Posterior neck muscles Reminder muscles Skeletal striated Rope

Posterior neck muscles

Reminder muscles • Skeletal striated • Rope! – Epimysium – whole muscle – Perimysium – bundles of fibres – Endomysium –muscle fibre • Myofilaments – Thin/actin – Thick/myosin • Sarcomere – NB this bit shortens completely, depending on strength of contraction required depends on how many • Muscle contraction – Isotonic – movement • Concentric - shorter • Eccentric - longer – Isometric – no movement • same length

Reminder Muscles continued • Types of fibre - NB all muscles a mixture of fibres – Type I – slow twitch – predominant in postural muscles • – • Red -high myoglobin, High ATP generation, Slower ATP use, Resistant to fatigue Type II – fast twitch – faster contraction, fatigue more quickly • Type IIA – red, high ATP generation, high ATP use (infrequent) • Type IIB – white, lower ATP generation (anaerobic), fast ATP use Muscle Tone - State of resting tension in a muscle – maintain posture, balance and prepares for action/response to danger e. g. pull on muscle increases • Maintained by muscle spindles and golgi tendon organs • Low tone/hypotonia – flaccidity, reduced stretch reflex • High tone/hypertonia – increased stretch reflex • – Spasticity – velocity dependent resistance – Rigidity – velocity independent • Cogwheel – jerky resistance • Lead pipe – same throughout Butter!!!

Reminder of joints in the neck • Atlanto-occipital • !st class lever – fulcrum between effort and load • Atlantoaxial • Facets • Intervertebral discs

Function Nodding head • takes place predominantly through flexion and extension at the atlanto-occipital joint. However, the cervical spine is comparatively mobile, and some component of this movement is due to flexion and extension of the vertebral column itself. Shaking head • The movement rotating the head left and right happens almost entirely at the atlanto-axial joint. A small amount of rotation of the vertebral column itself contributes to the movement.

Neck muscles • Back muscles stabilize and move vertebral column and are grouped according to length and direction • Posterior – Superficial – Deep • Lateral – Superficial – Deep • Anterior – Superficial – Deep

Suboccipital muscles • • Rectus capitis posterior major – Spinous process axis to occiput nuchal line – Extension ipsilateral rotation Rectus capitis posterior minor – Tubercle posterior arch atlas occiput medial nuchal line – Extension ipsilateral rotation Obliquus capitis inferior – Spine axis to transverse process atlas – Rotation ipsilateral Obliquus capitis superior – Transverese process atlas to occiput superior and inferior nuchal line – Extension lateral flexion

Segmental muscles • At all levels • Connect processes of adjacent vertebrae • Interspinales – spinous processes • Anterior and posterior intertransversarii – transverse processes

Muscles – erector spinae, semispinalis, multifidus

Transversospinales muscles • They are at all levels in the back • Cross a few segments • Semispinalis muscles – Run from transverse processes to spinous processes of more superior vertebrae – involved in rotation and extension of vertebral column. – Semispinalis capitis • – Semispinalis cervicis • – • transverse processes of upper thoracic vertebrae to spinous processes of C 1 -C 5 Semispinalis thoracis • • transverse processes of upper thoracic and lower cervical vertebrae to occiput between superior and inferior nuchal line transverse processes of vertebrae T 6 -T 10 to spinous processes of vertebrae C 6 -T 4. Multifidus – Cervical, thoracic and lumbar – Bridge 3 -6 levels transverse to spinous process – Action – bilateral extension, unilateral side flexion and contralateral rotation Rotatores cervicis (thoracis and lumborum) – transverse processes of inferior vertebrae to the laminae and transverse processes of the vertebrae 1 -2 levels above.

Erector Spinae • Majority of the muscle mass of the back at all levels • Cross many segmental levels • Actions – Primary extensor of the vertebral column – Controls flexion, lateral flexion, and rotation (maintains lumbar curve) • Comprises 3 groups – Iliocostalis (laterally placed) group • Iliocostalis cervicis, thoracis, lumborum – Longissimus (intermediately placed) group • Longisimus capitis, cervicis, thoracis – Spinalis (medially placed) group. • Spinalis capitis, cervicis, thoracis

Muscles – erector spinae, semispinalis, multifidus

Superficial • Splenius muscles originate at midline and run laterally and superiorly • Action – extension, lateral flexion, rotation – Splenius capitis • Spinus process C 5 -T 3 to mastoid process temporal bone – Splenius cervicis • Spinus processes T 3 -T 6 to

Poor head position • Domino effect • Head comes forward – Centre of gravity forward • Upper body drifts back – To Compensate • The pelvis tilts forward – To compensate • Poor head position causes problems with all levels of the back (and body)

Problem with poor head position • NB head 8. 2% body weight – 11 st/70 kg person head weighs 12. 5 lbs/5. 75 kg – Weight of a 3 month old baby! (Awake? !? ) • Every 1 inch forwards add 12 lb weight!!!