Superficial Muscles of the Back: Layers, Origins, Insertions, and Functions

Name: Superficial Back Muscles (Division, Origin, Insertion, Function)
Uploaded: 2026-01-11T17:04:10.206176+00:00
Channel: Taim Talks Med
Description: Summary and key takeaways on Superficial Muscles of the Back: Layers, Origins, Insertions, and Functions, covering Introduction In this article we explore the

Taim Talks Med

Jan 11, 2026

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2 min read

YouTube video ID: S0KjdRIvr1I

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Introduction

In this article we explore the superficial muscles of the back, their layered organization, key origins, insertions, and primary actions. Understanding these muscles is essential for anatomy students, clinicians, and anyone interested in shoulder and thoracic movement.

Layer Overview

The superficial back muscles are arranged in three distinct layers: - 1st layer: Trapezius, Latissimus dorsi - 2nd layer: Rhomboid major, Rhomboid minor, Levator scapulae - 3rd layer: Serratus posterior superior, Serratus posterior inferior

1st Layer

Trapezius

Parts: Superior, middle, inferior fibers
Origins:
Superior: superior nuchal line, external occipital protuberance, nuchal ligament
Middle: spinous processes C7‑T3/T4
Inferior: spinous processes T4‑T12
Insertions:
Superior: acromial end of clavicle, acromion of scapula
Middle & inferior: spine of scapula, acromion
Functions:
Superior fibers: elevate scapula, assist neck extension
Middle fibers: retract scapula toward midline
Inferior fibers: depress scapula; together they coordinate scapular movement.

Latissimus Dorsi

Origins:
Spinous processes T7‑T12
Thoracolumbar fascia
Iliac crest
Inferior surface of ribs 9‑12
Inferior angle of scapula
Insertion: crest of the lesser tubercle of the humerus
Functions: internal rotation, adduction, and extension (dorsiflexion) of the arm.

2nd Layer

Rhomboid Major

Origin: spinous processes T1‑T4
Insertion: lower two‑thirds of medial border of scapula
Functions: elevation, retraction, and internal rotation of scapula.

Rhomboid Minor

Origin: spinous processes C6‑C7
Insertion: upper one‑third of medial border of scapula (above rhomboid major)
Functions: similar to rhomboid major – elevation, retraction, internal rotation of scapula.

Levator Scapulae

Origin: spinous processes C1‑C6
Insertion: superior angle of scapula
Function: elevation of the scapula.

3rd Layer

Serratus Posterior Superior

Origin: spinous processes C6‑T2
Insertion: external surface of ribs 2‑5
Function: elevates ribs, aiding inspiration by expanding the thoracic cavity.

Serratus Posterior Inferior

Origin: spinous processes T11‑L2
Insertion: external surface of ribs 9‑12
Function: depresses ribs, assisting expiration.

Summary

The superficial back musculature is organized into three layers, each contributing to scapular positioning, arm movement, or respiratory mechanics. Mastery of their origins, insertions, and actions provides a foundation for deeper study of back anatomy.

The superficial back muscles, arranged in three layers, work together to control scapular motion, arm movements, and breathing; knowing their anatomy is essential for any study of the posterior torso.

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Full Transcript YouTube

Hey What’s up. Meditay here and in this video, 
we’ll be covering the Superficial muscles of  
the back. Alright. Generally, the muscles 
of the back consist of superficial muscles  
and deep muscles. So let’s take a 
closer look at the superficial muscles.  
These muscles are divided into layers. So, 
the 1st layer is the most superficial one.  
It consist of the Trapezius, as you 
see here, and the Latissimus Dorsi.  
The 2nd layer are the Rhomboid Major, Rhomboid 
Minor and Levator Scapula, and the 3rd layer of  
muscles consists of the Serratus Posterior 
superior and Serratus Posterior inferior. 
So these are the muscles we’re going 
to go through throughout this video.  
We’ll start with the 1st Layer, the Trapezius.
Now the trapezius Is this large muscle  
that take up the majority of your shoulders. They 
can also be classified as a cardiothoracic muscle,  
in addition to being one of the 
superficial muscles of the back. 
Now the Trapezius consists of 3 parts. There’s a 
Superior Part, a Middle part and an inferior part.  
The superior part will originate from the Superior 
nuchal line, the external occipital protuberance,  
and the nuchal ligament.
It’s then going to insert  
at the Acromial end of the clavicle, as you see 
here, as well as the acromion of the scapula. 
Then we have the middle part, which originates 
from the spinous process of the C7-T3 or T4,  
and it’s going to insert at the Spine of the 
Scapula as you see here, and the acromion. 
Then we have the Inferior Part, which 
originates from the spinous process of T4-T12  
and insert at the spine of scapula as well. 
Ok. So what is the function of the Trapezius? 
The Inferior part will pull the shoulder 
downwards, Middle and superior fibers  
will pull the scapula towards the midline, as well 
as elevating the scapula. They may also extend the  
head to the side as well in strong contraction. 
But primarily, they’re associated with movement  
of the scapula. So that is the Trapezius.
Next we have the Latissimus Dorsi. And  
the latissimus dorsi has several origin 
points, so let’s go through them one by one. 
It’s first going to originate from the spinous 
process of T7 to T12. It’s also going to originate  
from the thoracolumbar fascia. And From the 
Iliac Crest. And from the Inferior surface  
of the 9th to 12th Rib. And the Inferior angle 
of the Scapula. The fibers are then going to go  
from all of these places and unite to insert at 
the crest of the lesser tubercle on the humerus,  
as you see here. The overall function of the 
Latissimus dorsi is to internally rotate,  
adduct and dorsal flex the arm. So that was the 
1st layer of the superficial muscles of the back. 
Then if you remove the Trapezius and the 
Latissimus Dorsi, you’ll get to the 2nd layer,  
which consist of the Rhomboid Major, as you 
see here. This muscle originates from the  
Spinous process of T1-T4, and insert at the 
Lower 2/3 of the medial border of Scapula. 
It’s function is to elevate 
an retract the scapula,  
as well as internal rotation of the scapula. Then 
we have the Rhomboid Minor. Which is this one. 
It originates from the Spinous Process of C6-C7, 
and insert at the Upper 1/3 of the medial border  
of scapula, so it’s superior to the rhomboid 
major. Its function is also more or less the same,  
which is elevation an retraction of scapula, 
as well as internal rotation of the scapula.  
Then there’s the Levator Scapulae. This one. It 
originates from the spinous processes of C1-C6  
and insert at the Superior angle of the 
Scapula. Its function is to elevate the scapula. 
And that was the 2nd layer of the superficial back 
muscles. Now. If you remove these three muscles,  
we’ll get to the 3rd and last layer, which 
consists of the Serratus Muscles. First,  
we have the Serratus Posterior Superior, which 
is here, underneath the rhomboids. It originates  
from the Spinous Process of C6-T2 and Insert 
at the External Surface of the 2nd to 5th Ribs. 
Its function is to Elevate the ribs, to help with 
inspiration by expanding the thoracic cavity so  
that air can come in. The other muscle is the 
Serratus Posterior Inferior. Which is down here. 
It originates from the Spinous Processes of 
T11-L2 and insert at the External Surface of the  
9th-12th ribs. And its function it the opposite 
of the serratus posterior superior. This one is  
going to pull the ribs down, to aid the process of 
Expiration, breathing out basically. And that was  
the 3rd layer of the superficial back muscles.
In the next video, we’ll go through the  
classification system and all the muscles that 
are considered a part of the deep back muscles.