Anatomy dissection 10

Question 1

What can the deltoid muscle be split up into and what is the function for each part ?

Answer 1

The deltoid muscle can be split up into a anterior, middle and posterior part

• Anterior - flexes the arm at the shoulder
• Middle - major abductor of the arm (takes over the subscapularis at about 15 degrees)
• Posterior - extends the arm at the shoulder

Question 2

What are the main functions of the trapezium muscle ?

Answer 2

To elevate or depress the scapula and rotates scapula during abduction

Question 3

What is the function of the levator scapulae?

Answer 3

Elevation of the scapula and inferior rotation of the glenoid fossa

Question 4

What are the rhomboids and where do they attach ?

Answer 4

There is a major and minor rhomboid - they attach to the medial border of the scapula

Question 5

What is the function of the rhomboids ?

Answer 5

Retraction of scapula and inferior rotation of glenoid fossa

Question 6

What are the rotator cuff muscles of the shoulder joint and the acronym to remember them ?

Answer 6

• Subscapularis
• Infraspinatus
• Teres minor
• Supraspinatus

SITS

Question 7

What is the function of the rotator cuff muscles ?

Answer 7

• Subscapularis - first 15 degrees of Abduction
• Rest (Supra and infraspinatus and teres minor) - all help stabalise shoulder joint and internally rotate it

Question 8

What is the function of the teres major muscle ?

Answer 8

Adduction/medial rotation of the shoulder

Question 9

In general what are the attachments of the rotator cuff muscles ?

Answer 9

Attach between the scapula proximally and the tubercles of the head of the humerus distally.

Question 10

What are specifically the distal insertions of the rotator cuff muscles ?

Answer 10

• The supra, infraspinatus and teres minor all attach distally to the greater tubercle of the humerus
• The subscapularis distally attaches to the lesser tubercle of the humerus

Question 11

What is the innervation of the supra and infraspinatus muscles ?

Answer 11

Suprascapular nerve

Question 12

What is the innervation of the Subscapularis muscle ?

Answer 12

Subscapularis nerve

Question 13

What is the innervation of the teres minor muscle ?

Answer 13

Axillary nerve

Question 14

Revise the scapula osteology

Answer 14

Question 15

What is the most common rotator cuff injury and how does it present ?

Answer 15

• Partial/complete tear of the supraspinatus tendon
• A patient with supraspinatus paralysis/tendon tear will throw their upper limb to the side to initiate abduction.