A10 - Art. humeri, and its muscles

Question 1

Shoulder joint (art. humeri)

Answer 1

• Synovial
• ​Spheoid joint (multiaxial) (but functions as a hinge joint)
• Arti. simplex
• ​Movement:
  
  • Eq, ru: only flexion - extension
  • Ca: also rotation, abduction - adduction
• With cavum glenoidale → caput humeri
• One joint capsule with: (interspecies riktig??)
  
  • Eq, ru: 3 cranial and 2 caudal pouches
  • Ca: 2 cranial and 1 caudolateral pouches
• Labrum glenoidale
  
  • ​Ligg. glenohumeralia (eq, ca)
    
    • Thickened part of the capsule in:
      
      • Ca: medial and lateral walls
      • Eq: medial, lateral and cranial walls
  • Lig. coracohumerale (eq, ru)
    
    • Capsular ligament between scapula → humerus
• No collateral ligament, instead:
  
  • M. infraspinatus (lateral)
  • M. subscapularis (medial)
• Ca: part of the joint capsule surrounds tendon of m. biceps brachii and forms vagina synovialis intertubercularis
• Eq, bo: bursa bicipitalis under tendon of m. biceps brachii

Question 2

Shoulder joint (art. humeri)

List the flexors and extensors of the shoulder joint

Answer 2

Flexors of the shoulder (ca):

1. ​M. deltoideus
   
   1. ​Pars acromialis (ca, ru)
   2. Pars scapularis (ca, ru)
2. M. infraspinatus
3. M. teres minor
4. M. teres major
5. M. triseps brachii, caput longum
6. M. subscapularis

Extensors of the shoulder (ca)

1. M. supraspinatus
2. M. biceps brachii
3. M. coracobrachialis
4. M. subscapularis

Other muscles:

• Lateral head of m. triceps brachii – Flexion
• M. latissimus dorsi - Flexion
• M. articularis humeri (eq)

Question 3

Give the shoulder muscles

Answer 3

Lateral shoulder muscles:

• M. supraspinatus
• M. infraspinatus
• M. deltoidea
  
  • ​Pars acromialis (ca, ru)
  • Pars scapularis (ca, ru)
• M. teres minor

Medial shoulder muscles:

• M. subscapularis
• M. teres minor
• M. coracobrachialis
• M. articularis humeri (eq)

Question 4

M. supraspinatus

Answer 4

• Origin: Fossa supraspinatus and the cranial border of the scapula
• Insertion: T**uerculum major of the humerus
• Action:
  
  • Extend shoulder joint
  • Stabilize shoulder joint
• Innervation: N. suprascapularis

Question 5

M. infraspinatus

Answer 5

• Origin:
  
  • Fossa infraspinatus
  • Spina scapula
  • Margo caudalis scapulae
• Insertion: Facies m. infraspinati of humerus
• Action:
  
  • Flexes shoulder joint
  • Acts as a lateral collateral ligament for shoulder joint
  • Ca: Assists in supination and abduction of the humerus
• Innervation: N. suprascapularis

Question 6

M. deltoideus

Answer 6

• In ca and ru it can be divided into:
  
  1. Pars acromialis
  2. Pars scapularis
• Origin:
  
  • Pars scapularis: Caudal edge of spina scapulae
  • Pars acromialis: Acromium of the scapula
  • Eq, sus: Spina scapula (the two parts of the muscle are fused)
• Insertion: The tuberosita deltoidea of humerus
• Action: Flex shoulder joint
• Innervation: N. axillaris

Question 7

M. teres minor

Answer 7

• Origin:
  
  • Tuberculum infraglenoidale
  • Distal part of margo caudalis scapulae
• Insertion: Tuberositas teres minor of the humerus (laterally)
• Action: Flexes shoulder joint
• Innervation: N. axillaris

Question 8

M. subscapularis

Answer 8

• Origin: F**ossa subscapularis
• Insertion: Tuberculum minus of humerus
• Action:
  
  • Extend shoulder joint (and helps with flexion)
  • Act as a collateral ligament
  • Adduct
  • Stabilize the shoulder joint
• Innervation: N. axillaris

Question 9

M. teres major

Answer 9

• Origin:
  
  • Margo caudalis scapulae
  • Angulus caudalis scapulae
• Insertion: Tuberositas teres major of the humerus (same as m. latissimus dorsi)
• Action:
  
  • ​Flex the shoulder joint
  • Rotates the limb inwards (medially)
• Innervation: N. axillaris

Question 10

M. coracobrachialis

Answer 10

• Origin: Processus coracoideus of the scapula
• Insertion: Crista tuberculi minor of humerus
• Action:
  
  • Extend shoulder joint
  • Adduct

Question 11

M. articularis humeri

Answer 11

Eq, and sometimes Sus

• Action: To tense the joint capsule

Question 12

M. triceps brachii, caput longum

Answer 12

• Origin: M**argo caudalis scapulae, distal 2/3
• Insertion:Tuber olecrani of the ulna
• Action:
  
  • Flexes shoulder joint
    Extends elbow joint
• Innervation: N. radialis

Question 13

M. biceps brachii

Answer 13

• Origin: Tuberculum supraglenoidale
  
  • ​A retinaculum transversum fixes its tendon in the intertubercular groove (between tuberculum majus and minus)
• Insertion: (same as m. brachialis)
  
  • Tuberositas radii
  • Tuberositas ulnae (proc. coronoideus medialis)
• Action:
  
  • Extends the shoulder
  • Flexes the elbow joint
• Innervation: N. musculocutaneous

Question 14

M. latissimus dorsi

Answer 14

• Origin:
  
  • Superficial layer of thoracolumbar fascia
  • From spinous process of last 7-8 thoracic and lumbar vertebrae
  • Proximally to the last few ribs
• Insertion: Tuberositas m. teres major (together with m. Teres major)
• Action:
  
  • Draws free limb caudally
  • With teres major: Flexes shoulder
• Innervation: N. thoracodorsalis