Module 2.1 - Thorax and Upper Limb

Question 1

Diaphragm

Answer 1

Origin: Xiphoid Process, lower six costal cartilages, L1-L3 vertebrae
Insertion: Converge into CENTRAL TENDON
Innervation: Phrenic Nerve
Action: Draws central tendon down and forward during inspiration
Muscle group: Posterior Abdominal Wall

Question 2

External Intercostal

Answer 2

Origin: Lower Border of Ribs
Insertion: Upper border of rib below rib of origin
Innervation: Intercostal Nerves
Action: Supports inspiration and expiration, elevates ribs in inspiration
Muscle group: Thoracic Wall

Question 3

Innermost Intercostal

Answer 3

Origin: Lower border of ribs 
Insertion: upper border of rib below rib of origin 
Innervation: intercostal nerves
Action: Elevates ribs 
Muscle group: Thoracic Wall

Question 4

Internal Intercostal

Answer 4

Origin: Lower border of ribs
Insertion: Costal cartilage and edge of costal groove of rib above rib of origin
Innervation: Intercostal nerves
Action: Prevents pushing out or drawing in of intercostal spaces in inspiration and expiration, lower ribs in forced expiration
Muscle group: Thoracic wall

Question 5

Levator costarum

Answer 5

Origin: Transverse processes of C7 and T1-T11
Insertion: Subjacent ribs between tubercle and angle
Innervation: Dorsal ramus of lower thoracic nerves
Action: Elevates ribs
Muscle Group: Thoracic Wall

Question 6

Pectoralis major

Answer 6

Origin: Sternal half of clavicle, sternum to 7th rib, cartilages of true ribs, aponeurosis of external oblique muscle
Insertion: Lateral lip of intertubercular sulcus of humerus
Innervation: Medial and lateral pectoral nerves
Action: Flexes and adducts arm, rotates arm medially
Muscle group: Pectoral/axilla region

Question 7

Pectoralis minor

Answer 7

Origin: Outer surface of upper margin of ribs 3-5
Insertion: Coracoid process of scapula
Innervation: Medial pectoral nerve
Action: Lowers lateral angle of scapula and protracts scapula
Muscle group: Pectoral/axilla group

Question 8

Serratus anterior

Answer 8

Origin: Lateral surfaces of 8-9 ribs
Insertion: Costal surface of medial border of scapula
Innervation: Long thoracic nerve
Actions: Protracts scapula and holds it against thoracic wall
Muscle group: Pectoral/axilla group

Question 9

Serratus posterior inferior

Answer 9

Origin: Spinous processes of T11-L2 
Insertion: Inferior aspect of ribs 9-12 
Innervation: Ventral rami of lower thoracic nerves 
Action: Depresses ribs 
Muscle group: Superficial Back

Question 10

Serratus posterior superior

Answer 10

Origin: Ligamentum nuchae, spinous processes of C7-T3
Insertion: Superior aspect of ribs 2-4
Innervation: Ventral rami of UPPER thoracic nerves
Action: Elevates Ribs
Muscle group: Superficial Back

Question 11

Subcostal

Answer 11

Origin: Internal surface of lower ribs near their angles
Insertion: Superior borders of 2nd-3rd rib below
Innervation: Intercostal nerves
Action: Depresses ribs
Muscle group: Thoracic wall

Question 12

Transversus thoracis

Answer 12

Origin: Internal surface of costal cartilage 2-6
Insertion: Posterior surface of lower sternum
Innervation: Intercostal nerves
Action: Depresses ribs and costal cartilages
Muscle group: Thoracic wall

Question 13

Abductor digiti minimi

Answer 13

Origin: Pisiform bone and tendon flexor carpi ulnaris
Insertion: Medial side of base of proximal phalanx of little finger (5th)
Innervation: Ulnar Nerve
Action: Abducts little finger (5th)
Muscle group: Hand

Question 14

Abductor pollicis brevis

Answer 14

Origin: Flexor retinaculum, tubercles of scaphoid and trapezium
Insertion: Lateral side of base of proximal phalanx of thumb
Innervation: Median Nerve (recurrent branch)
Actions: Abducts thumb
Main group: Hand

Question 15

Abductor pollicis longus

Answer 15

Origin: Posterior surface of ulna, radius, and interosseous membrane
Insertion: Base of 1st metacarpal
Innervation: Radial Nerve (posterior interosseous)
Action: Abducts and extends thumb at carpometacarpal joint
Muscle group: Posterior forearm

Question 16

Adductor Pollicis

Answer 16

Origin: (Oblique head) Bases of 2nd and 3rd metacarpals and capitate and adjacent bones ; (Transverse Head) Anterior surface of 3rd metacarpal
Insertion: Medial side of base of proximal phalanx of thumb
Innervation: Ulnar nerve(deep branch)
Action: Adducts thumb
Muscle group: Hand

Question 17

Anconeus

Answer 17

Origin: Posterior surface of lateral epicondyle of humerus
Insertion: Lateral surface of olecranon and posterior proximal ulna
Innervation: Radial Nerve (c5-t1)
Action: Assists triceps in extending elbow, abducts ulna in pronation
Muscle group: arm

Question 18

Biceps brachii

Answer 18

Origin: (Long head) Supraglenoid tubercle of scapula (Short head) Tip of coracoid process of scapula
Insertion: Radial tuberosity, fascia of forearm via bicipital aponeurosis
Innervation: Musculucutaneous nerve
Action: Flexes and supinates forearm at elbow
Muscle group: Arm

Question 19

Brachialis

Answer 19

Origin: Distal half of anterior surface of humerus
Insertion: Coronoid process and tuberosity of ulna
Innervation: Musculocutaneous nerve and radial nerve (C7)
Action: Flexes forearm at elbow
Muscle group: Arm

Question 20

Brachioradialis

Answer 20

Origin: Proximal 2/3 of lateral supracondylar ridge of humerus
Insertion: Lateral side of distal end of radius
Innervation: Radial Nerve
Action: Weak flexion of forearm when forearm is midpronated
Muscle group: Posterior Forearm

Question 21

Coracobrachialis

Answer 21

Origin: Tip of coracoid process of scapula
Insertion: Middle third of medial surface of humerus
Innervation: Musculucutaneous Nerve
Action: Flexes and adducts arm at shoulder
Muscle group: Arm

Question 22

Deltoid

Answer 22

Origin: Lateral third of anterior clavicle, lateral acromion, inferior edge of spine of scapula
Insertion: Deltoid tuberosity of humerus
Innervation: Axillary Nerve
Action: (Clavicular) Flexes and medially rotates arm ; (Acromial) Abducts arm beyond 15 degrees by supraspinatus ; (Spinal) Extends and laterally rotates arm
Muscle group: Shoulder

Question 23

Extensor carpi radialis brevis

Answer 23

Origin: Lateral Epicondyle of humerus
Insertion: Dorsal base of 3rd metacarpal and slip to 2nd metacarpal
Innervation: Radial Nerve (deep)
Action: Extends and abducts hand and wrist
Muscular group: Posterior forearm

Question 24

Extensor carpi radialis longus

Answer 24

Origin: Distal third of lateral supracondylar ridge of humerus
Insertion: Dorsal base of 2nd metacarpal and slip to 3rd metacarpal
Innervation: Radial Nerve
Action: Extends and abducts hand and wrist
Muscular group: posterior forearm

Question 25

Extensor carpi ulnaris

Answer 25

Origin: Lateral epicondyle of humerus and posterior border of ulna
Insertion: Dorsal base of 5th metacarpal
Innervation: Radial Nerve (posterior interosseous)
Action: extends and adducts hand and wrist
Muscle group: posterior forearm

Question 26

Extensor digiti minimi

Answer 26

Origin: Lateral epicondyle of humerus
Insertion: Extensor expansion of 5th digit
Innervation: Radial nerve (posterior interosseous)
Action: extends 5th digit
Muscle group: posterior forearm

Question 27

Extensor digitorum

Answer 27

Origin: Lateral epicondyle of the humerus
Insertion: extensor expansions of medial four digits
Innervation: radial nerve
Action: Extends medial four digits and assist in wrist extension
Muscle group: posterior forearm

Question 28

Extensor indicis

Answer 28

Origin: Posterior surface of ulna and interosseous membrane
Insertion: Extensor expansion of 2nd digit
Innervation: radial nerve
Action: extends 2nd digit and helps extend hand
and wrist
Muscle group: posterior forearm

Question 29

Extensor pollicis brevis

Answer 29

Origin: Posterior surface of radius and interosseous membrane
Insertion: Dorsal base of proximal phalanx of the thumb
Innervation: radial nerve
Action: extends proximal phalanx of thumb at carpometacarpal joint
Muscle group: posterior forearm