Class 5 Ap1 Muscles

Muscles of the Trunk

Latissimus DorsiP: SPs of T7-L5, posterior sacrum,

and the posterior iliac crestD: Medial lip of bicipital groove

of the humerus

1. Medially rotates the arm at the shoulder joint

2. Adducts the arm at the shoulder joint

3. Extends the arm at the shoulder joint

4. Anteriorly tilts the pelvis at the lumbosacral joint

Latissimus Dorsi: SPs of T7-L5, Posterior sacrum, and Posterior iliac crest

Rhomboid Major and Minor

• P: SPs of C7-T5• D: Medial border of the

scapula from the root of the spine of the scapula to the inferior angle of the scapula

1. Retracts (Adducts) the scapula at the scapulocostal joint

2. Elevates the scapula

Rhomboids Major and Minor: SPs of C7-T5

Superficial Muscles of Back

Serratus Anterior

O: Ribs 1-9I: Anterior surface of the

entire medial border of the scapula

1. Protracts (abducts) the scapula at the scapulocostal joint

2. Upwardly rotates the scapula at the scapulocostal joint

Serratus Anterior: Ribs 1-9

Serratus Posterior Superior

• 1. Elevates ribs #2-5 at the sternocostal and costospinal joints

Serratus Posterior Inferior

• 1. Depresses ribs #9-12 at the sternocostal and costospinal joints

Three subgroups listed lateral to medial:

1. Iliocostalis2. Longissimus3. Spinalis

The iliocostalis attaches from the ilium to the ribs

The longissimusis the longest of the three subgroups. Only subgroup that attaches onto the head.

The spinalis attaches from SPs to SPs

Each subgroup can be further divided into three subgroups

Iliocostalis lumborum Iliocostalis thoracis Iliocostalis cervicis

Longissimus thoracisLongissimus cervicisLongissimus capitis

Spinalis thoracis Spinalis cervicisSpinalis capitis (The spinalis capitis

often blends with and is therefore considered to be a part of the semispinalis capitis of the transversospinalis group)

Erector Spinae Group

O: PelvisI: Spine, ribcage, and head

1. Extends the trunk, neck, and the head at the spinal joints

2. Laterally flexes the trunk, neck, and head at the spinal joints

3. Ipsilaterally rotates the trunk, neck, and head at the spinal joints

4. Anteriorly tilts the pelvis at the lumbosacral joint

The name tells us that the muscle group attaches from a TP to a SP. The TP is the inferior attachment and the SP is the superior attachment

Group is very deep; lies in the laminar groove

Divided into three subgroups: from superficial to deep:

1. Semispinalis 2. Multifidus 3. Rotatores

Transversospinalis GroupO: PelvisI: Spine and the head

1. Extends the trunk, neck, and head at the spinal joints

2. Laterally flexes the trunk, neck, and head at the spinal joints

3. Contralaterally rotates the trunk and the neck at the spinal joints

4. Anteriorly tilts the pelvis at the lumboscaral joint

Transversospinalis Group: Pelvis to the spine and head

Rotatores of transversospinalis group: attach to spine (Tp inferiorly to lamina superiorly: FYI)

Semispinalis of transversospinalis group: attaches to head

Transversospinalis Group

• Semispinalis

Transversospinalis Group

• Multifidus

Transversospinalis Group

• Rotatores

Quadratus LumborumP: 12th rib and the TPs of L1-

L4D: Posterior Iliac crest

1. Elevates the pelvis at the lumbosacral joint

2. Anteriorly tilts the pelvis at the lumbosacral joint

3. Laterally flexes the trunk at the spinal joints

4. Extends the trunk at the spinal joints

R

Intermediate Muscles of Back

Deep Muscles of Back

Pectoralis Major• P: Medial clavicle, sternum,

and the costal cartilages of ribs 1-7

• D: Lateral lip of the bicipital groove of the humerus

1. Adducts the arm at the shoulder joint

2. Medially rotates the arm at the shoulder joint

3. Flexes the arm at the shoulder joint (clavicular head)

Pectoralis Minor

P: Ribs 3-5D: Coracoid process of the

scapula

1. Protracts (abducts) the scapula at the scapulocostal joint

2. Depresses the scapula at the scapulocostal joint

3. Elevates ribs 3-5 at the sternocostal and costospinal joints

Diaphragm

• Increases the volume of the Thoracic Cavity (inspiration)

RectusAbdominis

P: Pubis D: Xiphoid process and

the cartilage of ribs 5-7

1. Flexes the trunk at the spinal joints

2. Posteriorly tilts the pelvis at the lumbosacral joint

External ObliqueP: Anterior iliac crest, pubic bone,

and the abdominal aponeurosisD: Lower 8 ribs (5-12)

1. Flexes the trunk at the spinal joints

2. Laterally flexes the trunk at the spinal joints

3. Contralateral rotates the trunk at the spinal joints

4. Posteriorly tilts the pelvis at the lumbosacral joints

Internal ObliqueO: Inquinal ligament, iliac crest,

and the thoracolumbar fasciaI: Lower three ribs (10-12) and

the abdominal aponeurosis

1. Flexes the trunk at the spinal joints

2. Laterally flexes the trunk at the spinal joints

3. Ipsilaterally rotates the trunk at the spinal joints

4. Posteriorly tilts the pelvis at the lumbosacral joints

Transverse Abdominis

• Compresses the abdominal contents

Have client seated with hands at their sidesPlace palpating hand on the client’s posterior

axillary foldAsk the client to push down on the table with

both hands, attempting to elevate the pelvis and trunk off the table. Feel for the contraction of the latissimus dorsi

Continue palpating the muscle toward its humeral attachment. It can be difficult to distinguish the tendon of the latissimus dorsi from the tendon of the teres major because they often blend together.

Have client seated with hand placed in the small of the back

Place palpating hand between the scapula at a level that is between the inferior angle and the root of the spine of the scapula and the spine

Ask the client to lift the hand away from the back and feel for the contraction of the rhomboids

Have client supine with the arm flexed to 90 degrees at the shoulder joint (hand pointed toward ceiling)

Locate the lateral border of the pectoralis major (anterior axillary fold) and then locate thelateral border of the latissimus dorsi (posterior axillary fold)

Place palpating hand between these two borders in the armpit and feel for the ribs and the serratus anterior

Now ask the client to protract the scapula by actively pushing the hand toward the ceiling and feel for contraction

Once found try to follow the muscle as far anterior as possible and as far posterior as possible

Have client pronePlace palpating hands lateral to the SPs of the

vertebral column in the lumbar region and feel for the vertical orientation of the fibers of the muscle

Continue palpating inferiorly and superiorlyAsk the client to actively extend the upper

part of the body off the table and feel for contraction of the erector spinae group

To palpate the erector spinae of the neck it is easier to have the client supine

Have the client supine with the forearm in the small of the back to relax the scapula

Place palpating hands in the posteromedial neck and feel for the semispinalis capitis

Continue palpating the muscle superiorly toward the occipital attachment between the superior and inferior nuchal lines

Have the client pronePlace palpating hands on either side of the

midline of the sacrumAsk the client to actively extend the upper

part of the body off the table and feel for the contraction of the multifidus

Continue palpating the muscle on either side of the midline in the sacral and lumbar regions

The rotatores are very small and extremely deep and are virtually impossible to palpate

Have the client pronePlace palpating hand superior to the iliac

crest and just lateral to the erector spinae. To locate lateral border have erectors ask client to raise the head off the table.

Ask the client to elevate the pelvis on the side you are palpating and feel for contraction of the quadratus lumborum

Continue palpating the muscle deep to the erectors, medially toward the lumbarTPs, superiomedially toward the 12th rib, and inferiomedially toward the iliac crest

Have client seatedHave client raise arm to 90 degrees of

abduction at the shoulder jointPlace palpating hand on the belly of the muscleAsk the client to actively horizontally flex the

arm at the shoulder joint against resistance and feel for the contraction of the pectoralis major

Continue palpating the muscle medially and superiorly toward its attachment s on the trunk and distally toward its humeral attachment

Have client seated with the forearm relaxed in the small of the back

Place palpating fingers just inferior to the coracoid process of the scapula

Ask the client to lift the hand away from the back and feel for contraction of the pectoralis minor

Have the client supine with a pillow under the knees

Place palpating hands between the xiphoid process of the sternum and the adjacent ribs superiorly and the pubis inferiorly

Ask the client to alternate between mild flexion of the trunk and relaxation so that you can feel for the contraction of the muscle

Palpate the rectus abdominis superiorly toward its ribcage attachment and inferiorly toward its pelvic attachment

Have client supine with a pillow placed under the knees

Place palpating hands on the anterolateral abdomen between the iliac crest and the lower ribs

Ask the client to rotate the trunk at the spinal joints actively to the opposite side along with slight flexion of the trunk and feel for contraction of the external oblique

Continue palpating superolaterally toward the rib attachments and inferomedially toward the iliac crest

Have the client supine with a pillow under the knees

Place palpating hands on the anterolateral abdomen between the iliac crest and the lower ribs

Ask the client to actively rotate the trunk at the spinal joints to the same side along with slight flexion of the trunk and feel for the contraction of the internal abdominal oblique

Distinguishing the contraction of the internal abdominal oblique from the external abdominal oblique will be difficult