Logan Steele
The flexor digitorum profundus is a muscle in the forearm that flexes the fingers. It is an extrinsic hand muscle, with its muscle belly located in the forearm. The flexor digitorum profundus is the main gripping muscle, and it acts to flex the wrist, metacarpophalangeal, and interphalangeal joints. It is one of two flexor muscles that is not supplied by the median nerve. The flexor digitorum profundus tendon splits into four slips that attach to the palmar surfaces of the bases of the distal phalanges of the index, middle, ring, and small fingers.
| Characteristics | Values |
|---|---|
| Muscle name | Flexor digitorum profundus (FDP) |
| Muscle type | Powerful finger flexor |
| Muscle group | Thenar muscle group |
| Muscle belly | Common muscle belly for the middle, ring, and small fingers |
| Muscle action | Flexes the fingers, or digits |
| Muscle function | Chief gripping muscle |
| Muscle origin | Upper 3/4 of the anterior and medial surfaces of the ulna, interosseous membrane and deep fascia of the forearm |
| Muscle insertion | Tips of the index, middle, ring, and small fingers |
| Muscle contraction | Produces mass action movement in all 4 tendons |
| Muscle power | Used to aid the lumbrical muscles in their role as extensors of the interphalangeal joints |
| Muscle blood supply | Muscular branches from the ulnar artery, anterior interosseous artery, and common interosseous artery |
| Muscle nerve supply | Anterior interosseous branch of the median nerve (C8 and T1) |
Explore related products
What You'll Learn
Flexor digitorum profundus
The flexor digitorum profundus (FDP) is a muscle in the forearm that flexes the fingers. It is considered an extrinsic hand muscle because it acts on the hand while its muscle belly is located in the forearm. It is the main gripping muscle, acting best when the wrist is extended.
The FDP originates in the upper 3/4 of the anterior and medial surfaces of the ulna, interosseous membrane, and deep fascia of the forearm. The muscle fans out into four tendons, one for each of the second to fifth fingers, which attach to the palmar base of the distal phalanx. The FDP is a flexor of the midcarpal (wrist), metacarpophalangeal, and interphalangeal joints.
The FDP aids the lumbrical muscles in their role as extensors of the interphalangeal joints. The lumbricals attach to the tendons of the FDP and transfer power to fully extend the fingers as well as flex the metacarpophalangeal joints. The tension generated by the FDP at the more distal joints is determined by wrist position. Flexion of the wrist causes muscle shortening, reducing the tension that can be generated more distally, and preventing full flexion of the fingers.
The FDP is one of two flexor muscles that is not exclusively supplied by the median nerve. It is a hybrid or composite muscle, innervated by the anterior interosseous nerve and ulnar nerves. The medial aspect of the muscle, which flexes the 4th and 5th digits, is supplied by the ulnar nerve, while the lateral aspect, which flexes the 2nd and 3rd digits, is innervated by the median nerve via the anterior interosseous branch.
Understanding Voluntary Muscles and Their Unique Functions
You may want to see also
Explore related products
Flexor digitorum superficialis
The flexor digitorum superficialis (FDS) is an extrinsic flexor muscle of the fingers at the proximal interphalangeal joints. It is found in the anterior compartment of the forearm, originating from the medial epicondyle (an elbow bone) and arising from the medial epicondyle of the humerus and the medial border of the coronoid process of the ulna. The FDS is sometimes considered the deepest part of the superficial layer of the anterior compartment, while others consider it a distinct "intermediate layer".
The flexor digitorum superficialis has four independent muscle bellies, from which four tendons arise. These tendons attach to the anterior margins on the bases of the intermediate phalanges of the four fingers (excluding the thumb). The primary function of the FDS is to bend the middle phalanges of these four fingers at the proximal interphalangeal joints. However, under continued action, the FDS also flexes the metacarpophalangeal and wrist joints. The independence of each finger's FDS contributes to the hand's skill in performing tasks that require dexterity, such as using chopsticks.
The FDS is innervated by the median nerve (C7, C8, T1) and is enclosed by a common flexor sheath, sharing this with the flexor digitorum profundus. The median nerve travels between the FDS and the flexor digitorum profundus in the forearm. The FDS and flexor digitorum profundus also share a common synovial sheath.
The FDS can be tested by flexing one finger at the proximal interphalangeal joint against resistance while keeping the remaining three fingers fully extended to inactivate the flexor digitorum profundus. Another test is Modified Baker's test, where the patient flexes the proximal interphalangeal joint of the little finger while the examiner holds the other fingers extended. Then, the little and ring fingers are released to flex together to observe the improvement in joint flexion.
Separated Abdominal Muscles: Causes and Treatments
You may want to see also
Explore related products
Lumbrical muscles
The lumbrical muscles are a set of four intrinsic hand muscles that are essential for the fingers' precision grip and fine motor control. They are cylindrical and worm-like, resembling earthworms belonging to the genus Lumbricus, which is where the name "lumbrical" comes from. Each finger is connected to two lumbricals, except for the thumb, which is associated with only one lumbrical muscle.
The lumbricals are unusual in that they do not attach to bone. Instead, they attach proximally to the tendons of the flexor digitorum profundus and distally to the extensor expansions. The first and second lumbricals (the most radial two) are innervated by the median nerve, while the third and fourth lumbricals (the most ulnar two) are innervated by the ulnar nerve. This is the most common innervation pattern, occurring in 50-60% of individuals. However, there are also cases where the median nerve innervates only the first lumbrical (20-30% of individuals) or the lateral three lumbricals (20-30% of individuals).
The lumbricals flex the metacarpophalangeal (MCP) joints and extend the proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints. By coordinating with other hand muscles, the lumbricals help control the fine and delicate movements of the fingers. These actions are essential for gripping objects, typing, and performing various dexterous hand movements.
The lumbricals have a high number of muscle spindles, indicating that they play a role in proprioception and sensory feedback. This is important for precision pinch movements and the precise manipulation of objects. The lumbrical muscles are sometimes damaged in crush injuries to the hand, and they have also been shown to be relevant in carpal tunnel syndrome.
High Reps for Muscle Tone: Fact or Fiction?
You may want to see also
Explore related products
Flexor carpi ulnaris
The flexor carpi ulnaris (FCU) is a muscle in the forearm that flexes and adducts at the wrist joint. It is the most medial flexor muscle in the superficial compartment of the forearm. The FCU is the only muscle in the anterior compartment that is fully innervated by the ulnar nerve. The muscle is built for power, bending and deviating the wrist away from the thumb. This is useful in actions such as throwing a dart or using a hammer.
The FCU originates with two heads, a smaller humeral head and a larger ulnar head, which are linked by a tendinous arch. The humeral head arises from the common flexor origin on the medial epicondyle of the humerus, while the ulnar head originates from the olecranon and upper two-thirds of the dorsal border of the ulna. As the muscle fibres converge towards the wrist joint, they form a long tendon in the distal part of the forearm. This tendon passes into the palmar surface of the hand and inserts onto the pisiform, hook of the hamate, and base of the fifth metacarpal bone.
The FCU tendon insertion is a useful landmark for locating the ulnar nerve and ulnar artery, which lie lateral to the tendon at the wrist joint. The FCU shares a common tendon with the other wrist flexors and is involved in various pathologies, such as medial epicondylalgia. The muscle can be palpated by identifying bony landmarks such as the medial epicondyle, olecranon process, and pisiform bone.
The FCU can be strengthened through exercises such as wrist rollers and wrist curls with dumbbells, which help prevent injury to the ulnar collateral ligament of the elbow joint.
Running and Muscle Gain: Friends or Foes?
You may want to see also
Explore related products
Flexor carpi radialis
The flexor carpi radialis (FCR) is a muscle in the forearm that acts to flex and radially abduct the hand. The name is derived from the Latin 'carpus', meaning wrist, and so the flexor carpi radialis is a flexor of the wrist. It is a long, thin, superficial muscle of the forearm that belongs to the anterior muscle group. It is part of the superficial layer of the anterior forearm compartment, along with the pronator teres, flexor carpi ulnaris, palmaris longus, and flexor digitorum superficialis muscles. All these muscles share the function of flexing the hand on the wrist, which is why the entire compartment is also called the flexor compartment of the forearm.
The flexor carpi radialis originates from the medial epicondyle of the humerus, via the common flexor tendon, and surrounding fascia (antebrachial fascia and intermuscular septa). This common flexor tendon is a common origin for the six long flexor muscles in the forearm: flexor carpi radialis, palmaris longus, flexor carpi ulnaris, pronator teres, flexor digitorum superficialis, and profundus. From the medial epicondyle, the muscle belly courses obliquely, crossing from the ulnar to the radial part of the forearm. In the lower third of the forearm, it gives off a long tendon that passes below the flexor retinaculum into the palmar surface of the hand.
The FCR tendon uses the scaphoid tuberosity as a pulley to reach its distal insertion onto the second metacarpal. It has been hypothesised that FCR muscle contraction generates a dorsally directed vector that resists the scaphoid from rotating into flexion. The FCR tendon is visible on the anterior surface of the forearm, just proximal to the wrist, when the wrist is flexed. It is the tendon seen most lateral, closest to the thumb. The innervation of this muscle is provided by the median nerve (C6-C7). The flexor carpi radialis mainly receives its blood supply (high up in the forearm) via the anterior or posterior ulnar recurrent artery. The rest of its nutritional needs are fulfilled by 6-8 branches of the radial artery.
The FCR is prone to tendonitis or even rupturing. Flexor tendon ruptures in the wrist are uncommon, but FCR tendon rupture can occur in rheumatoid patients, following cortisone injection for tenosynovitis, and following trauma. Attritional FCR tendon ruptures are also seen with scaphotrapezial arthritis.
Muscle Growth and Flexibility: Friends or Foes?
You may want to see also
Frequently asked questions
The flexor digitorum profundus is a muscle in the forearm that flexes the fingers. It is considered an extrinsic hand muscle because it acts on the hand while its muscle belly is located in the forearm. It is the main gripping muscle.
The flexor digitorum profundus has four tendons that emerge from the muscle and pass through the carpal tunnel, inserting into the tips of the index, middle, ring, and small fingers. It is able to bend all three finger joints. It usually works in synergy with the flexor digitorum superficialis, lumbricals, and flexor digiti minimi brevis muscles.
Some conditions that can affect the flexor digitorum profundus include Quadrigia and Jersey finger. Quadrigia occurs when the tendons to the medial three digits fuse with the tendon to the index finger, resulting in the patient's inability to make a full fist and weak grasp. Jersey finger is an FDP tendon rupture close to the base of a distal phalanx, affecting the fourth digit in most cases.
