Download 2 - Back (tutor)

The Back
The Spine:
Vertebrae
Number and Function
Cervical
7
Supports and moves
head
Thoracic
12
Support for thorax
Lumbar
Sacral
5
Support for abdomen
5 fused
Transmit weight to
lower limbs through
pelvic bones
Coccygeal
Identifying Features
Transverse foramen,
C1: atlas and C2: axis,
small size, bifid spines,
Sloped zygapophysial
(ZP) joints
Uncovertebral joints:
between bodies of
vertebrae
Facets and demifacets
for rib articulations,
Vertical ZP joints
Large body, mammillary
processes, “Scotty Dog”
from oblique view,
Wrapped ZP joints
Articulate with pelvis, 4
pairs of sacral foramen
(anterior and posterior)
Fused into coccyx, no
vertebral arches or
canal
3-4 fused
Spinal Nerves
C1-C8
(superior to associated
vertebra)
T1-T12
(inferior to associated
vertebra)
L1-L5
(inferior to associated
vertebra)
S1-S5
(inferior to associated
vertebra)
Co
(inferior to associated
vertebra)
Superficial Back Muscles: movement of appendicular skeleton
Muscle
Innervation
Accessory nerve, C3-C4
Trapezius
Latissimus dorsi
Thoracodorsal nerve (C6-8)
Levator Scapulae
C3-C4 and Dorsal scapular nerve
(C4, C5)
Dorsal scapular nerve (C4, C5)
Dorsal scapular nerve (C4, C5)
Rhomboid Major
Rhomboid Minor
Function
Rotate scapula in arm abduction
beyond horizontal; elevate,
adduct, and depress scapula
Extends, adducts, and medially
rotates humerus
Elevate scapula
Retracts and elevates scapula
Retracts and elevates scapula
Intermediate Back Muscles: respiratory function
Muscle
Serratus posterior superior
Serratus posterior inferior
Innervation
T2 to T5
T9 to T12
Function
Elevate ribs 2 to 5
Depress ribs 9 to 12
Deep Back Muscles: intrinsic muscles that move the head/neck and vertebral column
Group
Muscle
Spinotransversales
Splenius capitis
Splenius cervicis
Erector Spinae
Iliocostalis
Longissimus
Spinalis
Transversospinales
Semispinalis
Multifidus
Rotatores
Segmental
Levatores Costarum
Interspinales
Intertransversarii
Suboccipital: all
innervated by C1
Rectus capitis posterior
major
Rectus capitis posterior
minor
Attachments
Lower ligamentum
nuchae, spinous
processes C7-T4; mastoid
process
Spinous processes T3 to
T6; Transverse processes
C1 to C3
Common tendon of
origin, lower ribs; upper
ribs, lower cervical
vertebrae
Common tendon of
origin; base of skull
Interconnects spinous
processes of adjacent
vertebrae
Lower thoracic region;
back of skull, crossing
between 4 and 6
vertebrae
Pass from lateral
insertions upward and
medially to spinous
processes, spanning 2 to
4 vertebrae
Transverse processes to
spinous processes,
crossing 2 vertebrae
(long) or attaching to
adjacent vertebrae
(short)
Transverse process to rib
below
Between spinous process
on each side of
interspinous ligament
Between transverse
processes
Spinous process of C2 to
lateral occipital bone
below inferior nuchal line
Posterior tubercle of C1
to medial occipital bone
Function
Extend neck, rotate
head to same side
Extend neck, rotate
head to same side
Major extensor of
vertebral column and
head, lateral flexion
Major extensor of
vertebral column and
head, lateral flexion
Major extensor of
vertebral column and
head, lateral flexion
Extension and rotation
of vertebral column
Extension and rotation
of vertebral column
Extension and rotation
of vertebral column
Elevates rib
Postural-stabilization
Postural-stabilization
Extend head, rotate face
to same side as muscle
Extend head
Obliquus capitis
superior
Obliquus capitis inferior
below inferior nuchal line
Transverse process of C1
to occipital bone
between superior and
inferior nuchal lines
Spinous process of C2 to
transverse process of C1
Extend head, bends it to
same side
Rotates face to same
side
*Suboccipital Triangle: borders made up by rectus capitis posterior major, obliquus capitis superior, and
obliquus capitis inferior. The triangle contains the posterior ramus of C1, the vertebral artery, and
associated veins
*Spinal Cord: from foramen magnum to L1 or 2 (conus medullaris), Subarachnoid space ends at S2
Meninges:
Meninges
Location
Structure
Dura Mater
Outermost
Thick, fibrous
Arachnoid Mater
Middle
Thin, delicate, contains
blood vessels
Pia Mater
Innermost
Vascular membrane
adhered to surface of
spinal cord
Significance
Becomes epineurium of
spinal nerves and their
roots
Subarachnoid space (b/t
arachnoid and pia)
contains CSF
Forms denticulate
ligaments that extend
laterally from the cord
toward the arachnoid
and dura, anchoring the
spinal cord in place
*Spinal Nerves: 31 pairs, each is connected to the spinal cord by anterior roots (motor nerve fibers) and
posterior roots (sensory neuron processes, whose cell bodies are located in spinal ganglion). Spinal
nerves exit the intervertebral foramen and branch into posterior rami (innervate intrinsic back muscles
and the dermatomes of the back) and anterior rami (innervates most other muscles of the body and the
remaining portions of skin).
* Curvatures of Spine:
- Primary (concave anteriorly): Thoracic, Sacral/Coccygeal
- Secondary (concave posteriorly): Cervical, Lumbar
* Identify: Bones, Ligaments of Vertebral Column, Intrinsic and Extrinsic Muscles of Back, Vasculature of
Back, Spinal Cord and associated Spinal Nerves and Branches, Meningeal Layers, Surface Anatomy
Clinical Considerations
Injury/Disorder
Spina Bifida Occulta
Patient Presentation
Tuft of hair over
spinous processes
Anatomy Involved
Vertebral arches
(usually lumbar)
Abnormal lateral
curvature in spine
Vertebrae tend to be
normal in structure but
are abnormally aligned
or rotated
Scoliosis
Kyphosis: thoracic
region (humpback)
Lordosis: lumbar region
Herniated Disc
Spinal Stenosis
Pars Interarticularis
Fracture
Back pain, loss of
motor/sensation in area
of body
Loss of motor/sensory
capabilities
Fracture of ZP joint
causing vertebrae to
slip anteriorly and
compress the vertebral
canal
Mechanism of Injury
Developmental- failure
of fusion in posterior
arches of vertebrae
Congenital, idiopathic,
nerve abnormalities
(cerebral palsy, polio),
muscular dystrophy,
tumors and disc
protrusions
Tear in anulus fibrosis
allowing nucleus
pulposis to seep.
Intervertebral disks,
spinal cord or spinal
roots or nerves
Degeneration of
annulus fibrosis
Ligament flava,
zygapophysial joints,
intervertebral discs
Dimensions of the
vertebral canal are
reduced by hypertrophy
or degeneration of
surrounding structures
Superior and inferior
facets making up the ZP
joints, usually L4-5
Trauma, common in
athletes