Editing Neck (section)

== '''Muscles''' ==

=== '''Platysma''' ===

** Broad sheet of muscle fibres
** Extends from midline      downwards beyond clavicle, superiorly up to mandible where it blends with      facial muscles, and as far posteriorly as about EJV
** Supplied by cervical branch      of facial nerve

=== '''Digastric''' ===

** Anterior belly arises from      the back of mandible, in a fossa near the midline
** Intermediate tendon held by      a fibrous sling to the hyoid
** Posterior belly passes      backwards and upwards to insert on the medial side of mastoid process      (deep and anterior to SCM)
*** Crosses internal and       external carotid arteries, the hypoglossal nerve, IJV, the transverse       process of the atlas, and the accessory nerve
** Supplied by a branch from      the facial nerve
**

=== '''Sternocleidomastoid''' ===

** Arises from the front of      manubrium and superior surface of medial clavicle, and ascends obliquely      backwards to insert into the outer surface of the mastoid process and the      anterior part of the superior nuchal line
** EJV courses across it from      below the earlobe to about the midpoint of the clavicle, from where it      plunges deep
** Cutaneous nerves of neck are      closely related (see below)
** Nerve supply from accessory      nerve from the muscle's deep surface, about 5cm below mastoid process
** Main function is level      rotation of the head

=== '''Scalenes''' ===

** Descend from transverse      process of first six or seven cervical vertebrae to insert in the first      two ribs
** Subclavian artery and      brachial plexus found between middle and anterior scalenes
** Lateral border of anterior      scalene is about the same as lateral border of SCM
** Supplied by branches of the      cervical nerve roots
** Thyrocervical trunk of      subclavian artery typically arises alongside the medial border of the      scalenus anterior muscle
** Phrenic nerve crosses      anterior scalene from lateral to medial
**

=== '''Infrahyoid     strap muscles''' -     function of swallowing, depressing larynx; depressing hyoid. Nerve supply     via ansa cervicales, often dual innervation above level of lower border of     thyroid cartilage and also at level of suprasternal notch - so divide     midway between lower border of thyroid cartilage and suprasternal notch. ===

** '''Sternohyoid'''
*** Originates from back of       manubrium; ascends to body of hyoid
** '''Omohyoid'''
*** Inserts immediately lateral       sternohyoid on hyoid bone; passes downwards to an intermediate tendon       behind SCM (held in position by a condensation of cervical fascia       attaching it to clavicle); then passes obliquely to upper border of       scapula, near scapula notch
** '''Sternothyroid'''
*** Arises from back of       manubrium inferior to origin of sternohyoid; passes upwards; inserts on       thyroid cartilage
** '''Thyrohyoid'''
*** Direct extension of       sternothyroid
*** Arises from line of       insertion of sternothyroid; inserts to body and greater cornu of hyoid