Muscle · Head

Rectus capitis posterior minor

Musculus rectus capitis posterior minor

Rectus capitis posterior minor is the smallest and deepest of the suboccipital muscles, running from the posterior tubercle of the atlas — the first neck vertebra — straight up to the skull just off the midline. It extends the head on the neck, but its more interesting property is structural: it has fibrous connections, the myodural bridge, to the membrane and dura at the back of the skull, giving it a mechanical relationship with the covering of the spinal cord. Combined with the very high muscle-spindle density of the suboccipital group, that makes it a tiny muscle with an outsized role in the sense of where the head is — and it sits at the centre of the region Momentum's system implicates in tension headache.