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