Background: Ear cartilage is a preferred graft material in rhinoplasty. However, after harvest, instability of the auricular framework may arise as a form of donor site morbidity. In the harvest of ear cartilage, the posterior auricular ligament (PAL) is usually sacrificed in order to obtain as much cartilage as possible. Since damage to the PAL may cause auricular instability, we studied the periauricular anatomy using cadavers and evaluated auricular stability during surgery. Methods: Six ears from hemifacial cadavers were studied to clarify the exact anatomy of the PAL. Then, the recoil force of the auricle was serially measured to evaluate the stability of the auricular framework in 30 patients during surgery: before making the skin incision (M1), before and after cutting the PAL (M2, M3), and after harvesting the cymba concha (M4). The differences in force observed after cutting the PAL (ΔM2–M3) and after harvesting the cymba concha (ΔM3–M4) were statistically analyzed. Results: In the cadaveric study, the PAL was identified between the superficial and deep mastoid fasciae and connected the caudal aspect of the cymba concha to the deep mastoid fascia. During surgery, the PAL accounted for 16.20% of the total auricular recoil force. The recoil force decreased by 13.61 N and 11.25 N after cutting the PAL and harvesting the cymba concha, respectively. These decreases were statistically significant (P<0.05). Conclusions The results suggest that the PAL is a supporting structure of the auricle. Therefore, to preserve auricular stability, minimizing damage to the PAL while harvesting the ear cartilage may be helpful.