Extrafusal muscle fiber Extrafusal muscle fiber Extrafusal muscle fibers are the skeletal standard muscle fibers that are innervated by alpha motor neurons and generate tension by contracting, thereby allowing for skeletal movement. They make up the large mass of skeletal muscle tissue and are attached to bone by fibrous tissue extensions (tendons). Each alpha motor neuron and the extrafusal muscle fibers innervated by it make up a motor unit. The connection between the alpha motor neuron and the extrafusal muscle fiber is a neuromuscular junction, where the neuron's signal, the action potential, is transduced to the muscle fiber by the neurotransmitter acetylcholine. Extrafusal
Lateral parts of occipital bone jugular foramen. The jugular notch may be divided into two by a bony spicule, the intrajugular process, which projects lateralward above the hypoglossal canal. The under surface of the jugular process is rough, and gives attachment to the Rectus capitis lateralis muscle and the lateral atlanto-occipital ligament; from this surface an eminence, the paramastoid process, sometimes projects downward, and may be of sufficient length to reach, and articulate with, the transverse process of the atlas. Laterally the jugular process presents a rough quadrilateral or triangular area which is joined to the jugular surface of the temporal bone by a plate