Description

Humerus Anatomy: Landmarks, Surfaces & Clinical Notes | Upper Arm Bone

This video covers the detailed anatomy of the humerus, the long bone of the upper arm, which connects the shoulder joint (glenohumeral joint) to the elbow joint. We explore its proximal, shaft, and distal parts — including all muscle insertions, surface landmarks, clinical relevance, and articulations.

Major Sections of the Humerus:
• Proximal end – Participates in the shoulder joint
• Shaft (Body) – Attachment point for major arm muscles
• Distal end – Forms the upper half of the elbow joint

Proximal Humerus Structures:
• Head of humerus (Caput humeri) – Articulates with glenoid cavity
• Anatomical neck (Collum anatomicum) – Separates the head from tubercles
• Greater tubercle (Tuberculum majus) – Insertion for supraspinatus, infraspinatus, teres minor
• Lesser tubercle (Tuberculum minus) – Insertion for subscapularis
• Intertubercular sulcus (Sulcus intertubercularis) – Pathway for long head of biceps brachii tendon
• Crest of greater tubercle (Crista tuberculi majoris) – Insertion of pectoralis major
• Crest of lesser tubercle (Crista tuberculi minoris) – Insertion of teres major
• Floor of sulcus – Insertion of latissimus dorsi
• Surgical neck (Collum chirurgicum) – Common fracture site; surrounds axillary nerve and circumflex humeral arteries
• Deltoid tuberosity (Tuberositas deltoidea) – Insertion of deltoid muscle

Shaft of Humerus – Landmarks & Clinical Points:
• Radial (spiral) groove (Sulcus nervi radialis) – Contains radial nerve and deep brachial artery
• Radial nerve injury – Wrist drop in midshaft fractures
• Nutrient foramen (Foramen nutricium) – Entry point for nutrient artery
• Surfaces:
 • Anterolateral surface (Facies anterolateralis)
 • Anteromedial surface (Facies anteromedialis)
 • Posterior surface (Facies posterior)
• Borders:
 • Medial border (Margo medialis)
 • Lateral border (Margo lateralis)

Distal Humerus Structures:
• Medial epicondyle (Epicondylus medialis) – Origin for forearm flexors
• Medial supracondylar ridge (Crista supracondylaris medialis) – Muscle and fascia attachment
• Groove for ulnar nerve (Sulcus nervi ulnaris) – “Funny bone” site; vulnerable to trauma
• Lateral epicondyle (Epicondylus lateralis) – Origin for forearm extensors
• Lateral supracondylar ridge (Crista supracondylaris lateralis) – Attachment for brachioradialis, extensor carpi radialis longus

Articular Surfaces & Fossae:
• Coronoid fossa (Fossa coronoidea) – Receives coronoid process of ulna during flexion
• Radial fossa (Fossa radialis) – Receives head of radius during flexion
• Olecranon fossa (Fossa olecrani) – Receives olecranon during extension
• Trochlea (Trochlea humeri) – Articulates with ulna (hinge joint)
• Capitulum (Capitulum humeri) – Articulates with head of radius

Muscles Mentioned & Insertions:
• Supraspinatus, Infraspinatus, Teres Minor – Greater tubercle
• Subscapularis – Lesser tubercle
• Pectoralis Major – Crest of greater tubercle
• Teres Major – Crest of lesser tubercle
• Latissimus Dorsi – Floor of bicipital groove
• Deltoid – Deltoid tuberosity
• Triceps Brachii (lateral/medial heads) – Near radial groove
• Brachioradialis – Lateral supracondylar ridge
• Extensor carpi radialis longus – Lateral supracondylar ridge
• Forearm flexor group – Medial epicondyle
• Forearm extensor group – Lateral epicondyle

Clinical Concepts Covered:
• Surgical neck fractures
• Axillary nerve injury
• Radial nerve palsy (wrist drop)
• Midshaft humerus fractures
• Ulnar nerve entrapment at medial epicondyle
• Lateral epicondylitis (Tennis elbow)
• Medial epicondylitis (Golfer’s elbow)
• Elbow joint mechanics (flexion, extension, radial articulation)

Elbow Joint Articulations (briefly shown):
• Trochlea → Ulna
• Capitulum → Radius
• Coronoid fossa → Coronoid process (ulna)
• Radial fossa → Head of radius
• Olecranon fossa → Olecranon (ulna)

Sources:
• Kozlowski, T. (2017). Memorix Anatomy, 2nd ed.
• Standring S. (2020). Gray’s Anatomy, 42nd edition
• Tubbs RS, Shoja MM, Loukas M. (2016). Bergman’s Encyclopedia of Human Anatomic Variation
• White TD, Folkens PA. (2005). The Human Bone Manual

Programs used: Complete Anatomy, Biorender, PowerPoint

Transcript

Introduction & Content
0:00
This is the humerus, the long bone of your upper arm. It fits right here,
0:05
between the shoulder and the elbow. And if we now remove the skin, we can see the
0:09
humerus in context. This is the third bone in our upper limb series, after the clavicle and scapula.
0:15
So what we’re going to do in this video, is to make you an expert on the humerus,
0:18
by visually going through the parts of the humerus, Its surface landmarks,
0:22
and the structures that relate to it What’s up everyone, my name is Taim. I’m
0:25
a medical doctor, and I make animated medical lectures to make different topics in medicine
0:29
visually easier to understand. If you’d like a PDF version or a quiz of this presentation, you can
0:34
find it on my website, along with organized video lectures to help with your studies.
Humerus Anatomy
0:37
Alright, let’s get started. The humerus is a long bone, as you see here.
0:42
And we divide it into three parts, a proximal end, proximal meaning closer to the center of the
0:48
body or the point of attachment; then we have the shaft or body of the humerus; and the last part is
0:53
the distal, or lower, end, which articulates with the bones of the forearm at the elbow.
Proximal Humerus
0:58
Let’s now cover all structures associated with the proximal end first.
1:03
At the top, we have the head of the humerus. This smooth, rounded surface fits nicely into
1:08
the glenoid cavity of the scapula, forming the glenohumeral joint. This is what allows your arm
1:15
to move in such a wide range of motion. Let’s now remove the scapula again,
1:19
and take a second to orient ourselves. Trust me it makes it so much easier
1:23
once you orientate around this bone. So, this is the anterior view of the humerus,
1:28
meaning we’re looking at it from the front. And here, on the left side of the screen,
1:32
is the posterior view, showing the back side of the bone. You with me so far?
1:37
Let’s now isolate the bone and place both views side-by-side. This will help us cover
1:43
all the different features from each surface. You’ll notice the head is clearly visible from
1:47
the posterior side as well. Awesome, let’s go ahead and cover some other proximal landmarks.
1:53
First up, right behind the head of the humerus, we can see the anatomical neck, which is a narrow
1:59
groove separating the head from the tubercles. Then we have the greater tubercle, this is more
2:04
lateral and is an important site for muscle attachment.
2:08
Right next to it is the lesser tubercle which sits more anteriorly. And between the two,
2:13
running vertically, we have the intertubercular sulcus, also called the bicipital groove. This
2:18
sulcus provides a channel for the long head of the biceps tendon.
2:23
Let’s now see these structures in context by adding in some structures.
2:27
Here’s the greater tubercle again, and look, this is where the supraspinatus, infraspinatus,
2:32
and teres minor muscles insert. All three are part of the rotator cuff and contribute
2:38
to stabilizing the shoulder joint. Each of them inserts into a facet on the greater tubercle.
2:43
The lesser tubercle is here. And what we can see is that this is where the subscapularis
2:49
muscle inserts, which is also one of the rotator cuff muscles. It’s the only one that
2:54
sits on the anterior surface and helps with internal rotation of the humerus.
2:59
Another muscle that has partial attachment here is the teres major, although it inserts a bit lower.
3:05
Now, let’s bring in the intertubercular sulcus. This groove makes way for the long head of the
3:11
biceps brachii tendon to pass through it. So the tendon travels through this channel and continues
3:17
up to its origin on the supraglenoid tubercle of the scapula. This groove also provides space
3:22
for accompanying synovial sheath and vessels. So that’s those landmarks. What else can we see?
3:29
Just below the tubercles, you’ll notice two crests. These are called the crest of
3:34
the greater tubercle, running downward from the greater tubercle, and directly opposite to it,
3:39
we’ve got the crest of the lesser tubercle. You’ll hear these names a lot when we talk
3:43
about muscle insertions, especially ones coming from the chest and back.
3:47
Another important landmark in this region is the surgical neck of the humerus. But before we get
3:52
to that, let’s look at these crests in a bit more context by bringing in the surrounding muscles.
3:58
Here, you can see the pectoralis major inserting directly onto the crest of the greater tubercle.
4:03
Now on the crest of the lesser tubercle, we can see the teres major. And just nearby, inserting
4:09
into the floor of the intertubercular sulcus and partially overlapping this region, we’ve got
4:14
the latissimus dorsi. These two muscles, teres major and lat dorsi, are closely related, both
4:21
in action and position, and they sort of go from the back and attach here on the anterior surface.
4:27
Just so you get a better visual understanding, here’s the posterior view, we can see the
4:32
latissimus dorsi more clearly. It spans all the way from the lower spine and iliac crest,
4:37
inserting onto the crest of the lesser tubercle. Alright, back to that clinically
Surgical Neck Clinical Note
4:41
relevant structure, the surgical neck. This is the narrowed region just below the
4:46
tubercles. And it’s one of the most common sites of fractures in the proximal humerus, especially
4:51
in elderly patients following a fall. The reason it’s called the surgical neck isn’t because we
4:57
like to cut here, it’s because fractures in this region often require surgical intervention to fix.
5:03
Now, what makes this spot especially important is what runs around it. If you pay attention to this
5:09
area, you can see that around the surgical neck are the anterior and posterior circumflex humeral
5:15
arteries, as well as the axillary nerve. So when this region breaks, there’s a risk of damaging
5:21
those structures, which can lead to loss of shoulder abduction or even necrosis of the
5:26
humeral head due to compromised blood flow. Let’s quickly analyze this x-ray. This is a
5:32
transverse fracture of the surgical neck and the greater tubercle of the right humerus.
5:36
You can clearly see the separation and displacement of the fragments. In cases like this,
5:41
especially with displacement, the treatment is usually ORIF, that’s open reduction and
5:46
internal fixation, where plates and screws are used to realign and stabilize the bone.
5:53
Alright, so that wraps up the proximal part of the humerus. We’ve now covered the head,
5:58
necks, tubercles, sulcus, and muscular insertions around the top.
Shaft of Humerus, Landmarks & Clinical Points
6:03
Let’s now move on to the shaft of the humerus. The shaft is the long middle portion of the bone,
6:09
and although it may seem pretty straightforward, there are actually several important surface
6:14
landmarks we need to go through. Let’s begin with this one right here, the deltoid tuberosity. It’s
6:20
a rough, raised area on the lateral side of the humerus, and as the name suggests,
6:25
it’s where the deltoid muscle inserts. Now let’s look at the back side of the shaft,
6:31
because here’s something super clinically relevant, this is the radial groove,
6:35
or the spiral groove. It runs obliquely down the posterior surface of the humerus. This groove is
6:42
important because it contains the radial nerve and the deep brachial vessels. These structures
6:48
travel tightly along this path, nestled between the medial and lateral heads of the triceps.
6:53
This is why fractures to the midshaft of the humerus are often associated with radial nerve
6:58
injuries. If someone comes in after trauma and suddenly can’t extend their wrist or fingers, we
7:04
start thinking radial nerve palsy, and this is the spot we worry about. So just remember: midshaft
7:10
humerus fracture. Always check for wrist drop. Now while we’re at the shaft, let me just quickly
7:17
mention two more things: the nutrient foramen, which is a tiny opening along the shaft that
7:23
allows blood vessels to enter the bone to nourish the marrow, and broadly speaking, the shaft has
7:29
an anterolateral, anteromedial, and posterior surface, as well as medial and lateral borders.
7:35
Alright, that was the shaft of the humerus. Let’s now zoom in and take a closer look at
Distal Humerus Structures
7:40
the distal end of the humerus, the part that forms the upper half of the elbow joint.
7:46
Starting medially, here’s the medial epicondyle, a large, prominent bump. It’s easily palpable on
7:52
your inner elbow, and it serves as an origin site for many of the flexor muscles of the
7:57
forearm. Just above it, you’ll see the medial supracondylar ridge, where some
8:02
of those muscles and fascia also anchor. And we can see this little groove right
8:07
behind the medial epicondyle. This one’s famous for causing that shocking, tingling
8:12
pain when you hit your elbow at a specific point. That’s the groove for the ulnar nerve.
8:17
The ulnar nerve runs through here unprotected, which is why bumping it feels like an electric
8:22
zap. That’s what people mean when they say they’ve hit their “funny bone”, although, neurologically
8:26
speaking, there’s nothing funny about it. Anyways here you see also that many of the
8:31
flexor muscles of the hand originate from this region too. I have a video on their specific
8:36
function if you’re interested, but for now, just know they start from this medial side.
8:41
Now let’s shift to the lateral side. This is the lateral epicondyle, and
8:46
compared to the medial one, it’s a bit smaller. It serves as the common origin for the extensor
8:52
muscles of the forearm. Just above it, we have the lateral supracondylar ridge, which provides
8:58
additional surface area for muscle attachments. And if we look at this in context, we can see
9:03
some of the muscles that anchor here, like the brachioradialis and extensor carpi radialis
9:08
longus, as well as the rest of the extensor group more posteriorly. So, medial side = flexors,
9:14
lateral side = extensors. Easy to remember. Now let’s go a little deeper and look at
9:20
the articular surfaces and fossae that contribute to the elbow joint.
9:25
On the anterior side of the distal humerus, you’ll see two depressions:
9:30
the coronoid fossa on the medial side, and the radial fossa on the lateral side. These
9:35
are where the coronoid process of the ulna and the head of the radius tuck in during elbow flexion.
9:41
Flip around to the posterior side and you’ll see a deeper fossa called the olecranon fossa. This is
9:47
where the olecranon process of the ulna fits when the elbow is extended. So, these fossae basically
9:53
accommodate the ulna and radius during different movements, allowing smooth flexion and extension.
10:00
Now, right below those fossae, we get to the articular parts: the trochlea on the medial side,
10:05
which articulates with the ulna, and the capitulum on the lateral side,
10:09
which articulates with the radius. Together, these structures form the hinge-like elbow joint.
10:16
Let’s look at that joint in context. Here you see the Radius and Ulna. And here we can see
10:21
how the trochlea interacts with the ulna and how the capitulum lines up with the radius.
10:26
This setup allows for that classic hinge motion, flexion and extension at the elbow.
10:32
And from the posterior view again, you can see how the olecranon process of the ulna sits nicely
10:37
into the olecranon fossa during full extension. Alright, that wraps up the distal end of the
Summary and Next Topic
10:42
humerus. We’ve covered the epicondyles, ridges, fossae, and the articulating
10:47
surfaces that form the elbow joint. And that’s it for the humerus! You’ve
10:52
now seen every major surface and landmark. In the next video, we’re going to cover the joint
10:57
that is formed right about here, called the elbow joint. So if you’ve ever wondered how your elbow
11:02
flexes, extends, and allows rotation between the radius and ulna, that’s what we will be covering
11:08
next. Click the next video and i’ll see you there. If you want a handmade PDF version of this
11:12
lecture, take a quiz to test your knowledge, or access an organized list of all my videos,
11:16
you can find everything on my website. Thanks for watching! See you in the next one.