Muscles Week 6 Lab

Question 1

Digastric

Answer 1

Action: Open mouth and depress mandible
Origin: lower margin of mandible (anterior belly)
Insertion: by a connective tissue loop to hyoid bone
Nerve Supply: mandibular branch of trigeminal nerve (cranial V)

Question 2

Masseter

Answer 2

Action: closes jaw
Origin: zygomatic arch
Insertion: ramus of mandible
Nerve supply: mandibular branch of trigeminal nerve (cranial V)

Question 3

pectoralis major

Answer 3

Action: adducts arm
Origin: sternum
Insertion: fibers converge to insert by a short tendon into greater tubercle of humerus
Nerve supply: lateral and medial pectoral nerves (C5-C8, and T1)

Question 4

Pectoralis minor

Answer 4

Action: with ribs fixed, protracts and rotates scapula downward
Origin: anterior surfaces of ribs 3-5
Insertion: coracoid process of scapula
Nerve Supply: medial and lateral pectoral nerves (C6-C8)

Question 5

Rectus abdominus

Answer 5

Action: flex and rotate lumbar region of vertebral column
Origin: pubic crest
Insertion: xiphoid process
Nerve Supply: intercostal nerves (T6 or T7-T12)

Question 6

external oblique

Answer 6

Action: flex vertebral column
Origin: by fleshy strips from outer surfaces of lower eight ribs
Insertion: into linea alba via a broad aponeurosis
Nerve Supply: intercostal nerves (T7-T12)

Question 7

internal oblique

Answer 7

Action: flex vertebral column
Origin: iliac crest
Insertion: linea alba
Nerve Supply: Intercostal nerves (T7-T12)

Question 8

Transverse Abdominus

Answer 8

Action: compress abdominal contents
Origin: inguinal ligament
Insertion: linea alba
Nerve Supply: intercostal nerves (T7-T12)