Kubota K, Komatsu S, Nakamura M, Masegi T
Anat Rec. 1980 Aug;197(4):413-22. doi: 10.1002/ar.1091970405.
The jaw-closing muscles of two bovine fetuses average 1,177 muscle spindles on one side of the face: 549 in the masseter, 433 in the temporalis, 192 in the medial pterygoid, and three in the lateral pterygoid. The jaw-opening muscles have no spindles.