Video: Ligaments of the wrist and hand

Hey there! Welcome to the Museum of Natural History. Thanks for joining me today. I'm Kavita, the daytime security guard. There's something not quite right about the skeleton's hand. It looks like a ligament is completely ruptured. Now, how on earth would that happen?

I need to call maintenance. What ligament should I say needs fixed? Ahhh…any ideas? I think we're going to need to go through the normal anatomy of the ligaments of the wrist and hand first then maybe we might have the answer. Let's take a look at what we're going to learn today.

There's no two ways about it. There are a lot of ligaments in the wrist and hand and they can be a real pain to learn. So to make things easier, we've categorized the ligaments into more manageable subgroups based on the bones and joints they're associated with.

We'll cover all of the ligaments associated with the distal radioulnar joint, the radiocarpal joint, the intercarpal joints, the carpometacarpal joints, the intermetacarpal joints, the metacarpophalangeal joints, the interphalangeal joints, and finally, the ligaments of the phalanges. We'll then finish the tutorial off with some clinical notes to help consolidate our knowledge.

Ligaments are important soft tissue structures which usually attach bone to bone, and therefore, it is essential that you understand the bony structure of the hand and wrist before you learn about their associated ligaments. So let's just have a quick look at the bones of the wrist and hand now.

The distal end of the radius and ulna, which are the two bones of the forearm, articulate to form the distal radioulnar joint. This joint lies just proximal to the radiocarpal or wrist joint. The wrist is made up of the distal end of the radius, the triangular fibrocartilaginous complex, and the carpal bones.

There are eight carpal bones altogether which can be divided into proximal and distal rows. Let's start with the proximal row. This is the scaphoid, the lunate, the triquetrum, and the small pea-shaped bone is the pisiform bone. The distal row is made up of the trapezium, the trapezoid, the capitate, and the hamate bones. The carpal bones articulate with each other to form the intercarpal joints.

The distal row of carpal bones articulates with the next group of bones of the hand – the metacarpal bones – at the carpometacarpal joints. These bones can be numbered from 1 to 5, from lateral to medial as we can see here. You can also name them by their associated digit; for example, the 2nd metacarpal is the metacarpal of the index finger. The base of each metacarpal bone articulates with the adjacent metacarpal bone at the intermetacarpal joints.

The distal end of each metacarpal articulates with the final group of bones – the phalanges – forming the metacarpophalangeal joints. The phalanges are the bones of our fingers. They can be divided into proximal, middle, and distal phalanges. These phalanges articulate with their proximal and distal counterparts at the interphalangeal joints.

That was a very brief overview of the bones of the wrist and hand. If you want to find out more, feel free to check out our tutorial on the bones of the hand. Now on to the ligaments themselves, starting with the ligaments of the distal radioulnar joint.

The distal radioulnar joint is formed by the articulations between the head of the ulna and the ulnar notch of the radius. Stabilizing this joint is the distal radioulnar ligament group which is made up of two ligaments – the palmar radioulnar ligament and the dorsal radioulnar ligament. Let's take a look at each of these ligaments now, beginning with the palmar radioulnar ligament.

As its name suggests, this ligament is located on the palmar or volar surface of the distal radioulnar joint. It attaches to the palmar aspect of the distal radius and extends to attach to the head of the ulna. The dorsal radioulnar ligament can be found on the dorsal surface of the distal radioulnar joint. It attaches the dorsal aspect of the distal radius to the base of the styloid process of the ulna. The palmar and dorsal radioulnar ligaments work together to stabilize the radioulnar and ulnocarpal joints while also facilitating movement at the wrist joint.

Now moving distally, we come to the ligaments of the wrist. Let's begin with a look at the ligaments which surrounds the radiocarpal, or as it's more commonly known, the wrist joint.

As its name suggests, this joint is made up of the articulations between the distal end of the radius and three carpal bones of the hand, namely, the scaphoid, lunate, and triquetrum bones. The distal portion of the ulna does not directly articulate with the carpal bones but articulates with the triangular fibrocartilage complex of the wrist which in turn articulates with the carpal bones of the hand. Many of the ligaments which surround this joint are thickenings of the joint capsule and can be tricky to decipher so just keep that in mind.

We'll look at the five main ligaments here – the palmar and dorsal radiocarpal ligaments, the palmar ulnocarpal ligament, and the radial and ulnar collateral ligaments. You'll notice that quite conveniently most ligaments of the hand and wrist are named after the bones they connect so the radiocarpal ligament, for example, attaches the radius to the carpal bones.

Maybe they're not so bad after all.

The first ligament is the palmar radiocarpal ligament. It is a flat broad ligament that extends from the radius to the carpal bones. This ligament is made up of four ligamentous bands known as the palmar radioscaphocapitate ligament, the palmar radioscapholunate ligament, and the short and long palmar radiolunate ligaments.

The radiolunate ligaments have been historically known as the radiolunotriquetral ligament as some fibers extend to the triquetrum bone. However, those fibers have been shown to be fine and few, so the term radiolunate ligaments is preferred. These four bands stretch from the distal end of the radius to attach to the scaphoid, lunate, triquetrum, and capitate bones of the hand. These ligaments function to limit hyperextension of the hand at the wrist joint.

If we flip our wrist around to the dorsal aspect, we can find the dorsal radiocarpal ligament. This ligament is much smaller and weaker than its palmar counterpart and functions to limit hyperflexion at the wrist joint. It extends in a medial and inferior direction from the dorsal radial tubercle of the distal radius to reach the dorsal aspect of the triquetrum bone and the lunotriquetral interosseous ligament which we will meet soon.

Moving back around to the palmar surface of the wrist, we find the palmar ulnocarpal ligament. This ligament arises from the anterior margin of the triangular fibrocartilage complex, the palmar radioulnar ligament, and the styloid process of the ulna. It divides into four parts and courses distally and obliquely towards the capitate, lunate, triquetrum, and pisiform bones forming the ulnocapitate, ulnolunate, ulnotriquetral, and ulnopisiform divisions, respectively. Let's take a quick look at each of these divisions.

The ulnocapitate ligament, as we can see here, extends from the palmar aspect of the ulnar head to reach the capitate bone as its name suggests. The ulnolunate ligament arises from the ulna indirectly via the palmar radioulnar ligament and extends to reach the lunate bone. The ulnotriquetral ligament also extends from the palmar radiolunate ligament and from the styloid process of the ulna. It travels distally to insert onto the triquetrum bone of the hand.

The final division of the palmar ulnocarpal ligament is the ulnopisiform ligament. It extends from the distal aspect of the ulna to attach to the small pisiform bone. This ligament is considered by some sources as a subdivision of the ulnar collateral ligament of the wrist, which we'll see in a bit. So don't be surprised if you see it labeled as the accessory ulnar collateral ligament.

Working together, these ligaments serve to prevent palmar translocation of the ulna and carpal bones and allow the hand to follow the radius in its movements. They also limit adduction and ulnar deviation at the wrist joint.

Now that we've met the dorsal and palmar ligaments of the wrist, let's take a look at the collateral ligaments of the wrist joint. These ligaments are located on the medial and lateral aspects of the wrist.

The radial collateral ligament of the wrist joint is located on the radial or lateral aspect of the wrist and extends from the styloid process of the radius to the scaphoid bone. It aids in strengthening the articular capsule and provides stability to the radiocarpal articulation.

The ulnar collateral ligament of the wrist joint lies on the ulnar or medial aspect of the wrist, as its name suggests. This ligament arises from the styloid process of the ulna and extends distally to insert onto the triquetrum bone of the hand. This ligament is much less robust, but much like the radial collateral ligament of the wrist, it also strengthens the articular capsule and aids in stabilizing the joint.

Before we move on to the intercarpal ligaments, let's just take a quick look at the triangular fibrocartilaginous complex.

The triangular fibrocartilaginous complex is a load-bearing structure located on the medial aspect of the wrist. It is both a cartilaginous and ligamentous structure which acts as a major stabilizer of both the radiocarpal and ulnocarpal joints. The triangular fibrocartilaginous complex contains a fibrocartilaginous articular disc. This is the triangle of fibrocartilage.

The rest of the complex is composed of the ulnar collateral ligament, dorsal and palmar radioulnar ligaments, the extensor carpi ulnaris tendon sheath, the ulnocarpal meniscus homologue, and the ulnolunate and ulnotriquetral parts of the palmar ulnocarpal ligament. It extends from the ulnar notch of the radius and from the base of the styloid process of the ulna. From there, the complex extends to attach to the sheath of the extensor carpi ulnaris tendon; the lunate, hamate, and triquetrum carpal bones; and finally, to the base of the 5th metacarpal through the fibers of the ulnar collateral ligament.

Now that we've looked at some of the ligaments of the wrist joint, let's take a look at the intercarpal ligaments.

The intercarpal ligaments are the ligaments which originate and insert at the carpal bones. The eight carpal bones articulate with each other forming numerous intercarpal joints which are named after their articulating bones. The proximal and distal rows of carpal bones articulate with each other at the midcarpal joint. The intercarpal ligaments can be divided into three groups – the palmar intercarpal ligaments, the dorsal intercarpal ligaments, and the intercarpal interosseous ligaments.

Before we jump in to take a look at the intercarpal ligaments, let's take a look at two ligamentous bands which lie just superficial to these intercarpal ligaments. Arching over the palmar surface of the carpal bones of the hand is a fibrous band known as the flexor retinaculum. This structure is sometimes also referred to as the transverse carpal ligament although some anatomy scholars do not consider it a ligament. Whatever you want to call it, it's a connective tissue structure worth knowing about. It attaches to the scaphoid and trapezium bones extending to insert onto the pisiform and hamate bones. It also partially attaches to the palmar aponeurosis and deep fascia of the forearm. This structure forms the roof of the carpal tunnel and helps stabilize the carpal bones.

If we flip the hand over to its dorsal surface, we will also find an extensor retinaculum present. This is a flat ligamentous sheet stretching from the distal radius to the pisiform and triquetrum bones of the hand. This fibrous band functions to maintain the alignment of the extensor tendons of the forearm.

Deep to the flexor retinaculum, we meet the first group of intercarpal ligaments – the palmar intercarpal ligaments. The palmar intercarpal ligaments are a collection of fibrous transverse bands which extend across the palmar surface of adjacent carpal bones forming multiple ligamentous connections. These ligaments can be broken down into several separate ligaments which are named after the bones they connect. Let's take a look at each of them now.

The radiate carpal ligaments are a fan-shaped group of ligaments located on the palmar surface as we can see here. As a structure, it forms the floor of the carpal tunnel. In literature, the palmar intercarpal ligaments and radiate carpal ligaments are often used interchangeably to refer to the ligaments located on the palmar surface of the carpal bones. However, the term radiate carpal ligaments specifically refers to a set of palmar intercarpal ligaments which radiate from the capitate bone. Its fibers originate from the capitate bone to insert onto the triquetrum, scaphoid, hamate, and trapezoid carpal bones forming several separate ligaments. This ligament aids in stabilizing the intercarpal joints which they cross.

Let's take a look at the four palmar intercarpal ligaments which fall into the radiate carpal ligament category.

The first ligament which radiates from the capitate bone is the scaphocapitate ligament. It is part of the deep fibers of the radiate carpal ligament. This ligament connects the scaphoid bone to the capitate bone. Next is the triquetrocapitate ligament. This short fibrous band travels in a transverse direction connecting the distal margin of the triquetrum bone to the body of the capitate bone. The palmar capitohamate ligament is another small ligament within the radiate carpal category. As its name suggests, it attaches the capitate to the hamate bone of the carpals. The final ligament of the radiate carpal ligaments is the palmar trapezoideocapitate ligament. This is a short ligament which extends transversely from the trapezoid to the capitate bone.

The other six palmar intercarpal ligaments do not radiate from the capitate bone, but sit between adjacent carpal bones on the palmar surface. Let's take a quick look at these now.

This ligament is a bit of a mouthful. The scaphotrapeziotrapezoidal ligament is a V-shaped ligament which as its name suggests connects the distal point of the scaphoid bone to the trapezoid and trapezium bones. Another ligament which attaches to the scaphoid bone is the palmar scaphotriquetral ligament. You'll find that most sources do not include this ligament when talking about the ligaments of the hand, however, a study has shown its existence, so we have outlined its approximate location here. This ligament extends transversely across the palmar surface of the carpal region from the scaphoid to triquetrum bone. Its function is not fully understood but it's thought to support the head of the capitate bone during wrist extension.

The next ligament that contributes to the formation of the palmar intercarpal ligaments is the palmar lunotriquetral ligament. This ligament travels transversely connecting the lunate and triquetrum bones. The triquetrohamate ligament extends distally from the distal end of the triquetrum to reach the hook of the hamate bone.

Next, we'll meet two ligaments which attach to the pisiform carpal bone of the hand. The pisotriquetral ligament is a really tiny ligament extending from the triquetrum to the dorsal aspect of the small pisiform bone. Stretching between the pisiform bone and the hook of the hamate, we find the final palmar intercarpal ligament – the pisohamate ligament. It is continuous with the tendon of the flexor carpi ulnaris muscle and therefore can be quite difficult to identify.

These ten palmar intercarpal ligaments all work together to stabilize the intercarpal joints and prevent the dorsal displacement of the carpal bones.

Now let's flip the hand around and take a look at the dorsal surface of the carpal bones. This main ligament here is naturally known as the dorsal intercarpal ligament. It is formed by multiple fibrous bands which extend transversely across the dorsal surface of the carpal bones. It arises from the dorsal tubercle of the triquetrum bone and attaches to the dorsal groove of the scaphoid bone sometimes passing additional fibers to the trapezium, trapezoid, and capitate bones. This ligament aids in stabilizing the proximal row of carpal bones.

Also on the dorsal aspect, but separate from the dorsal intercarpal ligament, we find a short fibrous band known as the dorsal triquetrohamate ligament. You know the drill by now. Just break down the name and you'll have the bones it connects – the triquetrum and the hamate. You might not have heard of this small structure as some sources do not include it when talking about the ligaments of the hand but we don't discriminate and we decided to add it to our list.

Many of the intercarpal ligaments travel over bones connecting them to each other; however, some ligaments lie directly between adjacent bones. These ligaments are known as interosseous ligaments and usually present as short fibrous bands. These ligaments lie within the joint capsule unlike the palmar and dorsal intercarpal ligaments which are bound in the substance of the joint capsule.

There are two interosseous ligaments in the proximal row of the carpal bones. The first is the scapholunate interosseous ligament which extends between the scaphoid and lunate bones. We have added this ligament to the dorsal aspect of the hand to help visualize its location but note that the interosseous ligaments are located between two bones and can be virtually invisible from the surface a lot of the time. Another interosseous intercarpal ligament is the lunotriquetral interosseous ligament. This ligament spans between the lunate and triquetrum bones as its name suggests.

Moving on to the distal row, we first encounter the trapeziotrapezoidal interosseous ligament. It sits just between the trapezium and trapezoid bones. Here is the trapezoideocapitate ligament. As we can see from this dorsal view of the carpal bones, this ligament stretches between the trapezoid and adjacent capitate bone of the hand. The final interosseous intercarpal ligament is the capitohamate interosseous ligament. This ligament stretches between the capitate and adjacent hamate bone.

These interosseous intercarpal ligaments aid in providing stability to the intercarpal joints.

Phew! That's quite a lot of ligaments. Why don't we take a brief intermission here, give our minds a break, and watch the waves crashing on this relaxing beach.

Okay, we're back. Now that we've had a look at the ligaments of the intercarpal joints, let's move distally to look at the ligaments of the carpometacarpal joints.

The distal row of carpal bones articulate with the five metacarpal bones of the hand forming the carpometacarpal joints. We're going to look at two ligaments which stabilize and support each of the five carpometacarpal joints – the dorsal carpometacarpal ligaments and the palmar carpometacarpal ligaments. Let's begin on the dorsal surface of the hand this time.

Here you'll find the dorsal carpometacarpal ligaments. These ligaments span across the bases of the metacarpal bones creating a ligamentous bridge between the distal row of carpal bones and metacarpal bones. At the base of the 2nd metacarpal are two dorsal carpometacarpal ligaments which attach to the trapezium and trapezoid carpal bones. The 3rd metacarpal has two ligaments, attaching to the trapezoid and capitate bones of the hand; the 4th metacarpal bone, another two ligaments which attach to the capitate and hamate bones; and finally, the 5th metacarpal has only one ligament which attaches to the hamate bone.

This collection of ligaments aids in stabilizing the carpometacarpal joints while also allowing for limited gliding movements at the joints.

Moving over to the palmar surface of the hand, we have the palmar carpometacarpal ligaments. These ligaments are very similar to the dorsal carpometacarpal ligaments except that they are found on the palmar surface. The ligament arrangement is quite similar to their dorsal counterparts. There are two bands associated with the 2nd metacarpal – one to the trapezoid, and one to the trapezium bone. The 4th metacarpal is connected to the capitate and the hamate while the 5th metacarpal only has one band anchoring it to the hamate bone.

The difference lies at the 3rd metacarpal bone which has three associated ligaments. These three ligaments span from the 3rd metacarpal and attach to the trapezoid, capitate, and hamate bones on the palmar surface of the hand. Of special note is the pisometacarpal ligament. This small ligament attaches from the palmar aspect of the pisiform to the base of the 5th metacarpal. Although this ligament attaches to a metacarpal bone, it functions more like an intercarpal ligament as it stabilizes the pisotriquetral joint as it passes over it.

As well as being anchored to the carpal bones, the metacarpals are joined to each other at the intermetacarpal joints which brings us to our next group of ligaments – the intermetacarpal ligaments. The metacarpal bones articulate with each other at the proximal end or base forming intermetacarpal joints. Let's take a look now at the three types of metacarpal ligaments which surround these joints.

On the palmar surface, you will find the four palmar metacarpal ligaments. These ligaments similarly attach the palmar surfaces of the bases of adjacent metacarpal bones connecting the five metacarpal bones together. These four palmar metacarpal ligaments contribute to the intermetacarpal joint stability. On the dorsal aspect of the hand are the dorsal metacarpal ligaments. These four short ligaments connect the five metacarpal bones together. They attach to the base of the dorsal aspect of each metacarpal bone and aid in stabilizing movements through the intermetacarpal joints.

The final ligaments which contribute to the intermetacarpal joint stability are the interosseous metacarpal ligaments. As with all interosseous ligaments, these ligaments sit right between the articulating metacarpal bones and thus are covered by their palmar and dorsal counterparts.

If you look at a radiological image, however, you can see it sitting snuggly between two adjacent metacarpal bones. They can be found between the base of each metacarpal inside the joint capsule. Their function? You guessed it. They contribute to joint stability.

Traveling distally, we meet our next group of ligaments – the ligaments of the metacarpophalangeal joints.

At the distal ends of the metacarpal bones, we meet the metacarpophalangeal joints. These joints represent the articulations between the metacarpal head and the proximal phalanx of each of the five digits. These joints are also known as your knuckles as they form that bony protrusions that appear when you flex your fingers at the metacarpophalangeal joints. Let's look at the types of ligaments which aid in stabilizing these joints.

On either side of each metacarpophalangeal joint are the collateral ligaments consisting of three separate bands. The first are the proper collateral metacarpophalangeal ligaments which lie on the medial and lateral aspects of each joint. They attach to the posterior tubercle of each distal metacarpal and extend distally to attach to the palmar aspect of the base of each proximal phalanx.

The accessory collateral metacarpophalangeal ligaments arise from the anterior tubercle of each metacarpal head extending obliquely towards the palmar surface of the hand to attach to the palmar metacarpophalangeal ligaments.

The most superficial of the collateral ligaments are the phalangoglenoid ligaments. These ligaments extend obliquely from the base of the proximal phalanx and attach to the collateral ligament, the annular ligament, and the palmar plates. Together with the accessory collateral ligaments, the phalangoglenoid ligaments help distribute the force from the flexor tendons they are closely related to thus stabilizing the metacarpophalangeal joints.

On the palmar aspect of the metacarpophalangeal joints, you will find the palmar metacarpophalangeal ligaments. These are dense fibrocartilaginous thickenings of the metacarpophalangeal joint capsule. They are loosely attached to the palmar aspect of the metacarpal neck but firmly adhered to the palmar surface of the base of the corresponding proximal phalanx. The primary function of these ligaments is to prevent hyperextension at the metacarpophalangeal joints.

The final ligament of the metacarpophalangeal joints is the deep transverse metacarpal ligament. You might wonder why it's called the deep ligament. Historically, it has a superficial counterpart embedded in the fascia of the hand. This superficial ligament is now more commonly known as the natatory ligament.

The deep transverse metacarpal ligament consists of three narrow fibrous bands that run across the palmar aspect of the 2nd to 5th metacarpophalangeal joints connecting them together. Their palmar surfaces are connected to the digital slips of the central palmar aponeurosis. These ligaments mainly contribute to the stability at the MCP joints during gripping actions.

We're now on to the last joints of the hand, and therefore, our last group of ligaments. We're now looking at the interphalangeal joints and their ligaments as well as the ligaments associated with the phalanges.

There are nine interphalangeal joints in the hand – one in the thumb and two each in the other four digits. These joints are formed by the articulation of the proximal, middle, and distal phalanges except for the thumb which lacks a middle phalanx. Each of these joints is covered with a fibrous joint capsule. Associated with these joints are the palmar and collateral interphalangeal ligaments. Let's start off by taking a closer look at the palmar interphalangeal ligaments.

These ligaments present as a thick plate of fibrocartilage and are located on the palmar surface of each interphalangeal joint. They are often referred to as the palmar or volar plates. These ligaments have a characteristic upside down U-shape with its distal part arching across and attaching to the base of the more distal phalanx.

The proximal aspect of this ligament attaches and blends with the periosteum of the proximally-situated phalanx. These ligaments prevent hyperextension at the corresponding interphalangeal joint.

The final ligaments of the interphalangeal joints are the collateral interphalangeal ligaments of the hand. These ligaments can be found on either side of each interphalangeal joint arising from the head of the more proximal phalanx and extending to the palmar aspect of its distal counterpart.

At the proximal interphalangeal joints, we will normally find the same three divisions we saw at the metacarpophalangeal joints – the collateral proper, the accessory collateral, and the phalangoglenoid ligaments. At the distal interphalangeal joints, however, normally only collateral proper and accessory collateral ligaments are present. These ligaments help to prevent excessive adduction-abduction movements of the interphalangeal joints.

We're on to our last two groups of ligaments for the day and they aren't strictly associated with the interphalangeal joints but rather with the phalanges themselves.

The first is a slightly peculiar-looking group of ligaments known as the annular ligaments. Rather than being simple bands, the annular ligaments form small hoops on the palmar surface of the digits through which the flexor digitorum tendons pass. There are two annular ligaments associated with the phalanges of the thumb and five in each of the four fingers.

The other group is the cruciform ligaments. In some sources, also known as the cruciate ligaments, these structures consist of two obliquely-crossed bands. These ligaments are only present in digits 2 to 4 and there are three associated with each digit. While two are normally easily distinguished, the most distal cruciform ligament normally blends with the annular ligaments. The thumb is devoid of cruciform ligaments and instead has a Y-shaped stabilizing ligament located between the two annular ligaments.

The cruciform and annular ligaments contribute to the flexor tendon sheath. The sheath facilitates gliding of the tendons. The ligaments also anchor the tendons to the digits preventing the bowstring effect. The tendons tighten during flexion of the metacarpophalangeal and interphalangeal joints and have to be anchored to the phalanges to maintain their strength and maximize the range of motion of the fingers. Finally, the positioning of the ligaments allows for force distribution from the tendons to the phalanges.

Phew! That was a lot of ligaments. By now, we should be in a good place to answer the question at the start of the video. Just before we finish up though, let's have a look at some clinical notes on the joints of the wrist and hand.

As we now know, the scapholunate ligament is one of the ligaments which connects the scaphoid and lunate carpal bones. It is one of the most commonly injured carpal ligaments. Scapholunate ligament tears are usually caused by sudden weightbearing injuries such as falling onto an outstretched hand. The sudden onset of weight to the scapholunate joint can lead to a rupture or tear in the ligament which can subsequently lead to carpal instability. Scapholunate ligament tears present with dorsal and radial wrist pain, wrist instability and weakness, a clicking or catching at the wrist, and swelling. On examining the wrist, you might notice limited grip strength – a good indicator to investigate further.

The gold standard for diagnosing a scapholunate tear is through the use of arthroscopy. Treatment for any ligamentous injuries can be long and arduous and the scapholunate ligament is no exception. Conservative treatment involves the use of nonsteroidal anti-inflammatory drugs, the application of RICE (RICE, RICE, baby), and splinting. In most cases, surgical intervention is necessary and may even involve the use of tissue engineering processes in order to increase ligament strength.

Before we finish this tutorial, let's take a look at a quick summary of what we learned today.

We began this tutorial by taking a look at the ligaments of the distal radioulnar joint. Here we met the palmar and dorsal radioulnar ligaments which extend between the distal portion of the radius and ulna. Next, we had a look at the ligaments of the radiocarpal joint. Here, there were five groups of ligaments. The first of these was the palmar radiocarpal ligament located on the palmar surface of the wrist. We identified its five ligamentous bands which are known as the palmar radioscaphocapitate ligament, the palmar radioscapholunate ligament, the palmar radiolunotriquetral ligament, and the short and long palmar radiolunate ligaments.

On the dorsal aspect of the wrist, we met the dorsal radiocarpal ligament which extends from the dorsal surface of the distal radius to reach the triquetrum and lunotriquetral interosseous ligament.

Moving back around to the palmar surface of the wrist, we identified the four ligaments which form the palmar ulnocarpal ligaments – the ulnocapitate ligament, the ulnolunate ligament, the ulnotriquetral ligament, and the ulnopisiform ligament. The final ligaments of the radiocarpal joint were the radial collateral ligament and the ulnar collateral ligament which are located on the lateral and medial aspects of the wrist.

Before we moved on to the ligaments of the intercarpal joints, we had a quick look at the triangular fibrocartilage complex which can be found at the distal aspect of the radius and ulna. This structure stabilizes both the radiocarpal and ulnocarpal joints.

Ligaments of the intercarpal joints came next. Here we met the flexor retinaculum, which is a broad ligamentous band that stretches over the palmar surface of the carpal bones. This structure forms the roof of the carpal tunnel and aids in stabilizing the carpal bones. On the dorsal aspect of the hand, we also met the extensor retinaculum which similarly stretches over the dorsal surface of the carpal bones. This ligamentous band functions to maintain the alignment of the extensor tendons of the forearm.

On the palmar surface of the carpal bones, we met the palmar intercarpal ligaments which are formed by ten separate ligaments. Four of these ligaments radiate from the capitate bone. This group of palmar ligaments are known as the radiate carpal ligaments and include the scaphocapitate ligament, the triquetrocapitate ligament, the palmar capitohamate ligament, and the palmar trapezoideocapitate ligament.

The other six palmar intercarpal ligaments do not radiate from the capitate bone but sit between the adjacent carpal bones on the palmar surface. These six palmar ligaments include the scaphotrapeziotrapezoidal ligament, the palmar scaphotriquetral ligament, the palmar lunotriquetral ligament, the triquetrohamate ligament, the pisotriquetral ligament, and the pisohamate ligament.

On the dorsal surface of the carpal bones, we also met the dorsal intercarpal ligament. This ligament aids in stabilizing the proximal row of carpal bones. Here we found another ligament – the dorsal triquetrohamate ligament. This is a short ligament which stretches from the triquetrum to the hamate.

Extending between adjacent carpal bones are the five interosseous intercarpal ligaments which are named by the bones which they connect. These five ligaments include the scapholunate interosseous ligament, the lunotriquetral interosseous ligament, the trapeziotrapezoidal interosseous ligament, the trapezoideocapitate interosseous ligament, and the capitohamate interosseous ligament.

Next, we move to distally to take a look at the ligaments surrounding the carpometacarpal joints. Here we met the dorsal carpometacarpal ligaments, the palmar carpometacarpal ligaments, and the pisometacarpal ligament. We also had a look at the three intermetacarpal ligaments which connect the bases of the metacarpal bones together. We met the palmar metacarpal ligaments, which attach to the base of the palmar aspect of each metacarpal bone, and the dorsal metacarpal ligaments, which attach to the base of the dorsal aspect of each metacarpal bone.

The final ligaments which contribute to the intermetacarpal joint stability are the interosseous metacarpal ligaments.

Moving distally, we came to the articulations between the metacarpal heads and proximal phalanges known as the metacarpophalangeal joints. Here we explored ligaments which surround this joint. We met the collateral metacarpophalangeal ligaments which are made up of the proper collateral metacarpophalangeal ligaments and the accessory collateral metacarpophalangeal ligaments. This group of ligaments act as the main stabilizers of the metacarpophalangeal joints.

On the palmar aspect of the metacarpophalangeal joints, we identified the phalangoglenoid ligaments. These ligaments work together with the accessory collateral ligaments to distribute the force from the flexor tendons, stabilizing the metacarpophalangeal joints.

Next, we met the palmar metacarpophalangeal ligaments. These are dense fibrocartilaginous thickenings located on the palmar aspect of the metacarpophalangeal joint capsule. The final metacarpophalangeal ligament was the deep transverse metacarpal ligament which runs across the palmar aspect of metacarpals 2 to 5.

The penultimate group of ligaments that we looked at today were the ligaments which surround and stabilize the interphalangeal joints. The palmar interphalangeal ligaments can be found on the palmar surface of the interphalangeal joints. These ligaments prevent hyperextension at each corresponding interphalangeal joint. Located on either side of each interphalangeal joint are the collateral interphalangeal ligaments. These ligaments prevent excessive adduction-abduction movements of the interphalangeal joints.

The final two ligaments that we looked at today were the ligaments associated with the phalanges, namely, the annular and cruciform ligaments. The annular ligaments are transverse fibrous bands found on the palmar aspect of the phalanges which aid in preventing bowstringing of the flexor tendons. The cruciform ligaments are two obliquely-crossed fibrous bands which are only present in digits two to four. These ligaments work together with the annular ligaments to prevent bowstringing of the flexor tendons.

To finish off today's tutorial, we had a quick look at the scapholunate ligament tears, which can occur after falling onto an outstretched hand. We explored their presentation, diagnosis, and treatment.

And we did it! I hope you enjoyed learning about the many ligaments of the wrist and hand. See you next time and happy studying!