Variations In Length Of Posterior Muscles

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Gastroc Length
normal length of the gastroc-soleus.
Hamstring Lengthening

Excessive length of the upper back muscles, slight shortness of the muscles in the mid back and in gastroc-soleus. Hamstrings and low back are normal in length.

Hamstring Shortness

Excessive flexibility of the back overcompensates for shortness of the hamstrings.

Hamstring Shortness

This subject is unable to touch his toes because of shortness in the gastroc-soleus, and slight limitation of flexibility in the mid-back area. The upper back shows some excessive flexion.

Hamstring LengthHamstring Length Normal

Normal length of the upper back muscles and short lower back, hamstring and gastroc-soleus muscles.

Normal length of the upper back muscles and contracture of lower back muscles with paralysis and excessive length of extremity muscles.

TRUNK MUSCLES

Trunk muscles consist of back extensors that bend the trunk backward, lateral flexors that bend it sideways, anterior abdominals that bend it forward or tilt posteriorly, and combinations of these muscles that rotate the trunk in a clockwise or a counter-clockwise manner. All these muscles play a role in stabilizing the trunk, but the back extensors are the most important in this regard. The loss of stability that accompanies paralysis or marked weakness of the back muscles offers dramatic evidence of their importance. Fortunately, marked weakness of these muscles seldom occurs.

The term weak back, as frequently used in connection with low back pain, mistakenly suggests a weakness of the low back muscles. The feeling of weakness that occurs with a painful back is associated with the faulty alignment the body assumes, and it is often caused by weakness of the abdominal muscles. Persons who have faulty posture with roundness of the upper back may exhibit weakness in the upper back extensors but have normal strength in those of the low back.

Despite the fact that the low back muscles are the most important trunk stabilizers, relatively little space will be devoted to them in this chapter compared to the detailed discussion of the abdominal muscles. Testing back muscles is less complicated than testing abdominal muscles, and in the field of exercise, few errors occur regarding back exercises. Many misconceptions and errors, however, occur regarding proper abdominal exercises. Furthermore, in contrast to the back muscles, weakness of the abdominal muscles is more prevalent. It is important to know how to test for strength and how to prescribe proper exercises for the abdominal muscles because of the effect that weakness of these muscles has on overall posture and the relationship of such weakness to painful postural problems.

Illustrations, definitions, and descriptions of basic concepts are used to help achieve this purpose. Both the illustrations of the trunk muscles that follow and the accompanying text provide information in detail about the origins, insertions and actions of these muscles. This information is essential to understanding the functions of these important trunk muscles.

Anteroposterior: Low back muscles oppose anterior abdominal muscles.

Lateral: Lateral trunk muscles oppose each other.

Rotary: Muscles that produce clockwise rotation oppose those that produce counter-clockwise rotation.

TRUNK MUSCLES ATTACHED TO PELVIS

With the pelvis pivoting on the femora, the opposing groups of muscles act not only in straight anteroposterior opposition but also combine their pulls to tilt the pelvis forward or backward as well as laterally. There are four main groups of muscles in anteroposterior opposition:

1. The erector spinae, quadratus lumborum, and other posterior back muscles attached to the posterosuperior part of the pelvis exert an upward pull posteriorly.

2. The anterior abdominals, especially the rectus abdo-minis with its insertion on the symphysis pubis and the external oblique with its attachment on the anterior iliac crest, exert an upward pull anteriorly.

3. The gluteus maxim us and hamstrings, with attachments on the posterior ilium, sacrum and ischium, exert a downward pull posteriorly.

4. The hip flexors, including the rectus femoris, tensor fasciae latae and sartorius, with attachments on the anterior, superior, and inferior spines of the ilium, and the iliopsoas, with attachment on the lumbar spine and inner surface of the ilium, exert a downward pull anteriorly.

The low back muscles act with the hip flexors (especially the psoas, with its direct pull from the lumbar spine to the femur) to tilt the pelvis downward and forward (i.e., anterior tilt). They are opposed in action by the combined pull of the anterior abdominals, pulling upward anteriorly, and the hamstrings and gluteus maximus, pulling downward posteriorly, to level the pelvis from a position of anterior tilt.

There are two main groups of pelvic muscles in lateral opposition:

1. The leg abductors (mainly the gluteus minimus and medius), which arise from the lateral surface of the pelvis, pull downward on the pelvis when the leg is fixed as in standing.

2. The lateral trunk muscles, attached to the lateral crest of the ilium, pull upward laterally on the pelvis.

Hip abductors on one side and lateral trunk muscles on the other side combine in action to tilt the pelvis laterally: Right abductors pull downward on the right side of the pelvis as left lateral trunk muscles pull upward on the left side, and vice versa. These actions are assisted by hip adductors on the same side as the lateral mink muscles.

In combination, right hip abductors, left hip adductors, and left lateral trunk muscles oppose left hip abductors, right hip adductors and right lateral trunk muscles.

Motorpoint Adductor Muscles

Splenius

Splenitis capitis

Splenius cervicis

Longissimus thoracis liiocostalis thoracis liiocostalis lumborum

Semispinalis

Semispinalis thoracis

Intertransversarii

Erector Spinae

(Superficial layer)

Longissimus capitis

Spinalis cervicis Longissimus cervicis liiocostalis cervicis

Semispinalis capitis

Muscles//Verves

j Origin

J Insertion

(superficial) Iliocostals lumboru m/Spinal

Common origin from anterior surface of broad tendon attached to medial crest of the sacrum, spinous processes of lumbar and 11th and 12th thoracic vertebrae, posterior part of medial lip of iliac crest, supraspinous ligament, and lateral crests of sacrum

By tendons into inferior borders of angles of lower six or seven ribs

Extension of vertebral column in lower thoracic area; draws ribs downward.

lliocostalis thoracis/Spina/

By tendons from upper borders of angles of lower six ribs

Cranial borders of angles of upper six ribs and dorsum of transverse process of seventh cervical vertebra

Extension and lateral flexion of vertebral column in upper | thoracic area; draws ribs downward.

Iliocostal cervicis/Sp/na/

Angles of third through sixth ribs

Posterior tubercles of transverse processes of fourth through sixth cervical vertebrae

Extension of vertebral column in upper thoracic and lower cervical areas.

Longissimus thoracis/Sp/na/

In lumbar region, blended with iliocostalis lumborum, posterior surfaces of transverse and accessory processes of lumbar vertebrae, and anterior layer of thoracolumbar fascia

By tendons into tips of transverse processes of all thoracic vertebrae and by fleshy digi-tations into lower 9 or 10 ribs between tubercles and angles

Extension and lateral flexion of vertebral column in thoracic area; draws rib downward.

Longissimus cervicis/Sp/na/

By tendons from transverse processes of upper four or five thoracic vertebrae

By tendons into posterior tubercles of transverse processes of second through sixth cervical vertebrae

Extension and lateral flexion of vertebral column in cervical area; draws ribs downward.

Longissimus capitis. Cervical

By tendons from transverse processes of upper four or five thoracic vertebrae and articular processes of lower three or four cervical vertebrae

Posterior margin of mastoid process deep to splenius capitis and sternocleidomastoid

Extension, lateral flexion and rotation of cervical spine; turning the head to face toward the same side.

Spinalis thoracis/ Spinal

By tendons from spinous processes of first two lumbar and last two thoracic vertebrae

Spinous processes of upper four to eight (variable) thoracic vertebrae

Extension of vertebral column in thoracic area.

Spinalis cervicis/ Spinal

Ligamentum nuchae, lower part; spinous process of seventh cervical vertebra and, sometimes, from spinous process of first and second thoracic vertebrae.

Spinous process of axis and, occasionally, into the spinous processes of C3 and C4

Extension of vertebral column in upper cervical area.

Spinalis capitis/ Spinal

Inseparably connected with semispinals capitis (see facing page)

Same as semispinals capitis (see facing page)

Same as Semispinals capitis. See facing page

Muscles/Nerves _

Origin

Insertion

Action

1 Transversospinal (deep) First layer Semispinalis thoracis/Sp/na/

Transverse processes of lower 6 to 10 thoracic vertebrae

By tendons into spinous processes of first four thoracic and last two cervical vertebrae

Extension of vertebral column and rotation toward opposite side in thoracic area.

Semispinalis cervicis/Sp/na/

Transverse processes of upper five or six thoracic vertebrae

Cervical spinous processes of second through fifth cervical vertebrae

Extension of vertebral column and rotation toward opposite side in upper thoracic and cervical areas.

Semispinalis capitis/Cerv/ca/

Tips of transverse processes of upper six or seven thoracic and seventh cervical vertebrae and articular processes of fourth through sixth cervical vertebrae.

Between superior and inferior nuchal lines of occipital bone

Extension of neck and rotation of head toward opposite side.

Second layer Multifidi/Sp/na/

Sacral region: Posterior surface of sacrum, medial surface of posterior iliac spine and postero-sacroiliac ligaments.

Lumbar, thoracic, and cervical regions: Transverse processes of 15 through C4.

Spanning two to four vertebrae, inserted into spinous process of one of vertebra above from last lumbar to axis (second cervical vertebra)

Extension of vertebral column and rotation toward opposite side.

Third layer Rotatores/Sp/na/

Transverse processes of vertebrae

Base of spinous process of vertebra above

Extension of vertebral column and rotation toward opposite side.

Interspinales/ Spinal

Placed in pairs between spinous processes of contiguous vertebrae

Cervical: six pairs Thoracic: two or three pairs; between first and second (second and third) and 11th and 12th vertebrae. Lumbar: four pairs

Extension of vertebral column.

Intertransversarii anterior and posterior/Spinal

Small muscles placed between transverse processes of contiguous vertebrae in cervical, thoracic, and lumbar regions

1

Lateral flexion of vertebral column.

Splenius cervicis/

Cervical --- -

Spinous processes of third through sixth thoracic vertebrae

Posterior tubercles of transverse processes of first two or three cervical vertebrae

Extension, lateral flexion and rotation of neck, turning face toward same side. Both sides acting together, extension of neck.

Splenius capitis/ Cervical

1

Caudal Va of (igamentum nuchae, spinous process of seventh cervical vertebrae, and spinous process of first three or four thoracic vertebrae

Occipital bone inferior to lateral /3 of superior nuchal line; mastoid process of temporal bone

Extension, lateral flexion, and rotation of neck, turning face toward same side. Both sides acting together, extension of neck.

For back extensors to raise the trunk from a prone position, the hip extensors must fix the pelvis in extension on the thigh.

Normally, extension of the hip joints and extension of the lumbar spine are initiated simultaneously, not as two separate movements.

The illustrations on this page show the variations that occur depending on the strength of the two primary muscle groups.

If slight tightness exists in the hip flexors, there is no range of extension in the hip joint, and all the movement in the direction of raising the leg backward is accomplished by lumbar spine hyperextension and pelvic tilt.

For hip extensors to raise the extremity backward from a prone position through the few degrees of true hip joint extension (*10°), the back extensors must stabilize the pelvis to the trunk.

A subject with strong back extensor muscles and strong hip extensor muscles can raise the trunk in extension.

Trunk Extensors

Raising the extremity higher is accomplished by hyperextension of the lumbar spine and anterior tilting of the pelvis. In this latter movement, the back extensors are assisted by hip flexors on the opposite side that help to tilt the pelvis anteriorly.

Trunk Extensors

A subject with strong back extensor muscles and markedly weak or paralyzed hip extensor muscles can hyperextend the lumbar spine. However, the trunk cannot be lifted high from the table.

In an effort to lift the extremity, the back muscles contract to fix the pelvis on the trunk, but with little or no strength in the hip extensors, the thigh cannot be extended on the pelvis. The unopposed pull of the back muscles results in hyperextension of the back, and the hip joint is passively drawn into flexion despite the effort to extend it.

A subject with weak or paralyzed back extensor muscles and strong hip extensor muscles cannot raise the trunk in extension. The hip extensors, in their action to fix the pelvis, are unopposed: The pelvis tilts posteriorly, and the lumbar spine flexes.

In an effort to lift the extremity, the hip extensors contract. The extremity cannot be lifted, however, because the back muscles are unable to stabilize the pelvis. The pelvis tilts posteriorly because of the pull of the hip extensors and the weight of the extremity, instead of tilting anteriorly as it would if the back extensors were normal.

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Reasonable care has been taken to ensure that the information presented in this book is accurate. However, the reader should understand that the information provided does not constitute legal, medical or professional advice of any kind.

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  • Daniela
    How to fix posterior gastrocsoleus area?
    2 years ago

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