Shoulder (Pectoral) Girdle – Muscles and Movements – Human Anatomy | Kenhub

Shoulder (Pectoral) Girdle – Muscles and Movements – Human Anatomy | Kenhub


Hello again, everyone! It’s Matt from Kenhub,
and in this tutorial, we will discuss the muscles and movements of the shoulder girdle. The shoulder girdle consists of two bones:
the scapula, and the clavicle (or the collar bone), and the muscles that attach to and
move these bones. They are the rhomboids, trapezius, subclavius, pectoralis minor, and
levator scapulae muscles. The rhomboid muscles are two diamond-shaped
muscles of the shoulder girdle, both extend from the vertebral column to the medial border
of the scapula. They lie over the autochthonous back muscles but under the trapezius. In this
area, they are both palpable and often visible. The rhomboid muscles are divided into the
rhomboid major and the rhomboid minor muscle. Usually, there is a small space between both
rhomboid muscles. However, in some cases, one may find one, single blended muscle instead.
Both major and minor rhomboids perform the same movement. Their contraction causes a
craniomedial movement of the scapula, known as adduction and elevation. At the same time, the inferior angle of the
scapula is moved towards the vertebral column, known as rotation. That movement mainly supports
lowering of the elevated arm. Another function of the rhomboid musculature
is the stabilization of the scapula during both rest and arm movement. The trapezius muscle is a triangular, flat
muscle of the shoulder girdle and is divided into three parts: the descending or superior
part, the transverse or middle part, and the ascending or inferior part. The trapezius has numerous tasks. It stabilizes
and secures the shoulder blade at the thorax. It moves the shoulder blade medially and rotates
it outward. In addition, the descending part causes elevation of the scapula, while the
ascending part depresses this bone. The subclavius muscle is a short muscle of
the shoulder girdle. Due to its location (lying behind the pectoralis major) and relatively
small size, the muscle is hardly palpable. The main task of this muscle is the act of
stabilization of the clavicle in the sternoclavicular joint during movements of the shoulder and
arm. The pectoralis minor is a fan-shaped muscle
of the shoulder girdle. It is located under the pectoralis major, and with that muscle
forms the anterior wall of the axilla where the contracted muscle can be easily palpated. The pectoralis minor has two main functions.
First, it pulls the scapula anteriorly and inferiorly towards the ribs, abduction and
depression respectively. This leads to a dorsomedial movement of the inferior angle of the scapula.
This movement is both helpful when retracting the elevated arm as well as moving the arm
posteriorly behind the back. Second, the pectoralis minor elevates the
third to fifth ribs, given a fixed scapula, and expands the rib cage. By those means,
it can also serve as an accessory muscle during inspiration. The levator scapulae is a long muscle of the
shoulder girdle. The upper part of this muscle lies under the splenius capitis and sternocleidomastoid
muscles, and it’s lower part under the trapezius. Only the middle part of the levator scapulae
remains uncovered in the lateral cervical region, and for that reason, the muscle can
be most easily palpated in this area. As the name indicates, the main function of
the levator scapulae is the elevation of the scapula. While elevating, it simultaneously
pulls the entire scapula medially. This movement is helpful when bringing the elevated arm
back to the neutral position. In addition, the muscle also moves the inferior
angle away from the back, causing a small upward tilt of the scapula. If the scapula
is fixed, a contraction of the levator scapulae leads to the bending of the cervical vertebral
column to the side, known as lateral flexion. This video is more fun than reading a textbook,
right? If you want more videos, interactive quizzes, articles, and an atlas of human anatomy,
click on the “Take me to Kenhub” button. It is time to say goodbye to your old textbooks
and say hello to your new anatomy learning partner, Kenhub! See you there! https://www.kenhub.com

16 Replies to “Shoulder (Pectoral) Girdle – Muscles and Movements – Human Anatomy | Kenhub”

  1. There are many factors in learning human anatomy. One plan I found which successfully combines these is the Anatomy Blueprint Pro (check it out on google) without a doubt the most useful info that I've heard of. Check out this  amazing site.

  2. Hey everyone! We hope you liked our video tutorial on the muscles and movements of the shoulder girdle. Which features would you like to see in future videos to help you learn human anatomy the best and most efficient way posible? Let us know in the comments! Don't miss our free related article about the movements and muscles of the upper limb on https://khub.me/st7m4
    Have fun reading! 🙂

  3. Which muscle helps in retraction of shoulder girdle? Pectorialis major or rhomboid? Is it a concentric contraction or eccentric contraction?

  4. I think the Serratous anterior is one. Of the pectolis grille because is insert the medial border of the scapula (sorry for the wrong spelling)

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