GA #2 SA Forelimb Musculoskeletal

Question 1

? % of the weight of the animal is transferred to the thoracic limbs when ?
and the rest ?% is carried by ? limbs

Front limb for ?
hindlimb for ? (the action of driving or pushing ?)

the weight of the ?, ? and ? transfers to the forelimb

Answer 1

60 % of the weight of the animal is transferred to the thoracic limbs when ?
and the rest 40 % is carried by pelvic/hind limbs

Front limb for support
hindlimb for propulsion (the action of driving or pushing forward)

the weight of the head, neck and trunk transfers to the forelimb

(note: in image top most line is scapula, second top most line is humerus or femur,
bottom line is radius and ulna,
recall: horses have long metacarpals)

Question 2

The forelimb is attached to trunk via ? muscles (? - the junction of two or more bones using attached muscles)

• The weight of the head, neck and trunk transfers to forelimb via the ? and ? (refer to image)
• imagine the 2 thoracic limbs as posts btw which the trunk is suspended by the 2 serratus ventralis as a “? muscles”

Answer 2

The forelimb is attached to trunk via extrinsic muscles (synsarcosis - the junction of two or more bones using attached muscles)

• The weight of the head, neck and trunk transfers to forelimb via the serratus ventralis and pectoral mm. (refer to image: cranial view of TLs and thorax)
• imagine the 2 thoracic limbs as posts btw which the trunk is suspended by the 2 serratus ventralis as a “? muscles”

Question 3

Extrinsic Muscles of the Thoracic Limb (TL)

• Originate on the head, neck, and/or ? (so this stays fixed while the insertion one moves)
• Insert on the ?
• “Movement occurs in single or both? directions (red arrows):”
  – If no body weight is placed on limb, the limb will move towards head/neck/trunk.
  – If limb is weight-bearing, then head/neck/trunk will move relative to the limb (which will stay fixed to the ground).

Answer 3

Extrinsic Muscles of the Thoracic Limb (TL)

• Originate on the head, neck, and/or trunk (so this stays fixed while the insertion one moves)
• Insert on the limb
• “Movement occurs in BOTH directions (red arrows):”
  – If no body weight is placed on limb, the limb will move ? head/neck/trunk.
  – If limb is weight-bearing, then head/neck/trunk will move relative to the limb (which will stay fixed to the ground).

Question 4

example: deep pectoral muscle (dog digging vs walking)

dog digging (refer to left pic)
- forelimb moves
- limb lifted towards trunk as “non weight bearing”

muscle propels trunk forward
- limb fixed = “weight bearing” (note triangle in second picture is a lil tilted to the left)

Question 5

Shoulder (glenohumeral) joint

• Ball and socket joint; no ? ligaments so ? stabilization needed (Supra-, infraspinatus and subscapularis muscles).
• Range of movements:
  primary - ?/?;
  also allows some ?/?, lateral and medial ?

Answer 5

Shoulder (glenohumeral) joint

• Ball and socket joint; no collateral ligaments so muslcle stabilization needed (Supra-, infraspinatus and subscapularis muscles).
• Range of movements:
  primary - extension/flexion;
  also allows some adduction/abduction, lateral and medial rotation