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CHAPTER 9:PART 1
THE SPINAL COLUMN
AND THORAX
KINESIOLOGY
Scientific Basis of Human Motion, 12th edition
Hamilton, Weimar & Luttgens
Presentation Created by
TK Koesterer, Ph.D., ATC
Humboldt State University
Revised by Hamilton & Weimar
McGraw-Hill/Irwin
Copyright © 2012 by The McGraw-Hill Companies, Inc. All rights reserved.
OBJECTIVES
1. Name, locate, & describe the structure & ligamentous
reinforcements of the joints of the spinal column.
2. Name & demonstrate movements possible.
3. Name & locate muscles & muscle groups, and name
their primary actions.
4. Analyze the fundamental movements with respect to
joint & muscle actions.
5. Describe common injuries.
9A-2
SPINAL COLUMN: STRUCTURE
7 Cervical Vertebrae
 12 Thoracic Vertebrae
 5 Lumbar Vertebrae
 Sarcrum
 Coccyx

(7
)
(12
)
(5
)
Fig 9.1
(5
)
9A-3
ARTICULATION OF VERTEBRAL BODIES


Cartilaginous joint.
Intervertebral discs of
fibrocartilage.




Outer fibrous rim
(annulus fibrosus).
Nucleus pulposus
Permits compression in
any direction & some
torsion.
Shock absorbers.
Fig 9.2
9A-4
LIGAMENTOUS REINFORCEMENT
Anterior longitudinal ligaments.
 Posterior longitudinal ligament.

Fig 9.3a & 9.4a
9A-5
ARTICULATION OF VERTEBRAL ARCHES





Facets are nonaxial.
Enclosed in a capsule.
Permit gliding.
Motion determined by
the direction that the
facets face.
Motion between
vertebrae only a few
degrees.

Cummulative motion
from 40º to 70°.
Fig 9.5
9A-6
ARTICULATION OF VERTEBRAL ARCHES:
CERVICAL




Slant at about 45°
Favors rotation & lateral
flexion.
Movements are flexion &
hyperextension, lateral
flexion, & rotation.
Rotation moderate from C2
down.
Fig 9.6a
9A-7
ARTICULATION OF VERTEBRAL ARCHES:
THORACIC
Facets face backward,
slightly upward &
laterally.
 Permit rotation &
lateral bending.

Fig 9.6b
9A-8
ARTICULATION OF VERTEBRAL ARCHES:
LUMBAR
Facets face inward &
slightly backward.
 Locked against
rotation.
 Permits flexion &
hyperextension.

Fig 9.6c
9A-9
ARTICULATION OF VERTEBRAL ARCHES:
LIGAMENTS
Fig 9.7
9A-10
ATLANTO-OCCIPITAL ARTICULATION
Condyles of occipital bone
articulate with articular
fossa of the atlas.
 The two joints act like a
hinge joint.
 Permit flexion & extension.

Fig 9.8
9A-11
ATLANTOAXIAL ARTICULATION
Perfect example of a pivot joint.
 Sole function is rotation.
 Odontoid process projects upward from
axis, held in place by transverse ligament.

Fig 9.9
9A-12
MOVEMENTS OF THE SPINE AS A WHOLE
Flexion
Fig 9.11a & b
Hyperextension
9A-13
MOVEMENTS OF THE SPINE AS A WHOLE
Lateral flexion
Fig 9.11c & d
Rotation
9A-14
REGIONAL CLASSIFICATION OF SPINAL
MOVEMENTS
 Atlanto-occipital joint
 Flexion
& extension, hyperextension.
 Slight lateral flexion.

Atlantoaxial joint
 Rotation

Remaining cervical joints
 Flexion
& extension, hyperextension.
 Lateral flexion.
 Rotation
9A-15
REGIONAL CLASSIFICATION OF SPINAL
MOVEMENTS

Thoracic region
 Moderate
flexion
 Slight hyperextension
 Moderate lateral flexion
 Rotation

Lumbar
 Flexion
& extension, hyperextension
 Lateral flexion
 Slight rotation
9A-16
FACTORS INFLUENCING STABILITY & MOBILITY
OF THE SPINE

Pressure & Tension Stresses:
Discs push vertebrae apart & ligaments pull
them together.

Anteroposterior Curves:
Influence the nature & degrees of motion in different
regions.

Relative Thickness & Shape of Discs:
Greater freedom of motion where discs are thick.

Thickness & Strength of Ligaments:
Regional differences influence motions permitted.
9A-17
FACTORS INFLUENCING STABILITY & MOBILITY
OF THE SPINE


Direction & Obliquity of Articular Facets:
Regional characteristics determine motion
permitted.
Size & Obliquity of Spinous Processes:
Thoracic overlap & limit hyperextension; lumbar
are horizontal & do not restrict motion.

Articulations of Ribs with Vertebrae:
Limit lateral flexion in thoracic region.
9A-18
MUSCLES OPERATING SPINAL COLUMN:
ANTERIOR ASPECT

Cervical Region
 Prevertebral
muscles (longus capitis & coli,
rectus capitis anterior & lateralis).
 Hyoid muscles (suprahyoids & infrahyoids).

Thoracic
 Abdominal
muscles:
 Obliquus
externus & internus abdominis
 Rectus abdominis
 Transverse abdominis
9A-19
MUSCLES OPERATING SPINAL COLUMN:
POSTERIOR ASPECT

Cervical Region Only
 Splenius
capitis & cervicis.
 Suboccipitals

Cervical, Thoracic & Lumbar Region
 Erector
spinae.
 Deep posterior spinal muscles.
 Semispinalis thoracis, cervicis, and capitis
9A-20
MUSCLES OPERATING SPINAL COLUMN:
LATERAL ASPECT

Cervical Region
 Scalenus
anterior, posterior, & medius.
 Sternocleidomastoid.
 Levator scapulae.

Lumbar Region
 Quadratus
lumborum.
 Psoas major.
9A-21
MUSCLES OPERATING SPINAL COLUMN
Prevertebral Muscles
Function:
 Singly: laterally flex &
rotate to opposite side.
 Together: flex head &
neck.
Fig 9.13
9A-22
MUSCLES OPERATING SPINAL COLUMN
Hyoid Muscles
Function:
 Flex head & neck, aid
swallowing.
Fig 9.14
9A-23
MUSCLES OPERATING SPINAL COLUMN
Obliquus Externus
Abdominis
Function:
 Singly: laterally flex & rotate
spine to opposite side.
 Together: flex thoracic &
lumbar spine.
Fig 9.15
9A-24
MUSCLES OPERATING SPINAL COLUMN
Obliquus Internus
Abdominis
Function:
 Singly: laterally flex &
rotate spine to the same
side.
 Together: flex thoracic &
lumbar spine.
Obliquus
Internus
abdominis
Thoracolumbar
fascia
Rectus
sheath
(anterior leaf)
Inguinal
ligament
Fig 9.16
9A-25
MUSCLES OPERATING SPINAL COLUMN
Rectus Abdominis
Function:
 Singly: laterally flex spine.
 Together: flex thoracic &
lumbar spine.
Fig 9.17
9A-26
MUSCLES OPERATING SPINAL COLUMN
Transversus
Abdominis
Function:
 Stabilize trunk.
Fig 9.18
9A-27
MUSCLES OPERATING SPINAL COLUMN
Splenius Capitis &
Cervicis
Function:
 Singly: laterally flex head
& neck, and rotate them
to the same side.
 Together: extend &
hyperextend head &
neck.
Fig 9.19
9A-28
MUSCLES OPERATING SPINAL COLUMN
Levator Scapulae
Function:
 Singly: laterally flex
neck.
 Together: stabilize
neck.
Fig 9.19
9A-29
MUSCLES OPERATING SPINAL COLUMN
Suboccipital Group
Function:
 Singly: laterally flex head, or rotates it to the
same side.
 Together: extend & hyperextend head.
Fig 9.20
9A-30
MUSCLES OPERATING SPINAL COLUMN
Erector Spinae
Function:
 Bilateral: extends head &
spine.
 Unilateral: rotates spine to
same side.
Fig 9.21
9A-31
MUSCLES OPERATING SPINAL COLUMN
Deep Posterior Spinal
Muscles
Function:
 Symmetrical: extends &
hyperextends spine.
 Asymmetrical: rotates spine to
opposite side and assists in
lateral flexion.
Fig 9.22
9A-32
MUSCLES OPERATING SPINAL COLUMN
Semispinalis Thoracis,
Cervicis, & Capitis
Function:
 Singly: lateral flexion & rotates
spine to opposite side.
 Together: extend & hyperextend
thoracic & cervical spine.
Fig 9.23
9A-33
MUSCLES OPERATING SPINAL COLUMN
Scalenus Anterior,
Posterior, & Medius
Function:
 Singly: laterally flex neck.
 Together: flex cervical
spine.
 Elevate upper ribs in
forced inspiration.
Fig 9.24
9A-34
MUSCLES OPERATING SPINAL COLUMN
Sternocleidomastoid
Function:
 Together: flex neck &
head.
 Singly: laterally flex head
& neck, and rotate to
opposite side.
Fig 9.25
9A-35
MUSCLES OPERATING SPINAL COLUMN
Quadratus Lumborum
Function:
 Singly: laterally flex
lumbar spine.
 Together: stabilize
pelvis & lumbar spine.
Fig 9.26
9A-36
MUSCLES OPERATING SPINAL COLUMN
Psoas
Function:
 Singly: laterally flex lumbar
spine.
 Together: stabilize spine.
Fig 7.14
9A-37
MUSCULAR ANALYSIS OF FUNDAMENTAL
MOVEMENTS OF HEAD & SPINE
Cervical Spine & Atlanto-Occipital Joint:

Flexion:
Sternocleidomastoid, scalenes, prevertebral muscles.

Extension & Hyperextension:
Splenius capitis & cervicis, erector spinae capitis &
cervicis, semispinalis, deep posterior spinal muscles,
suboccipitalis.

Lateral flexion:
Splenius capitis & cervicis, erector spinae, semispinalis,
scalenes, sternocleidomastoid.

Rotation:
Sternocleidomastoid, deep posterior spinal muscles,
splenius, erector spinae, occipitalis.
9A-38
MUSCULAR ANALYSIS OF FUNDAMENTAL
MOVMENTS OF HEAD & SPINE
Thoracic & Lumbar Spine

Flexion:
Abdominals.

Extension & Hyperextension:
Erector spinae, semispinalis thoracis, deep posterior spinal
muscles.

Lateral flexion:
Erector spinae, oblique abdominals, quadratus lumborum.

Rotation to Left:
Left internal oblique & erector spinae, right external
oblique, semispinalis thoracis, other deep posterior
spinal muscles.
9A-39