Brachiocephalicus

MUSCLES OF PECTORAL GIRDLE - BRACHIOCEPHALICUS
  • This muscle extends from the head, along the neck to the arm. Its upper border is in close apposition with the trapezius and the lower border forms the upper boundary of the jugular furrow. It consists of a dorsal part (cleido-occipitalis) and a ventral part (cleido-mastoideus), the division being indicated by the position of exit of cutaneous branches of the ventral divisions of the cervical spinal nerves.
  • Origin: Dorsal part - occipital bone, ligamentum nuchae. Ventral part - mastoid process, wing of atlas and the mandible.
  • Insertion: The united portion of the two divisions is inserted along with the anterior superficial pectoral to the anterior edge of the humerus.
  • Action: When the head and neck are fixed, to draw the limb forwards and extend the shoulder joint; when the limb is fixed, the two side muscles together extend the head and neck. Each side muscle acting by itself to incline the head and neck to its own side.
    • Note: The deep face of the muscle receives at the lower part of the neck a small bright red fasciculus of muscle, which arises from the cartilage of the first rib. This is the vestige of man.
  • Blood supply: Inferior cervical, carotid and vertebral arteries.
  • Nerve supply: Cervical spinal and axillary nerves.
Last modified: Thursday, 13 October 2011, 10:07 AM