Starting from the upper nuchal line with aponeurosis, the external occipital protuberance, nuchal ligament, spinous process of the seventh cervical vertebra and all thoracic spinous processes

Lateral 1\3 of clavicle, acromion and scapular spine

Pull the scapula closer to the spine, the upper muscle bundle lifts the scapula, and the lower muscle bundle lowers the scapula

Contract one side of the muscle and bend the neck to the same side, turning the face to the opposite side. Contract both sides at the same time to tilt the head back.

It starts from the aponeurosis of the lower 6 thoracic spinous processes, all lumbar spinous processes, the median sacral crest and the posterior part of the iliac crest, etc.

lesser tuberosity ridge of humerus

During contraction, the shoulder joint extends, adducts, and internally rotates

When the upper limbs are fixed, pull-ups can be performed

Muscle contraction on one side causes the spine to flex to the same side, and both sides simultaneously extend the spine and raise the head.

The inner 2\3 segments of the clavicle, the front of the sternum and the front of the 1st to 6th costal cartilage

Inserting on the greater tubercle crest of the humerus with the flat tendon

During contraction, the shoulder joint adducts and rotates internally, and the clavicle muscles make the shoulder joint forward.

The upper limbs are fixed, the body is pulled upward, and the ribs can be lifted to help inhale.

It starts from the outside of the 8th to 9th rib with muscle teeth.

medial border and inferior angle of scapula

When contracting, the scapula is pulled forward and close to the chest, and the lower muscle bundles externally rotate the lower angle of the scapula to help abduct the arm and raise it high.

When the scapula is fixed, lift the ribs to help with deep inhalation

The lower edge of the aponeurosis is curled and thickened, and is connected between the anterior superior iliac spine and the pubic junction.

The external oblique aponeurosis forms a triangular hole just outside and above the pubic junction.

involuntary muscles

The subclavian artery and brachial plexus pass through the space between the anterior middle scalene muscle and the first intercostal space.

muscle fiber

myofibrillar bundles