SAEM Clinical Images Series: An Unusual Arm Conundrum
A 58-year-old female with a past medical history significant for osteoporosis presented with right shoulder pain after a witnessed mechanical fall down two stairs. She sustained no headstrike or loss of consciousness. She endorses severe right shoulder pain without numbness/tingling over any part of her arm. Since the fall, she has been unable to move her arm, which remains abducted overhead.
General: Right arm fixed, abducted position and elevated over her head.
Vascular: 2-second capillary refill in all nail beds, strong palpable radial pulse.
Neuro: Sensation intact to light touch on medial and lateral aspects of all distal digits, and throughout entire axillary, radial, ulnar and median nerve distribution.
Motor: Flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) intact in digits 2 through 5. Extensor digitorum communis (EDC) and extensor indicis proprius (EIP) intact. Normal finger abduction and adduction. Normal thumb opposition. Normal OK sign. Wrist flexors and extensors intact.
None
Luxatio erecta (inferior shoulder dislocation) is a rare type of shoulder dislocation. The majority of shoulder dislocations are anterior (over 95%), with a smaller number being posterior (2-4%). Inferior dislocations are the least common injury pattern (0.5%), but prompt identification and treatment are crucial due to the high risk of neurovascular damage. Radiographs will typically demonstrate the humeral head lying inferior to the glenoid fossa, with the humeral shaft parallel to the spine of the scapula. Classically, the entire arm is held in abduction.
Inferior shoulder dislocation most commonly occurs either due to hyperabduction of the shoulder (such as when grasping at a tree branch above while falling) or through an axial load from above on a hyperabducted arm (as seen in falls or motor vehicle accidents). Patients presenting with inferior shoulder dislocation are at substantial risk for neurovascular compromise, particularly of the axillary nerve, leading to impaired upper extremity movement and sensation. Due to the substantial injury mechanism, patients with inferior shoulder dislocations are also at increased risk for rotator cuff pathology. Treatment of inferior shoulder dislocation is immediate closed reduction to reduce the risk of neurovascular complications. Once reduced, the arm should be placed in an immobilizer to prevent recurrent dislocation.
Take-Home Points
Patients with inferior shoulder dislocations often present holding their arm above their head. Often, patients cannot adduct their arm.
Axillary nerve injuries occur in about 60% of inferior dislocations. Compared to other dislocations, inferior dislocations have the highest incidence of axillary nerve injuries.
Patients with inferior dislocations often present with neurovascular compromise of the affected arm, so be sure to do a thorough exam after reduction.
Grate I Jr. Luxatio erecta: a rarely seen, but often missed shoulder dislocation. Am J Emerg Med. 2000 May;18(3):317-21. doi: 10.1016/s0735-6757(00)90127-x. PMID: 10830689.
Nambiar M, Owen D, Moore P, Carr A, Thomas M. Traumatic inferior shoulder dislocation: a review of management and outcome. Eur J Trauma Emerg Surg. 2018 Feb;44(1):45-51. doi: 10.1007/s00068-017-0854-y. Epub 2017 Oct 3. Erratum in: Eur J Trauma Emerg Surg. 2018 Feb;44(1):53. doi: 10.1007/s00068-017-0878-3. PMID: 28975397.
