Coccygeus and levator ani muscles in the rabbit: morphology and proprioceptive innervation.

The Authors have studied the morphological features and the proprioceptive nervous component in the coccygeus and levator ani muscles of the rabbit, using Ruffini's and Barker-Ip's impregnations. The coccygeus muscle originates from ischiatic spine and inserts on the last three sacral vertebrae and on the first four or five caudal vertebrae. The levator ani muscle originates from the ischiatic spine and the coccygeus muscle aponeurosis and inserts directly on the caudal vertebrae 3-5 or 4-6. The proprioceptive innervation in both muscles is constituted by muscle spindles and Golgi tendon organs with a typical structure. Muscle spindles are more numerous than Golgi tendon organs and the spindle density is higher in the levator ani muscle.