Muscles of the body

Question 1

How can the pectoral girdle muscles be divided ?

Answer 1

Anterior thoracic muscles (subclavius, serratus anterior, pec minor) and posterior thoracic muscles (trapezius, rhomboids, leveator scapula)

Question 2

What is the origin, insertion, action, and innervation of the subclavius muscle?

Answer 2

Origin - rib 1
insertion - subclavius groove of inferior clavicle
action - depresses and stabilizes clavicle
innervation - nerve to subclavius

Question 3

what is the origin, insertion, action, and innervation of serratus anterior “boxers muscle”

Answer 3

Origin - ribs 1-9
inserts- medial border and inferior angle of scapula
action - protracts the scapula and rotates it upward
innervation - long thoracic nerve

Question 4

what is the origin, insertion, action, and innervation of pectoralis minor

Answer 4

originates - ribs 3,4,5
inserts - coracoid process of the scapula
action - protraction + downward rotation of scapula
innervation - medial pectoral nerve

Question 5

What is the origin, insertion, action, and innervation of the trapezius muscle

Answer 5

origin - occipital bone, ligamentum nuche, c7-t12
insertion - acromion process, spine of scapula, and clavicle
action - retract and upward rotation of scapula
innervation - accessory nerve

Question 6

origin, insertion, action, and innervation of leveator scapule

Answer 6

origin - transverse process of c1-c4
insertion - superior border
action - elevates scapula and downward rotation
insertion - dorsal scapular nerve

Question 7

origin, insertion, action, and innervation of the rhomboids ?

Answer 7

Rhom minor comes off c7-t1 and major comes off t2-t5
Both insert onto the medial border of scapula, minor is superior to spine
Both act as a retractor / adduction, elevation, and downward rotation
innervated by the dorsal scapular nerve

Question 8

Which pectoral girdle muscle(s) is NOT involved in downward rotation of the scapula?
A)Pectoralis minor
B) Leveator scapula
C) Rhomboids
D)Trapezius
E)Serratus Anterior

Answer 8

D and E

Question 9

How can the muscles that move the shoulder be divided?

Answer 9

Axial and scapular?
Axial = Pectoralis major, lattismus dorsi
Scapular = rotator cuff (4) + teres major, coracobrachialis, and deltoid

Question 10

What is the origin, insertion, action, and innervation of the Pectoralis Major?

Answer 10

Origin = clavicle, sternum, and costal cartilages 2-6
Insertion= greater tubercle of humerus
Action= adduction and medial rotation
Innervation= medial and lateral pectoral nerve

Question 11

Origin, insertion, action, and innervation of Lattismus dorsi

Answer 11

Origin = T7-L5 spinous process, ribs, iliac and sacral crests
insertion= intertubercular sulcus of humerus
action= extends, adducts, medial rotation
innervation= thoracodorsal nerve

Question 12

Name the four rotator cuff muscles, and their O,I,A,S

Answer 12

• ALL act as stabilizers
  Supraspinatus = supraspinous fossa to greater tubercle, abduction, suprascapular N
  Infraspinatus= infraspinous fossa to greater tubercle, lateral rotation, suprascapular N
  subscapularis= subscap fossa to lesser tubercle, medial rotation, up down subscap N
  Teres minor= lateral border of scapula to greater tubercle, extension + lateral rotation, Axillar nerve innervation

Question 13

Which rotator cuff muscle is most susceptible to impingement syndrome

Answer 13

Supraspinatus due to it running under the acromion process, to and from head of humerus and supraspinous fossa

Question 14

Which two muscles involve the SAC and what do they have in common

Answer 14

SAC= Spine of scapula, acromion process, and clavicle
Trapezius attaches here and deltoid originates here
Both innervated by the axillar nerve

Question 15

What is the action of the deltoid muscle?

Answer 15

Flexion, abduction, and extension, medial and lateral rotation

Question 16

Origin, insertion, action, and innervation of the teres major muscle

Answer 16

origin= inferior angle of scapula
insertion=intertubercular sulcus
action=extension, adduction, medial rotation
innervation= lower subscapular nerve

Question 17

Origin, insertion, action, and innervation of the coracobrachialis

Answer 17

origin= coracoid process
insertion= shaft of humerus
action= flexion of shoulder, adduction
Innervation = musculocutaneous nerve

Question 18

What are the three forearm flexor muscles?

Answer 18

Biceps brachii, brachioradialis, brachialis

Question 19

Where do the two heads of the biceps brachii originate?

Answer 19

Long head = supraglenoid tubercle

Short head = coracoid process of scapula

Question 20

Where does the biceps brachii insert? Action here? Innervation?

Answer 20

Inserts onto the radial tuberosity and bicipital aponeurosis
Actions as a forearm flexor, supinator, shoulder flexor
innervated by the musculocutaneous nerve

Question 21

What is the origin, insertion, action, and innervation of the brachialis

Answer 21

Originates = distal shaft of humerus
Inserts = ulnar tuberosity and coronoid process
Acts = forearm flexor
Innervated by musculocutaneous and radial nerve

Question 22

What is the origin, insertion, action, and innervation of the Triceps Brachii?

Answer 22

Long head originates off infraglenoid tubercle, lateral head off posterior lateral shaft of humerus, medial head off entire posterior shaft of humerus
All insert onto the olecranon of ulna
Extends forearm and shoulder
Innervated by the radial nerve

Question 23

What is the origin, insertion, innervation, and action of the anconeus?

Answer 23

Originates off of lateral epicondyle of humerus
Inserts onto olecranon and superior shaft
Extends forearm
Innervated by radial nerve