Overview
The most superficial muscle of the scapular region. In cattle it has two parts, separated by an aponeurotic strip over the spine of the scapula:
- Cervical part (pars cervicalis): from the nuchal ligament to the spine of the scapula. Its fibres run caudoventrally.
- Thoracic part (pars thoracica): from the spinous processes of the cranial thoracic vertebrae to the spine of the scapula. Its fibres run cranioventrally.
Origin
Funicular part of the nuchal ligament (cervical part) and supraspinous ligament of the thoracic vertebrae (thoracic part).
Insertion
Spine of the scapula (spina scapulae).
Action
Elevates and abducts the thoracic limb. The cervical part draws the scapula craniodorsally, the thoracic part caudodorsally.
Innervation
Dorsal branch of the accessory nerve (n. accessorius, cranial nerve XI).
Clinical relevance
The cervical part lies at the dorsal edge of the lateral neck region used for injections in cattle. Beef quality guidelines recommend injecting in this area of the neck, in front of the scapula and below the nuchal ligament, and not in the hindquarter.