GA Scapular and Pectoral Muscles, Vasculature and Innervation

Question 1

Scapulohumeral Muscles

Answer 1

also known as intrinsic shoulder musces, 6 muscles 4 of which are rotator cuff muscles
deltoid muscle, Teres Major muscle, Serratus Anterior, Supraspinatus muscle, Infraspinatus muscle, Teres Minor muscle, Subscapularis muscle

Question 2

Deltoid Muscle

Answer 2

divided into unipennate and multipennate pares
O- later 1/3 of clavicle; acromion and spine of scapula
I - deltiod tuberosity of humerus
A - Anterior fibers-flexion and MR of humerus, Middle fibbers-ABD from 15-90 degrees, Posterior fibbers-extension and LR of humerus
N - Axillary n. (C5,C6)
B - Ant. and Post. humeral circumflex aa.; acromial and deltoid branches of thoracoacromial trunk

Question 3

Tere Major Muscle

Answer 3

O - Post. surface of inferior angle of scapula
I - Medial lip IT groove of humerus
A - ADD and MR of humerus; assists with ext. from flexed position
N - Lower subscapular n. (C5,C6)
B - Thoracodorsal a.

Question 4

Supraspinatus Muscle

Answer 4

one of the rotator cuff muscles, only one that does not rotate humerus
O - Supraspinous fossa of scapula
I - Superior facet greater tubercle of humerus
A - Initiates ABD for first 15 degrees
N - Suprascapular n. (C4,C5,C6)
B - Suprascapular a.

Question 5

Infraspinatus Muscle

Answer 5

O - Infraspinous fossa of scapula
I - Middle facet greater tubercle of humerus
A - LR of humerus
N - Suprascapular n. (C5,C6)
B - Suprascapular a.

Question 6

Teres Minor Muscle

Answer 6

often hard to separate from infraspinatus m.
O - Middle part, lateral border of scapula
I - Inferior facet greater tubercle of humerus
A - LR of humerus; assists with ADD of humerus
N - Axillary n. (C5,C6)
B - Circumflex scapular aa.

Question 7

Subscapularis Muscle

Answer 7

O - Subscapular fossa (most anterior surface of scapula)
I - Lesser tubercle of humerus
A - Most powerful MR of humerus; assists in ADD of humerus
N - Upper and lower subscapular nn. (C5,C6,C7)
B - Subscapular a.

Question 8

Suprascapular artery

Answer 8

from the thyrocervical trunk, passes superior to transverse scapular l. to supraspinous fossa, passes thru spinoglenoid notch to infraspinous fossa, participates in scapular anastomoses

Question 9

Dorsal Scapular artery

Answer 9

from the subclavian artery, passes thru the trunk of the brachial plexus, runs along the medial border of scapula, also participates in scapular anastomoses

Question 10

Thoracoacromial trunk

Answer 10

from the 2nd part of axillary artery, gives off the clavicular, acromial, deltoid and pectoral branches

Question 11

Subscapular artery

Answer 11

from the 3rd part of axillary a., descends along lateral border of subscapularis m.
terminates as thoracodorsal artery and the circumflex scapular artery

Question 12

Thoracodorsal artery

Answer 12

from the subscapular a. continues path of subscapular a.

Question 13

Circumflex artery

Answer 13

from the subscapular a., curves around lateral border of scapula, found in the triangular space and is the KEY player in scapular anastomoses

Question 14

Anterior humeral circumflex artery

Answer 14

from the 3rd part of axillary a., encircles surgical neck of humerus, anastomoses with posterior humeral circumflex a. laterally who it often shares a common trunk with

Question 15

Posterior Humeral Circumflex artery

Answer 15

from the 3r part of the axillary a., encircles the surgical neck of humerus, traverses the quadrangular space

Question 16

Suprascapular nerve

Answer 16

from the superior trunk of brachial plexus, often recieves fibers from C4, passes thru suprascapular notch inferior to transverse scapular l., runs with suprascapular a., supplies the supraspinatus and infraspinatus mm.

Question 17

Axillary nerve

Answer 17

is the terminal branch of posterior cord of brachial plexus, exits axilla posteriorly, passes thru quadrangular space with post. humeral circumflex a., superior lateral cutaneous n. supplies skin over inferior part of deltoid

Question 18

Upper subscapular nerve

Answer 18

from the posterior cord of brachial plexus, supplies superior portion of subscapularis m.

Question 19

Lower subscapular nerve

Answer 19

from the posterior cord of brachial plexus, supplies inferior portion of subscapularis m. and teres major

Question 20

Anterior Axioappendicular Muscles

Answer 20

four anterior muscles that move pectoral girdle, also known as the thoracoappendicular or pectoral arm
pectoralis major muscle, pectoralis minor muscle, subclavian muscle, serratus anterior muscle

Question 21

Pectoralis Major muscle

Answer 21

has clavicular and sternocostal heads, lateral border of muscle makes up most of anterior wall of axilla, inferior border forms anterior axillary folds
O - Clavicular head-anterior surface of medial 1/2 of clavicle, Sternal head-anterior surface of sternum, sup. 6 costal cartilages, aponeurosis of external oblique m.
I - Lat. lip of IT groove of humerus
A - ADD, MR of humerus; clav head-flexus humerus, sternal head-extends from flexed position
N - Medial and lateral pectoral nn. (Clav head- C5,C6, Sternal Head-C7,C8,T1)
B - Pectoral branches of thoracoacromial trunk

Question 22

Pectoralis Minor muscle

Answer 22

O - 3-5th ribs (sometimes 6) of costal cartilages
I - medial border of superior surface coracoid process
A - stabilizes scapula by drawing it anterior and inferior against thoracic wall; accessory m. in inspiration
N - Medial perctoral n. (C8,T1)
B - Pectoral branches from thoracoacromial trunk

Question 23

Subclavius Muscle

Answer 23

O - Junction of 1st rib and its costal cartilage
I - inferior surface, middle 1/3 of clavicle
A - anchors and depresses clavicle
N - Nerve to subclavius (C5,C6)
B - Clavicular branches of thoracoacromial trunk

Question 24

Serratus Anterior Muscle

Answer 24

O - external surface of lateral parts of 1st-8th ribs (sometimes 9th)
I - Anterior surface of medial border of scapula
A - Scapular protraction and upward rotation; fixes scapula against thoracic wall
N - Long thoracic nerve (C5,C6,C7)
B - Superior and lateral thoracic aa.

Question 25

Superior Thoracic Artery

Answer 25

from 1st part of axillary artery, supplies superior part of serratus anterior muscle

Question 26

Lateral thoracic artery

Answer 26

from 2nd part of axillary a., descends along thoracic wall with long thoracic n., supplies serratus anterior

Question 27

Thoracoacromial Trunk

Answer 27

from 2nd part of axillary a., gives off clavicular, acromial, deltoid and pectoral branches

Question 28

Cephalic Vein

Answer 28

formed on the dorsum of the hand, ascends in subcutaneous tissue, superiorly found in deltopectoral groove, enters clavipectoral triangle, drains into terminal part of axillary vein

Question 29

Nerve to subclavius

Answer 29

from superior trunk of brachial plexus, supplies the subclavius m.

Question 30

Long thoracic nerve

Answer 30

from the VPR of C5, C6, and C7

descend post. to roots of brachial plexus, run on superficial surface of serratus anterior m and supply it

Question 31

Lateral pectoral nerve

Answer 31

lateral cord of brachial plexus, on deep surface of pectoralis major m. and supply it

Question 32

Medial Pectoralis nerve

Answer 32

from medial cord of brachial plexus, pierces pectoralis minor m. and enters deep surface of pectorals major m., supplies pectorals minor m. and sternal head of pectoralis major m.