Deep Back Muscles, Suboccipital Triangle Flashcards
What makes up the torso?
Head, neck, and trunk
What makes up the skeleton of the torso?
axial skeleton plus pelvic girdle
Two functions of the vertebral column
stability and flexibility, considered diametrically opposed
_____ are required for mobility
joints
Functional unit of the vertebral column
two vertebral bodies, an intervertebral disc, and two pairs of facet joints
What does the functional unit of the vertebrae do?
bears compressive loads and also allows for flexibility
How is movement of the vertebrae amplified?
each functional unit as a small range of movement but can be amplified by summation to allow for large flexibility over the length of the vertebrae
The joints of the vertebrae are considered to be what type of functional joint
amphiarthrotic joints
What do the facet joints do?
determine type of movement that occurs around intervertebral disc and limit its range of motion
Facet joints are considered what type of functional joint?
synovial joints
How many vertebral lever arms of each vertebra?
3
What are the 3 vertebral lever arms?
spinous processes, paired transverse processes, paired costal elements (ribs)
Which vertebrae express vertebral arms? Which vertebral region has the best development of them?
all vertebrae express vertebral arms, but they are best developed in the thoracic region
The thoracic vertebrae are specialized to form the ______, which has what function?
thoracic cage; moves air in and out of the lungs
Which set of ribs is the most highly specialized set of lever arms?
thoracic ribs
What do the thoracic ribs exhibit?
synovial articulations with both the vertebral bodies and sternum
The anterior portions of the thoracic costal elements (ribs) are what type of joint?
cartilaginous, therefore they provide flexibility
The cartilaginous anterior portions of the thoracic ribs enables it to do what?
act as bellows, increasing its transverse diameter
How many groups of muscles in the torso?
three
What are the three groups of the torso?
muscles of the trunk walls, muscular diaphragms, muscles of the head and neck
Description of muscles of the trunk walls
somatic muscles following a segmental pattern
Description of the muscular diaphragms
thoracic, pelvic, and urogenital diaphragms, larynx and pharyngeal
constrictors and suprapleural membranes
Description of the muscles of the head and neck
some are from embryonic somites but most are derived from embryonic branchial (gill) arches and have a complex organization
Intrinsic muscles of the back
-fall within the group of muscles of the trunk wall, posterior paired longitudinal groups of muscles
Where do intrinsic muscles of the back attach?
attach to lever arms of the vertebrae and only lever arms of the vertebrae
Are intrinsic muscles of the back superficial or deep?
Deep
The deep muscles of the back are often collectively referred to as
erector spinae muscle mass
Action of the erector spinae muscle mass
maintenance of posture and movements of the head ands vertebral
column
What are the muscle groups of the back?
superficial, intermediate, and deep
Superficial group is responsible for?
Limb movement
Intermediate group is responsible for?
Respiration
Intermediate extrinsic muscles (2 of them)
-serratus posterior superior and serratus posterior inferior
Where are the intermediate extrinsic muscles found?
under the rhomboids and latissimus dorsi
What are the intermediate extrinsic muscles innervated by?
dorsal rami of the intercostal nerves
Serratus posterior superior action
elevator of the ribs
Serratus posterior inferior action
depressor or fixor of the lower ribs
What muscles are in the superficial layer of the intrinsic muscles of the back
splenius captius and splenius cervicis
Splenius capitis attachment
origin: half of the ligamentum
nuchae as well as the spinous
processes of T1-6
insertion: mastoid process and lateral 1/3 of the superior nuchal line on the occipital bone
Splenius cervicis attachment
Origin: half of the ligamentum
nuchae as well as the spinous
processes of T1-6
Insertion: posterior tubercles
of the transverse processes
of C1-4 deep to the levator
scapulae
Action of spenius mm. together and separate
separate: laterally flex and rotate the head to the same side
together: they extend the head and neck
What muscles are in the intermediate layer of intrinsics?
3 muscles collectively called the erector spinae; separate they are the spinalis, longissimus, iliocostalis
Attachment of the spinalis m.
common inferior origin to the sacrum, iliac crest and sacroiliac ligament and extends to rom spinous process to spinous process
(medical column)
Attachment of the longissimus muscle
common inferior origin to the sacrum, iliac crest and sacroiliac ligament and extends to the transverse processes and ribs
Attachment of the iliocostalis m.
common inferior origin to the sacrum, iliac crest and sacroiliac ligament and extends to the angles of the ribs
(medial column)
Function of the erector spinae
extend the head and vertebral column and can unilaterally flex it
Muscles of the deep layer of intrinsics (1st group)?
semispinalis capitis, semispinalis cervicis, semispinalis thoracis, multifidus
-collectively called the transversospinal group
Transversospinal group attachment
extend obliquely from transverse process below to spines or laminae above,
missing several vertebrae between origin and insertion
Multifidus location
superficial to the rotators and misses one or two vertebrae between origin and insertion
Muscles of the deep layer of intrinsic muscles (second group)?
-rotatores and intertransverse
Rotatores action and attachment
action: rotation (turning side to side)
attachment: deepest muscles in the groove between spinous and transverse processes; they span spinous to transverse process along the whole column
Where is the rotatores m. best visualized?
thoracic region
Intertransverse m. action and attachment
action: lateral flexors
attachment: linking adjacent transverse processes
Interspinales mm. attachment and action
Action: extensors
attachment: uniting the spinous processes of adjacent vertebrae
The interspinales and intertransverse groups are best developed where?
lumbar and cervical regions
Suboccipital triangle location
-triangular area around the articulation between the occipital bone of the
skull and the superior end of the vertebral column (C1 - the atlas and C2 - the axis)
-region is deep to the semispinalis capitus
Suboccipital triangle boundaries
floor: atlanto-occipital membrane
roof: semispinalis capitus m.
lateral: superior oblique m.
medial: rectus capitus major
inferior: inferior oblique m.
Main constituent of the suboccipital triangle
vertebral artery
Location of vertebral artery in the suboccipital triangle
passes medially after ascending through transverse foramina of the cervical vertebrae, and before it accesses the cranial cavity through the foramen magnum
Where is the foramen magnum located?
occipital bone
Why is the suboccipital triangle clinically important?
because of the vertebral artery
artherosclerosis, prolonged turning of the head - or looking upward (hyper-extension)
- may cause dizziness due to impaired blood flow in this region
4 muscles of the subpoccipital region
-rectus capitis major m.
-rectus capitis minor m.
-superior oblique m.
-inferior oblique m.
-
Attachment of rectus capitis major
extends from C2 to the skull
Attachment of rectus capitis minor
extends from C1 to the skull
Action of rectus capitus major and minor
together: extend head and posture
separate: rotate head to the same side
Superior oblique attachment
extends from C1 to the skull
Inferior oblique attachment
extends from C2 to C1 (pulls on the atlas)
What is the atlas
1st cervical vertebra
Contents of the suboccipital triangle
- vertebral artery
- suboccipital n.
What spinal nerve does the suboccipital n. branch from?
C1; it is the dorsal ramus of C1
