Anatomy Lecture 1: Muscles in the Back

Extrinsic muscle

Originate in one area and insert into another

intrinsic muscles

Fully contained within the structure under consideration

What are the superficial muscles of the back?

trapezius and latissimus dorsi

What are the attachments of the trapezius muscle?

External occipital protuberance, spinal process, spine of scapula and acromion

What are the actions of the descending trapezius?

elevate the scapula by shorting the distance.

What are the actions of the transverse trapezius?

Retraction of the scapula by contracting

What are the actions of the Ascending trapezius?

Depression of the scapula

Descending Trapezius

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Transverse Trapezius

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Ascending Trapezius

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Trapezius innervation

accessory nerve (cranial nerve XI)

Accessory nerve origin

spinal cord segments C1-C6

What foramen does the accessory nerve enter?

foramen magnum

What foramen does the accessory nerve exit?

jugular foramen

Latissumus dorsi

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Where does the latissimus dorsi attach?

intertubercular bicipital groove

What is another place the latissimus dorsi attaches

thoracolumbar fascia and iliac crest

What is the action of the latissimus dorsi?

extends, adducts, and medially rotates humerus

Latissimus dorsi innervation

thoracodorsal nerve

thoracodorsal nerve

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triangle of ascultation

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rhomboid major

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Rhomboid minor

0

Where do the rhomboids attach?

medial border of scapula

Where do the rhomboids insert?

spinous process and nuchal ligament

What is rhomboid major and minors action?

medially rotate and retract the scapula

When working with the Levator scapula the rhomboids help to ?

elevate the scapula

Levator scapula

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What is the action of the Levator scapula?

Elevation of the scapula

Where does the levator scapulae insert?

superior angle of scapula and cervical vertebrae.

dorsal scapular nerve

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Splenius muscle

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Where does the splenius attach?

mastoid process

What is the bilateral action of the splenius ?

extension of the head

What is the unilateral action of the splenius ?

laterally flexion of the head

What is the ipsilateral action of the splenius ?

lateral rotation of the head

innervation of splenius capitis

dorsal rami

Serratus Posterior Inferior

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Serratus Posterior Superior

0

serratus posterior inferior action

depress ribs during exhalation

serratus posterior superior action

elevates ribs in inspiration

erector spinae

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Iliocostalis

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Longissimus

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Spinalis

0

What is the bilateral action of the erector spinae?

Extend the head and trunk

What is the unilateral action of the erector spinae?

lateral flexion

What is the ipsilateral action of the erector spinae?

rotate the trunk

Transversospinalis muscles

0

What is the action of the tranversospinalis muscles?

Allow for fine muscle movements and adjustments of the spine

semispinalis capitis

0

What is the bilateral action of the semispinalis capitis?

Extension of the head

What is the unilateral action of the semispinalis capitis?

lateral flexion of the head

suboccipital muscles

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Rectus Capitis Posterior Major

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Rectus Capitus Posterior Minor

0

Obliquus capitis inferior

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Obliquus Capitus Superior

0

What is the inferior attachment of the rectus capitis posterior major?

Spinous process of C2

What is the Superior attachment of the rectus capitis posterior major?

Lateral inferior nuchal line

What is the inferior attachment of the rectus capitis posterior minor?

Posterior tubercle of C1

What is the superior attachment of the rectus capitis posterior minor?

Medial inferior nuchal line

What is the inferior attachment of the Obliquus capitis inferior?

Spinous process of C2

What is the superior attachment of the Obliquus capitis inferior?

Tranvers process of C1

What is the inferior attachment of the rObliquus capitis superior?

Tranverse process of C1

What is the Superior attachment of the Obliquus capitis superior?

Between superior and inferior nuchal lines

What is the action of the rectus capitis posterior minor?

extend the head

What is the bilateral action of the rectus capitis posterior major?

Extends the head

What is the unilateral action of the rectus capitis posterior major?

rotates the head

What is the bilateral action of the obliquus capitis superior?

Extends the head

What is the unilateral action of the obliquus capitis superior?

laterally flex head

What is the bilateral action of the obliquus capitis inferior?

extends the head

What is the unilateral action of the obliquus capitis inferior?

Rotates the head

Least occipital nerve

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Greater occipital nerve

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suboccipital nerve

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suboccipital triangle

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Accessory Nerve (XI)

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