Knowt
MUSCLES OF THE BACK PART 1
Muscles of the back consist of extrinsic and intrinsic groups:
• the extrinsic muscles -move the upper limbs and the ribs
• the intrinsic muscles -maintain posture and move the vertebral column
• movements include flexion (anterior bending), extension, lateral
flexion, and rotation.
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The muscles of the back are organised as follows:
• ==Extrinsic muscles== are involved in the Upper Limb (UL) and thoracic wall movement and are innervated by the anterior rami.
a)Superficial group - is related to and involved in movement of the UL.
b)Intermediate group - is related to the thoracic wall and serve as a respiratory function.
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==• Intrinsic muscles==: are deep in position and innervated by the posterior rami. Support and move the vertebral column and head
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**TRAPEZIUS**
• The Motor innervation of the trapezius muscle is ==**accessory nerve**.==
• The Origin of the trapezius is from Sup nuchal line, ext. occipital protuberance, Ligamentum nuchae, spinous processes of Cervical 7 to Thoracic12
•The insertion of the trapezius muscle is Lateral 1/3 of the clavicle, acromion and spine of the scapula
•The function of the trapezius muscle is to Assist in rotating the scapula during abduction of the humerus, Upper fibres ==elevate==, middle fibres ==retract== the scapula, and lower fibers ==depress== scapula.
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**LATISSIMUS DORSI**
•Latissimus dorsi Is large, flat and triangular at lower portion of the back and ends in a tendon that attaches to the humerus.
• Latissimus dorsi's Motor innervation is ==**the thoracodorsal nerve.**==
• the Latissimus dorsi originates from Spinous processes of Thoracic 7 to Lumbar 5, sacrum, iliac crest, ribs X to XII
•The Insertion of the Latissimus dorsi is Floor of the intertubercular sulcus of humerus
• the function of the Latissimus dorsi Is to Extend, adduct, medially rotate the humerus, holds the inferior angle of scapula in place
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LEVATOR SCAPULA
\-levator scapula Is a slender muscle that descends from the transverse processes of the cervical vertebrae to upper portion of the medial border of the scapula.
\-Motor innervation of the levator scapula is ==**dorsal scapular nerve, C3-C4 ant rami**==
\-The function of the levator scapula is to Elevate the scapula.
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Rhomboid minor
\-Rhomboid minor arises from ligamentum nuchae, spinous processes of CVII
Rhomboid minor attaches to medial scapula border.
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\-Rhomboid major arises from Thoracic two to Thoracic 5 spinous processes
Rhomboid major attaches to medial scapula border below rhomboid minor.
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\-Motor innervation of the Rhomboid minor and major is ==**dorsal scapular nerve**==
\-The function of the Rhomboid muscles is to work together to retract the scapula to the vertebral column.
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• The muscles in the intermediate group are two flat muscular sheets that lie in the superior and inferior aspects of the back.
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• The fibres from Serratus posterior superior and inferior pass outwards from the vertebral column to attach to the ribs. Referred to as the respiratory group.
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• Serratus posterior superior is deep to the rhomboid muscles.Their Fibres descend from vertebral column.
• Serratus posterior inferior is deep to Lattisimus dorsi.Their Fibres ascend from vertebral column.
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Motor innervation of the Serratus posterior superior is ==**ant rami of T2-T5**==
Motor Innervation of Serratus posterior inferior is ==**ant rami of T9-T12**==
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Function of the Serratus posterior superior is to Elevate ribs 2-5
Function of Serratus posterior inferior is to depresses ribs 9-12
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DEEP GROUP OF MUSCLES include:
1)SUPERFICIAL LAYER: Extensors & rotators of the head and neck, which are
2)INTERMEDIATE LAYER- Extensors & rotators of the vertebral column- which is erector spinae
3)DEEP LAYER-TRANSVERSOSPINALES MUSCLE GROUP: which are semispinalis, multifidus, rotatores
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\-Innervation to the deep muscles is by ==**posterior rami of spinal nerves.**==
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• splenius capitus and cervicis muscles run from the spinous processes and ligamentum nuchae vertically upwards and laterally
• Splenius capitus: Is supplied by ==**Posterior primary rami of middle cervical nerves**==
\-Splenius capitus Originates from the Lower ½ Lig. Nuchae, spinous processes of Cervical 7 to Thoracic 4
\-The splenius capitus Insertion is the Mastoid process, skull
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• Splenius cervicis is supplied by the ==**Posterior rami of lower cervical nerves**==
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\-The splenius cervicis Originates from the Spinous process of Thoracic 3 to Thoracic 6
\-The splenius cervicis Inserts to the Transverse process of cervical 1 to cervical 3
\-The function of the both splenius cervicis and capitus is to Extend the neck.
\-The function of the individual splenius muscle is to rotate the head to one
side
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ERECTOR SPINAE
•The Erector spinae is covered by thoracolumbar fascia and serratus post. Inf, rhomboids, splenius muscles.
•The outermost/laterally placed column of muscles of erector spinae is iliocostalis
•The middle/intermediate column of the erector spinae is the longissimus, Largest of
the subdivisions of erector spinae
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• the extrinsic muscles -move the upper limbs and the ribs
• the intrinsic muscles -maintain posture and move the vertebral column
• movements include flexion (anterior bending), extension, lateral
flexion, and rotation.
\
The muscles of the back are organised as follows:
• ==Extrinsic muscles== are involved in the Upper Limb (UL) and thoracic wall movement and are innervated by the anterior rami.
a)Superficial group - is related to and involved in movement of the UL.
b)Intermediate group - is related to the thoracic wall and serve as a respiratory function.
\
==• Intrinsic muscles==: are deep in position and innervated by the posterior rami. Support and move the vertebral column and head
\
**TRAPEZIUS**
• The Motor innervation of the trapezius muscle is ==**accessory nerve**.==
• The Origin of the trapezius is from Sup nuchal line, ext. occipital protuberance, Ligamentum nuchae, spinous processes of Cervical 7 to Thoracic12
•The insertion of the trapezius muscle is Lateral 1/3 of the clavicle, acromion and spine of the scapula
•The function of the trapezius muscle is to Assist in rotating the scapula during abduction of the humerus, Upper fibres ==elevate==, middle fibres ==retract== the scapula, and lower fibers ==depress== scapula.
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**LATISSIMUS DORSI**
•Latissimus dorsi Is large, flat and triangular at lower portion of the back and ends in a tendon that attaches to the humerus.
• Latissimus dorsi's Motor innervation is ==**the thoracodorsal nerve.**==
• the Latissimus dorsi originates from Spinous processes of Thoracic 7 to Lumbar 5, sacrum, iliac crest, ribs X to XII
•The Insertion of the Latissimus dorsi is Floor of the intertubercular sulcus of humerus
• the function of the Latissimus dorsi Is to Extend, adduct, medially rotate the humerus, holds the inferior angle of scapula in place
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LEVATOR SCAPULA
\-levator scapula Is a slender muscle that descends from the transverse processes of the cervical vertebrae to upper portion of the medial border of the scapula.
\-Motor innervation of the levator scapula is ==**dorsal scapular nerve, C3-C4 ant rami**==
\-The function of the levator scapula is to Elevate the scapula.
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Rhomboid minor
\-Rhomboid minor arises from ligamentum nuchae, spinous processes of CVII
Rhomboid minor attaches to medial scapula border.
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\-Rhomboid major arises from Thoracic two to Thoracic 5 spinous processes
Rhomboid major attaches to medial scapula border below rhomboid minor.
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\-Motor innervation of the Rhomboid minor and major is ==**dorsal scapular nerve**==
\-The function of the Rhomboid muscles is to work together to retract the scapula to the vertebral column.
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• The muscles in the intermediate group are two flat muscular sheets that lie in the superior and inferior aspects of the back.
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• The fibres from Serratus posterior superior and inferior pass outwards from the vertebral column to attach to the ribs. Referred to as the respiratory group.
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• Serratus posterior superior is deep to the rhomboid muscles.Their Fibres descend from vertebral column.
• Serratus posterior inferior is deep to Lattisimus dorsi.Their Fibres ascend from vertebral column.
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Motor innervation of the Serratus posterior superior is ==**ant rami of T2-T5**==
Motor Innervation of Serratus posterior inferior is ==**ant rami of T9-T12**==
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Function of the Serratus posterior superior is to Elevate ribs 2-5
Function of Serratus posterior inferior is to depresses ribs 9-12
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DEEP GROUP OF MUSCLES include:
1)SUPERFICIAL LAYER: Extensors & rotators of the head and neck, which are
2)INTERMEDIATE LAYER- Extensors & rotators of the vertebral column- which is erector spinae
3)DEEP LAYER-TRANSVERSOSPINALES MUSCLE GROUP: which are semispinalis, multifidus, rotatores
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\-Innervation to the deep muscles is by ==**posterior rami of spinal nerves.**==
\
• splenius capitus and cervicis muscles run from the spinous processes and ligamentum nuchae vertically upwards and laterally
• Splenius capitus: Is supplied by ==**Posterior primary rami of middle cervical nerves**==
\-Splenius capitus Originates from the Lower ½ Lig. Nuchae, spinous processes of Cervical 7 to Thoracic 4
\-The splenius capitus Insertion is the Mastoid process, skull
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• Splenius cervicis is supplied by the ==**Posterior rami of lower cervical nerves**==
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\-The splenius cervicis Originates from the Spinous process of Thoracic 3 to Thoracic 6
\-The splenius cervicis Inserts to the Transverse process of cervical 1 to cervical 3
\-The function of the both splenius cervicis and capitus is to Extend the neck.
\-The function of the individual splenius muscle is to rotate the head to one
side
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ERECTOR SPINAE
•The Erector spinae is covered by thoracolumbar fascia and serratus post. Inf, rhomboids, splenius muscles.
•The outermost/laterally placed column of muscles of erector spinae is iliocostalis
•The middle/intermediate column of the erector spinae is the longissimus, Largest of
the subdivisions of erector spinae
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