Lecture 6: Muscles of neck Flashcards
Name the 2 groups of neck muscles
Neck/head extensors
Neck/head flexors
Describe neck/head extensors
Between zygopophyseal and intervertebral joints
= posterior group extrinsics sternocleidomastoid most superficial
+ intrisics = 3 layers = splenius, semi spinalis capitis, suboccipital muscles
Describe neck/head extensors- innervation
Anterior rami = extrinsic
Intrinsic = posterior rami
And trap = cn 11
Describe neck/head flexors
Anterior aspect of zygopophyseal joints and intervertebral
Superficial anterior group = sternocleidomastoid and hyoid muscles
Deep anterior group
Lateral group
Describe neck/head flexors innervation
Anterior rami
What are common functions of neck muscles
Neck/head lateral flexion and extension and some axial rotation
Describe splenius = which layer is it
Superficial posterior
Can see a bit, below traps, rhomboids and deep to serratus posterior superior
Most superifical of group, visible superior laterally but deep to extrinsics of back muscles
What does splenius mean
Bandage
V shaped muscle in 2 parts = capitis (head) and cervis (neck)
Describe splenius capitis - attachments
From nuchal ligemnt midline and spinous processes of c7-t3/4 to mastoid process
Enters head = actions on Atlanto occipital joint
Describe splenius cervicis - attachments
From spinous processes of t3-t6 to transverse processes of c1-c3
Not into head, stops at transverse processes
Describe functions of splenius
bilateral = Extension of cervical spine and head = both, atlanto occipital joint, not much movement of head tho
Unilateral = lateral flexion and rotation of head and cervical spine (particularly where splenius capitis attached = axial rotation, makes x with traps)
Describe innervation of splenius
Posterior rami of cervical nerves
Name deeper posterior muscles
Erector spinae and semi spinalis capitis
Describe erector spinae
All have own head = iliocostalis cervicis, longissimus capitis, spinalis
Action on altanto occipital, continues to mastoid process
Slips extend into head/neck with similar actions
Describe semi spinalis capitis
Intermediate layer
Deep to splenius
Palpable at base of head, lateral to trapezius
Describe semi spinalis capitis Attachments
From sides of c4-t6 (articulate and transverse processes) to occipital bone
(Posterior to zygopo joints)
Describe semi spinalis capitis Functions
Bilateral = extension of cervical spine and head
Unilateral = lateral flexion
(Not much axial rot bc fibres v clsoe and parallel to atlanto axis pivot joint)
Describe semi spinalis capitis Innervation
Posterior rami of cervical spinal nerves c2 (greater occipital) and c3
Describe suboccipital muscles
4 deep paired posterior muscles that control posture and find movement of head and gaze
Name the suboccipital muscles
Rectus capitis posterior minor
Rectus capitis posterior major
Obliquus capitis superior
Obliquus capitis Inferior
Describe recuts capitis posterior
Straight of head
Minor and major
Describe recuts capitis posterior MINOR attachments
Spinous process of c1 to occipital
Describe recuts capitis posterior MAJOR attachments
Spinous process c2 to occipital
Describe recuts capitis posterior MAJOR FUNCTION
Bilateral extension
Unilateral ispilateral flexion of head
Ipsilateral rotation fo head - especially major, maximal gaze position
DESCRIBE obliquus capitis
Oblique of head
DESCRIBE obliquus capitis SUPERIOR
Transverse processes of c1 to Occipital
DESCRIBE obliquus capitis INFERIOR
Spinous process of c2 to transverse process c1
DESCRIBE obliquus capitis INFERIOR FUNCTION
Bilateral extension
Ispilateral flexion fo head
Ipsilateral rotation of head (inferior, great at axial rotation bc crosses c1 and c2)
DESCRIBE SUBOCCIPITAL MUSCLES INNVERVATION
Posterior rami fo spinal nerve c1 = suboccipital nerves
WHAT IS suboccipital triangle
Space bounded by muscles
Sup = rectus capitis posteror major
Lat = obliquus capitals superior
Inf = obliquus capitis inferior
Roof = semi spinalis capitis
What does suboccipital triangle allow passage of
Suboccipital nerve (post ramus c1) to all suboccipital muscles
Contains vertebral artery on way to brian
Describe vertebral artery
Ascending through transverse foramina of cervical vertebrae = till c6
Major blood supply to head
What is clinical correlate of suboccipital triangle
Important surgical landmark
Prevent damage to vertebral artery - takes sharp medial turn, travels horizontally in triangle where it may become entrapped or compressed = compromise blood flow to posterior brain and cerebellum
Find it so can avoid, also muscles can compress it
Describe general attachments of neck/back muscles - on underside fo head
Longissimus capitis = on side head
Traps = insertion of them on ext occipital protuberance
Obliquus capitis suerior
Rectus capitis major and minor
Semi spinalis capitis = big attachment
Splneius capitis = on mastoid process
Sternocleidomastoid too
Describe tension headaches
Dull vibe like pain around scalp/skull
May be partly cause by excessive tension = contraction of posterior neck muscles countering flexion torques at altanto occipital joint and building on soft tissues and periosteum of skull
Strains muscles bc fighting torque generated by looking down
Name superficial anterior muscles of neck
Platysma
Sternocleidomastoid
Hyoid muscles
Describe platysma
Very small
Muscle of facial expression
What are attachments of sternocleidomastoid
Infeirorly = sternum and clavicle
Superior = mastoid process
Describe functions fo sternocleiodmastoids
Bilateral = extension fo head/neck (sup vertebrae) or flexion fo neck (inferior cervical vertebrae)
Unilateral = contra lateral rotation, ispilateral lateral flexion
Describe innvertaion of sternocleidomastoud
CNXI = spinal accessory nerve
Describe whole of functions of sternocleidomastoid - specifically
Posteriorly = head extension, posterior to atlanto occipital joint —> scm fibres change positives relative to intervertebral joints —> neck flexion, anterior to intervertebral joints
Has diff actions
Describe hyoid muscles
Infra and supra hyoid muscles
PRIMARILY = Involved in moving hyoid during swallowing
Secondarily = depress mandible
Pass anterior to cervical vertebral joints = can also assist in NECK Flexion
Name deep anterior muscles
Rectus capitis anterior
Rectus capitis Lateralis
Longus capitis
Longus colli
Describe rectus capitis anterior = attachments and functions
C1 transverse process to occipital
Ispilateral rotation
Minimal flexion
Describe rectus capitis lateralis = attachments and functions
C1 transverse process to occipital
Ispilateral lateral head flexion
Describe longus capitis = attachments and functions
C3-c5 transverse processes to occipital
Head flexion, neck ispilateral flexion
*note = all muscles synergistic = cannot just recruit one muscle
Describe longus coil = attachments and functions
Does not cross into head, stays in neck
Body cervical/thoracic vertebrae to body or transverse process of cervical vertebrae
Bilateral = neck flexion
Unilateral = ispilateral flexion fo cervical spine - neck
Describe innvertaion of deep anterior muscles
Ant rami c1-c8
Describe lateral muscles
Scalenes
Stepwise ladder arrangements
Describe scalene attachments
Transverse proceses of cervical vertebrae c1-c7
To
First rib (anterior and middle scalenes) or second rib (posterior scalenes)
Describe scalene functions
Bilateral = flexion cervical spine or elevate ribs as accessory muscles of respiration
Unilateral = ispilateral lateral flexion fo cervical spine
Describe scalene innvertaion
Ant rami fo c1-c8
Why are scalenes improatnt
Anatomical landmark = brachial plexus (roots c5-t1) emerge between anterior and middle scalenes
Describe arterial blood supply to intrinsic posterior neck muscles
Vertebral artery and deep cervical artery (branches of subclavian) also occipital artery (branch eternal carotid)
Describe blood supply - Gen
Subclavian —> vertebral artery + deep cervical artery
These anastomose
And go to semi spinalis capitis and splenius capitus
What is periosteum
Thin layer
Richly innevrated
Surrounds al bones
