fibrosis; 
             - inserts on ulnar side of the lesser tuberosity, rather than as a cylinder on the center of the tuberosity;
             - lacertus fibrosus typically originates from the distal short head of the biceps tendon
             - references:
                      - The anatomy of the bicipital tuberosity and distal biceps tendon. 
                      - Distal Biceps Tendon Anatomy: A Cadaveric Study. 

                    

    - action:
             - flexes and supinates the forearm at the elbow;
             - reversed origin insertion action: both hands of biceps brachi are active during flexion of arm at shoulder joint, with the long head being more active;
    - long head of biceps: 
        - see: biceps tendonitis / tendonopathy / proximal biceps tendon rupture
        - attaches to the supraglenoid tubercle of glenoid & has stabilizing and depressing action on humeral head;
        - it can act as a tether and block closed reductions of proximal humerus;
        - it is a useful landmark from which the rotator interval can be identified so that bone fragments are properly identified & rotator cuff  are preserved;
        - references:
              - The role of the long head of the biceps brachii in superior stability of the glenohumeral joint.
              - The Transverse Humeral Ligament. A Separate Anatomical Structure or a Continuation of the Osseous Attachment of the Rotator Cuff? 
              - Subluxations and dislocations of the tendon of the long head of the biceps



- Pathologic Conditions:
    - biceps tendonitis / tendonopathy :
    - distal biceps tendon rupture:
    - proximal biceps tendon rupture:
    - erb's palsy :
         - persistent absence of biceps muscle function at age 6 months in pts w/ C5-6 brachial plexus palsy from birth has been shown to correlate
                  w/ a poor prognosis for functional recovery;
         - early brachial plexus exploration & nerve grafting will improve f(x) 


Traumatic closed transection of the biceps brachi in the military parachutist.

Rupture through the short head of the biceps muscle belly. A case report.

A technique for maximizing biceps recovery in brachial plexus reconstruction

Anatomy and Histology of the Transverse Humeral Ligament