A6 Forelimb 2

Question 1

Identify extrinsic muscles of the forelimb

Answer 1

Cranial group:
- trapezius m.
- omotransversarius m.
- brachiocephalicus m.

Caudal group:
- latissimus dorsi m.

Dorsal group:
- rhomboideus m.

Ventral group:
- superficial pectoral m.
- deep pectoral m.

Medial group:
- serratus ventralis m.

Question 2

Identify the intrinsic muscles of the shoulder

Answer 2

Extensors:
- supraspinatus m.
- infraspinatus m.
- subscapularis m.
- coracobrachialis m.
- biceps brachii m.

Flexors:
- deltoideus m.
- teres major m.
- teres minor m.

Question 3

Describe the actions of the extrinsic muscles of the forelimb

Answer 3

Cranial group: raise/advance limb
- trapezius m.
- omotransversarius m.
- brachiocephalicus m.

Caudal group: retracts limb
- latissimus dorsi m.

Dorsal group: raise/adduct limb
- rhomboideus m.

Ventral group: adduct limb
- superficial pectoral m.
- deep pectoral m.

Medial group: retraction & protraction of limb
- serratus ventralis m.

Question 4

State the innervation of the extrinsic muscles

Answer 4

Cranial group: accessory nerve (CN XI)
- trapezius m.
- omotransversarius m.
- brachiocephalicus m.

Caudal group: thoracodorsal nerve
- latissimus dorsi m.

Dorsal group: brachio plexus nn.
- rhomboideus m.

Ventral group: pectoral nn.
- superficial pectoral m.
- deep pectoral m.

Medial group: long thoracic n.
- serratus ventralis m.

Question 5

Describe the actions of the intrinsic muscles of the scapula

Answer 5

Extensors:
- supraspinatus m. (advance limb)
- infraspinatus m. (Iateral rotation, abduction)
- subscapularis m. (adduction)
- coracobrachialis m. (adduction)
- biceps brachii m. (flexes elbow)

Flexors:
- deltoideus m. (abduction of humerus)
- teres major m. (medial rotation of shoulder)
- teres minor m.

Question 6

State the innervation of the intrinsic muscles

Answer 6

Extensors:
- supraspinatus m. (suprascapular n.)
- infraspinatus m. (suprascapular n.)
- subscapularis m. (subscapularis n.)
- coracobrachialis m. (musculocutaneous n.)
- biceps brachii m. (musculocutaneous n.)

Flexors: axillary n.
- deltoideus m.
- teres major m.
- teres minor m.