UE Axio-appendicular Muscles

Question 1

Trapezius

Answer 1

Extrinsic Superficial Back Muscle

Proximal attachment: Superior nuchal line, external occipital protuberance, ligamentum nuchae (on back of head)

Distal attachment: lateral 1/3 of the clavicle, acromion, and spine of scapula

Action: scapular elevation and depression, retraction, and upward rotation

Innervation: Accessory nerve (motor) & C3-4 (sensory)

Question 2

Latissimus dorsi

Answer 2

Extrinsic Superficial Back Muscle

Proximal attachment: Lower thoracic spinous processes, thoracolumbar fascia, iliac crest

Distal attachment: Floor of intertubercular sulcus of humerus

Actions: Extends, adducts, and medially rotates humerus

Innervation: Thoracodorsal nerve

Common Spinal Segments: C6, C7, C8

Question 3

Levator scapulae

Answer 3

Extrinsic Superficial Back Muscle

Proximal attachment: Transverse spinal processes C1-C4

Distal Attachment: Superior angle and superomedial border of the scapula

Actions: elevation and downward rotation of scapula

Innervation: Dorsal scapular nerve (sensory: direct branches of C3-C4)

Common Spinal Segments: C4-C5

Question 4

Rhomboids

Answer 4

Extrinsic Superficial Back Muscle

Proximal attachment: nuchal ligament (back of head) down from spinal processes C7-T5

Distal attachment: Medial border of scapula

Actions: scapular retraction, elevation, and downward rotation

Innervation: Dorsal scapular nerve (sensory: direct branches of C3-C4)

Common Spinal Segments: C4-C5

Question 5

Extrinsic Intermediate Back Muscle(s)

Answer 5

Superior and inferior serratus posterior

-facilitates respiration & proprioception

Question 6

Intrinsic Superficial Back Muscles

Answer 6

1. Splenius capitis (head)

2. Splenius cervicis (neck)

Question 7

Intrinsic Intermediate Back Muscles

Answer 7

Erector Spinae (3)

1. Spinalis
2. Longissimus
3. Iliocostalis

Question 8

Intrinsic Deep Back Muscles

Answer 8

Transversospinalis (3)

1. Semispinalis capitis
2. Multifidus
3. Rotatores

Question 9

Pectoralis major

Answer 9

Superficial Pectoral muscle: 2 heads

Proximal attachment: clavicle, costal cartilages, sternum, & aponeurosis of the external oblique

Distal attachment: Lateral lip of the intertubercular sulcus of the humerus

Action: Humeral adduction, flexion, and medial rotation (sternocostal portion assists with extension of the flexed arm)

Innervation: Medial & Lateral Pectoral nerves

Common Spinal Segments: clavicular head C5-C6, sternocostal head C7-T1

Question 10

Pectoralis minor

Answer 10

Deep Pectoral muscle

Proximal attachment: Coracoid process

Distal attachment: Outer surfaces of ribs 3-5

Action: anterior tilt of scapula, assists with depression of shoulder and forced inspiration

Innervation: Medial & Lateral Pectoral nerves

Common Spinal Segments: C5-T1

Question 11

Serratus anterior

Answer 11

Pectoral region muscle

Proximal attachment: Outer surfaces & superior borders of upper 8-10 ribs

Distal attachment: Medial border of the scapula

Action: Scapular protraction & upward rotation

Innervation: Long thoracic nerve

Common Spinal Segments: C5-C7

Question 12

Subclavius

Answer 12

Deep Pectoral region muscle

Proximal attachment: 1st rib & cartilage

Distal attachment: undersurface of clavicle

Action: Depresses & stabilizes clavicle

Innervation: Subclavian nerve

Common Spinal Segments: C5-6