Gross Lecture 1: Pectoral Region (8-18-14)

Question 0

Define arm

Answer 0

Part between shoulder and elbow containing the humerus and muscles within region.

Question 1

Define pectoral girdle

Answer 1

Bony ring formed by the scapula and clavicle

Question 2

Define forearm

Answer 2

Part between elbow and wrist containing the ulna, radius, and muscles within region.

Question 3

Define hand

Answer 3

Part of upper limb distal to forearm containing carpus, metacarpus, and phalanges.

Question 4

What are bony characteristics of these scapula?

Answer 4

1. Glenoid cavity (fossa)
2. Infraglenoid tubercle
3. Scapular neck
4. Scapular spine and acromion process
5. Coracoid process
6. Superior border
7. Suprascapular notch
8. Medial (vertebral) and lateral (axillary) borders
9. Superior and inferior angles
10. Supraspinous, infraspinous, and subscapular fossae

Question 5

What are bony characteristics of the proximal humerus?

Answer 5

1. Head
2. Anatomical & surgical necks
3. Greater and lesser tubercles
4. Intertubercular (bicipital) groove or sulcus - with lateral/medial lips
5. Shaft
6. Deltoid tuberocity

Question 6

What are the muscles of the pectoral and shoulder regions?

Answer 6

1. Teres major m.
2. Deltoid m.
3. Rotator cuff m.
4. Pectoralis major m.
5. Pectoralis minor m.
6. Subclavius m.
7. Serratus anterior m.

Question 7

All nerves innervating the appendicular muscles are branches of what structure and what spinal nerves form it?

Answer 7

1. The brachial plexus

2. Formed by ventral rami of spinal nerves C5, 6, 7, 8, and T1

Question 8

List the origin, insertion, nerve supply, blood supply, and actions of the Teres major m.

Answer 8

1. Origin: posterior side of scapula near inferior angle
2. Insertion: medial lip of intertuberclar groove, near Lat. dorsi insertion
3. Nerve: lower subscapular n.
4. Blood: primarily the subscapular artery
5. Actions: extension, adduction, and medial rotation of humerus (same as Latissimus dorsi m)

Question 9

List the origin, insertion, nerve supply, blood supply, and actions of the Deltoid m.

Answer 9

1. Origin: lateral 1/3 of clavicle, acromion, and spine of scapula (same as trapezius insertion)
2. Insertion: deltoid tuberocity of humerus
3. Nerve: axillary n. (supplies skin over deltoid, courses with posterior circumflex artery)
4. Blood: posterior circumflex humeral artery
5. Actions: flexion/extension
   abduction
   medial/lateral rotation

Question 10

What boarders the quadrangular space?

Answer 10

1. Teres major m.
2. Teres minor m.
3. Long head of triceps brachii m.
4. Surgical neck of the humerus

Question 11

What is clinically significant about the surgical neck of the humerus?

Answer 11

Frequent location of proximal humerus fractures

Question 12

What structures course within the quadrangular space and what is clinically significant about their location?

Answer 12

1. The axillary nerve and posterior circumflex humeral artery
2. Vulnerable with a posterior dislocation of the humerus

Question 13

Where is the location of the synovial bursa in the shoulder and what is its purpose?

Answer 13

1. Between the greater tubercle of the humerus and the deltoid m. and the acromion
2. Its a flat sac of synovial membrane enclosing synovial fluid and functions to lubricate motion
3. May have 2 separate bursae (subdeltoid and subacromial) or one large bursa

Question 14

What muscles form the rotator cuff muscles?

Answer 14

1. Subscapularis m.
2. Supraspinatus m.
3. Infraspinatus m.
4. Teres minor m.

Question 15

List the origin, insertion, nerve supply, blood supply, and actions of the Subscapularis m.

Answer 15

1. Origin: subscapular fossa
2. Insertion: superior part of greater tubercle of humerus
3. Nerves: upper and lower subscapular nn.
4. Blood: subscapular a.
5. Actions: medially rotates humerus (only RTC m. with this action)

Question 16

List the origin, insertion, nerve supply, blood supply, and actions of the supraspinatus m.

Answer 16

1. Origin: supraspinous fossa
2. Insertion: superior part of greater tubercle of humerus
3. Nerve: suprascapular n.
4. Blood: suprascapular a.
5. Actions: abducts the humerus

Question 17

List the origin, insertion, nerve supply, blood supply, and actions of the Infraspinatus m.

Answer 17

1. Origin: infraspinous fossa
2. Insertion: posterior side of greater tubercle of the humerus
3. Nerve: suprascapular n.
4. Blood: Circumflex scapular a.
5. Actions: laterally rotates the humerus

Question 18

List the origin, insertion, nerve supply, blood supply, and actions of the Teres minor m.

Answer 18

1. Origin: posterior side of scapular near lateral border (lateral to Teres major m. origin)
2. Insertion: posterior side of greater tubercle of humerus (inferior to Infraspinatus m. origin)
3. Nerve: axillary n.
4. Blood: Circumflex scapular a.
5. Actions: laterally rotates humerus

Question 19

What are the segments of the deltoid and what are their actions?

Answer 19

1. Anterior (clavicular) part - flexes and medially rotates
2. Lateral (acromial) part - abducts
3. Posterior part (from scapular spine) - extends and laterally rotates