Download Musculature Neck and Trunk

Neck and Trunk
Vertebral Curves
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The vertebrae are arranged in such a way
as to form anterior-posterior (concaveconvex) curves in the vertebral column,
which can be seen from the side. These
curves provide the vertebral column with
much more strength and resilience,
approximately 10 times more than if it
were a straight rod.
Spinal column
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7 cervical vertebrae
12 thoracic vertebrae
5 lumbar vertebrae
Sacrum is composed of 5 fused vertebrae
Joint Motions
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The vertebral column is considered
triaxial, with motion in all three planes:
Flexion
Extension
Hyperextension
Lateral bending
Rotation
Cervical Spine
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Atlanto-occipital joint: articulation
between the head and C1 (atlas)
Primary motion is flexion and extension,
however, rotation also occurs between the
atlas and axis, with articulation between
the dens of the axis and atlas permitting
rotation movement.
Common Vertebral Column
Pathologies
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Thoracic outlet syndrome: compression of brachial plexus and
subclavian artery and vein that runs from neck to axilla. The
thoracic outlet is located between the first rib, clavicle and scalene
muscles.
Torticollis: “twisted neck:” head is laterally bent to one side and
rotated toward the opposite side
Sciatica: pain that runs down the posterior thigh and leg, d/t
pressure on the sciatic nerve
Lordosis: abnormally increased curve of the lumbar spine
(“swayback”)
Flat back: abnormally decreased lumbar curve
Kyphosis: abnormally increased thoracic curve
Scoliosis: any amount of lateral curve in spinal column
Common Vertebral Column
Pathologies
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Spondylosis: degenerative disorder of the vertebral structure and
function, which may lead to nerve root and spinal cord compression
Spinal stenosis: a narrowing of the vertebral canal
Herniated disks: weakness or degeneration of the annulus
fibrosus, allowing a portion of the nucleus pulposus to bulge
(herniated) through the annulus. Symptoms occur when herniation
places pressure on spinal cord or nerve root. L4 and L5 are most
common sites for disk lesions.
Spondylolysis: vertebral defect in the pars interarticularis (the part
of the lamina between the superior and inferior articular processes).
Spondylolisthesis: one vertebra slips forward in relation to an
adjacent vertebra (commonly L5 slipping anterior on S1)
Osteoporosis: disease in which bone is removed faster than it can
be laid down, leading to a decrease in bone mass and density
Muscles of the Neck and Trunk
Neck
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Sternocleidomastoid
Scalenes
Prevertebral group (4)
Erector spinae group (3)
Splenius capitis
Splenius cervicis
Suboccipital group (4)
Muscles of the Neck and Trunk
Trunk
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Rectus abdominis
External oblique
Internal oblique
Transverse abdominis
Erector spinae group (3)
Transversospinalis group (3)
Interspinales
Intertransversarii
Quadratus lumborum
Sternocleidomastoid
Sternocleidomastoid
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O: Sternum and clavicle
I: Mastoid process
A: Bilaterally: flexes neck, hyperextends
head
Unilaterally: laterally bends the neck;
rotates head to opposite side
N: Accessory nerve (cranial nerve XI);
second and third cervical nerves
Scalene
Scalene
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O: Transverse processes of the cervical
vertebrae
I: First and second ribs
A: Bilaterally: assists in neck flexion
Unilaterally: neck lateral bending
N: Lower cervical nerve
Prevertebral Group
Longus colli
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O: Bodies and transverse processes of C3T2
I: Transverse processes and bodies of C1C6
A: Flex neck
Longus capitis
Longus capitis
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O: Transverse processes of C3-C6
I: Occipital bone
A: Flex head
Rectus capitis anterior
Rectus capitis anterior
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O: Atlas
I: Occipital bone
A: Flex head
Rectus capitis lateralis
Rectus capitis lateralis
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O: Transverse process of atlas
I: Occipital bone
A: Laterally bends head
Suboccipital Muscles
Suboccipital Muscles
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Obliquus capitis superior: extension
Obliquus capitis inferior: extension, lateral
bending, rotation to the same side
Rectus capitis posterior minor: extension
Rectus capitis posterior major: extension, lateral
bending, rotation to the same side
All suboccipital muscles are located posteriorly
Splenius Capitis
Splenius Capitis
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O: Lower half of nuchal ligament; spinous
processes of C7 through T3
I: Lateral occipital bone; mastoid process
A: Bilaterally: extend head and neck
Unilaterally: rotate and laterally bend
the head to same side
N: Middle and lower cervical nerves
Splenius Cervicis
Splenius Cervicis
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O: Spinous processes of T3 thorugh T6
I: Transverse processes of C1 through C3
A: Bilaterally: extend neck
Unilaterally: rotate and laterally bend
the neck to same side
N: Middle and lower cervical nerves
Muscles of the Trunk
Rectus Abdominis
Rectus Abdominis
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O: Pubis
I: Xiphoid process and costal cartilages of
fifth, sixth, and seventh ribs
A: Trunk flexion; compression of abdomen
N: Seventh through twelfth intercostal
nerves
External Oblique
External Oblique
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O: Lower eight ribs laterally
I: Iliac crest and linea alba
A: Bilaterally: trunk flexion; compression
of abdomen
Unilaterally: lateral bending; rotation
to opposite side
N: Eighth through twelfth intercostal,
iliohypogastric, and ilioinguinal nerves
Internal Oblique
Internal Oblique
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O: Inguinal ligament, iliac crest, thoracolumbar
fascia
I: Tenth, eleventh, and twelfth ribs; abdominal
aponeurosis
A: Bilaterally: trunk flexion; compression of
abdomen
Unilaterally: lateral bending; rotation to same
side
N: Eighth through twelfth intercostal,
iliohypogastric, and ilioinguinal nerves
Transverse Abdominis
Transverse Abdominis
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O: Inguinal ligament, iliac crest,
thoracolumbar fascia, and last six ribs
I: Abdominal aponeurosis and linea alba
A: Compression of abdomen
N: Seventh through twelfth intercostal,
iliohypogastric, and ilioinguinal nerves
Erector Spinae Muscles
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Iliocostalis
Longissimus
Spinalis
Erector Spinae Muscles
Erector Spinae Muscles
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O: Spinous processes, transverse processes and
ribs from the occiput to the sacrum and ilium
I: Spinous processes, transverse processes and
ribs from the occiput to the sacrum and ilium
A: Bilaterally: extend
Unilaterally: lateral bend
N: Spinal nerves
Transversospinalis Muscles
Transversospinalis Muscles
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O: Transverse processes
I: Spinous processes of vertebra above
A: Bilaterally: extend
Unilaterally: rotate to opposite side
N: Spinal nerves
Interspinales Muscles
Interspinales Muscles
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O: Spinous process below
I: Spinous process above
A: Trunk extension
N: Spinal nerves
Intertransversarii Muscles
Intertransversarii Muscles
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O: Transverse process below
I: Transverse process above
A: Trunk lateral bending
N: Spinal nerves
Quadratus Lumborum
Quadratus Lumborum
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O: Iliac crest
I: Twelfth rib, transverse processes of all
five lumbar vertebrae
A: Trunk lateral bending
N: Twelfth thoracic and first lumbar nerves
*Hip hiking (elevation) of one side of the pelvis*