šWhen the supraspinatus tendon sustains a large or āmassiveā tear, the issue isnāt just local tissue damageāit fundamentally alters how the shoulder moves and functions.
š§ The supraspinatus plays a key role in initiating shoulder abduction and, more importantly, in stabilizing the humeral head within the glenoid. When that stabilizing force is compromised, the biomechanics of the shoulder begin to shift.
šHereās what typically happens:
⢠Loss of humeral head controlWithout adequate supraspinatus function, the humeral head tends to migrate superiorly during arm elevation. This reduces the available subacromial space and increases mechanical compression of surrounding structures.
⢠Deltoid dominance without restraintThe deltoid continues to generate upward force, but without the counterbalance of the rotator cuff, that force becomes less efficient. Instead of producing smooth rotation, it drives excessive superior translation.
⢠Altered force couplingThe rotator cuff normally works as a coordinated unit. With a massive tear, this balance is disrupted, often leading to compensatory overactivity of the remaining cuff and scapular musculature.
⢠Functional limitationsPatients often report difficulty with overhead movements, weakness, and in more severe cases, an inability to actively elevate the arm (sometimes referred to as pseudoparalysis).
ā Over time, these changes can contribute to chronic dysfunction, pain, and even rotator cuff arthropathy if left unmanaged.