I Hope Print Isn't Completely Dead Because I'm Making a Book!

A recent occurrence in the life of a friend (to be elaborated upon later) spurred an unexpected dive into a project I've been thinking about for years. Writing and diagramming for a blog is all fine and dandy, but despite my love of electronic media and its infinite educational possibilities, I still have a soft spot for print. So I've always dreamed of creating a book. A book with thick creamy pages that smells like a printing press. A book I can crack open for the first time and run my fingers over after hugging the UPS guy and dragging my eagerly awaited shipment box into the house. Until recently this dream has been next to impossible without an official publisher, but now that the printing process has evolved beyond the expensive and limiting, it's possible for us less-than-famous-or-well-known-or-prolific writers to get some of our own goofy little projects printed.

As such, I'm inhaling deeply and jumping into the world of print-- for a short time anyway. Yep, I'm making a little booklet of anatomical landmarks references for figure artists. It will include diagrammed photos, illustrations, and concise explanations of labeled structures. Its intended purpose is to function as a handy reference guide for figure artists who are stuck on any particular area of the body and would like some extra anatomical guidance.

The book will be organized by body regions, including head, neck, shoulders, anterior, lateral, and posterior torso, upper arm, forearm, hand, hip, thigh, lower leg, and foot. Heck, I may even throw in an ear and eye page is there is enough space. Each area will be shown from a variety of angles and everything will be labeled clearly and thoroughly.

Below is a sample photo from the book, showing the axilla and medial upper arm. It also shows one of my cabinets and some dishes in it because, yeah, I'm not a professional photographer. No matter, we can see lots of anatomical structures, right? Not sure if this specific image will make it into the final cut (I'm still shooting and slashing and re-shooting and editing) but we'll see. Regardless, why don't we take a little time now to talk about what we're seeing here?

OK, first a word about the weird numbering. In this image, I used the same numbers as in another photo on the page (in which they are in order.) Ah, it'll make sense when it's in print. I hope!

The axilla (the anatomical term for the armpit) is formed by two muscles-- the pectoralis major (10) anteriorly, and the latissimus dorsi (11) posteriorly. Up inside the axilla, we can see a short muscle called coracobrachialis (12.) It is given this name because it runs from the coracoid process on the antero-superior scapula down to the humerus bone in the upper arm. (The Latin root brachio- refers to the upper arm.)

Just before coracobrachialis inserts on the humerus, it tucks under biceps brachii (4), the most obvious superficial muscle on the anterior upper arm. Just deep to biceps brachii at its distal end is the brachialis muscle (13) which can be seen peeking out on either side of biceps brachii (although its borders are not very obvious here.) We can also see the long (8) and medial head of the triceps on the medial upper arm. The only bony landmark we see on the medial upper arm is the medial epicondyle at the distal end of the humerus. Another visible structure in the area is the deltoid muscle (3) that covers the top of the shoulder.

Just posterior to the coracobrachialis (12) we can see another soft lump of tissue labeled with an F. This is not a muscle, but a small mass of fat tissue that cushions and protects a few structures that course through the underarm, including the basilic vein, the median and ulnar nerves, the brachial artery, and some lymph nodes, which feel like lumpy little jelly beans in the armpit.

There are also a few structures in the image that, while unrelated to the upper arm, warranted acknowledgment for their clarity. Those are the clavicle (C) and the sternocleidomastoid (SCM) muscle on the anterior neck.

The book should be printed and on sale by sometime in June! I will post more information then. See you next time!

Vestigial Traits: You May Not Need Us, But We're Still Here

Short post today. I have a side project in the works, the details of which are soon to come! Until then, how about a short post about human vestigial traits! 

Because my anatomy course is for art students, its content is designed almost entirely around the human body's superficial structures-- mostly muscles and bony landmarks-- that dictate the external human form. But occasionally (well, OK, often) we go off on random tangents during which students asks about other anatomical structures or physiological processes. And I have to admit, these random questions are one of my favorite parts of the class.

One subject that comes up often is that of human vestigial anatomical structures. Vestigial structures are those that had a purpose in earlier evolutionary forms of ourselves, but now have little or no function. As evolution allows us, as a species, to slowly adapt to our environment and our circumstances, certain structures become unnecessary. With each generation these structures become slightly less prominent, until they are slowly phased out altogether. Our vestigial structures (and reflexes, for that matter) are those which still remain in some form but no longer serve much of a purpose. One example is our coccyx bone, which is the remains of what use to be caudal vertebrae, or bones of a tail.

Here is a nice summary of ten vestigial traits that still occur in humans today. Enjoy, and I will be back soon with a new posterior torso post as well as more news about my new project!

The Annular Ligament: Full Circle!

It's a big day here today-- it's Human Anatomy For The Artist's first anniversary! Yep, it was one year ago today that the debut post, The Ventral Forearm: What are those Tendons? went live. Today, 366 days, 28 posts, and 80,314 page views later, I am happy to say that my goofy little blog is still going strong. As of this morning, Human Anatomy for the Artist has 89 Blogger followers, 51 Networked Blogs followers, and 2,032 Facebook followers. Writing and drawing about this topic is such a great joy, so I want to thank you for all the wonderful forms of encouragement, including your regular visits, words of gratitude, and messages from around the world. It's so gratifying to know that people are learning from these posts. Please keep spreading the word as we head into our second year!

Year 2 dangles many new post ideas before us; there are so many structures and concepts I still want to cover. It is quite awesome (and reassuring somehow) that a finite science like Anatomy can still have such vast depth. I can't imagine trying to write about a subject such as space or philosophy, whose possibilities are truly endless, without going a tad crazy.

The fact that we've come full circle today gave me the idea to write about an anatomical structure that also comes full circle. The annular ligament is named for its circular, or ring-like structure; the Latin word anulus means ring, so annular means "ring like." Quite fittingly this morning, both the words annual and anniversary come from a related Latin root; when an event is annual, it has come full circle from the previous year. Like the annular ligament, this blog comes full circle today. And even more fittingly, this structure was discussed in the very first post a year ago today.

Here is the image from that post again, with only the ligament and some related tendons labeled. Before going further, I should point that this particular annular ligament is not the only one in the human body. This name is given to most any ring-shaped ligament, and this is just one of at least five. As you can see, this one is located at the distal forearm. (Some of the others are located on the proximal radius, the ankle, the knee, and the trachea.)

The annular ligament in the wrist isn't something we artists think about much when we draw the human figure. You can't really see it on the surface. But it does affect surface appearance. There are two fairly visible tendons on the ventral wrist, the tendon of flexor carpi radialis and the tendon off palmaris longus. The tendon of palmaris longus is usually more visible than that of flexor carpi radialis because it runs outside the annular ligament. So if you're drawing the two ventral wrist tendons, it's important to make sure the correct one is more visible. Palmaris longus, the more visible of the two, is closer to the ulnar (pinky) side of the hand. This is explained in much more detail in the first post from one year ago, and some photographic and illustrative examples are shown there as well.

The function of the annular ligament on the distal wrist is to retain the position of the long forearm tendons that reach into the hand (with the exception of the palmaris longus tendon, whose distinction is its unique course outside the annular ligament.) This annular ligament's function is reflected in its more commonly used name, retinaculum. This term comes from the Latin retinere, which means to hold back.

Thank again for sticking around for the past year, and I look forward to working on upcoming posts! There are several series from the past year that need to be continued, including those on direction and location, back muscles, and the elbow joint. More in those series to come soon, plus more new material. See you soon!

Student Work! A Sneak Preview with Bad iPhone Shots

The Spring semester has just ended at the American Academy of Art, and over the past few days I've had the pleasure of looking through all the lovely anatomical drawings my Advanced Anatomy students did this semester. I would like to scan and post some of my favorites over the summer, but for now I'm going to offer a little sneak preview. I'm sorry about the quality. These were taken with my iPhone in the midst of a grading frenzy.

Justine Herrera's rendering of anterior neck muscles.

Chase McNicholas's rendering of anterior torso muscles.

I will post many more images soon, after I sleep for about 15 hours and then do some scanning! Thanks, Justine and Chase.

Quick Forearm Study: My Pal Rich

Here's a quick forearm muscle study using my pal and fellow illustration instructor, Rick Kryczka. We see mostly the extensor/supinator group here, which is discussed more thoroughly in The Dorsal Forearm Part 1: Compartment Search, The Dorsal Forearm Part 2: Which Side Are You On, Anyway?, and The Dorsal Forearm Part 3: The Final Chapter. There are also smaller updates on this area in The Dorsal Forearm: One Last Encore and Landmark Sightings Part 1: Bruce Lee. 

You might start orienting yourself on this image by first identifying the olecranon process of the ulna and the lateral epicondyle of the humerus. From there you can identify anconeus, the small triangular elbow muscle that originates between those two landmarks and then points into the crease between the extensor and flexor forearm muscle groups groups. (And if you keep following it distally, will take you to the crest of the ulna.) From there you can identify the twin muscles (extensor carpi ulnaris and extensor digitorum) and then extensor digiti minimi between them, and so on. The links mentioned above explain all this in much greater detail.

Bony landmarks to find first: lateral epicondyle (LE), olecranon process (OP), and the ulna itself, whose crest
and head show at the distal and of the arm. The extensor muscles will follow: Anconeus (Anc), extensor carpi
 ulnaris (ECU), extensor digitorum (ED),  extensor carpi radialis brevis (ECRB), extensor carpi radialis longus
(ECRL), and brachiradialis (Brr). Some thumb muscles can also be seen: Abductor pollucis longus (APL),
extensor pollucis brevis (EPB) and the tendon of extensor pollucis longus (EPL.) Finally, a few upper arm
muscles are shown: Biceps brachii (BB), brachialis (Br), the lateral head of the triceps (Tlat) and the triceps
tendon (TT).

Posterior Torso Muscles, Part 2: Under the Radar

You may have noticed that I keep describing the forearm as the most difficult part of human anatomy to teach (and the most difficult to understand!) This area is so difficult for some pretty straightforward reasons: 1) There are so many forearm muscles, and 2) they all look very much alike. But sometimes I forget that the posterior torso muscles, although they are large and varied, are also among the most difficult to understand. In my class, they sometimes require as many days to get through as the forearm muscles. But the posterior torso muscles are confusing for a completely different reason-- unlike most muscles that concern the figure artist, they like to live under the radar.

Like most areas of the body, the posterior torso has several layers of muscle. When rendering most areas of the body, we artists tend to think primarily about the superficial muscle layers-- the ones that are visible at the surface and contribute most to the body's outward appearance. But things are a little different on the posterior torso. Its muscles are exceptionally broad, thin, and flat, which means we sometimes can see deeper muscles showing right through them. This is pretty cool, but it does make things a little more confusing.

In fact, sometimes the deeper muscles of the posterior torso show more clearly on the surface than the superficial muscles. How can that be? This happens because the superficial muscles are often so thin and flat that they just don't look like much on the surface. But the muscles underneath them are rounder and more defined, so it's actually easier to pick out their shapes. 

There are some wonderful examples of this in the figure renderings of Brian Skol. Brian is a student at the Ravenswood Atelier in Chicago, and during his time there he has developed a solid, stunning figure drawing technique and turned out an impressive collection of work. Brian also took my Anatomy course at AAA several years back, and while he is among several top students who mastered the class, he is distinctive in that he's the only one who's ever said the Anatomy final exam was not difficult enough! This comment was unexpected and refreshing, as I'm used to hearing just the opposite.

Several of Brian's figure drawings lovingly demonstrate the posterior torso landscape, but today (and in a few upcoming posts) we'll concentrate on this one. First let's look at the subtle ridges that help define the structure of the back.

Each of the skin ridges in Brian's figure drawing subtly reveals a muscular relationship on the posterolateral torso. Ridge 1 shows the point at which the latissimus dorsi meets the lumbar sheath. Ridge 2 demonstrates the furrow at which the external oblique muscle meets the rectus abdominis muscle. Ridge 3 shows where the serratus anterior muscle travels back toward its insertion on the underside of the scapula. (It's actually under latissimus dorsi at this point, but we can still see it because latissimus dorsi is so thin.) Ridge 4 shows the teres major muscle as it extends laterally toward the upper arm, where it will insert on the anterior side of the proximal humerus. The lower edge of teres major is hidden under latissimus dorsi, but it still shows. Finally, ridge 5 shows the posterior edge of the deltoid.

I know, I know. I did say subtle, right? But part of the beauty of the human body is that so much of it is a mystery; its structures are always there, doing their job, making things happen, but many don't necessarily need to be right in your face; they'd prefer to stay under the radar and let you discover them. 

So let's take a closer look at these shy little devils. The first step in this process was to block in some overall muscle shapes and a few bony landmarks, then to identify them.

Drawing in these basic structure shapes was the starting point for exploring each of the posterior torso ridges more closely. The iliac crest is shown in yellow but unlabeled. The large posterior torso muscles are trapezius (T) and latissimus dorsi (LD). Together with deltoid (D), they form a triangular window, in which we can see infraspinatus (Inf) and teres major (TM). Teres minor is barely peeking out between infraspinatus and teres major, but I didn't label it. Just anterior to latissimus dorsi, we can see two anterior torso muscles: external oblique (EO) and rectus abdominis (RA). I've also included some structures just under the iliac crest: Gluteus maximus (Gmax), gluteus medius (Gmed),  and tensor fasciae latae (TFL) all surround the greater trochanter of the femur (GT). Distal to that we can see vastus lateralis (VL) and the iliotibial band (ITB).

Now let's take a look at the ridges that are so beautifully and accurately rendered in Brian's drawing. We'll start with ridge number 1, where the lumbar sheath meets the latissimus dorsi muscle. First, here's how these structures look from a direct posterior view.

The lumbar sheath is a flat, diamond shaped aponeurosis covering a large portion of the lower back. It serves at an origin point for the large, bilateral latissimus dorsi muscles. We can often see a ridge along the lower back where these two structures meet. Note that both latissimus dorsi and the lumbar sheath have been removed on the right side of the body in this image.

You might recall this image from my first posterior torso post. At that time we looked at the relationships of the larger back muscles and the small triangular window they form (in which we can see some smaller muscles on the posterior surface of the scapula.) Now let's use this image to look at the landscape of the lower back. Occupying most of its space is the lumbar sheath, a diamond shaped aponeurosis (which is broad, flat, tendinous muscle covering.) The lumbar sheath serves as an origin point for the large bilateral latissimus dorsi muscles that run across the lower back and sides. Because the lumbar sheath is not muscle tissue, doesn't bulk up with use. So it can appear somewhat flat in comparison to the lumbar sheath. This means we can often see a ridge where these two structures meet. That's what we're seeing on the area labeled number 1 on Brian's drawing.

In this next image, the basic shapes of latissimus dorsi and the lumbar sheath are placed on top of Brian's rendering. This shows the placement of the individual structures and their meeting point. 

The lumbar sheath (shown in white) is an origin point for latissimus dorsi (LD). Because the lumbar sheath is flat and the latissumus dorsi has some bulk, we can often see a ridge on the back where the two meet. This ridge forms one of the upper edges of the lumbar sheath. The lower edges are formed by a small corner of the external oblique that reaches around to the back and attaches to the iliac crest.

We can see here that both the latissimus dorsi muscle and the external oblique form borders around the lumbar sheath. The angles of these borders give the lumbar sheath its diamond shape. On a more muscular individual, the flat lumbar sheath would stand out more obviously against the surrounding muscles and would become even more visible.

I am looking forwarding to explaining the other four ridges that can be seen in this lovely rendering, but this is getting a little long, so I'm going to sign off for now. I will cover ridges 2 through 5 in an upcoming post, and I'm also working on the rest of the elbow joint posts. See you soon! 

Batman's Anterior Thigh Compartment

So... I saw this photo and couldn't resist diagramming it out. We haven't covered the anterior thigh on this blog just yet, but do not fret, my anatomy friends! It will come very soon. For now let me just explain the muscular organization of the thigh. First, the photo:

Batman certainly uses his anterior thigh muscles when rollerskating. I mean, look at that definition! When I saw this photo awhile back, it went right into my "Must Diagram" folder. Because it provides a wonderful, clear example of the anterior thigh landscape in a weight bearing leg.

The human thigh is divided into three muscle compartments. Within these compartments are specific muscle groups. The difference between a muscle compartment and a muscle group is this: A muscle compartment is based on location (such as anterior compartment, posterior compartment, etc.) and a muscle group is based on function (such as flexor group, adductor group, etc.)

The human thigh has three muscle compartments, and each of these compartments has its own muscle group:

• The anterior compartment (on the anterior side of the thigh) houses the leg extensor group (the muscles that extend, or straighten, the leg at the knee joint.)

• The posterior compartment (on the posterior side of the thigh) houses the leg flexor group (the muscles that flex, or band, the leg at the knee joint.)

• The medial compartment (on the medial side of the thigh) houses the leg adductor group (the muscles that adduct the thigh, or pull it inward toward the midline. More about the midline here.)

There is no lateral compartment on the thigh, although there is one structure on the lateral side of the thigh that does not belong to any specific compartment-- the iliotibial band. We can see the iliotibial band when drawing the figure and we discussed it briefly in a previous post, The Lateral Knee: A Change of Scenery. In the photo shown here, we can also see tensor fasciae latae, the muscle responsible for tensing the iliotibial band, on the lateral side of the thigh. (Tensor fasciae latae means tensor of the wide band.)

OK, let's diagram this thing out:

Here we see three muscles of the thigh's anterior compartment, plus a few other structures. (As a side note, there are actually four muscles in the anterior compartment, but one is not superficial so we can't see it.) The three anterior compartment muscles that we can see here are rectus femoris (a bipennate muscle that runs down the middle of the anterior thigh, directly above the patella,) vastus medialis, and vastus lateralis. The fourth anterior compartment muscle, which we cannot see on the surface, is called vastus intermedius.

Because there are four muscles in the anterior compartment that all insert into the same tendon, they are often collectively referred to as the quadriceps, which means four-headed muscle. And the tendon into which they insert is called the quadriceps tendon. You might sometimes see this referred to as the patellar tendon, as it attaches superiorly to the patella.

There will be more detailed thigh posts later, in which we'll explore each compartment much more thoroughly. But next time, we'll be returning to the elbow joint. See you then!