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The Peripheral nervous system

The peripheral nervous system is concerned with all nerves situated outside the central nervous system, and consists of:

  • 31 pairs of spinal nerves – which emerge from in-between the vertebrae of the spinal column.  These are mixed nerves and they have two points of attachment to the spinal cord and these are referred to as roots.  The names of the 31 pairs of spinal nerves depend on the region of the spine they emerge from:-
  • 8 pairs of cervical nerves
  • 12 pairs of thoracic nerves
  • 5 pairs of lumbar nerves
  • 5 pairs of sacral nerves
  • one pair of coccygeal nerves

Each spinal nerve is divided into several branches, forming a network of nerves or plexuses which supply different parts of the body:

  • the cervical plexuses of the neck supply the skin and muscles of the head, neck and upper region of shoulders

  •  the brachial plexuses supply the skin and muscle of the arm, shoulder and upper chest

  •  the lumbar plexuses supply the front and sides of the abdominal wall and part of the thigh

  • the sacral plexuses at the base of abdomen supply the skin, muscles and organs of the pelvis
  • the coccygeal plexus supplies the skin in the area of the coccyx and muscles of the pelvic floor

Facials Nerves

It is especially important within the beauty and aesthetics industry to be aware of where the specific nerves are within the face to avoid any unnecessary damage to them that could result in permeant damage to your client.

Olfactory Nerve: sensory nerve for smell

Optic Nerve:  sensory nerve for vision

Oculomotor Nerve:  nerve that innervates both internal and external muscles of the eye and a muscle of the upper eyelid

Trochlear Nerve: Smallest of the cranial nerves and is a motor nerve that innervates the superior oblique muscle of the eyeball that helps you look upwards

Trigeminal Nerve: Mixed nerve (containing motor and sensory nerves) that conducts impulses to and from several areas in the face and neck. It also controls the muscles of mastication (the masseter, the temporalis and the pterygoids). The Trigeminal nerve has three main branches Ophthalmic branch, Maxillary branch  and the  Mandibular branch

  • The ophthalmic branch – carries sensations from the eye, nasal cavity, skin or forehead, upper eyelid, eyebrow and part of the nose
  • The maxillary branch – carries sensations from the lower eyelid, upper lip, gums, teeth, cheek, nose, palate and part of the pharynx
  • The mandibular branch – carries sensations from the lower gums, teeth, lips, palate and part of the tongue

Abducens: Mixed nerve that innervates only the lateral rectus muscle of the eye which helps you look to the side

Facial: Mixed nerve that conducts impulses to and from several areas in the face and neck.  The sensor branches are associated with the taste receptors on the tongue and the motor fibres transmit impulses to the muscles of facial expression.

Glossopharyngeal: Mixed nerve that innervates structures in the mouth and throat.  It supplies motor fibres to part of the pharynx and to the parotid salivary glands and sensory fibres to the posterior third of the tongue and the soft palate.

Vagus: Unlike the other cranial nerves in that it has branches to numerous organs in the thorax and abdomen, as well as the neck.  It supplies motor nerve fibres to the muscles of swallowing and motor nerve fibres to the heart and organs of the chest cavity.  Sensory fibres carry impulses from the organs of the abdominal cavity and the sensation of taste from the mouth.

Accessory: This functions primarily as a motor nerve, innervating muscles in the neck and upper back (such as the trapezius and the stern mastoid), as well as muscles of the palate, pharynx and larynx.

Hypoglossal: Motor nerve that innervates the muscles of the tongue