Week 8 - scap humeral muscles

Question 1

DELTOID

Answer 1

Attachments:

P: 3 heads
1. lateral 1/3 clavicle (anterior),
2. acromion (middle),
3. scapula spine (posterior)
D: deltoid tuberosity of humerus

Action: ABD (strong), FL, EXT GHJ

Function: resist downward weight of arm. Lifting shopping bags.
NS: Axillary n.

Question 2

Which muscles work together on the arm to resist downward dislocation?

Answer 2

Deltoids, bicep brachii, coracobrachialis, triceps brachii, supraspinatus

Question 3

The rotator cuff dynamic stabilisers (4) and function

Answer 3

SITS
Subscapularis (LT)
Infraspinatus (GT)
Teres minor (GT)
Supraspinatus (GT)

STABILISE THE HUMERAL HEAD
IN THE GLENOID FOSSA

BALANCE DELTOID FORCES

Question 4

SUPRASPINATUS

Answer 4

Attachments:

P: supraspinous fossa
D: greater tubercle of humerus (superior)

Action: initiates & assists ABD in GHJ

Function: stabilise head of humerus in glenoid
fossa

NS: Suprascapular n.

Question 5

INFRASPINATUS

Answer 5

Attachments:

P: infraspinous fossa
D: greater tubercle of humerus (middle)

Action: external rotation of GHJ

Function: stabilise head of humerus in
glenoid fossa

NS: Suprascapular n.

Question 6

TERES MINOR

Answer 6

Attachments:

P: middle part lateral border scapula
D: greater tubercle of humerus (inferior)

Action: external rotation of GHJ

Function: stabilise head of humerus in
glenoid fossa

NS: Axillary n.

Question 7

SUBSCAPULARIS

Answer 7

Attachments:

P: subscapular fossa
D: lesser tubercle of humerus

Action: medial rotation of GHJ

Function: stabilise head of humerus
in glenoid fossa

NS: upper and lower subscapular n.

Question 8

TERES MAJOR

Answer 8

Attachments:

P: posterior surface of inferior angle of scapula
D: medial lip intertubercular sulcus of humerus

Action: ADD & medial rotation of GHJ

NS: Lower subscapular n. (C5-6)