Educational resource developed at the Veterinary Anatomy Section, ICAR-Indian Veterinary Research Institute (ICAR-IVRI), Bareilly.
📝 STANDARD DESCRIPTION:
Type: Intrinsic, Scapulohumeral
Parts: Pars Scapularis (scapular spine/infraspinatus fascia) & Pars Acromialis (acromion process)
Insertion: Deltoid tuberosity on lateral humeral shaft
Function: Flexes shoulder joint and abducts arm.
📚 DETAILED DESCRIPTION:
THE LATERAL SHOULDER FLEXOR
Located lateral to the shoulder joint, this muscle flexes the shoulder and provides limited abduction.
TWO-PART ORIGIN:
• Pars Scapularis: Arises from the spine of the scapula and the aponeurosis covering the infraspinatus
• Pars Acromialis: Arises from the distinct acromion process of the scapula (which is prominent in ox unlike horse)
DELTOID TUBEROSITY: Inserts on this distinct lateral humeral prominences—key landmark for surgical approaches and palpation.
FUNCTIONAL ROLE: Acts during the swing phase to flex the shoulder (advance the limb) and provides minor abduction. Not primarily a weight-bearing stabilizer but assists in positioning the limb for landing.
// COMPARATIVE ANALYSIS
| HORSE |
Horse lacks distinct acromion; deltoid arises from clavicular intersection and scapular spine only. |
| DOG |
Has additional spinal and acromial heads. |
CLINICAL RELEVANCE
Cleobrachialis Association: Often works in conjunction with distal brachiocephalicus; both insert near deltoid tuberosity.
