Description

This video covers the muscles of the arm, including their origins, insertions, and functions.

Muscles of the Arm

• Anterior (Flexor) Group [3]
• Posterior (Extensor) Group [2]

Anterior (Flexor) Group [3]

Brachialis (Musculus Brachialis)

• Origin: Anterior diaphysis of the humerus
• Insertion: Tuberosity of Ulna (Tuberositas Ulnae)
• Function: Flexion

Coracobrachialis (Musculus Coracobrachialis)

• Origin: Coracoid Process (Processus Coracoideus Scapulae)
• Insertion: Anterior diaphysis of the humerus
• Function: Flexion, Adduction, and Internal Rotation

Biceps Brachii (Musculus Biceps Brachii)

• Long Head
  • Origin: Supraglenoid Tubercle (Tuberculum Supraglenoidale Scapulae)
• Short Head
  • Origin: Coracoid Process (Processus Coracoideus Scapulae)
• Insertion: Radial Tuberosity (Tuberositas Radii)
• Function:
  • Flexion + Supination of Forearm
  • Flexion + Abduction of Arm

Posterior (Extensor) Group [2]

Anconeus (Musculus Anconeus)

• Origin: Lateral Epicondyle of the Humerus (Epicondylus Lateralis Humeri)
• Insertion: Proximal Epiphysis of the Ulna
• Function: Extension of Lower Arm

Triceps Brachii (Musculus Triceps Brachii)

• Medial Head
  • Origin: Diaphysis of Humerus
• Lateral Head
  • Origin: Diaphysis of Humerus
• Long Head
  • Origin: Infraglenoid Tubercle
• Insertion: Olecranon of Ulna
• Function:
  • Extension of Forearm
  • Extension + Adduction of Arm

Transcript

Introduction
0:03
What’s up. Meditay here and in this video, we’ll be covering the muscles of the arm,
0:08
which as you know are a part of the upper limb. Alright. So the muscles of
0:11
the upper limb are divided into 4 parts according to their anatomical location.
0:16
The first group are muscles of the shoulder joint. Then we have the muscles of the arm, muscles of
0:21
the forearm and then the muscles of the hand. So again, muscles of the arm are what we’re gonna
Division of the Arm Muscles
0:26
focus on today. And they’re divided into two main groups. We have th Anterior group, which are also
0:32
called flexor muscles, there are 3 muscles there. And Posterior group, or the extensor muscles.
0:38
These are two muscles here in the posterior region.
0:41
So let’s do the anterior group first. Alright. The first muscle of the anterior
Brachialis
0:45
group is the brachialis muscle, which is here. This muscle originates from the Anterior
0:50
Diaphysis of the Humerus, and insert at the Tuberosity of the Ulna, as you see here.
0:55
And when this muscle contracts, it pulls the ulna upwards and flexes the lower arm.
Coracobrachialis
1:00
The next muscle is the coracobrachialis muscle. Which is here.
1:04
And as the name says, it originates from the Coracoid process of the Scapula,
1:09
and insert at the anterior diaphysis of the humerus. And when the fibers of this muscle
1:14
contract, it flexes the arm, adducts the arm, and also internally rotate the arm.
1:20
The last muscle of the anterior group is the Biceps brachii muscle, which is here. It’s called
Biceps Brachii
1:26
Bi-ceps, so it consist of two parts. It consists of a Long head, as you see here, and a short head.
1:32
The long head originates from the supraglenoid tubercle, and the short head originates from
1:37
the coracoid process of the scapula. The two heads then unite to insert at
1:42
the radial tuberosity on the radius, as you see here. This muscle is responsible
1:47
for flexion and supination of the forearm, and also flexion and abduction of the arm.
1:53
So that was the three muscles of the flexor group. Next, we have the Posterior, or extensor group,
1:59
so let’s go ahead and look at the posterior view of the arm.
Anconeus
2:02
The first one is the Anconeus. Which is here. Down here.
2:06
It originates from the Lateral Epicondyle of the Humerus and insert at the Epiphysis
2:11
of the Ulna. And when it contracts, it pulls the lower arm back to extend it.
Triceps Brachii
2:17
The last muscle is called Triceps Brachii. It’s called Tri-Ceps, so it has three heads.
2:23
It has a Medial head and a Lateral head. These two heads are located deep, next to the bone. And they
2:29
both originate from the posterior diaphysis of humerus as you see here, and they form
2:35
an important landmark. You know the grove for the radial nerve, from where the radial nerve passes?
2:40
The medial head will orginate under the groove for the radial nerve, and the lateral head will
2:46
originate above the groove for the radial nerve. The last head is called the Long head, and it lies
2:51
on top of the medial and lateral head as you see here. It’s called long head because it reaches
2:56
even further that the other two, and originate from the infraglenoid tubercle of the scapula.
3:03
All three parts of the triceps brachii are going to unite and insert at the olecranon of Ulna. And
3:09
the function of this muscle is to extend the forearm. As well as extend and adduct the arm.
3:15
And here is a little more realistic view of the triceps. This is the long head, this is
3:19
the lateral head and this is the medial head. So that was it for the muscles of the arm. I
3:25
really hope this video helped; the next video is going to be about the muscles of the forearm.