Fingers Joints Flexion and Extension PDF 1446 H/2024 A.D

# 1446 H/2024 A.D ## Fingers Joints Flexion, and Extension ## Objectives: At the end of this lecture the student will be able to: 1. Explain origin, insertion, nerve supply and the action of primary muscles involved in metacarpo-phalangeal joints flexion, and extension. 2. Identify the range of mo...

# 1446 H/2024 A.D ## Fingers Joints Flexion, and Extension ## Objectives: At the end of this lecture the student will be able to: 1. Explain origin, insertion, nerve supply and the action of primary muscles involved in metacarpo-phalangeal joints flexion, and extension. 2. Identify the range of motion of metacarpo-phalangeal joints flexion, and extension. 3. Know how to perform the test procedures of metacarpo-phalangeal joints flexion and extension. 4. Know the effect of weakness of metacarpo-phalangeal joints flexors, and extensors. 5. Identify origin, insertion, nerve supply and action of primary muscles involved in proximal and distal inter-phalangeal joints flexion and extension. 6. Identify the range of motion of proximal and distal inter-phalangeal joints flexion, and extension. 7. Know how to perform the test procedures of proximal and distal inter-phalangeal joints flexion and extension. ## Content 1. Anatomy of primary muscles of metacarpo-phalangeal joints flexion. 2. Range of motion of metacarpo-phalangeal joints flexion. 3. Test procedures of metacarpo-phalangeal joints flexion. 4. Effect of weakness of metacarpo-phalangeal joints flexion. 5. Anatomy of primary muscles of proximal and distal inter-phalangeal joints flexion. 6. Range of motion of proximal and distal inter-phalangeal joints flexion. 7. Test procedures of proximal and distal inter-phalangeal joints flexion. 8. Anatomy of primary muscles of metacarpo-phalangeal joints extension. 9. Range of motion of metacarpo-phalangeal joints extension. 10. Test procedures of metacarpo-phalangeal joints extension. ## Metacarpo-phalangeal Joints Flexion Motion ### Primary Muscles: 1. Flexor digitorum superficialis 2. Flexor digitorum profundus ### Range of Motion: The range of motion of metacarpophalangeal joints flexion accompanied with extension of the interphalangeal joints is of 0 to 90. ### Anatomy of *Flexor digitorum superficialis* * **Origin:** Humeralulnar head: common flexor origin of medial epicondyle humerus, medial ligament of elbow, and medial border of coronoid process and fibrous arch. * **Radial head:** whole length of anterior oblique line. * **Insertion:** Tendons split to insert onto sides of middle phalanges of medial four fingers. * **Nerve Supply:** Median nerve. * **Action:** * Primarily it flexes proximal interphalangeal joints. * Secondarily it flexes metacarpophalangeal joints and wrist. ### Anatomy of *Flexor digitorum profundus* * **Origin:** Medial olecranon, upper three quarters of anterior and medial surface of ulna. * **Insertion:** Distal phalanges of medial four fingers. * **Nerve Supply:** * Median nerve for the lateral part of muscle. * Ulnar nerve for the medial part of the muscle. * **Action:** * Primarily it flexes distal interphalangeal joints. * Secondarily it flexes proximal interphalangeal and metacarpophalangeal joints and wrist. ### Effects of Weakness: Weakness of these muscles results in Claw-Hand deformity. ## Proximal Interphalangeal Joints Flexion Motion ### Primary Muscles: * Flexor digitorum superficialis ### Accessory * Flexor digitorum profundus ### Range of motion: The range of motion of proximal interphalangeal joints flexion is of 0° to 120°. ## Distal Interphalangeal Joints Flexion Motion ### Primary Muscles: * Flexor digitorum profundus ### Range of motion: The range of motion of distal interphalangeal joints flexion is of 0° to 80°. ## Metacarpo-phalangeal Joints Extension Motion ### Primary Muscles: 1. Extensor digitorum communis 2. Extensor indicis proprius 3. Extensor digiti minimi ### Range of motion The range of motion of metacarpophalangeal joints extension is of 0° to 20°-30°. ### Anatomy of *Extensor digitorum communis* * **Origin:** It arises from the lateral epicondyle of the humerus, by the common tendon * **Insertion:** It inserted in the extensor expansion of middle and distal phalanges of the 2nd, 3rd, 4th, and 5th fingers * **Nerve Supply:** Radial nerve. * **Action:** 1. Acting to extend the metacarpophalangeal joint. 2. Extension of the proximal and distal interphalangeal joints. 3. It assists in extension of wrist and elbow. ### Anatomy of *Extensor indicis proprius* * **Origin:** posterior distal third of ulna and interosseous membrane. * **Insertion:** it projects into the dorsal aponeurosis of the index finger. * **Nerve Supply:** Radial nerve. * **Action:** 1. Extends index finger. 2. It assists in extension of wrist. ### Anatomy of *Extensor digiti minimi* * **Origin:** Common extensor origin on anterior aspect of lateral epicondyle of humerus. * **Insertion:** Extensor expansion of little finger. * **Nerve Supply:** Radial nerve. * **Action:** Extends all joints of little finger.