Posterior Axioappendicular Muscles

Question 1

Give the Origin, Insertion, Innervation, Action, and Test of:

Trapezius

Answer 1

Origin:
Medial 1/3 of superior nuchal line (occipital bone), External occipital protuberance (occipital bone), Nuchal ligament, Spinous processes of C7-T12.

Insertion:
Lateral 1/3 of clavicle, Acromion, Spine of Scapula

Innervation:
Spinal Accessory Nerve (CN XI) and C3,C4 spinal nerves (pain + proprioceptive fibres)

Action:

• Descending parts elevates the scapula
• Ascending part depresses the scapula
• Middle part (or all parts together) retract the scapula
• Ascending + descending parts work together to angle Glenoid cavity superiorly.

Test:
Ask patient to shrug against resistance of examiner - if normal, superior border of muscle can be easily seen and palpated.

Question 2

Give the Origin, Insertion, Innervation, Action, and Test of:

Latissimus Dorsi

Answer 2

Origin:
Inferior 6 thoracic vertebrae, Thoracolumbar fascia, Iliac crests, Inferior 3-4 ribs.

Insertion:
Floor of Intertubercular groove of humerus

Innervation:
Thoracodorsal Nerve (C6,7,8)

Action:
Extends, Adducts, and medially rotates humerus. Also pulls body towards arm in climbing.

Test:
Ask patient to abduct arm to 90 degrees and then adduct against examiner resistance. If acting normally, anterior aspect of muscle can be seen and palpated in posterior axillary fold (posterior of armpit)

Question 3

Give the Origin, Insertion, Innervation, Action, and Test of:

Levator Scapulae

Answer 3

Origin:
Posterior tubercles of transverse processes of C1-C4.

Insertion:
Medial border of scapula (superior to root of spine of scapula)

Innervation:
Dorsal Scapular Nerve (C5) and C3,4 nerves.

Action:

• Elevates scapula (with trapezius)
• Tilts Glenoid cavity inferiorly by rotating scapula (with rhomboids + pec. Minor)
• Extend neck + may help with lateral flexion of the neck.

Test:
None Listed.

Question 4

Give the Origin, Insertion, Innervation, Action, and Test of:

Rhomboid Major

Answer 4

Origin:
Spinous processes of T2-T5

Insertion:
Medial border of scapula (from scapular spine to inferior angle)

Innervation:
Dorsal scapular nerve (C5)

Action:

• Retract scapula
• Rotate scapula to depress Glenoid cavity (with levator scapulae)
• Assist Serratus anterior to hold scapula against thoracic wall

Test:
Ask patient to place hands posteriorly on hips and then to push elbows posteriorly against examiner resistance. If acting normally, rhomboid major can be palpated on medial border of scapula. Hard to see as it is deep to trapezius.

Question 5

Give the Origin, Insertion, Innervation, Action, and Test of:

Rhomboid Minor

Answer 5

Origin:
Nuchal ligament and spinous process of C7 + T1.

Insertion:
Smooth triangular area at medial end of scapula spine.

Innervation:
Dorsal scapular nerve (C5)

Action:

• Retract scapula
• Rotate scapula to depress Glenoid cavity
• Assist Serratus anterior to hold scapula against thoracic wall

Test:
Ask individual to place hands posteriorly on hips and to push elbows posteriorly against examiner resistance. If acting normally, can be palpated on medial border of scapula. Unlikely to see due to it being deep to trapezius.

Question 6

Name the posterior axioappendicular muscles

Answer 6

Trapezius
Latissimus Dorsi
Levator Scapulae
Rhomboid Major
Rhomboid Minor