Lecture “Muscles of the trunk, upper and lower extremities” MS

Muscles of the trunk

, as well as the neck muscles, are divided into two groups: native muscles and alien muscles.

The intrinsic muscles lie very deep, on the very bones of the axial skeleton, and through their contractions they move mainly the skeleton of the torso and head. During the development of the embryo, alien muscles appear on the body later and are therefore located on the surface of its own muscles. Alien muscles differ from their own muscles in that they are associated mainly with the work of the upper limbs, although under certain conditions they are capable of moving the torso and head. Intrinsic muscles are found in all areas of the body; alien muscles are located on the chest, back and neck.

Muscles located along the midline of the body have a longitudinal fiber direction, while those located on the side have an oblique direction.

Chest muscles

Own muscles

The fibers of the intrinsic chest muscles lie in three intersecting directions. This structure strengthens the chest wall.

Muscle	Start	Attachment	Function
External intercostal muscles	Lower edge of the overlying rib	Upper edge of the underlying rib	During contraction, the ribs are raised, increasing the volume of the chest in the anteroposterior and transverse directions. One of the main muscles of inspiration.
Muscles that lift the ribs	Transverse processes of the thoracic vertebrae	Angle of nearby edge	During contraction, the ribs are raised, increasing the volume of the chest in the anteroposterior and transverse directions. One of the main muscles of inspiration.
Internal intercostal muscles	Upper edge of the underlying rib	Lower edge of the overlying rib	By contracting, the ribs lower and, by reducing the size of the chest, promote exhalation.
Innermost intercostal muscles (internal bundles of internal intercostal muscles)	Upper edge of underlying ribs	Lower edge of overlying ribs	By contracting, the ribs lower and, by reducing the size of the chest, promote exhalation.
Transverse thoracis muscle	Xiphoid process of the sternum	Inner surface of the cartilages of the II-VI ribs	Lowers the ribs, promotes exhalation.
Subcostal muscles	X-XII ribs near their corners (inner surface)	Inner surface of overlying ribs	The ribs drop.
Diaphragm (stomach obstruction)	Sternum, ribs, lumbar vertebrae	Forms a tendon center	Main respiratory muscle. As it contracts, its dome lowers and the vertical size of the chest increases; at the same time, the lungs are mechanically stretched and inhalation is carried out.
Pectoralis major muscle	Medial half of the clavicle, manubrium and body of the sternum, cartilages of the II-VII ribs, anterior wall of the rectus sheath	Crest of the greater tubercle of the humerus	Brings the shoulder towards the body, lowers the raised shoulder. With fixed upper limbs, it raises the ribs and participates in the act of inhalation.

Alien muscles

The alien muscles that cover one's own chest muscles are powerfully developed in humans. They move and strengthen the upper limbs on the body.

Muscle	Start	Attachment	Function
Pectoralis major muscle	Sternal part of the clavicle, edge of the sternum, cartilages of the V-VI ribs	Crest of the greater tubercle of the humerus	By contracting, the muscle adducts and pronates the shoulder, pulling it forward.
Pectoralis minor muscle	II-V ribs	Coracoid process	When contracting, it pulls the scapula down and forward.
Serratus anterior muscle	II-IX ribs	Medial edge of the scapula and its inferior angle	When contracted, the muscle pulls the scapula forward and its lower angle outward, due to which the scapula rotates around the sagittal axis and its lateral angle rises. If the arm is abducted, the muscle, rotating the scapula, raises the arm above the level of the shoulder joint.

Notes

1. ↑ 1 2 R. D. Sinelnikov, Ya. R. Sinelnikov.
   Muscles of the head // Atlas of human anatomy. - 2nd. - M.:: Medicine, 1996. - T. 1. - P. 243. - 344 p. — 10,000 copies. — ISBN 5-225-02721-0.

Facial muscles
Muscles surrounding the palpebral fissure	Corrugator corrugator muscle Prouder muscle Depressor brow muscle Orbicularis oculi muscle
Muscles surrounding the mouth	Orbicularis oris · Zygomaticus major · Zygomaticus minor · Levator labii superioris · Levator labii superioris and ala nasi · Levator anguli oris · Buccal muscle · Laughter muscle · Depressor anguli oris · Depressor lower lip · Mentalis muscle · Transverse chin muscle
Muscles of the circumference of the nostrils	Nasalis muscle Depressor septum nasalis muscle

Masseter muscles Masseter muscle Temporalis muscle Lateral pterygoid muscle Medial pterygoid muscle Suboccipital muscles Rectus capitis anterior muscle · Rectus capitis lateralis · Rectus capitis posterior major · Rectus capitis posterior minor · Superior oblique capitis · Inferior oblique capitis Fascias of the capitis Temporalis fascia · Masseteric fascia · Parotid fascia · Buccopharyngeal fascia

This is a draft article on anatomy. You can help the project by adding to it.

Abdominal muscles

The abdominal wall is formed by a group of your own abdominal muscles. The external and internal oblique and transverse muscles are called the “latus abdominis.” The tendon fibers of their aponeuroses, intertwining in front, form the linea alba in the middle of the abdominal wall. The broad muscles have an oblique direction of fibers and lie, as on the chest, in three layers, with the external oblique abdominal muscle being a continuation of the external intercostal muscles, the internal oblique - the internal intercostal muscles, and the transverse abdominal muscle - the chest muscle of the same name. The quadratus lumborum muscle forms the posterior abdominal wall. The lower wall of the abdominal cavity (or pelvic floor) is called the “perineum.”

Muscle	Start	Attachment	Function
Rectus abdominis muscle	pubic bone	Cartilages of the V-VII ribs, xiphoid process of the sternum	By bringing the edges of the pelvis and chest closer together, it bends the spinal column, that is, it works as an antagonist of the back extensor muscle. With a fixed chest, it raises the pelvis.
Pyramidalis muscle	pubic ridge	Linea alba	The rudiment of the bursa muscle of mammals is often absent. When contracting, it stretches the linea alba.
External oblique muscle	Outer surface of ribs V-XII	Iliac crest, pubic symphysis, linea alba	In normal positions, when the pelvis serves as a support, the chest is rotated and tilted to the left and right sides. In cases where the chest serves as a support, and the pelvis with legs is “suspended” from it (for example, on a horizontal bar, uneven bars, etc.), lift the pelvis with legs and turn it in both directions.
Internal oblique muscle	Iliac crest	Cartilages of the lower ribs, linea alba	In normal positions, when the pelvis serves as a support, the chest is rotated and tilted to the left and right sides. In cases where the chest serves as a support, and the pelvis with legs is “suspended” from it (for example, on a horizontal bar, uneven bars, etc.), lift the pelvis with legs and turn it in both directions.
Transverse abdominis muscle	Inner surface of ribs VI-XII, iliac crest	Linea alba	Tenses when the lower abdomen is drawn in. At the moment of contraction, it compresses the internal organs. This helps empty the lungs of air, resulting in forced exhalation.
Quadratus lumborum muscle	Iliac crest, transverse processes of the lower lumbar vertebrae	XII rib, II-IV lumbar vertebrae, XII vertebral body	Pulls the ilium upward, and the 12th rib - downwards; participates in lateral flexion of the lumbar spine; with bilateral contraction, it pulls the lumbar spine backward.

Excerpt characterizing the anterior rectus capitis muscle

“She said... yes, she said: “girl (a la femme de chambre), put on the livree [livery] and come with me, behind the carriage, faire des visites.” [make visits.] Here Prince Hippolyte snorted and laughed much earlier than his listeners, which made an unfavorable impression for the narrator. However, many, including the elderly lady and Anna Pavlovna, smiled. - She went. Suddenly there was a strong wind. The girl lost her hat, and her long hair was combed... Then he could no longer hold on and began to laugh abruptly and through this laughter he said: - And the whole world knew... And that’s how the joke ended. Although it was not clear why he was telling it and why it had to be told in Russian, Anna Pavlovna and others appreciated the social courtesy of Prince Hippolyte, who so pleasantly ended Monsieur Pierre’s unpleasant and ungracious prank. The conversation after the anecdote disintegrated into small, insignificant talk about the future and the past ball, performance, about when and where they would see each other. Having thanked Anna Pavlovna for her charmante soiree [charming evening], the guests began to leave. Pierre was clumsy. Fat, taller than usual, broad, with huge red hands, he, as they say, did not know how to enter a salon and even less knew how to leave it, that is, to say something especially pleasant before leaving. Besides, he was distracted. Getting up, instead of his hat, he grabbed a three-cornered hat with a general's plume and held it, tugging at the plume, until the general asked to return it. But all his absent-mindedness and inability to enter the salon and speak in it were redeemed by an expression of good nature, simplicity and modesty. Anna Pavlovna turned to him and, with Christian meekness expressing forgiveness for his outburst, nodded to him and said:

Back muscles

The back muscles also traditionally include the muscles lying on the neck behind the spine.

Proprietary muscles of ventral origin

Muscle	Start	Attachment	Function
Serratus posterior superior muscle	From the lower part of the nuchal ligament, two (one) lower cervical and two upper thoracic vertebrae	II-V ribs	Raises the II-V ribs, expanding the chest during breathing.
Serratus posterior inferior muscle	From the spinous processes of 2 (1) lower thoracic vertebrae and 2 (3) upper lumbar vertebrae	IX-XII ribs	Lowers the IX-XII ribs, narrowing the chest during breathing.

Proprietary muscles of dorsal origin (deep muscles of the back)

I tract

Muscle	Start	Attachment	Function
Splenius capitis muscle	From the nuchal ligament, spinous processes of the 3 lower cervical and 3 upper thoracic vertebrae	Occipital bone	Turn, tilt the head to the side, with bilateral contraction - extension of the cervical spine.
Splenius neck muscle	From the spinous processes of 3-5 thoracic vertebrae	Posterior tubercles of the transverse processes of the 2-3 upper cervical vertebrae	With bilateral contraction, it pulls the head and neck backwards; with unilateral contraction, it pulls in its direction, turning the head and neck.

II tract

Muscle	Start	Attachment	Function
Erector spinae muscle	Spinous processes of the lumbar and lower thoracic vertebrae, sacrum, iliac crest	Angles of ribs, transverse processes of VI-VII cervical vertebrae	Keeps the body in an upright position, straightens the spine.
Iliocostal muscle	Spinous processes of the lumbar and lower thoracic vertebrae, sacrum, iliac crest	Transverse processes of the thoracic and cervical vertebrae, angles of the II-XII ribs, temporal bone	Together with the rest of the erector spinae muscle, it extends the spine; with unilateral contraction, it tilts the spine in its direction and lowers the ribs. The lower bundles of this muscle, pulling and strengthening the ribs, create support for the diaphragm.
Longissimus muscle	Spinous processes of the lumbar and lower thoracic vertebrae, sacrum, iliac crest	Transverse processes of the thoracic and cervical vertebrae, angles of the II-XII ribs, temporal bone	Together with the rest of the erector spinae muscle, it extends the spine; with unilateral contraction, it tilts the spine in its direction and lowers the ribs. The lower bundles of this muscle, pulling and strengthening the ribs, create support for the diaphragm.
Spinalis muscle	Spinous processes of the lumbar and lower thoracic vertebrae, sacrum, iliac crest	Spinous processes of the thoracic and cervical vertebrae, occipital bone	Extends the spine.

III tract

Muscle	Start	Attachment	Function
Transverse spinalis dorsi muscle	Transverse processes of vertebrae	Spinous processes of overlying vertebrae	With bilateral contraction, it extends the corresponding part of the spine; if it is unilateral, it tilts the spine in its direction.

IV tract

Muscle	Start	Attachment	Function
Intertransverse muscles	Transverse processes of vertebrae	Transverse processes of overlying vertebrae	Tilt the spine in your direction.
Interspinous muscles	Spinous processes of vertebrae	Spinous processes of overlying vertebrae	Extend the spine.
Short occipitovertebral muscles	Extend and rotate the head

Alien muscles

Surface layer

Muscle	Start	Attachment	Function
Trapezius muscle	Lower part of the occipital bone, spinous processes of the VII cervical and all thoracic vertebrae	Acromial end of clavicle, acromion, spine of scapula	Rotates, leads to the spine, raises and lowers the scapula; turns his head.
Latissimus dorsi muscle	Spinous processes of the six lower thoracic and all lumbar vertebrae, sacrum, iliac crest, ribs IX-VII	Crest of the lesser tubercle of the humerus (proximal)	Brings the shoulder to the body, rotates it inward.

Second layer

Muscle	Start	Attachment	Function
Rhomboid muscle	Spinous processes of the VII cervical and I-V thoracic vertebrae	Medial edge of the scapula	Brings the scapula closer to the spine while simultaneously moving it upward.
Levator scapulae muscle	Transverse processes of the four upper cervical vertebrae	Upper angle of the scapula	Raises the scapula, simultaneously bringing it closer to the spine; with a strengthened scapula, tilts the cervical part of the spine backwards and towards itself.