Lecture 3: Back and neck muscles Flashcards
What are the two major groups of back muscles?
Extrinsic and Intrinsic (Deep)
What group of muscles produce and control limb and respiratory movements?
Extrinsic back muscles
Group of muscles that specifically act on the vertebral column, producing movements and maintaining posture?
Intrinsic (Deep) back muscles
What muscles are included in the extrinsic back muscles?
-trapezius
-latissimus dorsi
-levator scapulae
-rhomboids
Where do the extrinsic back muscles receive their nerve supply?
Anterior Rami of Cervical Nerves
What functions do the extrinsic back muscles perform?
-connect the axial skeleton w/ the superior appendicular skeleton
-Produce and control movements
The trapezius receive its motor fibers from which cranial nerve?
CN XI (Spinal accessory nerve)
Which group of muscles does the serratus posterior superior and inferior belong to?
Intermediate extrinsic back muscles
Where dose the serratus posterior superior lie?
Deep to the rhomboid muscles
Where does the serratus posterior inferior lie?
Deep to the latissimus dorsi
The serratus muscles are innervated by which nerve?
Intercostal nerves
What are the functions of the serratus posterior superior and inferior?
-Commonly designated as superficial respiratory muscles, but are more likely proprioceptive rather than motor.
Which nerve innervates the intrinsic back muscles?
Posterior rami of the spinal nerves
What is the function of the intrinsic back muscles?
-Maintain posture
-control movements in vertebral column
What are the three intrinsic back muscle groups?
-superficial
-intermediate
-deep
What is the group name of the superficial layer of intrinsic back muscles?
Spinotransverse Group
What muscles are included in the Spinotransverse group?
-Splenius capitus
-Splenius cervicus
What is the group name of the intermediate layer of the intrinsic back muscles?
Sacropinalis Group
What muscles are included in the sacropinalis group?
Errector spinae (spinalis, longissimus, illiocostalis)
What is the group name of the deep layer of the intrinsic back muscles?
Transversospinalis group
What muscles are included in the transversospinalis group?
-Semispinalis
-Multifidus
-Rotators
What other muscles are also considered intrinsic back muscles but are not associated with a group?
-Interspinal
-Intertransverse
What is the name of the deep fascia that encloses the intrinsic back muscles?
Thoracolumbar fascia
Where is the origin and insertion of the thoracolumbar fascia?
Extends laterally from the spinous processes forming a thin layer over the thoracic region, and a strong thick covering in the lumbar region.
How many layers does the thoracolumbar fascia contain?
3 layers:
-Anterior
-Middle
-posterior
Describe the splenius muscles and their location:
-Thick & flat
-Lie on lateral and posterior aspects of the neck
What is the function of the splenius muscles?
Cover and hold the deep neck muscles in position.
What does splenion mean?
Bandage
What are the proximal attachments of the splenius muscles?
-Nuchal ligament
-Spinous processes of C7-T6
What are the distal attachments of the splenius capitis?
Fibers run superolateral to the mastoid bone, and lateral third of superior nuchal line of occipital bone.
Name the structures:
1) Splenius cervicis
2) Mastoid Process
3) Nuchal Ligament
4) Splenius Capitis
What are the distal attachments of the splenius cervicis?
Tubercles of transverse processes of C1-C3 or C4 vertebrae
What nerve supplies the splenius muscles?
Posterior rami of spinal nerves
What are the main actions of the splenius capitis?
Acting UNILATERALLY: laterally flexes the neck and rotates the head to side of active muscles
What are the main actions of the splenius cervicis?
Acting BILATERALLY: extend the neck and head
Are the erector spinae divided regionally? (ex: iliocostalis lumborum, iliocostalis thoracis, and iliocostalis cervicis) True or False
True
The chief extensors of the vertebral column are the erector spinae. (True/False)
True
Which muscle forms the lateral column of the erector spinae?
Iliocostalis
Which muscle forms the medial column of the erector spinae?
Spinalis
Which muscle forms the Intermediate column of the erector spinae?
Longissimus
What is the proximal attachment of the erector spinae?
Arises from a broad tendon of the posterior part of the iliac crest, posterior surface of the sacrum, sacro-iliac ligaments, sacral and inferior lumbar spinous processes, and supraspinous ligament
What is the distal attachment of the iliocostalis?
fibers run superiorly and slightly laterally attaching to angles of ribs and cervical TVP’s
What is the distal attachment of the longissimus?
fiber run superiorly attaching to TVP’s in thoracic and cervical regions and the mastoid process
What is the distal attachment of the spinalis?
fibers run superiorly within laminar groove attaching to SP’s in thoracic and cervical regions
What muscles are shorter and deep to the erector spinae?
transversospinalis muscle group:
-semispinalis
-multifidus
-rotators
Where does the transversospinalis muscle group mainly originate from?
TVP’s of vertebrae and pass to SP’s of more superior vertebrae. (occupying the “gutter” between the TVP’s and SP’s, the laminae between them, and the ligaments linking them together)
Which transversospinalis group muscle is the most superficial?
semispinalis
How many parts is the semispinalis divided into and what are their names?
3 parts:
-semispinalis capitis
-semispinalis cervicis
-semispinalis thoracis
What are the primary actions of the semispinalis muscles?
-Extension of the head, cervical spine, and thoracic spine
-contralateral rotation
What is the middle layer of the transversospinalis group called?
multifidus
What is the shape of the multifidus muscles?
short, triangular muscle bundles (thickest in the lumbar region)
What is the primary action of the multifidus muscle?
stabilization of vertebral column
What is the deepest layer of the transversospinalis muscle group?
Rotators
Where are the rotators best developed?
Thoracic region
What are the primary actions of the rotators?
stabilization of the vertebral column; proprioception of the vertebral column; may assist in small rotatory movements in thoracic spine
What are the minor deep back muscles that are also called “segmental muscles of the back”?
-interspinales
-intertransversarii
-levatores costarum
What do the intertransversarii and interspinales connect?
SP’s and TVP’s respectively
What is the action of interspinales?
Extension & rotation
What is the action of the Intertransversarii?
Stabilization and lateral flexion
What is the action of levatores costarum?
assist w/ respiration in elevation of ribs; lateral flexion of column
What region is a “compartment” deep to the superior part of the posterior cervical region, and deep to the trapezius, sternocleidomastoid, splenius, and semispinalis muscles?
Suboccipital region
What vertebrae are included in the suboccipital region?
C1 and C2
What are the four small muscles of the suboccipital region that lie deep (anterior) to the semispinalis capitis muscles?
- 2 rectus capitis posterior (major & minor)
-2 obliquus muscles
What nerve innervates the four small muscles of the suboccipital region?
Posterior ramus of C1 (suboccipital nerve)
What are the primary actions of the 4 small muscles of the occipital region?
-Extension of atlanto-occipital joint
-rotation of atlanto-axial joint
Name the structures:
1) Obliquus capitis superior
2) suboccipital nerve (C1)
3)Obliquus capitis inferior
4) Rectus capitis posterior minor
5) Rectus capitis posterior major
What are the two major groups of the anterior neck muscles?
Superficial and Deep
What muscles does the superficial group contain?
Platysma & sternocleidomastoid
What nerve innervates the anterior neck muscles?
Ventral rami
What is the origin of the platysma muscle?
Fascia over deltoid & pectoralis major muscles
What is the insertion of the platysma muscle?
Mandible & skin of the lower face
What are the actions of the platysma?
-Depresses lower lip inferiorly
-Depresses mandible @ TMJ
What is the nerve that innervates the platysma?
CN VII (facial nerve)
What is the origin of the sternocleidomastoid?
-Medial 1/3 of the clavicle
-manubrium of the sternum
What is the insertion of the sternocleidomastoid?
-the mastoid process of the temporal bone
-lateral 1/2 of superior nuchal line of occipital bone
What are the actions of the Unilateral contraction of the sternocleidomastoid?
-lateral flexion of head and neck
-contralateral rotation of head and neck
What are the actions of the bilateral contraction of the sternocleidomastoid?
-Extension of head and upper neck
-flexion of the lower neck
-elevation of sternum and clavicle (during forced inhalation)
What are the deep muscles of the anterior neck muscles?
-longus capitis
-longus coli
-rectus capitis anterior
-rectus capitis lateralis
-anterior scalene
-middle scalene
-posterior scalene
What nerve innervates the deep neck muscles?
ventral rami
Name the structures:
1) Longus capitis
2) Longus colli
Name the structures:
1) Rectus capitis anterior
2) Rectus capitis lateralis
What is the superior attachment of the Longus colli?
Anterior tubercle of the C1 & bodies of C1-C3 & transverse processes of the
What is the inferior attachment of the longus colli?
Bodies of C5-T3 and TVP’s of C3-C5
What is the nerve innervation of the longus colli?
Anterior rami of C2-C6
What is the main action of the longus colli?
flexes neck with rotation
What is the superior attachment of Longus capitis?
Basilar part of occipital bone
What is the inferior attachment of longus capitis?
anterior tubercles of C3-C6
What are the nerve innervations of longus capitis?
Anterior rami of C1-C3
What deep anterior neck muscles flex the head?
Longus capitis & rectus capitis anterior
What is the superior attachment of the rectus capitis anterior?
Base of cranium (anterior to occipital condyle)
What is the inferior attachment of rectus capitis anterior?
anterior surface of lateral mass of C1
What nerve innervates the rectus capitis anterior?
Branches from loop between C1 and C2 spinal nerves
What are the superior and inferior attachments of anterior scalene?
Superior: TVP’s of C3-C6
Inferior: 1st Rib
What nerve innervates the anterior scalene?
C4-C6 cervical spinal nerves
What is the superior and inferior attachments of the rectus capitis lateralis?
Superior: Jugular process of occipital bone
Inferior: TVP’s of Atlas
What nerve innervates the rectus capitis lateralis?
Branches from loop between C1 and C2 spinal nerves
What is the superior and inferior attachment of the middle scalene?
Superior: Posterior tubercles of TVP’s of C5-C7
Inferior: Superior surface of 1st rib; posterior to groove for subclavian artery
What nerve innervates the middle scalene?
Anterior Rami of Cervical spinal nerves
What actions do the rectus capitis lateralis perform?
Flexes head and helps stabilize it
What are the actions of the Middle scalene?
Flexes neck laterally; elevates first rib during forced inspiration
What are the superior and inferior attachments of the posterior scalene?
Superior: Posterior tubercles of the TVP’s of C5-C7
Inferior: External border of 2nd rib
What is the nerve innervation of the posterior scalene?
Anterior rami of cervical spinal nerves C7 & C8
What actions doe the posterior scalene perform?
-Flexes neck laterally
-Elevates 2nd rib during forced inspiration
Name all the structures:
1) Rectis capitis lateralis
2) Rectus Capitis anterior
3) Longus Capitis
4) Middle Scalene
5) Posterior scalene
6) Anterior scalene
7) Middle scalene
8) posterior scalene
9) Longus colli
10) Sternocleidomastoid
11) Splenius capitis
12) Middle scalene
13) Posterior scalene
14) Anterior scalene
How many intercostal spaces are there?
11
How many layers of intercostal muscles are there?
3 Flat layers (external, internal, and innermost)
What is the origin and insertion of the external intercostals?
O: Inferior border of the rib above
I: superior border of the rib below
What actions do the external intercostals perform?
Moves ribs superiorly during inspiration
What is the origin and insertion of the Internal intercostals?
O: superior border of the rib below
I: Inferior border of the rib above
What actions doe the internal intercostals perform?
moves ribs inferiorly during expiration
What nerves innervate the external and internal intercostals?
Intercostal nerves T1-T11
What are the diaphragm attachments?
-Xiphoid process
-costal margin
-end of ribs 11 & 12
-lumbar vertebrae (L1-L3)
-muscle fibers converge from the peripheral attachments of the muscle to join to the central tendon
What are the three main foramina of the diaphragm?
-Aortic hiatus opening (TXII level)
-Esophageal Hiatus or opening (TX level)
-Caval opening (TVIII Level)
What nerve supplies the diaphragm?
R & L phrenic nerves (C3,4,5)
What is the action of the diaphragm?
-Depresses domes therefore increases the volume of the thoracic cavity
-Increased volume, Decreased pressure ( major muscle of inspiration)
Modified sweat glands in the superficial fascia on the pectoral region are called what?
Mammary glands
Circular pigmented area of skin termed what?
Areola
The pectoral region anchors what?
The upper limb to the trunk
What is the arterial supply of the breast?
-Axillary A. (by the lateral thoracic branch)
-Internal thoracic A.
-2nd to 4th intercostal arteries
What is the venous drainage of the breast?
-Axillary
-Internal thoracic
-Intercostal veins
What nerves innervate the breast?
-2nd and 6th intercostal nerves
-Nipple: innervated by the 4th intercostal nerve
Where does the lymph of the breast drain to?
-75% into axillary nodes
-The rest, mainly into the parasternal lymph nodes
What is the arterial supply of the thoracic wall?
-Posterior Intercostal arteries: Branches of thoracic aorta
-Anterior Intercostal arteries: branches of internal thoracic artery (directly or indirectly)
What is the venous drainage of the thoracic wall?
-posterior intercostal veins:
R-side: azygos vein
L-side: hemiazygos
-anterior intercostal veins:
Directly or indirectly into internal thoracic veins which in turn drain into R & L brachiocephalic veins
What is the nerve supply of the thoracic wall?
Mainly the Anterior Rami of upper thoracic spinal nerves. (intercostal nerves T1-T11)
The anterior ramus of the spinal nerve T12 is called what?
The subcostal nerve
Where is the subcostal nerve found?
Under rib 12
Where do the subcostal nerve and Intercostal nerves innervate?
-Intercostal muscles
-the skin of the chest wall
-parietal pleura
Where do the lower intercostal nerves innervate?
-skin
-muscles
-parietal peritoneum of the abdominal wall
Name the nerves:
1) thoraco-abdominal nerves (T7-T11)
2) subcostal nerve (T12)
3) subcostal nerve (T12)
4)Illiohypogastric Nerve (L1)
5) Illio-inguinal nerve (L1)
What artery is a direct continuation of the internal thoracic artery?
Superior epigastric artery
Which artery is the branch of the external iliac artery?
Inferior epigastric
What are the vessels of the anterolateral abdominal wall?
-superior epigastric artery
-inferior epigastric artery
-Branches of the intercostal arteries
-Venous drainage of the abdominal wall is done through veins that run parallel to the above mentioned arteries
